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package utils
import (
"encoding/json"
"fmt"
"io"
"net/http"
"net/url"
"os"
"strings"
"github.com/blang/semver"
"github.com/gorilla/mux"
"github.com/pkg/errors"
"github.com/sirupsen/logrus"
)
type (
// VersionTree determines which API endpoint tree for version
VersionTree int
// VersionLevel determines which API level, current or something from the past
VersionLevel int
)
const (
// LibpodTree supports Libpod endpoints
LibpodTree = VersionTree(iota)
// CompatTree supports Libpod endpoints
CompatTree
// CurrentApiVersion announces what is the current API level
CurrentApiVersion = VersionLevel(iota)
// MinimalApiVersion announces what is the oldest API level supported
MinimalApiVersion
)
var (
// See https://docs.docker.com/engine/api/v1.40/
// libpod compat handlers are expected to honor docker API versions
// ApiVersion provides the current and minimal API versions for compat and libpod endpoint trees
// Note: GET|HEAD /_ping is never versioned and provides the API-Version and Libpod-API-Version headers to allow
// clients to shop for the Version they wish to support
ApiVersion = map[VersionTree]map[VersionLevel]semver.Version{
LibpodTree: {
CurrentApiVersion: semver.MustParse("1.0.0"),
MinimalApiVersion: semver.MustParse("1.0.0"),
},
CompatTree: {
CurrentApiVersion: semver.MustParse("1.40.0"),
MinimalApiVersion: semver.MustParse("1.24.0"),
},
}
// ErrVersionNotGiven returned when version not given by client
ErrVersionNotGiven = errors.New("version not given in URL path")
// ErrVersionNotSupported returned when given version is too old
ErrVersionNotSupported = errors.New("given version is not supported")
)
// IsLibpodRequest returns true if the request related to a libpod endpoint
// (e.g., /v2/libpod/...).
func IsLibpodRequest(r *http.Request) bool {
split := strings.Split(r.URL.String(), "/")
return len(split) >= 3 && split[2] == "libpod"
}
// SupportedVersion validates that the version provided by client is included in the given condition
// https://github.com/blang/semver#ranges provides the details for writing conditions
// If a version is not given in URL path, ErrVersionNotGiven is returned
func SupportedVersion(r *http.Request, condition string) (semver.Version, error) {
version := semver.Version{}
val, ok := mux.Vars(r)["version"]
if !ok {
return version, ErrVersionNotGiven
}
safeVal, err := url.PathUnescape(val)
if err != nil {
return version, errors.Wrapf(err, "unable to unescape given API version: %q", val)
}
version, err = semver.ParseTolerant(safeVal)
if err != nil {
return version, errors.Wrapf(err, "unable to parse given API version: %q from %q", safeVal, val)
}
inRange, err := semver.ParseRange(condition)
if err != nil {
return version, err
}
if inRange(version) {
return version, nil
}
return version, ErrVersionNotSupported
}
// SupportedVersionWithDefaults validates that the version provided by client valid is supported by server
// minimal API version <= client path version <= maximum API version focused on the endpoint tree from URL
func SupportedVersionWithDefaults(r *http.Request) (semver.Version, error) {
tree := CompatTree
if IsLibpodRequest(r) {
tree = LibpodTree
}
return SupportedVersion(r,
fmt.Sprintf(">=%s <=%s", ApiVersion[tree][MinimalApiVersion].String(),
ApiVersion[tree][CurrentApiVersion].String()))
}
// WriteResponse encodes the given value as JSON or string and renders it for http client
func WriteResponse(w http.ResponseWriter, code int, value interface{}) {
// RFC2616 explicitly states that the following status codes "MUST NOT
// include a message-body":
switch code {
case http.StatusNoContent, http.StatusNotModified: // 204, 304
w.WriteHeader(code)
return
}
switch v := value.(type) {
case string:
w.Header().Set("Content-Type", "text/plain; charset=us-ascii")
w.WriteHeader(code)
if _, err := fmt.Fprintln(w, v); err != nil {
logrus.Errorf("unable to send string response: %q", err)
}
case *os.File:
w.Header().Set("Content-Type", "application/octet; charset=us-ascii")
w.WriteHeader(code)
if _, err := io.Copy(w, v); err != nil {
logrus.Errorf("unable to copy to response: %q", err)
}
case io.Reader:
w.Header().Set("Content-Type", "application/x-tar")
w.WriteHeader(code)
if _, err := io.Copy(w, v); err != nil {
logrus.Errorf("unable to copy to response: %q", err)
}
default:
WriteJSON(w, code, value)
}
}
func WriteJSON(w http.ResponseWriter, code int, value interface{}) {
// FIXME: we don't need to write the header in all/some circumstances.
w.Header().Set("Content-Type", "application/json")
w.WriteHeader(code)
coder := json.NewEncoder(w)
coder.SetEscapeHTML(true)
if err := coder.Encode(value); err != nil {
logrus.Errorf("unable to write json: %q", err)
}
}
func FilterMapToString(filters map[string][]string) (string, error) {
f, err := json.Marshal(filters)
if err != nil {
return "", err
}
return string(f), nil
}
func getVar(r *http.Request, k string) string {
val := mux.Vars(r)[k]
safeVal, err := url.PathUnescape(val)
if err != nil {
logrus.Error(errors.Wrapf(err, "failed to unescape mux key %s, value %s", k, val))
return val
}
return safeVal
}
// GetName extracts the name from the mux
func GetName(r *http.Request) string {
return getVar(r, "name")
}
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