package v2 import ( "net/http" "net/url" "strings" "github.com/docker/distribution/digest" "github.com/docker/distribution/reference" "github.com/gorilla/mux" ) // URLBuilder creates registry API urls from a single base endpoint. It can be // used to create urls for use in a registry client or server. // // All urls will be created from the given base, including the api version. // For example, if a root of "/foo/" is provided, urls generated will be fall // under "/foo/v2/...". Most application will only provide a schema, host and // port, such as "https://localhost:5000/". type URLBuilder struct { root *url.URL // url root (ie http://localhost/) router *mux.Router } // NewURLBuilder creates a URLBuilder with provided root url object. func NewURLBuilder(root *url.URL) *URLBuilder { return &URLBuilder{ root: root, router: Router(), } } // NewURLBuilderFromString workes identically to NewURLBuilder except it takes // a string argument for the root, returning an error if it is not a valid // url. func NewURLBuilderFromString(root string) (*URLBuilder, error) { u, err := url.Parse(root) if err != nil { return nil, err } return NewURLBuilder(u), nil } // NewURLBuilderFromRequest uses information from an *http.Request to // construct the root url. func NewURLBuilderFromRequest(r *http.Request) *URLBuilder { var scheme string forwardedProto := r.Header.Get("X-Forwarded-Proto") switch { case len(forwardedProto) > 0: scheme = forwardedProto case r.TLS != nil: scheme = "https" case len(r.URL.Scheme) > 0: scheme = r.URL.Scheme default: scheme = "http" } host := r.Host forwardedHost := r.Header.Get("X-Forwarded-Host") if len(forwardedHost) > 0 { // According to the Apache mod_proxy docs, X-Forwarded-Host can be a // comma-separated list of hosts, to which each proxy appends the // requested host. We want to grab the first from this comma-separated // list. hosts := strings.SplitN(forwardedHost, ",", 2) host = strings.TrimSpace(hosts[0]) } basePath := routeDescriptorsMap[RouteNameBase].Path requestPath := r.URL.Path index := strings.Index(requestPath, basePath) u := &url.URL{ Scheme: scheme, Host: host, } if index > 0 { // N.B. index+1 is important because we want to include the trailing / u.Path = requestPath[0 : index+1] } return NewURLBuilder(u) } // BuildBaseURL constructs a base url for the API, typically just "/v2/". func (ub *URLBuilder) BuildBaseURL() (string, error) { route := ub.cloneRoute(RouteNameBase) baseURL, err := route.URL() if err != nil { return "", err } return baseURL.String(), nil } // BuildCatalogURL constructs a url get a catalog of repositories func (ub *URLBuilder) BuildCatalogURL(values ...url.Values) (string, error) { route := ub.cloneRoute(RouteNameCatalog) catalogURL, err := route.URL() if err != nil { return "", err } return appendValuesURL(catalogURL, values...).String(), nil } // BuildTagsURL constructs a url to list the tags in the named repository. func (ub *URLBuilder) BuildTagsURL(name reference.Named) (string, error) { route := ub.cloneRoute(RouteNameTags) tagsURL, err := route.URL("name", name.Name()) if err != nil { return "", err } return tagsURL.String(), nil } // BuildManifestURL constructs a url for the manifest identified by name and // reference. The argument reference may be either a tag or digest. func (ub *URLBuilder) BuildManifestURL(name reference.Named, reference string) (string, error) { route := ub.cloneRoute(RouteNameManifest) manifestURL, err := route.URL("name", name.Name(), "reference", reference) if err != nil { return "", err } return manifestURL.String(), nil } // BuildBlobURL constructs the url for the blob identified by name and dgst. func (ub *URLBuilder) BuildBlobURL(name reference.Named, dgst digest.Digest) (string, error) { route := ub.cloneRoute(RouteNameBlob) layerURL, err := route.URL("name", name.Name(), "digest", dgst.String()) if err != nil { return "", err } return layerURL.String(), nil } // BuildBlobUploadURL constructs a url to begin a blob upload in the // repository identified by name. func (ub *URLBuilder) BuildBlobUploadURL(name reference.Named, values ...url.Values) (string, error) { route := ub.cloneRoute(RouteNameBlobUpload) uploadURL, err := route.URL("name", name.Name()) if err != nil { return "", err } return appendValuesURL(uploadURL, values...).String(), nil } // BuildBlobUploadChunkURL constructs a url for the upload identified by uuid, // including any url values. This should generally not be used by clients, as // this url is provided by server implementations during the blob upload // process. func (ub *URLBuilder) BuildBlobUploadChunkURL(name reference.Named, uuid string, values ...url.Values) (string, error) { route := ub.cloneRoute(RouteNameBlobUploadChunk) uploadURL, err := route.URL("name", name.Name(), "uuid", uuid) if err != nil { return "", err } return appendValuesURL(uploadURL, values...).String(), nil } // clondedRoute returns a clone of the named route from the router. Routes // must be cloned to avoid modifying them during url generation. func (ub *URLBuilder) cloneRoute(name string) clonedRoute { route := new(mux.Route) root := new(url.URL) *route = *ub.router.GetRoute(name) // clone the route *root = *ub.root return clonedRoute{Route: route, root: root} } type clonedRoute struct { *mux.Route root *url.URL } func (cr clonedRoute) URL(pairs ...string) (*url.URL, error) { routeURL, err := cr.Route.URL(pairs...) if err != nil { return nil, err } if routeURL.Scheme == "" && routeURL.User == nil && routeURL.Host == "" { routeURL.Path = routeURL.Path[1:] } url := cr.root.ResolveReference(routeURL) url.Scheme = cr.root.Scheme return url, nil } // appendValuesURL appends the parameters to the url. func appendValuesURL(u *url.URL, values ...url.Values) *url.URL { merged := u.Query() for _, v := range values { for k, vv := range v { merged[k] = append(merged[k], vv...) } } u.RawQuery = merged.Encode() return u } // appendValues appends the parameters to the url. Panics if the string is not // a url. func appendValues(u string, values ...url.Values) string { up, err := url.Parse(u) if err != nil { panic(err) // should never happen } return appendValuesURL(up, values...).String() }