From 218934fa2ed1c702a6d3923d2aa2cc6b43c48684 Mon Sep 17 00:00:00 2001 From: Peter Bengtsson Date: Tue, 8 Dec 2020 14:43:23 -0500 Subject: initial commit --- files/th/web/http/cors/errors/index.html | 76 +++++ files/th/web/http/cors/index.html | 565 +++++++++++++++++++++++++++++++ files/th/web/http/index.html | 227 +++++++++++++ files/th/web/http/status/201/index.html | 41 +++ files/th/web/http/status/index.html | 171 ++++++++++ 5 files changed, 1080 insertions(+) create mode 100644 files/th/web/http/cors/errors/index.html create mode 100644 files/th/web/http/cors/index.html create mode 100644 files/th/web/http/index.html create mode 100644 files/th/web/http/status/201/index.html create mode 100644 files/th/web/http/status/index.html (limited to 'files/th/web/http') diff --git a/files/th/web/http/cors/errors/index.html b/files/th/web/http/cors/errors/index.html new file mode 100644 index 0000000000..d1dd12dc75 --- /dev/null +++ b/files/th/web/http/cors/errors/index.html @@ -0,0 +1,76 @@ +--- +title: CORS errors +slug: Web/HTTP/CORS/Errors +tags: + - CORS + - Errors + - HTTP + - HTTPS + - Messages + - NeedsTranslation + - Same-origin + - Security + - TopicStub + - console + - troubleshooting +translation_of: Web/HTTP/CORS/Errors +--- +
{{HTTPSidebar}}
+ +

Cross-Origin Resource Sharing ({{Glossary("CORS")}}) is a standard that allows a server to relax the same-origin policy. This is used to explicitly allow some cross-origin requests while rejecting others. For example, if a site offers an embeddable service, it may be necessary to relax certain restrictions. Setting up such a CORS configuration isn't necessarily easy and may present some challenges. In these pages, we'll look into some common CORS error messages and how to resolve them.

+ +

If the CORS configuration isn't setup correctly, the browser console will present an error like "Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at $somesite" indicating that the request was blocked due to violating the CORS security rules. This might not necessarily be a set-up mistake, though. It's possible that the request is in fact intentionally being disallowed by the user's web application and remote external service. However, If the endpoint is meant to be available, some debugging is needed to succeed.

+ +

Identifying the issue

+ +

To understand the underlying issue with the CORS configuration, you need to find out which request is at fault and why. These steps may help you do so:

+ +
    +
  1. Navigate to the web site or web app in question and open the Developer Tools.
    2. +
  2. Now try to reproduce the failing transaction and check the console if you are seeing a CORS violation error message. It will probably look like this:
    3. +
+ +

Firefox console showing CORS error

+ +

The text of the error message will be something similar to the following:

+ +
Cross-Origin Request Blocked: The Same Origin Policy disallows
+reading the remote resource at https://some-url-here. (Reason:
+additional information here).
+ +
+

Note: For security reasons, specifics about what went wrong with a CORS request are not available to JavaScript code. All the code knows is that an error occurred. The only way to determine what specifically went wrong is to look at the browser's console for details.

+
+ +

CORS error messages

+ +

Firefox's console displays messages in its console when requests fail due to CORS. Part of the error text is a "reason" message that provides added insight into what went wrong.  The reason messages are listed below; click the message to open an article explaining the error in more detail and offering possible solutions.

+ + + +

See also

+ + diff --git a/files/th/web/http/cors/index.html b/files/th/web/http/cors/index.html new file mode 100644 index 0000000000..195504e50f --- /dev/null +++ b/files/th/web/http/cors/index.html @@ -0,0 +1,565 @@ +--- +title: Cross-Origin Resource Sharing (CORS) +slug: Web/HTTP/CORS +tags: + - AJAX + - CORS + - Cross-Origin Resource Sharing + - Fetch + - Fetch API + - HTTP + - HTTP Access Controls + - NeedsTranslation + - Same-origin policy + - Security + - TopicStub + - XMLHttpRequest + - 'l10n:priority' +translation_of: Web/HTTP/CORS +--- +

Cross-Origin Resource Sharing ({{Glossary("CORS")}}) is a mechanism that uses additional {{Glossary("HTTP")}} headers to tell a browser to let a web application running at one origin (domain) have permission to access selected resources from a server at a different origin. A web application makes a cross-origin HTTP request when it requests a resource that has a different origin (domain, protocol, and port) than its own origin.

+ +

An example of a cross-origin request: The frontend JavaScript code for a web application served from http://domain-a.com uses {{domxref("XMLHttpRequest")}} to make a request for http://api.domain-b.com/data.json.

+ +

For security reasons, browsers restrict cross-origin HTTP requests initiated from within scripts. For example, XMLHttpRequest and the Fetch API follow the same-origin policy. This means that a web application using those APIs can only request HTTP resources from the same origin the application was loaded from, unless the response from the other origin includes the right CORS headers.

+ +

+ +

The CORS mechanism supports secure cross-origin requests and data transfers between browsers and web servers. Modern browsers use CORS in an API container such as XMLHttpRequest or Fetch to help mitigate the risks of cross-origin HTTP requests.

+ +

Who should read this article?

+ +

Everyone, really.

+ +

More specifically, this article is for web administrators, server developers, and front-end developers. Modern browsers handle the client-side components of cross-origin sharing, including headers and policy enforcement. But this new standard means servers have to handle new request and response headers. Another article for server developers discussing cross-origin sharing from a server perspective (with PHP code snippets) is supplementary reading.

+ +

What requests use CORS?

+ +

This cross-origin sharing standard is used to enable cross-site HTTP requests for:

+ + + +

This article is a general discussion of Cross-Origin Resource Sharing and includes a discussion of the necessary HTTP headers.

+ +

Functional overview

+ +

The Cross-Origin Resource Sharing standard works by adding new HTTP headers that allow servers to describe the set of origins that are permitted to read that information using a web browser. Additionally, for HTTP request methods that can cause side-effects on server's data (in particular, for HTTP methods other than {{HTTPMethod("GET")}}, or for {{HTTPMethod("POST")}} usage with certain MIME types), the specification mandates that browsers "preflight" the request, soliciting supported methods from the server with an HTTP {{HTTPMethod("OPTIONS")}} request method, and then, upon "approval" from the server, sending the actual request with the actual HTTP request method. Servers can also notify clients whether "credentials" (including Cookies and HTTP Authentication data) should be sent with requests.

+ +

CORS failures result in errors, but for security reasons, specifics about what went wrong are not available to JavaScript code. All the code knows is that an error occurred. The only way to determine what specifically went wrong is to look at the browser's console for details.

+ +

Subsequent sections discuss scenarios, as well as provide a breakdown of the HTTP headers used.

+ +

Examples of access control scenarios

+ +

Here, we present three scenarios that illustrate how Cross-Origin Resource Sharing works. All of these examples use the {{domxref("XMLHttpRequest")}} object, which can be used to make cross-site invocations in any supporting browser.

+ +

The JavaScript snippets included in these sections (and running instances of the server-code that correctly handles these cross-site requests) can be found "in action" at http://arunranga.com/examples/access-control/, and will work in browsers that support cross-site XMLHttpRequest.

+ +

A discussion of Cross-Origin Resource Sharing from a server perspective (including PHP code snippets) can be found in the Server-Side Access Control (CORS) article.

+ +

Simple requests

+ +

Some requests don’t trigger a CORS preflight. Those are called “simple requests” in this article, though the {{SpecName('Fetch')}} spec (which defines CORS) doesn’t use that term. A request that doesn’t trigger a CORS preflight—a so-called “simple request”—is one that meets all the following conditions:

+ + + +
Note: These are the same kinds of cross-site requests that web content can already issue, and no response data is released to the requester unless the server sends an appropriate header. Therefore, sites that prevent cross-site request forgery have nothing new to fear from HTTP access control.
+ +
Note: WebKit Nightly and Safari Technology Preview place additional restrictions on the values allowed in the {{HTTPHeader("Accept")}}, {{HTTPHeader("Accept-Language")}}, and {{HTTPHeader("Content-Language")}} headers. If any of those headers have ”non-standard” values, WebKit/Safari does not consider the request to meet the conditions for a “simple request”. What WebKit/Safari considers “non-standard” values for those headers is not documented except in the following WebKit bugs: Require preflight for non-standard CORS-safelisted request headers Accept, Accept-Language, and Content-Language, Allow commas in Accept, Accept-Language, and Content-Language request headers for simple CORS, and Switch to a blacklist model for restricted Accept headers in simple CORS requests. No other browsers implement those extra restrictions, because they’re not part of the spec.
+ +

For example, suppose web content on domain http://foo.example wishes to invoke content on domain http://bar.other. Code of this sort might be used within JavaScript deployed on foo.example:

+ +
var invocation = new XMLHttpRequest();
+var url = 'http://bar.other/resources/public-data/';
+
+function callOtherDomain() {
+  if(invocation) {
+    invocation.open('GET', url, true);
+    invocation.onreadystatechange = handler;
+    invocation.send();
+  }
+}
+
+ +

This will lead to a simple exchange between the client and the server, using CORS headers to handle the privileges:

+ +

+ +

Let us look at what the browser will send to the server in this case, and let's see how the server responds:

+ +
GET /resources/public-data/ HTTP/1.1
+Host: bar.other
+User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9.1b3pre) Gecko/20081130 Minefield/3.1b3pre
+Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
+Accept-Language: en-us,en;q=0.5
+Accept-Encoding: gzip,deflate
+Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
+Connection: keep-alive
+Referer: http://foo.example/examples/access-control/simpleXSInvocation.html
+Origin: http://foo.example
+
+
+HTTP/1.1 200 OK
+Date: Mon, 01 Dec 2008 00:23:53 GMT
+Server: Apache/2.0.61
+Access-Control-Allow-Origin: *
+Keep-Alive: timeout=2, max=100
+Connection: Keep-Alive
+Transfer-Encoding: chunked
+Content-Type: application/xml
+
+[XML Data]
+
+ +

Lines 1 - 10 are headers sent. The main HTTP request header of note here is the {{HTTPHeader("Origin")}} header on line 10 above, which shows that the invocation is coming from content on the domain http://foo.example.

+ +

Lines 13 - 22 show the HTTP response from the server on domain http://bar.other. In response, the server sends back an {{HTTPHeader("Access-Control-Allow-Origin")}} header, shown above in line 16. The use of the {{HTTPHeader("Origin")}} header and of {{HTTPHeader("Access-Control-Allow-Origin")}} show the access control protocol in its simplest use. In this case, the server responds with a Access-Control-Allow-Origin: * which means that the resource can be accessed by any domain in a cross-site manner. If the resource owners at http://bar.other wished to restrict access to the resource to requests only from http://foo.example, they would send back:

+ +

Access-Control-Allow-Origin: http://foo.example

+ +

Note that now, no domain other than http://foo.example (identified by the ORIGIN: header in the request, as in line 10 above) can access the resource in a cross-site manner. The Access-Control-Allow-Origin header should contain the value that was sent in the request's Origin header.

+ +

Preflighted requests

+ +

Unlike “simple requests” (discussed above), "preflighted" requests first send an HTTP request by the {{HTTPMethod("OPTIONS")}} method to the resource on the other domain, in order to determine whether the actual request is safe to send. Cross-site requests are preflighted like this since they may have implications to user data.

+ +

In particular, a request is preflighted if any of the following conditions is true:

+ + + +
Note: WebKit Nightly and Safari Technology Preview place additional restrictions on the values allowed in the {{HTTPHeader("Accept")}}, {{HTTPHeader("Accept-Language")}}, and {{HTTPHeader("Content-Language")}} headers. If any of those headers have ”non-standard” values, WebKit/Safari preflights the request. What WebKit/Safari considers “non-standard” values for those headers is not documented except in the following WebKit bugs: Require preflight for non-standard CORS-safelisted request headers Accept, Accept-Language, and Content-Language, Allow commas in Accept, Accept-Language, and Content-Language request headers for simple CORS, and Switch to a blacklist model for restricted Accept headers in simple CORS requests. No other browsers implement those extra restrictions, because they’re not part of the spec.
+ +

The following is an example of a request that will be preflighted.

+ +
var invocation = new XMLHttpRequest();
+var url = 'http://bar.other/resources/post-here/';
+var body = '<?xml version="1.0"?><person><name>Arun</name></person>';
+
+function callOtherDomain(){
+  if(invocation)
+    {
+      invocation.open('POST', url, true);
+      invocation.setRequestHeader('X-PINGOTHER', 'pingpong');
+      invocation.setRequestHeader('Content-Type', 'application/xml');
+      invocation.onreadystatechange = handler;
+      invocation.send(body);
+    }
+}
+
+......
+
+ +

In the example above, line 3 creates an XML body to send with the POST request in line 8. Also, on line 9, a "customized" (non-standard) HTTP request header is set (X-PINGOTHER: pingpong). Such headers are not part of the HTTP/1.1 protocol, but are generally useful to web applications. Since the request uses a Content-Type of application/xml, and since a custom header is set, this request is preflighted.

+ +

+ +

(Note: as described below, the actual POST request does not include the Access-Control-Request-* headers; they are needed only for the OPTIONS request.)

+ +

Let's take a look at the full exchange between client and server. The first exchange is the preflight request/response:

+ +
OPTIONS /resources/post-here/ HTTP/1.1
+Host: bar.other
+User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9.1b3pre) Gecko/20081130 Minefield/3.1b3pre
+Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
+Accept-Language: en-us,en;q=0.5
+Accept-Encoding: gzip,deflate
+Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
+Connection: keep-alive
+Origin: http://foo.example
+Access-Control-Request-Method: POST
+Access-Control-Request-Headers: X-PINGOTHER, Content-Type
+
+
+HTTP/1.1 200 OK
+Date: Mon, 01 Dec 2008 01:15:39 GMT
+Server: Apache/2.0.61 (Unix)
+Access-Control-Allow-Origin: http://foo.example
+Access-Control-Allow-Methods: POST, GET, OPTIONS
+Access-Control-Allow-Headers: X-PINGOTHER, Content-Type
+Access-Control-Max-Age: 86400
+Vary: Accept-Encoding, Origin
+Content-Encoding: gzip
+Content-Length: 0
+Keep-Alive: timeout=2, max=100
+Connection: Keep-Alive
+Content-Type: text/plain
+
+ +

Once the preflight request is complete, the real request is sent:

+ +
POST /resources/post-here/ HTTP/1.1
+Host: bar.other
+User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9.1b3pre) Gecko/20081130 Minefield/3.1b3pre
+Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
+Accept-Language: en-us,en;q=0.5
+Accept-Encoding: gzip,deflate
+Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
+Connection: keep-alive
+X-PINGOTHER: pingpong
+Content-Type: text/xml; charset=UTF-8
+Referer: http://foo.example/examples/preflightInvocation.html
+Content-Length: 55
+Origin: http://foo.example
+Pragma: no-cache
+Cache-Control: no-cache
+
+<?xml version="1.0"?><person><name>Arun</name></person>
+
+
+HTTP/1.1 200 OK
+Date: Mon, 01 Dec 2008 01:15:40 GMT
+Server: Apache/2.0.61 (Unix)
+Access-Control-Allow-Origin: http://foo.example
+Vary: Accept-Encoding, Origin
+Content-Encoding: gzip
+Content-Length: 235
+Keep-Alive: timeout=2, max=99
+Connection: Keep-Alive
+Content-Type: text/plain
+
+[Some GZIP'd payload]
+
+ +

Lines 1 - 12 above represent the preflight request with the {{HTTPMethod("OPTIONS")}} method. The browser determines that it needs to send this based on the request parameters that the JavaScript code snippet above was using, so that the server can respond whether it is acceptable to send the request with the actual request parameters. OPTIONS is an HTTP/1.1 method that is used to determine further information from servers, and is a {{Glossary("safe")}} method, meaning that it can't be used to change the resource. Note that along with the OPTIONS request, two other request headers are sent (lines 10 and 11 respectively):

+ +
Access-Control-Request-Method: POST
+Access-Control-Request-Headers: X-PINGOTHER, Content-Type
+
+ +

The {{HTTPHeader("Access-Control-Request-Method")}} header notifies the server as part of a preflight request that when the actual request is sent, it will be sent with a POST request method. The {{HTTPHeader("Access-Control-Request-Headers")}} header notifies the server that when the actual request is sent, it will be sent with a X-PINGOTHER and Content-Type custom headers. The server now has an opportunity to determine whether it wishes to accept a request under these circumstances.

+ +

Lines 14 - 26 above are the response that the server sends back indicating that the request method (POST) and request headers (X-PINGOTHER) are acceptable. In particular, let's look at lines 17-20:

+ +
Access-Control-Allow-Origin: http://foo.example
+Access-Control-Allow-Methods: POST, GET
+Access-Control-Allow-Headers: X-PINGOTHER, Content-Type
+Access-Control-Max-Age: 86400
+ +

The server responds with Access-Control-Allow-Methods and says that POST and GET are viable methods to query the resource in question. Note that this header is similar to the {{HTTPHeader("Allow")}} response header, but used strictly within the context of access control.

+ +

The server also sends Access-Control-Allow-Headers with a value of "X-PINGOTHER, Content-Type", confirming that these are permitted headers to be used with the actual request. Like Access-Control-Allow-Methods, Access-Control-Allow-Headers is a comma separated list of acceptable headers.

+ +

Finally, {{HTTPHeader("Access-Control-Max-Age")}} gives the value in seconds for how long the response to the preflight request can be cached for without sending another preflight request. In this case, 86400 seconds is 24 hours. Note that each browser has a maximum internal value that takes precedence when the Access-Control-Max-Age is greater.

+ +

Preflighted requests and redirects

+ +

Not all browsers currently support following redirects after a preflighted request. If a redirect occurs after a preflighted request, some browsers currently will report an error message such as the following.

+ +
+

The request was redirected to 'https://example.com/foo', which is disallowed for cross-origin requests that require preflight

+
+ +
+

Request requires preflight, which is disallowed to follow cross-origin redirect

+
+ +

The CORS protocol originally required that behavior but was subsequently changed to no longer require it. However, not all browsers have implemented the change, and so still exhibit the behavior that was originally required.

+ +

So until all browsers catch up with the spec, you may be able to work around this limitation by doing one or both of the following:

+ + + +

But if it’s not possible to make those changes, then another way that may be possible is to this:

+ +
    +
  1. Make a simple request (using {{domxref("Response.url")}} for the Fetch API, or {{domxref("XMLHttpRequest.responseURL")}}) to determine what URL the real preflighted request would end up at.
    2. +
  2. Make another request (the “real” request) using the URL you obtained from Response.url or XMLHttpRequest.responseURL in the first step.
    3. +
+ +

However, if the request is one that triggers a preflight due to the presence of the Authorization header in the request, you won’t be able to work around the limitation using the steps above. And you won’t be able to work around it at all unless you have control over the server the request is being made to.

+ +

Requests with credentials

+ +

The most interesting capability exposed by both {{domxref("XMLHttpRequest")}} or Fetch and CORS is the ability to make "credentialed" requests that are aware of HTTP cookies and HTTP Authentication information. By default, in cross-site XMLHttpRequest" or Fetch invocations, browsers will not send credentials. A specific flag has to be set on the XMLHttpRequest" object or the {{domxref("Request")}} constructor when it is invoked.

+ +

In this example, content originally loaded from http://foo.example makes a simple GET request to a resource on http://bar.other which sets Cookies. Content on foo.example might contain JavaScript like this:

+ +
var invocation = new XMLHttpRequest();
+var url = 'http://bar.other/resources/credentialed-content/';
+
+function callOtherDomain(){
+  if(invocation) {
+    invocation.open('GET', url, true);
+    invocation.withCredentials = true;
+    invocation.onreadystatechange = handler;
+    invocation.send();
+  }
+}
+ +

Line 7 shows the flag on {{domxref("XMLHttpRequest")}} that has to be set in order to make the invocation with Cookies, namely the withCredentials boolean value. By default, the invocation is made without Cookies. Since this is a simple GET request, it is not preflighted, but the browser will reject any response that does not have the {{HTTPHeader("Access-Control-Allow-Credentials")}}: true header, and not make the response available to the invoking web content.

+ +

+ +

Here is a sample exchange between client and server:

+ +
GET /resources/access-control-with-credentials/ HTTP/1.1
+Host: bar.other
+User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9.1b3pre) Gecko/20081130 Minefield/3.1b3pre
+Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
+Accept-Language: en-us,en;q=0.5
+Accept-Encoding: gzip,deflate
+Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
+Connection: keep-alive
+Referer: http://foo.example/examples/credential.html
+Origin: http://foo.example
+Cookie: pageAccess=2
+
+
+HTTP/1.1 200 OK
+Date: Mon, 01 Dec 2008 01:34:52 GMT
+Server: Apache/2.0.61 (Unix) PHP/4.4.7 mod_ssl/2.0.61 OpenSSL/0.9.7e mod_fastcgi/2.4.2 DAV/2 SVN/1.4.2
+X-Powered-By: PHP/5.2.6
+Access-Control-Allow-Origin: http://foo.example
+Access-Control-Allow-Credentials: true
+Cache-Control: no-cache
+Pragma: no-cache
+Set-Cookie: pageAccess=3; expires=Wed, 31-Dec-2008 01:34:53 GMT
+Vary: Accept-Encoding, Origin
+Content-Encoding: gzip
+Content-Length: 106
+Keep-Alive: timeout=2, max=100
+Connection: Keep-Alive
+Content-Type: text/plain
+
+
+[text/plain payload]
+
+ +

Although line 11 contains the Cookie destined for the content on http://bar.other, if bar.other did not respond with an {{HTTPHeader("Access-Control-Allow-Credentials")}}: true (line 19) the response would be ignored and not made available to web content.

+ +

Credentialed requests and wildcards

+ +

When responding to a credentialed request, the server must specify an origin in the value of the Access-Control-Allow-Origin header, instead of specifying the "*" wildcard.

+ +

Because the request headers in the above example include a Cookie header, the request would fail if the value of the Access-Control-Allow-Origin header were "*". But it does not fail: Because the value of the Access-Control-Allow-Origin header is "http://foo.example" (an actual origin) rather than the "*" wildcard, the credential-cognizant content is returned to the invoking web content.

+ +

Note that the Set-Cookie response header in the example above also sets a further cookie. In case of failure, an exception—depending on the API used—is raised.

+ +

Third-party cookies

+ +

Note that cookies set in CORS responses are subject to normal third-party cookie policies. In the example above, the page is loaded from foo.example, but the cookie on line 22 is sent by bar.other, and would thus not be saved if the user has configured their browser to reject all third-party cookies.

+ +

The HTTP response headers

+ +

This section lists the HTTP response headers that servers send back for access control requests as defined by the Cross-Origin Resource Sharing specification. The previous section gives an overview of these in action.

+ +

Access-Control-Allow-Origin

+ +

A returned resource may have one {{HTTPHeader("Access-Control-Allow-Origin")}} header, with the following syntax:

+ +
Access-Control-Allow-Origin: <origin> | *
+
+ +

Access-Control-Allow-Origin specifies either a single origin, which tells browsers to allow that origin to access the resource; or else — for requests without credentials — the "*" wildcard, to tell browsers to allow any origin to access the resource.

+ +

For example, to allow code from the origin http://mozilla.org to access the resource, you can specify:

+ +
Access-Control-Allow-Origin: http://mozilla.org
+ +

If the server specifies a single origin rather than the "*" wildcard, then the server should also include Origin in the {{HTTPHeader("Vary")}} response header — to indicate to clients that server responses will differ based on the value of the {{HTTPHeader("Origin")}} request header.

+ +

Access-Control-Expose-Headers

+ +

The {{HTTPHeader("Access-Control-Expose-Headers")}} header lets a server whitelist headers that browsers are allowed to access. For example:

+ +
Access-Control-Expose-Headers: X-My-Custom-Header, X-Another-Custom-Header
+
+ +

This allows the X-My-Custom-Header and X-Another-Custom-Header headers to be exposed to the browser.

+ +

Access-Control-Max-Age

+ +

The {{HTTPHeader("Access-Control-Max-Age")}} header indicates how long the results of a preflight request can be cached. For an example of a preflight request, see the above examples.

+ +
Access-Control-Max-Age: <delta-seconds>
+
+ +

The delta-seconds parameter indicates the number of seconds the results can be cached.

+ +

Access-Control-Allow-Credentials

+ +

The {{HTTPHeader("Access-Control-Allow-Credentials")}} header Indicates whether or not the response to the request can be exposed when the credentials flag is true. When used as part of a response to a preflight request, this indicates whether or not the actual request can be made using credentials. Note that simple GET requests are not preflighted, and so if a request is made for a resource with credentials, if this header is not returned with the resource, the response is ignored by the browser and not returned to web content.

+ +
Access-Control-Allow-Credentials: true
+
+ +

Credentialed requests are discussed above.

+ +

Access-Control-Allow-Methods

+ +

The {{HTTPHeader("Access-Control-Allow-Methods")}} header specifies the method or methods allowed when accessing the resource. This is used in response to a preflight request. The conditions under which a request is preflighted are discussed above.

+ +
Access-Control-Allow-Methods: <method>[, <method>]*
+
+ +

An example of a preflight request is given above, including an example which sends this header to the browser.

+ +

Access-Control-Allow-Headers

+ +

The {{HTTPHeader("Access-Control-Allow-Headers")}} header is used in response to a preflight request to indicate which HTTP headers can be used when making the actual request.

+ +
Access-Control-Allow-Headers: <field-name>[, <field-name>]*
+
+ +

The HTTP request headers

+ +

This section lists headers that clients may use when issuing HTTP requests in order to make use of the cross-origin sharing feature. Note that these headers are set for you when making invocations to servers. Developers using cross-site {{domxref("XMLHttpRequest")}} capability do not have to set any cross-origin sharing request headers programmatically.

+ +

Origin

+ +

The {{HTTPHeader("Origin")}} header indicates the origin of the cross-site access request or preflight request.

+ +
Origin: <origin>
+
+ +

The origin is a URI indicating the server from which the request initiated. It does not include any path information, but only the server name.

+ +
Note: The origin can be the empty string; this is useful, for example, if the source is a data URL.
+ +

Note that in any access control request, the {{HTTPHeader("Origin")}} header is always sent.

+ +

Access-Control-Request-Method

+ +

The {{HTTPHeader("Access-Control-Request-Method")}} is used when issuing a preflight request to let the server know what HTTP method will be used when the actual request is made.

+ +
Access-Control-Request-Method: <method>
+
+ +

Examples of this usage can be found above.

+ +

Access-Control-Request-Headers

+ +

The {{HTTPHeader("Access-Control-Request-Headers")}} header is used when issuing a preflight request to let the server know what HTTP headers will be used when the actual request is made.

+ +
Access-Control-Request-Headers: <field-name>[, <field-name>]*
+
+ +

Examples of this usage can be found above.

+ +

Specifications

+ + + + + + + + + + + + + + +
SpecificationStatusComment
{{SpecName('Fetch', '#cors-protocol', 'CORS')}}{{Spec2('Fetch')}}New definition; supplants W3C CORS specification.
+ +

Browser compatibility

+ + + +

{{Compat("http.headers.Access-Control-Allow-Origin")}}

+ +

Compatibility notes

+ + + +

See also

+ + + +
{{HTTPSidebar}}
diff --git a/files/th/web/http/index.html b/files/th/web/http/index.html new file mode 100644 index 0000000000..832303c8c0 --- /dev/null +++ b/files/th/web/http/index.html @@ -0,0 +1,227 @@ +--- +title: HTTP +slug: Web/HTTP +tags: + - HTTP + - Headers + - NeedsTranslation + - TopicStub +translation_of: Web/HTTP +--- +

{{ HTTPSidebar }}

+ +

Hypertext Transfer Protocol (HTTP) เป็นโปรโตคอลในระดับชั้นแอพพลิเคชัน(application-layer) ที่ใช้สำหรับการจัดส่งเอกสารประเภท hypermedia อย่างเช่นเอกสาร HTML และถูกออกแบบมาเพื่อใช้งานในการติดต่อสื่อสารระหว่าง web browser กับ web server และสามารถนำไปใช้ในจุดประสงค์อื่น ๆ ได้ด้วย ซึ่งรูปแบบการสื่อสารของโปรโตคอล HTTP เป็นไปตามโมเดลการสื่อสารแบบเครื่องลูกข่าย-แม่ข่าย(client-server model) ที่เครื่องลูกข่ายจะสร้าง connection เพื่อส่ง request ไปยังเครื่องแม่ข่าย และรอจนกว่าจะได้ response กลับมาจากเครื่องแม่ข่าย นอกจากนั้น HTTP เป็นโปรโตคอลแบบ stateless protocol เป็นลักษณะที่เครื่องแม่ข่ายไม่มีการจัดเก็บข้อมูล(state) ใด ๆ ที่เกิดขึ้นระหว่าง request เพราะข้อมูลแต่ละ request สามารถทำความเข้าใจได้ในตัวมันเอง และเนื่องจาก HTTP เป็นโปรโตคอลที่ใช้งานในระดับชั้นแอพพลิเคชัน ซึ่งอยู่ในระดับชั้นที่สูงกว่าโปรโตคอลในระดับล่างอย่าง TCP/IP ที่อยู่ในระดับ transport layer มันจึงสามารถใช้รูปแบบการติดต่อสื่อสารที่มีความน่าเชื่อถือของโปรโตคอลต่าง ๆ ในระดับชั้น transport ได้ อย่างเช่น อาจจะเลือกใช้โปรโตคอล RUDP ที่มีความน่าเชื่อถือกว่า UDP ที่มีโอกาสสูญเสียข้อมูลไปโดยไม่รู้ตัวได้

+ +

Documentation

+ +
+
HTTP Headers
+
HTTP message headers ใช้ในการบรรยายเกี่ยวกับ resource หรือ พฤติกรรมของเครื่องแม่ข่าย(server) หรือ เครื่องลูกข่าย(client) การสร้าง HTTP header ขึ้นใช้งานเอง สามารถทำได้ด้วยการเติมอักษร "X-" นำหน้าชื่อ header ที่ต้องการ โดย Header มาตรฐานต่าง ๆ สามารถศึกษาเพิ่มเติมได้จาก IANA registry เนื้อหาต้นฉบับจะถูกนิยามไว้ใน RFC 4229 โดยมี IANA เป็นผู้ดูแลเกี่ยวกับการลงทะเบียนเพื่อเสนอ HTTP header รูปแบบใหม่
+
HTTP cookies
+
การทำงานของ cookie ได้มีการนิยามไว้โดย RFC 6265 โดยกระบวนการเกิดขึ้นหลังจากที่เครื่องแม่ข่ายได้รับ HTTP request แล้ว เครื่องแม่ข่ายจะสามารถส่ง header ชื่อ Set-Cookie ไปกับ response ให้กับเครื่องลูกข่าย หลังจากนั้นเมื่อใดก็ตามที่เครื่องลูกข่ายต้องการส่ง request ไปยังเครื่องแม่ข่าย ค่าของ cookie จะถูกส่งไปพร้อม request ด้วยเสมอ ในรูปแบบของ HTTP header ชื่อ Cookie นอกจากนั้นยังสามารถกำหนดวันและเวลาหมดอายุของ cookie และการจำกัดการเข้าถึง domain และ path ได้
+
Basic access authentication
+
ในบริบทของการติดต่อสื่อสารบนโปรโตคอล HTTP นั้น การพิสูจน์ตัวจริงแบบพื้นฐานเพื่อการเข้าถึง (basic access authentication) เป็นวิธีการสำหรับ HTTP user agent ในการ request ไปยังเครื่องแม่ข่ายที่ต้องมีการจัดเตรียมรหัสผู้ใช้งาน (username) และรหัสผ่าน (password) เพื่อใช้ในการพิสูจน์ตัวจริง
+
HTTP pipelining FAQ
+
HTTP/1.1 Pipelining FAQ
+
HTTP access control (CORS)
+
Cross-site HTTP requests are HTTP requests for resources from a different domain than the domain of the resource making the request.  For instance, a resource loaded from Domain A (http://domaina.example) such as an HTML web page, makes a request for a resource on Domain B (http://domainb.foo), such as an image, using the img element (http://domainb.foo/image.jpg).  This occurs very commonly on the web today — pages load a number of resources in a cross-site manner, including CSS stylesheets, images and scripts, and other resources.
+
Controlling DNS prefetching
+
Firefox 3.5 performs DNS prefetching.  This is a feature by which Firefox proactively performs domain name resolution on both links that the user may choose to follow as well as URLs for items referenced by the document, including images, CSS, JavaScript, and so forth. This prefetching is performed in the background, so that the DNS is likely to already have been resolved by the time the referenced items are actually needed.  This reduces latency when, for example, the user actually clicks a link.
+
HTTP response codes
+
HTTP Response Codes indicate whether a specific HTTP requests has been successfully completed. Responses are grouped in five classes: informational responses, successful responses, redirections, client errors, and servers errors.
+
+ +

A brief history of HTTP

+ +

Since its original conception, as a protocol with one single method (GET) and returning only HTML pages, the HTTP protocol went through several revisions. The first documented version was HTTP/0.9 in 1991, corresponding to the original version. Very simple, it has a rudimentary search capability via the HTML {{ HTMLElement("isindex") }} element and an extension of the URL using the '?' character.

+ +

Then, in 1992, a version was published that became, with some minor changes, HTTP/1.0 (finalized in RFC 1945 in May 1996). One major improvement over the previous version was the ability to transmit files of different types, like images, videos, scripts, CSS documents, and so on, instead of only HTML files: this is achieved by using MIME types in conjunction with the Content-Type: header.

+ +

In 1995, the IETF  began developing a new version of HTTP, which would become HTTP/1.1. It quickly spread into wide usage, and it was officially standardized in 1997 in RFC 2068, with minor fixes in RFC 2616 two years later.

+ +

HTTP/1.1 brought the ability to reuse established connections for subsequent requests, greatly improving the performance of the protocol by lowering the latency between them; this is especially useful with complex HTML documents that need to fetch several subsequent files, like images or style sheets. It also brought the Host: header, which allows a single server, listening on a specific port, to receive requests for several websites; this paved the way for colocating numerous websites on one single server, greatly reducing the cost of hosting.

+ +

Since then, the HTTP protocol evolved by adding new headers, defining new behaviors without the need to fundamentally change the protocol. Unknown headers are simply ignored by servers or clients.

+ +

HTTP/1.1 is currently being revised by the IETF HTTPbis Working Group.

+ + + +

HTTP request methods

+ +

The request method indicates the action to be performed by the server. The HTTP/1.1 standard defines seven methods and allows other methods to be added later. Over the years, a few ones have been added in standards like WebDAV. The  IETF HTTPbis Working Group is currently working on an IANA registry to list them all. If a server receives a request method that it doesn't know, it must return a 501 Not implemented response; if it knows the method but is configured not to answer it, it must return a 405 Method not allowed response. Two methods are required to be supported: HEAD and GET; all others are optional.

+ +

Two specific semantics are defined in the standard and are crucial for web developers: the safety property and the idempotent property.

+ +

Safe methods

+ +

A safe method is a method that doesn't have any side-effects on the server. In other words, this property means that the method must be used only for retrieval of data. The safe HTTP methods defined in HTTP/1.1 are:

+ + + +
Notes: + + +
+ +

Idempotent methods

+ +

An idempotent method is a method such that the side-effects on the server of several identical requests with the method are the same as the side-effects of one single request.

+ + + +

Other methods

+ + + +

Many more methods, such as PROPFIND or PATCH are defined in other standards-track RFCs of the IETF, like WebDAV.

+ +

The CONNECT method is defined in RFC 2817.

+ +

HTTP Requests Methods in HTML Forms

+ +

In HTML, different HTTP request methods can be specified in the {{ htmlattrxref("method", "form") }} attribute of the {{ HTMLElement("form") }} element, but also to the {{ htmlattrxref("formmethod", "input") }} of the {{ HTMLElement("input") }} and {{ HTMLElement("button") }} elements. But not all HTTP methods can be used with these attributes; only GET and POST method are allowed by the HTML specification. See this StackExchange answer why other HTTP request methods are not allowed by the HTML specification.

+ +
Note: The choice of a GET or POST method for HTML forms is not neutral. Because the GET method is a safe method, it should be used only in cases where no side-effect is expected; e.g., it shouldn't be used to transmit an order, as this order is a side-effect. In all cases where such side-effects are expected, the POST method should be used.
+ +

HTTP response codes

+ +

When answering a client request, the server sends back a three-digit number indicating whether the request was successfully processed. These codes can be grouped in five categories:

+ + + +

A web developer shouldn't encounter many other response codes, but people building requests using the XMLHTTPRequest function may hit less usual response codes.

+ +

More on redirection responses

+ +

Starting in Gecko 9.0 {{ geckoRelease("9.0") }}, redirections (such as 301 and 307) that specify a javascript: URI are no longer performed. Instead, a bad connection error is presented. This helps avoid cross-site scripting attacks. See {{ bug(255119) }} if you want more details.

+ +

HTTP headers

+ +

HTTP headers allow the client and the server to pass additional information with the request or the response. A request header consists of its case-insensitive name followed by a colon ':', then by its value (without CRLF in it). Leading white space before the value is ignored.

+ +

Headers are grouped according the context in which they may appear:

+ +
+
General headers
+
These headers apply to both requests and responses but are unrelated to the data eventually transmitted in the body. They therefore apply only to the message being transmitted. There are only a few of them and new ones cannot be added without increasing the version number of the HTTP protocol. The exhaustive list for HTTP/1.1 is {{ httpheader("Cache-Control") }}, {{ httpheader("Connection") }}, {{ httpheader("Date") }}, {{ httpheader("Pragma") }}, {{ httpheader("Trailer") }}, {{ httpheader("Transfer-Encoding") }}, {{ httpheader("Upgrade") }}, {{ httpheader("Via") }} and {{ httpheader("Warning") }}.
+
Request headers
+
These headers give more precise information about the resource to be fetched or about the client itself. Among them one can find cache-related headers, transforming a GET method in a conditional GET, like {{ httpheader("If-Modified-Since") }}, user-preference information like {{ httpheader("Accept-Language") }} or {{ httpheader("Accept-Charset") }} or plain client information like {{ httpheader("User-Agent") }}. New request headers cannot officially be added without increasing the version number of the HTTP protocol. But, it is common for new request headers to be added if both the server and the client agree on their meaning. In that case, a client should not assume that they will be handled adequately by the server; unknown request headers are handled as entity headers.
+
Response headers
+
These headers give more information about the resource sent back, like its real location ({{ httpheader("Location") }}) or about the server itself, like its name and version ({{ httpheader("Server") }}). New response headers cannot be added without increasing the version number of the HTTP protocol. But, it is common for new response headers to be added if both the server and the client agree on their meaning. In that case, a server should not assume that they will be handled adequately by the client ; unknown response headers are handled as entity headers.
+
Entity headers
+
These headers give more information about the body of the entity, like its length ({{ httpheader("Content-Length") }}), an identifying hash ({{ httpheader("Content-MD5") }}), or its MIME-type ({{ httpheader("Content-Type") }}). New entity headers can be added without increasing the version number of the HTTP protocol.
+
+ +

Headers can also be grouped according to how caching and non-caching proxies handle them:

+ +
+
End-to-end headers
+
These headers must be transmitted to the final recipient of the message; that is, the server for a request message or the client for a response message. Such a header means that intermediate proxies must retransmit it unmodified and also that caches must store it.
+
Hop-by-hop headers
+
These headers are meaningful only for a single transport-level connection and must not be retransmitted by proxies or cached. Such headers are: {{ httpheader("Connection") }}, {{ httpheader("Keep-Alive") }}, {{ httpheader("Proxy-Authenticate") }}, {{ httpheader("Proxy-Authorization") }}, {{ httpheader("TE") }}, {{ httpheader("Trailers") }}, {{ httpheader("Transfer-Encoding") }} and {{ httpheader("Upgrade") }}. Note that only hop-by-hop headers may be set using the {{ httpheader("Connection") }} general header.
+
+ +

In order to learn about the specific semantic of each header, see its entry in the comprehensive list of HTTP headers.

+ +

Useful request headers

+ +

Among the numerous HTTP request headers, several are especially useful when set correctly. If you are building your own requests, by using XMLHTTPRequest or when writing an extension and sending custom HTTP requests via XPCOM, then it is important to ensure the presence of headers that are often set by browsers based on the preferences of the user.

+ +
+
Controlling the language of the resource
+
Most user-agents, like Firefox, allow the user to set a preference for the language for receiving a resource. The browser translate this into an {{ httpheader("Accept-Language") }} header. It is good practice for web developers, when building specific HTTP requests, to include such a header too.
+
Using conditional GET
+
Caching is a major tool to accelerate the display of web pages. Even when parts of a webpage are refreshed via an XMLHTTPRequest:, it is a good idea to use the {{ httpheader("If-Modified-Since") }} header (and other similar ones) in order to fetch the new content only if it has changed. This approach lowers the burden on the network.
+
+ +

Useful response headers

+ +

The configuration of a web server is a critical part to ensure good performance and optimal security of a web site. Among the numerous HTTP response headers, several are of specific importance and should be configured on the server

+ +

Restricting framing

+ +

Several cross-site scripting (XSS) attacks take advantage of the ability to put third-party content inside an {{ HTMLElement("frame") }} or {{ HTMLElement("iframe") }}. In order to mitigate that risk, modern browsers have introduced the CSP frame-ancestors directive. By setting it with the value 'none', it prevents the browser from displaying this resource inside of a frame. Using it on critical resources (like those containing a formularies or critical information) will reduce the risk caused by XSS attacks. Note that this specific HTTP response header is not the only way to mitigate XSS risks; other techniques, like setting some Content Security Policies, may be helpful too.

+ +

Compression

+ +

Minimizing the amount of data transferred accelerates the display of a web page. Though most techniques, like CSS Sprites, should be applied on the site itself, compression of data must be set at the web server level. If set, resources requested by the client with an {{ httpheader("Accept-Encoding") }} request header are compressed using the appropriate method and sent back with a {{ httpheader("Content-Encoding") }} response header. Setting these in Apache 2 servers is done by using the mod_deflate module.

+ +
Note: Be aware that not all data formats can be efficiently compressed. Already-compressed media data, like JPEG images or most audio and video formats, do not shrink using another pass of compression. In fact, they often become larger due to the overhead of the compression method. It is important not to try to compress these resource types any further; there is no advantage in size and the compression/decompression mechanism is resource-intensive.
+ +

Controlling cache

+ +

HTTP Caching is a technique that prevents the same resource from being fetched several times if it hasn't change. Configuring the server with the correct response headers allows the user-agent to adequately cache the data. In order to do that, be sure that:

+ + + +

Setting the correct MIME types

+ +

The MIME type is the mechanism to tell the client the kind of document transmitted: the extension of a file name has no meaning on the web. It is therefore important that the server is correctly set up so that the correct MIME type is transmitted with each document: user-agents often use this MIME-type to determine what default action to do when a resource is fetched.

+ +
Note: + + +
+ +

See also

+ + + +

{{ languages( { "ja": "ja/HTTP"} ) }}

diff --git a/files/th/web/http/status/201/index.html b/files/th/web/http/status/201/index.html new file mode 100644 index 0000000000..9cef9d44f9 --- /dev/null +++ b/files/th/web/http/status/201/index.html @@ -0,0 +1,41 @@ +--- +title: 201 Created +slug: Web/HTTP/Status/201 +translation_of: Web/HTTP/Status/201 +--- +
{{HTTPSidebar}}
+ +

หมายเลขสถานะของ HTTP หมายเลข 201 Created แสดงถึงการร้องขอนั้นสำเร็จและทำให้เกิดการสร้างทรัพยากรใหม่ ทรัพยากรใหม่นี้ถูกสร้างสำเร็จก่อนที่การตอบสนองจะถูกส่งกลับมา และทรัพยากรใหม่นี้ถูกส่งกลับมากับเนื้อหาของข้อความด้วย ที่ตั้งของมันเป็นได้ทั้ง URL ที่ใช้ในการร้องขอ หรือเนื้อหาในส่วน header ของ {{HTTPHeader("Location")}}

+ +

โดยปกติแล้วการใช้งานของหมายเลขสถานะนี้จะเป็นผลมาจากการร้องขอแบบ {{HTTPMethod("PUT")}}

+ +

สถานะ

+ +
201 Created
+ +

ข้อกำหนด

+ + + + + + + + + + + + +
ข้อกำหนดหัวข้อ
{{RFC("7231", "201 Created" , "6.3.2")}}Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content
+ +

การเข้ากันได้ของเบราเซอร์

+ + + +

{{Compat("http.status.201")}}

+ +

ดูสิ่งนี้ด้วย

+ + diff --git a/files/th/web/http/status/index.html b/files/th/web/http/status/index.html new file mode 100644 index 0000000000..e490502369 --- /dev/null +++ b/files/th/web/http/status/index.html @@ -0,0 +1,171 @@ +--- +title: HTTP response status codes +slug: Web/HTTP/Status +tags: + - HTTP + - NeedsTranslation + - Status codes + - TopicStub +translation_of: Web/HTTP/Status +--- +
{{HTTPSidebar}}
+ +

HTTP response status codes indicate whether a specific HTTP request has been successfully completed. Responses are grouped in five classes: informational responses, successful responses, redirects, client errors, and servers errors. Status codes are defined by section 10 of RFC 2616.

+ +

Information responses

+ +
+
{{HTTPStatus(100, "100 Continue")}}
+
This interim response indicates that everything so far is OK and that the client should continue with the request or ignore it if it is already finished.
+
{{HTTPStatus(101, "101 Switching Protocol")}}
+
This code is sent in response to an {{HTTPHeader("Upgrade")}} request header by the client, and indicates the protocol the server is switching too.
+
{{HTTPStatus(102, "102 Processing")}} ({{Glossary("WebDAV")}})
+
This code indicates that the server has received and is processing the request, but no response is available yet.
+
+ +

Successful responses

+ +
+
{{HTTPStatus(200, "200 OK")}}
+
The request has succeeded. The meaning of a success varies depending on the HTTP method:
+ GET: The resource has been fetched and is transmitted in the message body.
+ HEAD: The entity headers are in the message body.
+ POST: The resource describing the result of the action is transmitted in the message body.
+ TRACE: The message body contains the request message as received by the server
+
{{HTTPStatus(201, "201 Created")}}
+
The request has succeeded and a new resource has been created as a result of it. This is typically the response sent after a PUT request.
+
{{HTTPStatus(202, "202 Accepted")}}
+
The request has been received but not yet acted upon. It is non-committal, meaning that there is no way in HTTP to later send an asynchronous response indicating the outcome of processing the request. It is intended for cases where another process or server handles the request, or for batch processing.
+
{{HTTPStatus(203, "203 Non-Authoritative Information")}}
+
This response code means returned meta-information set is not exact set as available from the origin server, but collected from a local or a third party copy. Except this condition, 200 OK response should be preferred instead of this response.
+
{{HTTPStatus(204, "204 No Content")}}
+
There is no content to send for this request, but the headers may be useful. The user-agent may update its cached headers for this resource with the new ones.
+
{{HTTPStatus(205, "205 Reset Content")}}
+
This response code is sent after accomplishing request to tell user agent reset document view which sent this request.
+
{{HTTPStatus(206, "206 Partial Content")}}
+
This response code is used because of range header sent by the client to separate download into multiple streams.
+
{{HTTPStatus(207, "207 Multi-Status")}} ({{Glossary("WebDAV")}})
+
A Multi-Status response conveys information about multiple resources in situations where multiple status codes might be appropriate.
+
{{HTTPStatus(208, "208 Multi-Status")}} ({{Glossary("WebDAV")}})
+
Used inside a DAV: propstat response element to avoid enumerating the internal members of multiple bindings to the same collection repeatedly.
+
{{HTTPStatus(226, "226 IM Used")}} (HTTP Delta encoding)
+
The server has fulfilled a GET request for the resource, and the response is a representation of the result of one or more instance-manipulations applied to the current instance.
+
+ +

Redirection messages

+ +
+
{{HTTPStatus(300, "300 Multiple Choice")}}
+
The request has more than one possible responses. User-agent or user should choose one of them. There is no standardized way to choose one of the responses.
+
{{HTTPStatus(301, "301 Moved Permanently")}}
+
This response code means that URI of requested resource has been changed. Probably, new URI would be given in the response.
+
{{HTTPStatus(302, "302 Found")}}
+
This response code means that URI of requested resource has been changed temporarily. New changes in the URI might be made in the future. Therefore, this same URI should be used by the client in future requests.
+
{{HTTPStatus(303, "303 See Other")}}
+
Server sent this response to directing client to get requested resource to another URI with an GET request.
+
{{HTTPStatus(304, "304 Not Modified")}}
+
This is used for caching purposes. It is telling to client that response has not been modified. So, client can continue to use same cached version of response.
+
305 Use Proxy {{deprecated_inline}}
+
Was defined in a previous version of the HTTP specification to indicate that a requested response must be accessed by a proxy. It has been deprecated due to security concerns regarding in-band configuration of a proxy.
+
306 unused
+
This response code is no longer used, it is just reserved currently. It was used in a previous version of the HTTP 1.1 specification.
+
{{HTTPStatus(307, "307 Temporary Redirect")}}
+
Server sent this response to directing client to get requested resource to another URI with same method that used prior request. This has the same semantic than the 302 Found HTTP response code, with the exception that the user agent must not change the HTTP method used: if a POST was used in the first request, a POST must be used in the second request.
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{{HTTPStatus(308, "308 Permanent Redirect")}}
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This means that the resource is now permanently located at another URI, specified by the Location: HTTP Response header. This has the same semantics as the 301 Moved Permanently HTTP response code, with the exception that the user agent must not change the HTTP method used: if a POST was used in the first request, a POST must be used in the second request.
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Client error responses

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{{HTTPStatus(400, "400 Bad Request")}}
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This response means that server could not understand the request due to invalid syntax.
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{{HTTPStatus(401, "401 Unauthorized")}}
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Although the HTTP standard specifies "unauthorized", semantically this response means "unauthenticated". That is, the client must authenticate itself to get the requested response.
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402 Payment Required
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This response code is reserved for future use. Initial aim for creating this code was using it for digital payment systems however this is not used currently.
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{{HTTPStatus(403, "403 Forbidden")}}
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The client does not have access rights to the content, i.e. they are unauthorized, so server is rejecting to give proper response. Unlike 401, the client's identity is known to the server.
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{{HTTPStatus(404, "404 Not Found")}}
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The server can not find requested resource. In the browser, this means the URL is not recognized. In an API, this can also mean that the endpoint is valid but the resource itself does not exist. Servers may also send this response instead of 403 to hide the existence of a resource from an unauthorized client. This response code is probably the most famous one due to its frequent occurence on the web.
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{{HTTPStatus(405, "405 Method Not Allowed")}}
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The request method is known by the server but has been disabled and cannot be used. For example, an API may forbid DELETE-ing a resource. The two mandatory methods, GET and HEAD, must never be disabled and should not return this error code.
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{{HTTPStatus(406, "406 Not Acceptable")}}
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This response is sent when the web server, after performing server-driven content negotiation, doesn't find any content following the criteria given by the user agent.
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{{HTTPStatus(407, "407 Proxy Authentication Required")}}
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This is similar to 401 but authentication is needed to be done by a proxy.
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{{HTTPStatus(408, "408 Request Timeout")}}
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This response is sent on an idle connection by some servers, even without any previous request by the client. It means that the server would like to shut down this unused connection. This response is used much more since some browsers, like Chrome, Firefox 27+, or IE9, use HTTP pre-connection mechanisms to speed up surfing. Also note that some servers merely shut down the connection without sending this message.
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{{HTTPStatus(409, "409 Conflict")}}
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This response is sent when a request conflicts with the current state of the server.
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{{HTTPStatus(410, "410 Gone")}}
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This response would be sent when the requested content has been permenantly deleted from server, with no forwarding address. Clients are expected to remove their caches and links to the resource. The HTTP specification intends this status code to be used for "limited-time, promotional services". APIs should not feel compelled to indicate resources that have been deleted with this status code.
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{{HTTPStatus(411, "411 Length Required")}}
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Server rejected the request because the Content-Length header field is not defined and the server requires it.
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{{HTTPStatus(412, "412 Precondition Failed")}}
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The client has indicated preconditions in its headers which the server does not meet.
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{{HTTPStatus(413, "413 Payload Too Large")}}
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Request entity is larger than limits defined by server; the server might close the connection or return an Retry-After header field.
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{{HTTPStatus(414, "414 URI Too Long")}}
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The URI requested by the client is longer than the server is willing to interpret.
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{{HTTPStatus(415, "415 Unsupported Media Type")}}
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The media format of the requested data is not supported by the server, so the server is rejecting the request.
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{{HTTPStatus(416, "416 Requested Range Not Satisfiable")}}
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The range specified by the Range header field in the request can't be fulfilled; it's possible that the range is outside the size of the target URI's data.
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{{HTTPStatus(417, "417 Expectation Failed")}}
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This response code means the expectation indicated by the Expect request header field can't be met by the server.
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{{HTTPStatus(418, "418 I'm a teapot")}}
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The server refuses the attempt to brew coffee with a teapot.
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{{HTTPStatus(421, "421 Misdirected Request")}}
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The request was directed at a server that is not able to produce a response. This can be sent by a server that is not configured to produce responses for the combination of scheme and authority that are included in the request URI.
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{{HTTPStatus(422, "422 Unprocessable Entity")}} ({{Glossary("WebDAV")}})
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The request was well-formed but was unable to be followed due to semantic errors.
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{{HTTPStatus(423, "423 Locked")}} ({{Glossary("WebDAV")}})
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The resource that is being accessed is locked.
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{{HTTPStatus(424, "424 Failed Dependency")}} ({{Glossary("WebDAV")}})
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The request failed due to failure of a previous request.
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{{HTTPStatus(426, "426 Upgrade Required")}}
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The server refuses to perform the request using the current protocol but might be willing to do so after the client upgrades to a different protocol. The server sends an {{HTTPHeader("Upgrade")}} header in a 426 response to indicate the required protocol(s).
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{{HTTPStatus(428, "428 Precondition Required")}}
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The origin server requires the request to be conditional. Intended to prevent the 'lost update' problem, where a client GETs a resource's state, modifies it, and PUTs it back to the server, when meanwhile a third party has modified the state on the server, leading to a conflict.
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{{HTTPStatus(429, "429 Too Many Requests")}}
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The user has sent too many requests in a given amount of time ("rate limiting").
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{{HTTPStatus(431, "431 Request Header Fields Too Large")}}
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The server is unwilling to process the request because its header fields are too large. The request MAY be resubmitted after reducing the size of the request header fields.
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{{HTTPStatus(451, "451 Unavailable For Legal Reasons")}}
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The user requests an illegal resource, such as a web page censored by a government.
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Server error responses

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{{HTTPStatus(500, "500 Internal Server Error")}}
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The server has encountered a situation it doesn't know how to handle.
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{{HTTPStatus(501, "501 Not Implemented")}}
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The request method is not supported by the server and cannot be handled. The only methods that servers are required to support (and therefore that must not return this code) are GET and HEAD.
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{{HTTPStatus(502, "502 Bad Gateway")}}
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This error response means that the server, while working as a gateway to get a response needed to handle the request, got an invalid response.
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{{HTTPStatus(503, "503 Service Unavailable")}}
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The server is not ready to handle the request. Common causes are a server that is down for maintenance or that is overloaded. Note that together with this response, a user-friendly page explaining the problem should be sent. This responses should be used for temporary conditions and the Retry-After: HTTP header should, if possible, contain the estimated time before the recovery of the service. The webmaster must also take care about the caching-related headers that are sent along with this response, as these temporary condition responses should usually not be cached.
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{{HTTPStatus(504, "504 Gateway Timeout")}}
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This error response is given when the server is acting as a gateway and cannot get a response in time.
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{{HTTPStatus(505, "505 HTTP Version Not Supported")}}
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The HTTP version used in the request is not supported by the server.
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{{HTTPStatus(506, "506 Variant Also Negotiates")}}
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The server has an internal configuration error: transparent content negotiation for the request results in a circular reference.
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{{HTTPStatus(507, "507 Insufficient Storage")}}
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The server has an internal configuration error: the chosen variant resource is configured to engage in transparent content negotiation itself, and is therefore not a proper end point in the negotiation process.
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{{HTTPStatus(508, "508 Loop Detected")}} ({{Glossary("WebDAV")}})
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The server detected an infinite loop while processing the request.
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{{HTTPStatus(510, "510 Not Extended")}}
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Further extensions to the request are required for the server to fulfill it.
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{{HTTPStatus(511, "511 Network Authentication Required")}}
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The 511 status code indicates that the client needs to authenticate to gain network access.
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See also

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