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Diffstat (limited to 'vendor/google.golang.org/api/gensupport/resumable.go')
-rw-r--r-- | vendor/google.golang.org/api/gensupport/resumable.go | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/vendor/google.golang.org/api/gensupport/resumable.go b/vendor/google.golang.org/api/gensupport/resumable.go new file mode 100644 index 000000000..2552a6aca --- /dev/null +++ b/vendor/google.golang.org/api/gensupport/resumable.go @@ -0,0 +1,216 @@ +// Copyright 2016 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package gensupport + +import ( + "context" + "errors" + "fmt" + "io" + "net/http" + "sync" + "time" +) + +const ( + // statusTooManyRequests is returned by the storage API if the + // per-project limits have been temporarily exceeded. The request + // should be retried. + // https://cloud.google.com/storage/docs/json_api/v1/status-codes#standardcodes + statusTooManyRequests = 429 +) + +// ResumableUpload is used by the generated APIs to provide resumable uploads. +// It is not used by developers directly. +type ResumableUpload struct { + Client *http.Client + // URI is the resumable resource destination provided by the server after specifying "&uploadType=resumable". + URI string + UserAgent string // User-Agent for header of the request + // Media is the object being uploaded. + Media *MediaBuffer + // MediaType defines the media type, e.g. "image/jpeg". + MediaType string + + mu sync.Mutex // guards progress + progress int64 // number of bytes uploaded so far + + // Callback is an optional function that will be periodically called with the cumulative number of bytes uploaded. + Callback func(int64) + + // If not specified, a default exponential backoff strategy will be used. + Backoff BackoffStrategy +} + +// Progress returns the number of bytes uploaded at this point. +func (rx *ResumableUpload) Progress() int64 { + rx.mu.Lock() + defer rx.mu.Unlock() + return rx.progress +} + +// doUploadRequest performs a single HTTP request to upload data. +// off specifies the offset in rx.Media from which data is drawn. +// size is the number of bytes in data. +// final specifies whether data is the final chunk to be uploaded. +func (rx *ResumableUpload) doUploadRequest(ctx context.Context, data io.Reader, off, size int64, final bool) (*http.Response, error) { + req, err := http.NewRequest("POST", rx.URI, data) + if err != nil { + return nil, err + } + + req.ContentLength = size + var contentRange string + if final { + if size == 0 { + contentRange = fmt.Sprintf("bytes */%v", off) + } else { + contentRange = fmt.Sprintf("bytes %v-%v/%v", off, off+size-1, off+size) + } + } else { + contentRange = fmt.Sprintf("bytes %v-%v/*", off, off+size-1) + } + req.Header.Set("Content-Range", contentRange) + req.Header.Set("Content-Type", rx.MediaType) + req.Header.Set("User-Agent", rx.UserAgent) + + // Google's upload endpoint uses status code 308 for a + // different purpose than the "308 Permanent Redirect" + // since-standardized in RFC 7238. Because of the conflict in + // semantics, Google added this new request header which + // causes it to not use "308" and instead reply with 200 OK + // and sets the upload-specific "X-HTTP-Status-Code-Override: + // 308" response header. + req.Header.Set("X-GUploader-No-308", "yes") + + return SendRequest(ctx, rx.Client, req) +} + +func statusResumeIncomplete(resp *http.Response) bool { + // This is how the server signals "status resume incomplete" + // when X-GUploader-No-308 is set to "yes": + return resp != nil && resp.Header.Get("X-Http-Status-Code-Override") == "308" +} + +// reportProgress calls a user-supplied callback to report upload progress. +// If old==updated, the callback is not called. +func (rx *ResumableUpload) reportProgress(old, updated int64) { + if updated-old == 0 { + return + } + rx.mu.Lock() + rx.progress = updated + rx.mu.Unlock() + if rx.Callback != nil { + rx.Callback(updated) + } +} + +// transferChunk performs a single HTTP request to upload a single chunk from rx.Media. +func (rx *ResumableUpload) transferChunk(ctx context.Context) (*http.Response, error) { + chunk, off, size, err := rx.Media.Chunk() + + done := err == io.EOF + if !done && err != nil { + return nil, err + } + + res, err := rx.doUploadRequest(ctx, chunk, off, int64(size), done) + if err != nil { + return res, err + } + + // We sent "X-GUploader-No-308: yes" (see comment elsewhere in + // this file), so we don't expect to get a 308. + if res.StatusCode == 308 { + return nil, errors.New("unexpected 308 response status code") + } + + if res.StatusCode == http.StatusOK { + rx.reportProgress(off, off+int64(size)) + } + + if statusResumeIncomplete(res) { + rx.Media.Next() + } + return res, nil +} + +func contextDone(ctx context.Context) bool { + select { + case <-ctx.Done(): + return true + default: + return false + } +} + +// Upload starts the process of a resumable upload with a cancellable context. +// It retries using the provided back off strategy until cancelled or the +// strategy indicates to stop retrying. +// It is called from the auto-generated API code and is not visible to the user. +// Before sending an HTTP request, Upload calls any registered hook functions, +// and calls the returned functions after the request returns (see send.go). +// rx is private to the auto-generated API code. +// Exactly one of resp or err will be nil. If resp is non-nil, the caller must call resp.Body.Close. +func (rx *ResumableUpload) Upload(ctx context.Context) (resp *http.Response, err error) { + var pause time.Duration + backoff := rx.Backoff + if backoff == nil { + backoff = DefaultBackoffStrategy() + } + + for { + // Ensure that we return in the case of cancelled context, even if pause is 0. + if contextDone(ctx) { + return nil, ctx.Err() + } + select { + case <-ctx.Done(): + return nil, ctx.Err() + case <-time.After(pause): + } + + resp, err = rx.transferChunk(ctx) + + var status int + if resp != nil { + status = resp.StatusCode + } + + // Check if we should retry the request. + if shouldRetry(status, err) { + var retry bool + pause, retry = backoff.Pause() + if retry { + if resp != nil && resp.Body != nil { + resp.Body.Close() + } + continue + } + } + + // If the chunk was uploaded successfully, but there's still + // more to go, upload the next chunk without any delay. + if statusResumeIncomplete(resp) { + pause = 0 + backoff.Reset() + resp.Body.Close() + continue + } + + // It's possible for err and resp to both be non-nil here, but we expose a simpler + // contract to our callers: exactly one of resp and err will be non-nil. This means + // that any response body must be closed here before returning a non-nil error. + if err != nil { + if resp != nil && resp.Body != nil { + resp.Body.Close() + } + return nil, err + } + + return resp, nil + } +} |