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moby--moby/api/server/httputils/httputils.go
Brian Goff ebcb7d6b40 Remove string checking in API error handling
Use strongly typed errors to set HTTP status codes.
Error interfaces are defined in the api/errors package and errors
returned from controllers are checked against these interfaces.

Errors can be wraeped in a pkg/errors.Causer, as long as somewhere in the
line of causes one of the interfaces is implemented. The special error
interfaces take precedence over Causer, meaning if both Causer and one
of the new error interfaces are implemented, the Causer is not
traversed.

Signed-off-by: Brian Goff <cpuguy83@gmail.com>
2017-08-15 16:01:11 -04:00

111 lines
3 KiB
Go

package httputils
import (
"io"
"mime"
"net/http"
"strings"
"github.com/pkg/errors"
"github.com/sirupsen/logrus"
"golang.org/x/net/context"
)
// APIVersionKey is the client's requested API version.
const APIVersionKey = "api-version"
// 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 an 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()
}
}
}
type validationError struct {
cause error
}
func (e validationError) Error() string {
return e.cause.Error()
}
func (e validationError) Cause() error {
return e.cause
}
func (e validationError) InvalidParameter() {}
// 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 matchesContentType(ct, "application/json") {
return nil
}
return validationError{errors.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 validationError{err}
}
return nil
}
// 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) string {
if ctx == nil {
return ""
}
if val := ctx.Value(APIVersionKey); val != nil {
return val.(string)
}
return ""
}
// matchesContentType validates the content type against the expected one
func matchesContentType(contentType, expectedType string) bool {
mimetype, _, err := mime.ParseMediaType(contentType)
if err != nil {
logrus.Errorf("Error parsing media type: %s error: %v", contentType, err)
}
return err == nil && mimetype == expectedType
}