diff options
| -rw-r--r-- | errors.go | 3 | ||||
| -rw-r--r-- | object.go | 92 | ||||
| -rw-r--r-- | object_test.go | 2 |
3 files changed, 91 insertions, 6 deletions
@@ -27,6 +27,9 @@ import ( ) var ( + //ErrChecksumMismatch is returned by Object.Upload() when the Etag in the + //server response does not match the uploaded data. + ErrChecksumMismatch = errors.New("Etag on uploaded object does not match MD5 checksum of uploaded data") //ErrNoContainerName is returned by Request.Do() if ObjectName is given, but //ContainerName is empty. ErrNoContainerName = errors.New("missing container name") @@ -19,6 +19,10 @@ package schwift import ( + "bytes" + "crypto/md5" + "encoding/hex" + "hash" "io" "net/http" ) @@ -132,12 +136,47 @@ func (o *Object) Update(headers ObjectHeaders, opts *RequestOptions) error { //Upload creates the object using a PUT request. To add URL parameters, pass //a non-nil *RequestOptions. // +//If you do not have an io.Reader, but you have a []byte or string instance +//containing the object, wrap it in a *bytes.Reader instance like so: +// +// var buffer []byte +// o.Upload(bytes.NewReader(buffer), headers, opts) +// +// //or... +// var buffer string +// o.Upload(bytes.NewReader([]byte(buffer)), headers, opts) +// +//If content is a *bytes.Reader or a *bytes.Buffer instance, the Content-Length +//and Etag request headers will be computed automatically. Otherwise, it is +//highly recommended that the caller set these headers (if possible) to allow +//the server to check the integrity of the uploaded file. +// +//If Etag and/or Content-Length is supplied and the content does not match +//these parameters, http.StatusUnprocessableEntity is returned. If Etag is not +//supplied and cannot be computed in advance, Upload() will compute the Etag as +//data is read from the io.Reader, and compare the result to the Etag returned +//by Swift, returning ErrChecksumMismatch in case of mismatch. +// //This function can be used regardless of whether the object exists or not. // //A successful PUT request implies Invalidate() since it may change metadata. func (o *Object) Upload(content io.Reader, headers ObjectHeaders, opts *RequestOptions) error { - //TODO check hash - _, err := Request{ + if headers == nil { + headers = make(ObjectHeaders) + } + tryComputeContentLength(content, headers) + tryComputeEtag(content, headers) + + //could not compute Etag in advance -> need to check on the fly + var hasher hash.Hash + if !headers.Etag().Exists() { + hasher = md5.New() + if content != nil { + content = io.TeeReader(content, hasher) + } + } + + resp, err := Request{ Method: "PUT", ContainerName: o.c.name, ObjectName: o.name, @@ -147,10 +186,53 @@ func (o *Object) Upload(content io.Reader, headers ObjectHeaders, opts *RequestO ExpectStatusCodes: []int{201}, DrainResponseBody: true, }.Do(o.c.a.client) - if err == nil { - o.Invalidate() + if err != nil { + return err + } + o.Invalidate() + + if hasher != nil { + expectedEtag := hex.EncodeToString(hasher.Sum(nil)) + if expectedEtag != resp.Header.Get("Etag") { + return ErrChecksumMismatch + } + } + + return nil +} + +func tryComputeContentLength(content io.Reader, headers ObjectHeaders) { + h := headers.SizeBytes() + if h.Exists() { + return + } + switch r := content.(type) { + case *bytes.Buffer: + h.Set(uint64(r.Len())) + case *bytes.Reader: + h.Set(uint64(r.Len())) + } +} + +func tryComputeEtag(content io.Reader, headers ObjectHeaders) { + h := headers.Etag() + if h.Exists() { + return + } + switch r := content.(type) { + case *bytes.Buffer: + //bytes.Buffer has a method that returns the unread portion of the buffer, + //so this one is easy + sum := md5.Sum(r.Bytes()) + h.Set(hex.EncodeToString(sum[:])) + case *bytes.Reader: + //bytes.Reader does not have such a method, but it is an io.Seeker, so we + //can read the entire thing and then seek back to where we started + hash := md5.New() + n, _ := r.WriteTo(hash) + r.Seek(-n, io.SeekCurrent) + h.Set(hex.EncodeToString(hash.Sum(nil))) } - return err } //Delete deletes the object using a DELETE request. To add URL parameters, diff --git a/object_test.go b/object_test.go index fd47f95..967859d 100644 --- a/object_test.go +++ b/object_test.go @@ -39,7 +39,7 @@ func TestObjectLifecycle(t *testing.T) { expectBool(t, exists, false) _, err = o.Headers() - expectError(t, err, "expected 204 response, got 404 instead") + expectError(t, err, "expected 200 response, got 404 instead") expectBool(t, Is(err, http.StatusNotFound), true) expectBool(t, Is(err, http.StatusNoContent), false) |