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moby--moby/api/server/httputils/httputils.go
Mike Goelzer d1502afb63 Pass upstream client's user agent through to registry on image pulls
Changes how the Engine interacts with Registry servers on image pull.
Previously, Engine sent a User-Agent string to the Registry server
that included only the Engine's version information.  This commit
appends to that string the fields from the User-Agent sent by the
client (e.g., Compose) of the Engine.  This allows Registry server
operators to understand what tools are actually generating pulls on
their registries.

Signed-off-by: Mike Goelzer <mgoelzer@docker.com>
2016-03-20 04:30:09 -07:00

107 lines
3.1 KiB
Go

package httputils
import (
"encoding/json"
"fmt"
"io"
"net/http"
"strings"
"golang.org/x/net/context"
"github.com/docker/docker/api"
"github.com/docker/docker/pkg/version"
)
// APIVersionKey is the client's requested API version.
const APIVersionKey = "api-version"
// UAStringKey is used as key type for user-agent string in net/context struct
const UAStringKey = "upstream-user-agent"
// APIFunc is an adapter to allow the use of ordinary functions as Docker API endpoints.
// Any function that has the appropriate signature can be registered as a API endpoint (e.g. getVersion).
type APIFunc func(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error
// HijackConnection interrupts the http response writer to get the
// underlying connection and operate with it.
func HijackConnection(w http.ResponseWriter) (io.ReadCloser, io.Writer, error) {
conn, _, err := w.(http.Hijacker).Hijack()
if err != nil {
return nil, nil, err
}
// Flush the options to make sure the client sets the raw mode
conn.Write([]byte{})
return conn, conn, nil
}
// CloseStreams ensures that a list for http streams are properly closed.
func CloseStreams(streams ...interface{}) {
for _, stream := range streams {
if tcpc, ok := stream.(interface {
CloseWrite() error
}); ok {
tcpc.CloseWrite()
} else if closer, ok := stream.(io.Closer); ok {
closer.Close()
}
}
}
// CheckForJSON makes sure that the request's Content-Type is application/json.
func CheckForJSON(r *http.Request) error {
ct := r.Header.Get("Content-Type")
// No Content-Type header is ok as long as there's no Body
if ct == "" {
if r.Body == nil || r.ContentLength == 0 {
return nil
}
}
// Otherwise it better be json
if api.MatchesContentType(ct, "application/json") {
return nil
}
return fmt.Errorf("Content-Type specified (%s) must be 'application/json'", ct)
}
// ParseForm ensures the request form is parsed even with invalid content types.
// If we don't do this, POST method without Content-type (even with empty body) will fail.
func ParseForm(r *http.Request) error {
if r == nil {
return nil
}
if err := r.ParseForm(); err != nil && !strings.HasPrefix(err.Error(), "mime:") {
return err
}
return nil
}
// ParseMultipartForm ensures the request form is parsed, even with invalid content types.
func ParseMultipartForm(r *http.Request) error {
if err := r.ParseMultipartForm(4096); err != nil && !strings.HasPrefix(err.Error(), "mime:") {
return err
}
return nil
}
// WriteJSON writes the value v to the http response stream as json with standard json encoding.
func WriteJSON(w http.ResponseWriter, code int, v interface{}) error {
w.Header().Set("Content-Type", "application/json")
w.WriteHeader(code)
return json.NewEncoder(w).Encode(v)
}
// VersionFromContext returns an API version from the context using APIVersionKey.
// It panics if the context value does not have version.Version type.
func VersionFromContext(ctx context.Context) (ver version.Version) {
if ctx == nil {
return
}
val := ctx.Value(APIVersionKey)
if val == nil {
return
}
return val.(version.Version)
}