package v2 import ( "fmt" "net/http" "net/url" "strings" "github.com/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 relative bool } // NewURLBuilder creates a URLBuilder with provided root url object. func NewURLBuilder(root *url.URL, relative bool) *URLBuilder { return &URLBuilder{ root: root, router: Router(), relative: relative, } } // NewURLBuilderFromString works 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, relative bool) (*URLBuilder, error) { u, err := url.Parse(root) if err != nil { return nil, err } return NewURLBuilder(u, relative), nil } // NewURLBuilderFromRequest uses information from an *http.Request to // construct the root url. func NewURLBuilderFromRequest(r *http.Request, relative bool) *URLBuilder { var ( scheme = "http" host = r.Host ) if r.TLS != nil { scheme = "https" } else if len(r.URL.Scheme) > 0 { scheme = r.URL.Scheme } // Handle forwarded headers // Prefer "Forwarded" header as defined by rfc7239 if given // see https://tools.ietf.org/html/rfc7239 if forwarded := r.Header.Get("Forwarded"); len(forwarded) > 0 { forwardedHeader, _, err := parseForwardedHeader(forwarded) if err == nil { if fproto := forwardedHeader["proto"]; len(fproto) > 0 { scheme = fproto } if fhost := forwardedHeader["host"]; len(fhost) > 0 { host = fhost } } } else { if forwardedProto := r.Header.Get("X-Forwarded-Proto"); len(forwardedProto) > 0 { scheme = forwardedProto } if forwardedHost := r.Header.Get("X-Forwarded-Host"); 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. host, _, _ = strings.Cut(forwardedHost, ",") host = strings.TrimSpace(host) } } 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, relative) } // 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, values ...url.Values) (string, error) { route := ub.cloneRoute(RouteNameTags) tagsURL, err := route.URL("name", name.Name()) if err != nil { return "", err } return appendValuesURL(tagsURL, values...).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(ref reference.Named) (string, error) { route := ub.cloneRoute(RouteNameManifest) tagOrDigest := "" switch v := ref.(type) { case reference.Tagged: tagOrDigest = v.Tag() case reference.Digested: tagOrDigest = v.Digest().String() default: return "", fmt.Errorf("reference must have a tag or digest") } manifestURL, err := route.URL("name", ref.Name(), "reference", tagOrDigest) 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(ref reference.Canonical) (string, error) { route := ub.cloneRoute(RouteNameBlob) layerURL, err := route.URL("name", ref.Name(), "digest", ref.Digest().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 } // cloneRoute 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, relative: ub.relative} } type clonedRoute struct { *mux.Route root *url.URL relative bool } func (cr clonedRoute) URL(pairs ...string) (*url.URL, error) { routeURL, err := cr.Route.URL(pairs...) if err != nil { return nil, err } if cr.relative { return routeURL, nil } 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 }