package tusd import ( "encoding/base64" "errors" "io" "log" "net" "net/http" "os" "regexp" "strconv" "strings" "sync/atomic" "time" ) var ( reExtractFileID = regexp.MustCompile(`([^/]+)\/?$`) reForwardedHost = regexp.MustCompile(`host=([^,]+)`) reForwardedProto = regexp.MustCompile(`proto=(https?)`) reMimeType = regexp.MustCompile(`^[a-z]+\/[a-z\-\+]+$`) ) // HTTPError represents an error with an additional status code attached // which may be used when this error is sent in a HTTP response. // See the net/http package for standardized status codes. type HTTPError interface { error StatusCode() int } type httpError struct { error statusCode int } func (err httpError) StatusCode() int { return err.statusCode } // NewHTTPError adds the given status code to the provided error and returns // the new error instance. The status code may be used in corresponding HTTP // responses. See the net/http package for standardized status codes. func NewHTTPError(err error, statusCode int) HTTPError { return httpError{err, statusCode} } var ( ErrUnsupportedVersion = NewHTTPError(errors.New("unsupported version"), http.StatusPreconditionFailed) ErrMaxSizeExceeded = NewHTTPError(errors.New("maximum size exceeded"), http.StatusRequestEntityTooLarge) ErrInvalidContentType = NewHTTPError(errors.New("missing or invalid Content-Type header"), http.StatusBadRequest) ErrInvalidUploadLength = NewHTTPError(errors.New("missing or invalid Upload-Length header"), http.StatusBadRequest) ErrInvalidOffset = NewHTTPError(errors.New("missing or invalid Upload-Offset header"), http.StatusBadRequest) ErrNotFound = NewHTTPError(errors.New("upload not found"), http.StatusNotFound) ErrFileLocked = NewHTTPError(errors.New("file currently locked"), 423) // Locked (WebDAV) (RFC 4918) ErrMismatchOffset = NewHTTPError(errors.New("mismatched offset"), http.StatusConflict) ErrSizeExceeded = NewHTTPError(errors.New("resource's size exceeded"), http.StatusRequestEntityTooLarge) ErrNotImplemented = NewHTTPError(errors.New("feature not implemented"), http.StatusNotImplemented) ErrUploadNotFinished = NewHTTPError(errors.New("one of the partial uploads is not finished"), http.StatusBadRequest) ErrInvalidConcat = NewHTTPError(errors.New("invalid Upload-Concat header"), http.StatusBadRequest) ErrModifyFinal = NewHTTPError(errors.New("modifying a final upload is not allowed"), http.StatusForbidden) ) // UnroutedHandler exposes methods to handle requests as part of the tus protocol, // such as PostFile, HeadFile, PatchFile and DelFile. In addition the GetFile method // is provided which is, however, not part of the specification. type UnroutedHandler struct { config Config composer *StoreComposer isBasePathAbs bool basePath string logger *log.Logger extensions string // CompleteUploads is used to send notifications whenever an upload is // completed by a user. The FileInfo will contain information about this // upload after it is completed. Sending to this channel will only // happen if the NotifyCompleteUploads field is set to true in the Config // structure. Notifications will also be sent for completions using the // Concatenation extension. CompleteUploads chan FileInfo // TerminatedUploads is used to send notifications whenever an upload is // terminated by a user. The FileInfo will contain information about this // upload gathered before the termination. Sending to this channel will only // happen if the NotifyTerminatedUploads field is set to true in the Config // structure. TerminatedUploads chan FileInfo // UploadProgress is used to send notifications about the progress of the // currently running uploads. For each open PATCH request, every second // a FileInfo instance will be send over this channel with the Offset field // being set to the number of bytes which have been transfered to the server. // Please be aware that this number may be higher than the number of bytes // which have been stored by the data store! Sending to this channel will only // happen if the NotifyUploadProgress field is set to true in the Config // structure. UploadProgress chan FileInfo // CreatedUploads is used to send notifications about the uploads having been // created. It triggers post creation and therefore has all the FileInfo incl. // the ID available already. It facilitates the post-create hook. Sending to // this channel will only happen if the NotifyCreatedUploads field is set to // true in the Config structure. CreatedUploads chan FileInfo // Metrics provides numbers of the usage for this handler. Metrics Metrics } // NewUnroutedHandler creates a new handler without routing using the given // configuration. It exposes the http handlers which need to be combined with // a router (aka mux) of your choice. If you are looking for preconfigured // handler see NewHandler. func NewUnroutedHandler(config Config) (*UnroutedHandler, error) { if err := config.validate(); err != nil { return nil, err } // Only promote extesions using the Tus-Extension header which are implemented extensions := "creation,creation-with-upload" if config.StoreComposer.UsesTerminater { extensions += ",termination" } if config.StoreComposer.UsesConcater { extensions += ",concatenation" } handler := &UnroutedHandler{ config: config, composer: config.StoreComposer, basePath: config.BasePath, isBasePathAbs: config.isAbs, CompleteUploads: make(chan FileInfo), TerminatedUploads: make(chan FileInfo), UploadProgress: make(chan FileInfo), CreatedUploads: make(chan FileInfo), logger: config.Logger, extensions: extensions, Metrics: newMetrics(), } return handler, nil } // Middleware checks various aspects of the request and ensures that it // conforms with the spec. Also handles method overriding for clients which // cannot make PATCH AND DELETE requests. If you are using the tusd handlers // directly you will need to wrap at least the POST and PATCH endpoints in // this middleware. func (handler *UnroutedHandler) Middleware(h http.Handler) http.Handler { return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { // Allow overriding the HTTP method. The reason for this is // that some libraries/environments to not support PATCH and // DELETE requests, e.g. Flash in a browser and parts of Java if newMethod := r.Header.Get("X-HTTP-Method-Override"); newMethod != "" { r.Method = newMethod } handler.log("RequestIncoming", "method", r.Method, "path", r.URL.Path) go handler.Metrics.incRequestsTotal(r.Method) header := w.Header() if origin := r.Header.Get("Origin"); origin != "" { header.Set("Access-Control-Allow-Origin", origin) if r.Method == "OPTIONS" { // Preflight request header.Add("Access-Control-Allow-Methods", "POST, GET, HEAD, PATCH, DELETE, OPTIONS") header.Add("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Upload-Length, Upload-Offset, Tus-Resumable, Upload-Metadata") header.Set("Access-Control-Max-Age", "86400") } else { // Actual request header.Add("Access-Control-Expose-Headers", "Upload-Offset, Location, Upload-Length, Tus-Version, Tus-Resumable, Tus-Max-Size, Tus-Extension, Upload-Metadata") } } // Set current version used by the server header.Set("Tus-Resumable", "1.0.0") // Add nosniff to all responses https://golang.org/src/net/http/server.go#L1429 header.Set("X-Content-Type-Options", "nosniff") // Set appropriated headers in case of OPTIONS method allowing protocol // discovery and end with an 204 No Content if r.Method == "OPTIONS" { if handler.config.MaxSize > 0 { header.Set("Tus-Max-Size", strconv.FormatInt(handler.config.MaxSize, 10)) } header.Set("Tus-Version", "1.0.0") header.Set("Tus-Extension", handler.extensions) // Although the 204 No Content status code is a better fit in this case, // since we do not have a response body included, we cannot use it here // as some browsers only accept 200 OK as successful response to a // preflight request. If we send them the 204 No Content the response // will be ignored or interpreted as a rejection. // For example, the Presto engine, which is used in older versions of // Opera, Opera Mobile and Opera Mini, handles CORS this way. handler.sendResp(w, r, http.StatusOK) return } // Test if the version sent by the client is supported // GET methods are not checked since a browser may visit this URL and does // not include this header. This request is not part of the specification. if r.Method != "GET" && r.Header.Get("Tus-Resumable") != "1.0.0" { handler.sendError(w, r, ErrUnsupportedVersion) return } // Proceed with routing the request h.ServeHTTP(w, r) }) } // PostFile creates a new file upload using the datastore after validating the // length and parsing the metadata. func (handler *UnroutedHandler) PostFile(w http.ResponseWriter, r *http.Request) { // Check for presence of application/offset+octet-stream. If another content // type is defined, it will be ignored and treated as none was set because // some HTTP clients may enforce a default value for this header. containsChunk := r.Header.Get("Content-Type") == "application/offset+octet-stream" // Only use the proper Upload-Concat header if the concatenation extension // is even supported by the data store. var concatHeader string if handler.composer.UsesConcater { concatHeader = r.Header.Get("Upload-Concat") } // Parse Upload-Concat header isPartial, isFinal, partialUploads, err := parseConcat(concatHeader) if err != nil { handler.sendError(w, r, err) return } // If the upload is a final upload created by concatenation multiple partial // uploads the size is sum of all sizes of these files (no need for // Upload-Length header) var size int64 if isFinal { // A final upload must not contain a chunk within the creation request if containsChunk { handler.sendError(w, r, ErrModifyFinal) return } size, err = handler.sizeOfUploads(partialUploads) if err != nil { handler.sendError(w, r, err) return } } else { size, err = strconv.ParseInt(r.Header.Get("Upload-Length"), 10, 64) if err != nil || size < 0 { handler.sendError(w, r, ErrInvalidUploadLength) return } } // Test whether the size is still allowed if handler.config.MaxSize > 0 && size > handler.config.MaxSize { handler.sendError(w, r, ErrMaxSizeExceeded) return } // Parse metadata meta := parseMeta(r.Header.Get("Upload-Metadata")) info := FileInfo{ Size: size, MetaData: meta, IsPartial: isPartial, IsFinal: isFinal, PartialUploads: partialUploads, } id, err := handler.composer.Core.NewUpload(info) if err != nil { handler.sendError(w, r, err) return } // Add the Location header directly after creating the new resource to even // include it in cases of failure when an error is returned url := handler.absFileURL(r, id) w.Header().Set("Location", url) go handler.Metrics.incUploadsCreated() handler.log("UploadCreated", "id", id, "size", i64toa(size), "url", url) if handler.config.NotifyCreatedUploads { info.ID = id handler.CreatedUploads <- info } if isFinal { if err := handler.composer.Concater.ConcatUploads(id, partialUploads); err != nil { handler.sendError(w, r, err) return } info.Offset = size if handler.config.NotifyCompleteUploads { info.ID = id handler.CompleteUploads <- info } } if containsChunk { if handler.composer.UsesLocker { locker := handler.composer.Locker if err := locker.LockUpload(id); err != nil { handler.sendError(w, r, err) return } defer locker.UnlockUpload(id) } if err := handler.writeChunk(id, info, w, r); err != nil { handler.sendError(w, r, err) return } } handler.sendResp(w, r, http.StatusCreated) } // HeadFile returns the length and offset for the HEAD request func (handler *UnroutedHandler) HeadFile(w http.ResponseWriter, r *http.Request) { id, err := extractIDFromPath(r.URL.Path) if err != nil { handler.sendError(w, r, err) return } if handler.composer.UsesLocker { locker := handler.composer.Locker if err := locker.LockUpload(id); err != nil { handler.sendError(w, r, err) return } defer locker.UnlockUpload(id) } info, err := handler.composer.Core.GetInfo(id) if err != nil { handler.sendError(w, r, err) return } // Add Upload-Concat header if possible if info.IsPartial { w.Header().Set("Upload-Concat", "partial") } if info.IsFinal { v := "final;" for _, uploadID := range info.PartialUploads { v += handler.absFileURL(r, uploadID) + " " } // Remove trailing space v = v[:len(v)-1] w.Header().Set("Upload-Concat", v) } if len(info.MetaData) != 0 { w.Header().Set("Upload-Metadata", serializeMeta(info.MetaData)) } w.Header().Set("Cache-Control", "no-store") w.Header().Set("Upload-Length", strconv.FormatInt(info.Size, 10)) w.Header().Set("Upload-Offset", strconv.FormatInt(info.Offset, 10)) handler.sendResp(w, r, http.StatusOK) } // PatchFile adds a chunk to an upload. Only allowed enough space is left. func (handler *UnroutedHandler) PatchFile(w http.ResponseWriter, r *http.Request) { // Check for presence of application/offset+octet-stream if r.Header.Get("Content-Type") != "application/offset+octet-stream" { handler.sendError(w, r, ErrInvalidContentType) return } // Check for presence of a valid Upload-Offset Header offset, err := strconv.ParseInt(r.Header.Get("Upload-Offset"), 10, 64) if err != nil || offset < 0 { handler.sendError(w, r, ErrInvalidOffset) return } id, err := extractIDFromPath(r.URL.Path) if err != nil { handler.sendError(w, r, err) return } if handler.composer.UsesLocker { locker := handler.composer.Locker if err := locker.LockUpload(id); err != nil { handler.sendError(w, r, err) return } defer locker.UnlockUpload(id) } info, err := handler.composer.Core.GetInfo(id) if err != nil { handler.sendError(w, r, err) return } // Modifying a final upload is not allowed if info.IsFinal { handler.sendError(w, r, ErrModifyFinal) return } if offset != info.Offset { handler.sendError(w, r, ErrMismatchOffset) return } // Do not proxy the call to the data store if the upload is already completed if info.Offset == info.Size { w.Header().Set("Upload-Offset", strconv.FormatInt(offset, 10)) handler.sendResp(w, r, http.StatusNoContent) return } if err := handler.writeChunk(id, info, w, r); err != nil { handler.sendError(w, r, err) return } handler.sendResp(w, r, http.StatusNoContent) } // PatchFile adds a chunk to an upload. Only allowed enough space is left. func (handler *UnroutedHandler) writeChunk(id string, info FileInfo, w http.ResponseWriter, r *http.Request) error { // Get Content-Length if possible length := r.ContentLength offset := info.Offset // Test if this upload fits into the file's size if offset+length > info.Size { return ErrSizeExceeded } maxSize := info.Size - offset if length > 0 { maxSize = length } handler.log("ChunkWriteStart", "id", id, "maxSize", i64toa(maxSize), "offset", i64toa(offset)) var bytesWritten int64 // Prevent a nil pointer dereference when accessing the body which may not be // available in the case of a malicious request. if r.Body != nil { // Limit the data read from the request's body to the allowed maximum reader := io.LimitReader(r.Body, maxSize) if handler.config.NotifyUploadProgress { var stop chan<- struct{} reader, stop = handler.sendProgressMessages(info, reader) defer close(stop) } var err error bytesWritten, err = handler.composer.Core.WriteChunk(id, offset, reader) if err != nil { return err } } handler.log("ChunkWriteComplete", "id", id, "bytesWritten", i64toa(bytesWritten)) // Send new offset to client newOffset := offset + bytesWritten w.Header().Set("Upload-Offset", strconv.FormatInt(newOffset, 10)) go handler.Metrics.incBytesReceived(uint64(bytesWritten)) // If the upload is completed, ... if newOffset == info.Size { // ... allow custom mechanism to finish and cleanup the upload if handler.composer.UsesFinisher { if err := handler.composer.Finisher.FinishUpload(id); err != nil { return err } } // ... send the info out to the channel if handler.config.NotifyCompleteUploads { info.Offset = newOffset handler.CompleteUploads <- info } go handler.Metrics.incUploadsFinished() } return nil } // GetFile handles requests to download a file using a GET request. This is not // part of the specification. func (handler *UnroutedHandler) GetFile(w http.ResponseWriter, r *http.Request) { if !handler.composer.UsesGetReader { handler.sendError(w, r, ErrNotImplemented) return } id, err := extractIDFromPath(r.URL.Path) if err != nil { handler.sendError(w, r, err) return } if handler.composer.UsesLocker { locker := handler.composer.Locker if err := locker.LockUpload(id); err != nil { handler.sendError(w, r, err) return } defer locker.UnlockUpload(id) } info, err := handler.composer.Core.GetInfo(id) if err != nil { handler.sendError(w, r, err) return } // Set headers before sending responses w.Header().Set("Content-Length", strconv.FormatInt(info.Offset, 10)) contentType, contentDisposition := filterContentType(info) w.Header().Set("Content-Type", contentType) w.Header().Set("Content-Disposition", contentDisposition) // If no data has been uploaded yet, respond with an empty "204 No Content" status. if info.Offset == 0 { handler.sendResp(w, r, http.StatusNoContent) return } src, err := handler.composer.GetReader.GetReader(id) if err != nil { handler.sendError(w, r, err) return } handler.sendResp(w, r, http.StatusOK) io.Copy(w, src) // Try to close the reader if the io.Closer interface is implemented if closer, ok := src.(io.Closer); ok { closer.Close() } } // mimeInlineBrowserWhitelist is a map containing MIME types which should be // allowed to be rendered by browser inline, instead of being forced to be // downloadd. For example, HTML or SVG files are not allowed, since they may // contain malicious JavaScript. In a similiar fashion PDF is not on this list // as their parsers commonly contain vulnerabilities which can be exploited. // The values of this map does not convei any meaning and are therefore just // empty structs. var mimeInlineBrowserWhitelist = map[string]struct{}{ "text/plain": struct{}{}, "image/png": struct{}{}, "image/jpeg": struct{}{}, "image/gif": struct{}{}, "image/bmp": struct{}{}, "image/webp": struct{}{}, "audio/wave": struct{}{}, "audio/wav": struct{}{}, "audio/x-wav": struct{}{}, "audio/x-pn-wav": struct{}{}, "audio/webm": struct{}{}, "video/webm": struct{}{}, "audio/ogg": struct{}{}, "video/ogg ": struct{}{}, "application/ogg": struct{}{}, } // filterContentType returns the values for the Content-Type and // Content-Disposition headers for a given upload. These values should be used // in responses for GET requests to ensure that only non-malicious file types // are shown directly in the browser. It will extract the file name and type // from the "fileame" and "filetype". // See https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Disposition func filterContentType(info FileInfo) (contentType string, contentDisposition string) { filetype := info.MetaData["filetype"] if reMimeType.MatchString(filetype) { // If the filetype from metadata is well formed, we forward use this // for the Content-Type header. However, only whitelisted mime types // will be allowed to be shown inline in the browser contentType = filetype if _, isWhitelisted := mimeInlineBrowserWhitelist[filetype]; isWhitelisted { contentDisposition = "inline" } else { contentDisposition = "attachment" } } else { // If the filetype from the metadata is not well formed, we use a // default type and force the browser to download the content. contentType = "application/octet-stream" contentDisposition = "attachment" } // Add a filename to Content-Disposition if one is available in the metadata if filename, ok := info.MetaData["filename"]; ok { contentDisposition += ";filename=" + strconv.Quote(filename) } return contentType, contentDisposition } // DelFile terminates an upload permanently. func (handler *UnroutedHandler) DelFile(w http.ResponseWriter, r *http.Request) { // Abort the request handling if the required interface is not implemented if !handler.composer.UsesTerminater { handler.sendError(w, r, ErrNotImplemented) return } id, err := extractIDFromPath(r.URL.Path) if err != nil { handler.sendError(w, r, err) return } if handler.composer.UsesLocker { locker := handler.composer.Locker if err := locker.LockUpload(id); err != nil { handler.sendError(w, r, err) return } defer locker.UnlockUpload(id) } var info FileInfo if handler.config.NotifyTerminatedUploads { info, err = handler.composer.Core.GetInfo(id) if err != nil { handler.sendError(w, r, err) return } } err = handler.composer.Terminater.Terminate(id) if err != nil { handler.sendError(w, r, err) return } handler.sendResp(w, r, http.StatusNoContent) if handler.config.NotifyTerminatedUploads { handler.TerminatedUploads <- info } go handler.Metrics.incUploadsTerminated() } // Send the error in the response body. The status code will be looked up in // ErrStatusCodes. If none is found 500 Internal Error will be used. func (handler *UnroutedHandler) sendError(w http.ResponseWriter, r *http.Request, err error) { // Interpret os.ErrNotExist as 404 Not Found if os.IsNotExist(err) { err = ErrNotFound } // Errors for read timeouts contain too much information which is not // necessary for us and makes grouping for the metrics harder. The error // message looks like: read tcp 127.0.0.1:1080->127.0.0.1:53673: i/o timeout // Therefore, we use a common error message for all of them. if netErr, ok := err.(net.Error); ok && netErr.Timeout() { err = errors.New("read tcp: i/o timeout") } statusErr, ok := err.(HTTPError) if !ok { statusErr = NewHTTPError(err, http.StatusInternalServerError) } reason := err.Error() + "\n" if r.Method == "HEAD" { reason = "" } w.Header().Set("Content-Type", "text/plain; charset=utf-8") w.Header().Set("Content-Length", strconv.Itoa(len(reason))) w.WriteHeader(statusErr.StatusCode()) w.Write([]byte(reason)) handler.log("ResponseOutgoing", "status", strconv.Itoa(statusErr.StatusCode()), "method", r.Method, "path", r.URL.Path, "error", err.Error()) go handler.Metrics.incErrorsTotal(statusErr) } // sendResp writes the header to w with the specified status code. func (handler *UnroutedHandler) sendResp(w http.ResponseWriter, r *http.Request, status int) { w.WriteHeader(status) handler.log("ResponseOutgoing", "status", strconv.Itoa(status), "method", r.Method, "path", r.URL.Path) } // Make an absolute URLs to the given upload id. If the base path is absolute // it will be prepended else the host and protocol from the request is used. func (handler *UnroutedHandler) absFileURL(r *http.Request, id string) string { if handler.isBasePathAbs { return handler.basePath + id } // Read origin and protocol from request host, proto := getHostAndProtocol(r, handler.config.RespectForwardedHeaders) url := proto + "://" + host + handler.basePath + id return url } type progressWriter struct { Offset int64 } func (w *progressWriter) Write(b []byte) (int, error) { atomic.AddInt64(&w.Offset, int64(len(b))) return len(b), nil } // sendProgressMessage will send a notification over the UploadProgress channel // every second, indicating how much data has been transfered to the server. // It will stop sending these instances once the returned channel has been // closed. The returned reader should be used to read the request body. func (handler *UnroutedHandler) sendProgressMessages(info FileInfo, reader io.Reader) (io.Reader, chan<- struct{}) { progress := &progressWriter{ Offset: info.Offset, } stop := make(chan struct{}, 1) reader = io.TeeReader(reader, progress) go func() { for { select { case <-stop: info.Offset = atomic.LoadInt64(&progress.Offset) handler.UploadProgress <- info return case <-time.After(1 * time.Second): info.Offset = atomic.LoadInt64(&progress.Offset) handler.UploadProgress <- info } } }() return reader, stop } // getHostAndProtocol extracts the host and used protocol (either HTTP or HTTPS) // from the given request. If `allowForwarded` is set, the X-Forwarded-Host, // X-Forwarded-Proto and Forwarded headers will also be checked to // support proxies. func getHostAndProtocol(r *http.Request, allowForwarded bool) (host, proto string) { if r.TLS != nil { proto = "https" } else { proto = "http" } host = r.Host if !allowForwarded { return } if h := r.Header.Get("X-Forwarded-Host"); h != "" { host = h } if h := r.Header.Get("X-Forwarded-Proto"); h == "http" || h == "https" { proto = h } if h := r.Header.Get("Forwarded"); h != "" { if r := reForwardedHost.FindStringSubmatch(h); len(r) == 2 { host = r[1] } if r := reForwardedProto.FindStringSubmatch(h); len(r) == 2 { proto = r[1] } } return } // The get sum of all sizes for a list of upload ids while checking whether // all of these uploads are finished yet. This is used to calculate the size // of a final resource. func (handler *UnroutedHandler) sizeOfUploads(ids []string) (size int64, err error) { for _, id := range ids { info, err := handler.composer.Core.GetInfo(id) if err != nil { return size, err } if info.Offset != info.Size { err = ErrUploadNotFinished return size, err } size += info.Size } return } // Parse the Upload-Metadata header as defined in the File Creation extension. // e.g. Upload-Metadata: name bHVucmpzLnBuZw==,type aW1hZ2UvcG5n func parseMeta(header string) map[string]string { meta := make(map[string]string) for _, element := range strings.Split(header, ",") { element := strings.TrimSpace(element) parts := strings.Split(element, " ") // Do not continue with this element if no key and value or presented if len(parts) != 2 { continue } // Ignore corrent element if the value is no valid base64 key := parts[0] value, err := base64.StdEncoding.DecodeString(parts[1]) if err != nil { continue } meta[key] = string(value) } return meta } // Serialize a map of strings into the Upload-Metadata header format used in the // response for HEAD requests. // e.g. Upload-Metadata: name bHVucmpzLnBuZw==,type aW1hZ2UvcG5n func serializeMeta(meta map[string]string) string { header := "" for key, value := range meta { valueBase64 := base64.StdEncoding.EncodeToString([]byte(value)) header += key + " " + valueBase64 + "," } // Remove trailing comma if len(header) > 0 { header = header[:len(header)-1] } return header } // Parse the Upload-Concat header, e.g. // Upload-Concat: partial // Upload-Concat: final;http://tus.io/files/a /files/b/ func parseConcat(header string) (isPartial bool, isFinal bool, partialUploads []string, err error) { if len(header) == 0 { return } if header == "partial" { isPartial = true return } l := len("final;") if strings.HasPrefix(header, "final;") && len(header) > l { isFinal = true list := strings.Split(header[l:], " ") for _, value := range list { value := strings.TrimSpace(value) if value == "" { continue } id, extractErr := extractIDFromPath(value) if extractErr != nil { err = extractErr return } partialUploads = append(partialUploads, id) } } // If no valid partial upload ids are extracted this is not a final upload. if len(partialUploads) == 0 { isFinal = false err = ErrInvalidConcat } return } // extractIDFromPath pulls the last segment from the url provided func extractIDFromPath(url string) (string, error) { result := reExtractFileID.FindStringSubmatch(url) if len(result) != 2 { return "", ErrNotFound } return result[1], nil } func i64toa(num int64) string { return strconv.FormatInt(num, 10) }