--- title: nsIZipWriter slug: NsIZipWriter translation_of: Mozilla/Tech/XPCOM/Reference/Interface/nsIZipWriter ---

The nsIZipWriter interface provides an easy way for scripts to archive data in the Zip file format. Operations on the archive can be performed one by one, or queued for later execution.

Once all the operations you wish to perform are added to the queue, a call to processQueue() will perform the operations in the order they were added to the queue. Operations performed on the queue throw any errors that occur out to the observer.

Attempting to perform a synchronous operation on the interface while the background queue is in progress will throw an NS_ERROR_IN_PROGRESS exception.

File and directory names should use slashes ("/") as separators and should not begin with a slash.

Nota: Although it isn't necessary to add directory entries in order to add file entries within them, some Zip utilities may have problems with that, so it may be best to add the directory entries explicitly first.


modules/libjar/zipwriter/public/nsIZipWriter.idlScriptable
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  Last changed in Gecko 1.9 (Firefox 3)

Inherits from: nsISupports

Implemented by: @mozilla.org/zipwriter;1. To create an instance, use:

var zipWriter = Components.classes["@mozilla.org/zipwriter;1"]
                          .createInstance(Components.interfaces.nsIZipWriter);

Method overview

void addDirectoryEntry(in AUTF8String aZipEntry, in PRTime aModTime, in boolean aQueue);
void addEntryChannel(in AUTF8SZtring aZipEntry, in PRTime aModTime, in PRInt32 aCompression, in nsIChannel aChannel, in boolean aQueue)
void addEntryFile(in AUTF8SZtring aZipEntry, in PRInt32 aCompression, in nsIFile aFile, in boolean aQueue)
void addEntryStream(in AUTF8SZtring aZipEntry, in PRTime aModTime, in PRInt32 aCompression, in nsIInputStream aStream, in boolean aQueue)
void close()
nsIZipEntry getEntry(in AUTF8String aZipEntry);
boolean hasEntry(in AUTF8String aZipEntry);
void open(in nsIFile aFile, in PRInt32 aIoFlags);
void processQueue(in nsIRequestObserver aObserver, in nsISupports aContext)
void removeEntry(in AUTF8String aZipEntry, in boolean aQueue)

Attributes

Attribute Type Description
comment ACString Gets or sets the comment associated with the currently open Zip file. Throws NS_ERROR_NOT_INITIALIZED if there isn't an open Zip file.
inQueue boolean true if operations are being performed in the background queue, or false if background operations are not in progress. Read-only.
file nsIFile The Zip file being written to. Read-only.

Constants

Constant Value Description
COMPRESSION_NONE 0 Don't compress the file.
COMPRESSION_FASTEST 1 Use the fastest compression method when adding the file to the archive.
COMPRESSION_DEFAULT 6 Use the default compression method when adding the file to the archive.
COMPRESSION_BEST 9 Use the best compression method when adding the file to the archive.

Methods

addDirectoryEntry()

Adds a new directory entry to the Zip file.

Nota: Although it isn't necessary to add directory entries in order to add file entries within them, some Zip utilities may have problems with that, so it may be best to add the directory entries explicitly first.

 void addEntryDirectory(
   in AUTF8String aZipEntry,
   in PRTime aModTime,
   in boolean aQueue
 );
Parameters
aZipEntry
The path of the directory entry to add to the Zip file.
aModTime
The modification time of the entry in microseconds.
aQueue
If true, the operation is queued for later execution. If false, the operation is performed immediately.
Exceptions thrown
NS_ERROR_NOT_INITIALIZED
No Zip file is open.
NS_ERROR_FILE_ALREADY_EXISTS
The specified path already exists in the Zip file.
NS_ERROR_IN_PROGRESS
The Zip writer is already performing another operation.

addEntryChannel()

Adds data from a channel to the Zip file.

 void addEntryChannel(
   in AUTF8String aZipEntry,
   in PRTime aModTime,
   in PRInt32 aCompression,
   in nsIChannel aChannel,
   in boolean aQueue
 );
Parameters
aZipEntry
The path of the file entry to add to the Zip file. This is the path it will be located at within the Zip file.

Nota: You must use forward slashes in the path.

aModTime
The modification time of the entry in microseconds.
aCompression
One of the compression constants, indicating the compression method to use.
aChannel
The channel from which to get the data.
aQueue
If true, the operation is queued for later execution. If false, the operation is performed immediately.
Exceptions thrown
NS_ERROR_NOT_INITIALIZED
No Zip file is open.
NS_ERROR_FILE_ALREADY_EXISTS
The specified path already exists in the Zip file.
NS_ERROR_IN_PROGRESS
The Zip writer is already performing another operation.

addEntryFile()

Adds a new file or directory to the Zip file. If the specified file is a directory, this call is equivalent to:

 addDirectoryEntry(aZipEntry, aFile.lastModifiedTime, aQueue);

 void addEntryFile(
   in AUTF8String aZipEntry,
   in PRInt32 aCompression,
   in nsIFile aFile,
   in boolean aQueue
 );
Parameters
aZipEntry
The path of the file entry to add to the Zip file. This is the path it will be located at within the Zip file.

Nota: You must use forward slashes in the path.

aCompression
One of the compression constants, indicating the compression method to use.
aFile
The file from which to get the data and modification time.
aQueue
If true, the operation is queued for later execution. If false, the operation is performed immediately.
Exceptions thrown
NS_ERROR_NOT_INITIALIZED
No Zip file is open.
NS_ERROR_FILE_ALREADY_EXISTS
The specified path already exists in the Zip file.
NS_ERROR_IN_PROGRESS
The Zip writer is already performing another operation.

addEntryStream()

Adds data from an input stream to the Zip file.

 void addEntryStream(
   in AUTF8String aZipEntry,
   in PRTime aModTime,
   in PRInt32 aCompression,
   in nsIInputStream aStream,
   in boolean aQueue
 );
Parameters
aZipEntry
The path of the file entry to add to the Zip file. This is the path it will be located at within the Zip file.

Nota: You must use forward slashes in the path.

aModTime
The modification time of the entry in microseconds.
aCompression
One of the compression constants, indicating the compression method to use.
aStream
The input stream from which to get the data.
aQueue
If true, the operation is queued for later execution. If false, the operation is performed immediately.
Exceptions thrown
NS_ERROR_NOT_INITIALIZED
No Zip file is open.
NS_ERROR_FILE_ALREADY_EXISTS
The specified path already exists in the Zip file.
NS_ERROR_IN_PROGRESS
The Zip writer is already performing another operation.

close()

Closes the Zip file.

 void close();
Parameters

None.

Exceptions thrown
NS_ERROR_NOT_INITIALIZED
No Zip file is open.
NS_ERROR_IN_PROGRESS
The Zip writer is already performing another operation.

Other errors may be thrown if a failure to complete the Zip file occurs.

getEntry()

Returns a specified entry in the current Zip file.

 nsIZipEntry getEntry(
   in AUTF8String aZipEntry,
 );
Parameters
aZipEntry
The path of the file entry to get.
Return value

An nsIZipEntry object describing the specified entry, or null if there is no such entry.

hasEntry()

Determines whether or not a specific entry exists in the Zip file.

 boolean hasEntry(
   in AUTF8String aZipEntry,
 );
Parameters
aZipEntry
The path of the file entry to check for.
Return value

true if there is an entry with the given path in the Zip file, otherwise returns false.

open()

Opens the specified Zip file.

 void open(
   in nsIFile aFile,
   in PRInt32 aIoFlags
 );
Parameters
aFile
The Zip file to open.
aIoFlags
The open flags for the Zip file, from prio.h.
Exceptions thrown
NS_ERROR_ALREADY_INITIALIZED
A Zip file is already open.
NS_ERROR_INVALID_ARG
The aFile parameter is null.
NS_ERROR_FILE_NOT_FOUND
The specified file was not found and the flags didn't permit creating it. Or the directory for the file does not exist.
NS_ERROR_FILE_CORRUPTED
The specified file is not a recognizable Zip file.

Other errors may be thrown upon failing to open the file, such as if the file is corrupt or in an unsupported format.

processQueue()

Processes all queued items until the entire queue has been processed or an error occurs. The observer is notified when the first operation begins and when the last operation completes.

Any failures are passed to the observer.

The Zip writer will be busy until the queue is complete or an error halts processing of the queue early. In the event of an early failure, the remaining items stay in the queue; calling processQueue() again will continue where operations left off.

 void processQueue(
   in nsIRequestObserver aObserver,
   in nsISupports aContext
 );
Parameters
aObserver
The observer to receive notifications from the queue.
aContext
The context to pass to the observer.
Exceptions thrown
NS_ERROR_NOT_INITIALIZED
No Zip file is open.
NS_ERROR_IN_PROGRESS
The queue is already in progress.

removeEntry()

Removes an entry from the Zip file.

 void removeEntry(
   in AUTF8String aZipEntry,
   in boolean aQueue
 );
Parameters
aZipEntry
The path of the entry to remove from the Zip file.
aQueue
true to place the remove operation into the queue, or false to process it at once.
Exceptions thrown
NS_ERROR_NOT_INITIALIZED
No Zip file is open.
NS_ERROR_IN_PROGRESS
The queue is already in progress.
NS_ERROR_FILE_NOT_FOUND
No entry with the given path exists.

Other errors may occur if updating the Zip file fails.

Examples

Adding a comment to a Zip file

var zipWriter = Components.Constructor("@mozilla.org/zipwriter;1", "nsIZipWriter");
var zipW = new zipWriter();

zipW.open(myZipFilePath, PR_RDWR | PR_CREATE_FILE | PR_TRUNCATE);
zipW.comment = "This is a comment.";
zipW.close();

PR_RDWR and friends are constants that are not in any interface (see Bug 433295), so for the code above to work you need something like:

const PR_RDONLY      = 0x01;
const PR_WRONLY      = 0x02;
const PR_RDWR        = 0x04;
const PR_CREATE_FILE = 0x08;
const PR_APPEND      = 0x10;
const PR_TRUNCATE    = 0x20;
const PR_SYNC        = 0x40;
const PR_EXCL        = 0x80;

See PR_Open Documentation or File I/O Snippets for details.

Adding a file to a Zip archive

This code synchronously adds the file specified by the nsIFile theFile to the Zip archive.

var zipWriter = Components.Constructor("@mozilla.org/zipwriter;1", "nsIZipWriter");
var zipW = new zipWriter();

zipW.open(myZipFilePath, PR_RDWR | PR_CREATE_FILE | PR_TRUNCATE);
zipW.addEntryFile("Path/For/This/File/In/Zip Archive", Components.interfaces.nsIZipWriter.COMPRESSION_DEFAULT, theFile, false);
zipW.close();

The argument nyZipFilePath isn't a path but rather it has to be an nsIFile instance specifying the location of the new zip file. The file need not exist, but the directory that contains it (nsIFile.parent) must exist.

Other examples

For other examples, take a look at the unit tests in the source tree:

See also