tusd/handler.go

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package tusd
import (
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"encoding/base64"
"errors"
"io"
"log"
"net/http"
"net/url"
"os"
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"regexp"
"strconv"
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"strings"
"github.com/bmizerany/pat"
)
var logger = log.New(os.Stdout, "[tusd] ", 0)
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var reExtractFileId = regexp.MustCompile(`([^/]+)\/?$`)
var (
ErrUnsupportedVersion = errors.New("unsupported version")
ErrMaxSizeExceeded = errors.New("maximum size exceeded")
ErrInvalidEntityLength = errors.New("missing or invalid Entity-Length header")
ErrInvalidOffset = errors.New("missing or invalid Offset header")
ErrNotFound = errors.New("upload not found")
ErrFileLocked = errors.New("file currently locked")
ErrIllegalOffset = errors.New("illegal offset")
ErrSizeExceeded = errors.New("resource's size exceeded")
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ErrNotImplemented = errors.New("feature not implemented")
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ErrUploadNotFinished = errors.New("one of the partial uploads is not finished")
ErrInvalidConcat = errors.New("invalid Concat header")
ErrModifyFinal = errors.New("modifying a final upload is not allowed")
)
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// HTTP status codes sent in the response when the specific error is returned.
var ErrStatusCodes = map[error]int{
ErrUnsupportedVersion: http.StatusPreconditionFailed,
ErrMaxSizeExceeded: http.StatusRequestEntityTooLarge,
ErrInvalidEntityLength: http.StatusBadRequest,
ErrInvalidOffset: http.StatusBadRequest,
ErrNotFound: http.StatusNotFound,
ErrFileLocked: 423, // Locked (WebDAV) (RFC 4918)
ErrIllegalOffset: http.StatusConflict,
ErrSizeExceeded: http.StatusRequestEntityTooLarge,
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ErrNotImplemented: http.StatusNotImplemented,
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ErrUploadNotFinished: http.StatusBadRequest,
ErrInvalidConcat: http.StatusBadRequest,
ErrModifyFinal: http.StatusForbidden,
}
type Config struct {
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// DataStore implementation used to store and retrieve the single uploads.
// Must no be nil.
DataStore DataStore
// MaxSize defines how many bytes may be stored in one single upload. If its
// value is is 0 or smaller no limit will be enforced.
MaxSize int64
// BasePath defines the URL path used for handling uploads, e.g. "/files/".
// If no trailing slash is presented it will be added. You may specify an
// absolute URL containing a scheme, e.g. "http://tus.io"
BasePath string
}
type Handler struct {
config Config
dataStore DataStore
isBasePathAbs bool
basePath string
routeHandler http.Handler
locks map[string]bool
}
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// Create a new handler using the given configuration.
func NewHandler(config Config) (*Handler, error) {
base := config.BasePath
uri, err := url.Parse(base)
if err != nil {
return nil, err
}
// Ensure base path ends with slash to remove logic from absFileUrl
if base != "" && string(base[len(base)-1]) != "/" {
base += "/"
}
// Ensure base path begins with slash if not absolute (starts with scheme)
if !uri.IsAbs() && len(base) > 0 && string(base[0]) != "/" {
base = "/" + base
}
mux := pat.New()
handler := &Handler{
config: config,
dataStore: config.DataStore,
basePath: base,
isBasePathAbs: uri.IsAbs(),
routeHandler: mux,
locks: make(map[string]bool),
}
mux.Post("", http.HandlerFunc(handler.postFile))
mux.Head(":id", http.HandlerFunc(handler.headFile))
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mux.Get(":id", http.HandlerFunc(handler.getFile))
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mux.Del(":id", http.HandlerFunc(handler.delFile))
mux.Add("PATCH", ":id", http.HandlerFunc(handler.patchFile))
return handler, nil
}
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// Implement the http.Handler interface.
func (handler *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
go logger.Println(r.Method, r.URL.Path)
header := w.Header()
if origin := r.Header.Get("Origin"); origin != "" {
header.Set("Access-Control-Allow-Origin", origin)
if r.Method == "OPTIONS" {
// Preflight request
header.Set("Access-Control-Allow-Methods", "POST, HEAD, PATCH, OPTIONS")
header.Set("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Entity-Length, Offset, TUS-Resumable, Metadata")
header.Set("Access-Control-Max-Age", "86400")
} else {
// Actual request
header.Set("Access-Control-Expose-Headers", "Offset, Location, Entity-Length, TUS-Version, TUS-Resumable, TUS-Max-Size, TUS-Extension, Metadata")
}
}
// Set current version used by the server
header.Set("TUS-Resumable", "1.0.0")
// 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", "file-creation,concatenation,termination")
w.WriteHeader(http.StatusNoContent)
return
}
// Test if the version sent by the client is supported
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// 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, ErrUnsupportedVersion)
return
}
// Proceed with routing the request
handler.routeHandler.ServeHTTP(w, r)
}
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// Create a new file upload using the datastore after validating the length
// and parsing the metadata.
func (handler *Handler) postFile(w http.ResponseWriter, r *http.Request) {
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// Parse Concat header
isPartial, isFinal, partialUploads, err := parseConcat(r.Header.Get("Concat"))
if err != nil {
handler.sendError(w, err)
return
}
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// 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
// Entity-Length header)
var size int64
if isFinal {
size, err = handler.sizeOfUploads(partialUploads)
if err != nil {
handler.sendError(w, err)
return
}
} else {
size, err = strconv.ParseInt(r.Header.Get("Entity-Length"), 10, 64)
if err != nil || size < 0 {
handler.sendError(w, ErrInvalidEntityLength)
return
}
}
// Test whether the size is still allowed
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if handler.config.MaxSize > 0 && size > handler.config.MaxSize {
handler.sendError(w, ErrMaxSizeExceeded)
return
}
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// Parse metadata
meta := parseMeta(r.Header.Get("Metadata"))
info := FileInfo{
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Size: size,
MetaData: meta,
IsPartial: isPartial,
IsFinal: isFinal,
PartialUploads: partialUploads,
}
id, err := handler.dataStore.NewUpload(info)
if err != nil {
handler.sendError(w, err)
return
}
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if isFinal {
if err := handler.fillFinalUpload(id, partialUploads); err != nil {
handler.sendError(w, err)
return
}
}
url := handler.absFileUrl(r, id)
w.Header().Set("Location", url)
w.WriteHeader(http.StatusCreated)
}
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// Returns the length and offset for the HEAD request
func (handler *Handler) headFile(w http.ResponseWriter, r *http.Request) {
id := r.URL.Query().Get(":id")
info, err := handler.dataStore.GetInfo(id)
if err != nil {
handler.sendError(w, err)
return
}
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// Add Concat header if possible
if info.IsPartial {
w.Header().Set("Concat", "partial")
}
if info.IsFinal {
v := "final;"
for _, uploadId := range info.PartialUploads {
v += " " + handler.absFileUrl(r, uploadId)
}
w.Header().Set("Concat", v)
}
if len(info.MetaData) != 0 {
w.Header().Set("Metadata", serializeMeta(info.MetaData))
}
w.Header().Set("Entity-Length", strconv.FormatInt(info.Size, 10))
w.Header().Set("Offset", strconv.FormatInt(info.Offset, 10))
w.WriteHeader(http.StatusNoContent)
}
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// Add a chunk to an upload. Only allowed if the upload is not locked and enough
// space is left.
func (handler *Handler) patchFile(w http.ResponseWriter, r *http.Request) {
id := r.URL.Query().Get(":id")
// Ensure file is not locked
if _, ok := handler.locks[id]; ok {
handler.sendError(w, ErrFileLocked)
return
}
// Lock file for further writes (heads are allowed)
handler.locks[id] = true
// File will be unlocked regardless of an error or success
defer func() {
delete(handler.locks, id)
}()
info, err := handler.dataStore.GetInfo(id)
if err != nil {
handler.sendError(w, err)
return
}
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// Modifying a final upload is not allowed
if info.IsFinal {
handler.sendError(w, ErrModifyFinal)
return
}
// Ensure the offsets match
offset, err := strconv.ParseInt(r.Header.Get("Offset"), 10, 64)
if err != nil {
handler.sendError(w, ErrInvalidOffset)
return
}
if offset != info.Offset {
handler.sendError(w, ErrIllegalOffset)
return
}
// Get Content-Length if possible
length := r.ContentLength
// Test if this upload fits into the file's size
if offset+length > info.Size {
handler.sendError(w, ErrSizeExceeded)
return
}
maxSize := info.Size - offset
if length > 0 {
maxSize = length
}
// Limit the
reader := io.LimitReader(r.Body, maxSize)
err = handler.dataStore.WriteChunk(id, offset, reader)
if err != nil {
handler.sendError(w, err)
return
}
w.WriteHeader(http.StatusNoContent)
}
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// Download a file using a GET request. This is not part of the specification.
func (handler *Handler) getFile(w http.ResponseWriter, r *http.Request) {
id := r.URL.Query().Get(":id")
// Ensure file is not locked
if _, ok := handler.locks[id]; ok {
handler.sendError(w, ErrFileLocked)
return
}
// Lock file for further writes (heads are allowed)
handler.locks[id] = true
// File will be unlocked regardless of an error or success
defer func() {
delete(handler.locks, id)
}()
info, err := handler.dataStore.GetInfo(id)
if err != nil {
handler.sendError(w, err)
return
}
// Do not do anything if no data is stored yet.
if info.Offset == 0 {
w.WriteHeader(http.StatusNoContent)
return
}
// Get reader
src, err := handler.dataStore.GetReader(id)
if err != nil {
handler.sendError(w, err)
return
}
w.Header().Set("Content-Length", strconv.FormatInt(info.Offset, 10))
w.WriteHeader(http.StatusOK)
io.Copy(w, src)
}
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// Terminate an upload permanently.
func (handler *Handler) delFile(w http.ResponseWriter, r *http.Request) {
id := r.URL.Query().Get(":id")
// Ensure file is not locked
if _, ok := handler.locks[id]; ok {
handler.sendError(w, ErrFileLocked)
return
}
// Lock file for further writes (heads are allowed)
handler.locks[id] = true
// File will be unlocked regardless of an error or success
defer func() {
delete(handler.locks, id)
}()
err := handler.dataStore.Terminate(id)
if err != nil {
handler.sendError(w, err)
return
}
w.WriteHeader(http.StatusNoContent)
}
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// 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 *Handler) sendError(w http.ResponseWriter, err error) {
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// Interpret os.ErrNotExist as 404 Not Found
if os.IsNotExist(err) {
err = ErrNotFound
}
status, ok := ErrStatusCodes[err]
if !ok {
status = 500
}
w.Header().Set("Content-Type", "text/plain")
w.WriteHeader(status)
w.Write([]byte(err.Error() + "\n"))
}
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// 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 *Handler) absFileUrl(r *http.Request, id string) string {
if handler.isBasePathAbs {
return handler.basePath + id
}
// Read origin and protocol from request
url := "http://"
if r.TLS != nil {
url = "https://"
}
url += r.Host + handler.basePath + id
return url
}
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// 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 *Handler) sizeOfUploads(ids []string) (size int64, err error) {
for _, id := range ids {
info, err := handler.dataStore.GetInfo(id)
if err != nil {
return size, err
}
if info.Offset != info.Size {
err = ErrUploadNotFinished
return size, err
}
size += info.Size
}
return
}
// Fill an empty upload with the content of the uploads by their ids. The data
// will be written in the order as they appear in the slice
func (handler *Handler) fillFinalUpload(id string, uploads []string) error {
readers := make([]io.Reader, len(uploads))
for index, uploadId := range uploads {
reader, err := handler.dataStore.GetReader(uploadId)
if err != nil {
return err
}
readers[index] = reader
}
reader := io.MultiReader(readers...)
return handler.dataStore.WriteChunk(id, 0, reader)
}
// Parse the Metadata header as defined in the File Creation extension.
// e.g. Metadata: name bHVucmpzLnBuZw==,type aW1hZ2UvcG5n
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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
}
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// Serialize a map of strings into the Metadata header format used in the
// response for HEAD requests.
// e.g. 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
}
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// Parse the Concat header, e.g.
// Concat: partial
// 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
}
// Extract ids out of URL
result := reExtractFileId.FindStringSubmatch(value)
if len(result) != 2 {
err = ErrInvalidConcat
return
}
partialUploads = append(partialUploads, result[1])
}
}
// If no valid partial upload ids are extracted this is not a final upload.
if len(partialUploads) == 0 {
isFinal = false
err = ErrInvalidConcat
}
return
}