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406 lines
12 KiB
406 lines
12 KiB
// Copyright 2011 Google Inc. All rights reserved. |
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// Use of this source code is governed by a BSD-style |
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// license that can be found in the LICENSE file. |
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// Package googleapi contains the common code shared by all Google API |
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// libraries. |
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package googleapi // import "google.golang.org/api/googleapi" |
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import ( |
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"bytes" |
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"encoding/json" |
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"fmt" |
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"io" |
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"io/ioutil" |
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"net/http" |
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"net/url" |
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"strings" |
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"google.golang.org/api/googleapi/internal/uritemplates" |
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) |
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// ContentTyper is an interface for Readers which know (or would like |
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// to override) their Content-Type. If a media body doesn't implement |
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// ContentTyper, the type is sniffed from the content using |
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// http.DetectContentType. |
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type ContentTyper interface { |
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ContentType() string |
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} |
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// A SizeReaderAt is a ReaderAt with a Size method. |
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// An io.SectionReader implements SizeReaderAt. |
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type SizeReaderAt interface { |
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io.ReaderAt |
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Size() int64 |
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} |
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// ServerResponse is embedded in each Do response and |
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// provides the HTTP status code and header sent by the server. |
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type ServerResponse struct { |
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// HTTPStatusCode is the server's response status code. |
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// When using a resource method's Do call, this will always be in the 2xx range. |
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HTTPStatusCode int |
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// Header contains the response header fields from the server. |
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Header http.Header |
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} |
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const ( |
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Version = "0.5" |
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// UserAgent is the header string used to identify this package. |
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UserAgent = "google-api-go-client/" + Version |
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// The default chunk size to use for resumable uploads if not specified by the user. |
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DefaultUploadChunkSize = 8 * 1024 * 1024 |
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// The minimum chunk size that can be used for resumable uploads. All |
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// user-specified chunk sizes must be multiple of this value. |
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MinUploadChunkSize = 256 * 1024 |
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) |
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// Error contains an error response from the server. |
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type Error struct { |
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// Code is the HTTP response status code and will always be populated. |
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Code int `json:"code"` |
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// Message is the server response message and is only populated when |
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// explicitly referenced by the JSON server response. |
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Message string `json:"message"` |
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// Body is the raw response returned by the server. |
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// It is often but not always JSON, depending on how the request fails. |
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Body string |
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// Header contains the response header fields from the server. |
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Header http.Header |
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Errors []ErrorItem |
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} |
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// ErrorItem is a detailed error code & message from the Google API frontend. |
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type ErrorItem struct { |
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// Reason is the typed error code. For example: "some_example". |
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Reason string `json:"reason"` |
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// Message is the human-readable description of the error. |
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Message string `json:"message"` |
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} |
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func (e *Error) Error() string { |
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if len(e.Errors) == 0 && e.Message == "" { |
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return fmt.Sprintf("googleapi: got HTTP response code %d with body: %v", e.Code, e.Body) |
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} |
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var buf bytes.Buffer |
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fmt.Fprintf(&buf, "googleapi: Error %d: ", e.Code) |
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if e.Message != "" { |
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fmt.Fprintf(&buf, "%s", e.Message) |
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} |
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if len(e.Errors) == 0 { |
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return strings.TrimSpace(buf.String()) |
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} |
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if len(e.Errors) == 1 && e.Errors[0].Message == e.Message { |
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fmt.Fprintf(&buf, ", %s", e.Errors[0].Reason) |
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return buf.String() |
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} |
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fmt.Fprintln(&buf, "\nMore details:") |
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for _, v := range e.Errors { |
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fmt.Fprintf(&buf, "Reason: %s, Message: %s\n", v.Reason, v.Message) |
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} |
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return buf.String() |
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} |
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type errorReply struct { |
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Error *Error `json:"error"` |
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} |
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// CheckResponse returns an error (of type *Error) if the response |
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// status code is not 2xx. |
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func CheckResponse(res *http.Response) error { |
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if res.StatusCode >= 200 && res.StatusCode <= 299 { |
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return nil |
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} |
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slurp, err := ioutil.ReadAll(res.Body) |
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if err == nil { |
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jerr := new(errorReply) |
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err = json.Unmarshal(slurp, jerr) |
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if err == nil && jerr.Error != nil { |
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if jerr.Error.Code == 0 { |
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jerr.Error.Code = res.StatusCode |
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} |
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jerr.Error.Body = string(slurp) |
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return jerr.Error |
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} |
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} |
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return &Error{ |
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Code: res.StatusCode, |
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Body: string(slurp), |
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Header: res.Header, |
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} |
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} |
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// IsNotModified reports whether err is the result of the |
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// server replying with http.StatusNotModified. |
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// Such error values are sometimes returned by "Do" methods |
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// on calls when If-None-Match is used. |
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func IsNotModified(err error) bool { |
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if err == nil { |
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return false |
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} |
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ae, ok := err.(*Error) |
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return ok && ae.Code == http.StatusNotModified |
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} |
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// CheckMediaResponse returns an error (of type *Error) if the response |
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// status code is not 2xx. Unlike CheckResponse it does not assume the |
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// body is a JSON error document. |
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// It is the caller's responsibility to close res.Body. |
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func CheckMediaResponse(res *http.Response) error { |
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if res.StatusCode >= 200 && res.StatusCode <= 299 { |
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return nil |
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} |
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slurp, _ := ioutil.ReadAll(io.LimitReader(res.Body, 1<<20)) |
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return &Error{ |
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Code: res.StatusCode, |
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Body: string(slurp), |
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} |
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} |
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type MarshalStyle bool |
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var WithDataWrapper = MarshalStyle(true) |
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var WithoutDataWrapper = MarshalStyle(false) |
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func (wrap MarshalStyle) JSONReader(v interface{}) (io.Reader, error) { |
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buf := new(bytes.Buffer) |
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if wrap { |
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buf.Write([]byte(`{"data": `)) |
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} |
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err := json.NewEncoder(buf).Encode(v) |
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if err != nil { |
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return nil, err |
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} |
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if wrap { |
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buf.Write([]byte(`}`)) |
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} |
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return buf, nil |
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} |
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// endingWithErrorReader from r until it returns an error. If the |
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// final error from r is io.EOF and e is non-nil, e is used instead. |
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type endingWithErrorReader struct { |
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r io.Reader |
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e error |
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} |
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func (er endingWithErrorReader) Read(p []byte) (n int, err error) { |
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n, err = er.r.Read(p) |
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if err == io.EOF && er.e != nil { |
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err = er.e |
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} |
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return |
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} |
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// countingWriter counts the number of bytes it receives to write, but |
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// discards them. |
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type countingWriter struct { |
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n *int64 |
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} |
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func (w countingWriter) Write(p []byte) (int, error) { |
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*w.n += int64(len(p)) |
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return len(p), nil |
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} |
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// ProgressUpdater is a function that is called upon every progress update of a resumable upload. |
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// This is the only part of a resumable upload (from googleapi) that is usable by the developer. |
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// The remaining usable pieces of resumable uploads is exposed in each auto-generated API. |
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type ProgressUpdater func(current, total int64) |
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type MediaOption interface { |
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setOptions(o *MediaOptions) |
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} |
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type contentTypeOption string |
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func (ct contentTypeOption) setOptions(o *MediaOptions) { |
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o.ContentType = string(ct) |
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if o.ContentType == "" { |
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o.ForceEmptyContentType = true |
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} |
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} |
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// ContentType returns a MediaOption which sets the Content-Type header for media uploads. |
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// If ctype is empty, the Content-Type header will be omitted. |
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func ContentType(ctype string) MediaOption { |
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return contentTypeOption(ctype) |
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} |
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type chunkSizeOption int |
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func (cs chunkSizeOption) setOptions(o *MediaOptions) { |
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size := int(cs) |
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if size%MinUploadChunkSize != 0 { |
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size += MinUploadChunkSize - (size % MinUploadChunkSize) |
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} |
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o.ChunkSize = size |
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} |
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// ChunkSize returns a MediaOption which sets the chunk size for media uploads. |
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// size will be rounded up to the nearest multiple of 256K. |
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// Media which contains fewer than size bytes will be uploaded in a single request. |
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// Media which contains size bytes or more will be uploaded in separate chunks. |
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// If size is zero, media will be uploaded in a single request. |
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func ChunkSize(size int) MediaOption { |
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return chunkSizeOption(size) |
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} |
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// MediaOptions stores options for customizing media upload. It is not used by developers directly. |
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type MediaOptions struct { |
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ContentType string |
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ForceEmptyContentType bool |
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ChunkSize int |
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} |
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// ProcessMediaOptions stores options from opts in a MediaOptions. |
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// It is not used by developers directly. |
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func ProcessMediaOptions(opts []MediaOption) *MediaOptions { |
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mo := &MediaOptions{ChunkSize: DefaultUploadChunkSize} |
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for _, o := range opts { |
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o.setOptions(mo) |
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} |
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return mo |
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} |
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func ResolveRelative(basestr, relstr string) string { |
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u, _ := url.Parse(basestr) |
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rel, _ := url.Parse(relstr) |
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u = u.ResolveReference(rel) |
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us := u.String() |
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us = strings.Replace(us, "%7B", "{", -1) |
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us = strings.Replace(us, "%7D", "}", -1) |
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return us |
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} |
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// Expand subsitutes any {encoded} strings in the URL passed in using |
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// the map supplied. |
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// |
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// This calls SetOpaque to avoid encoding of the parameters in the URL path. |
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func Expand(u *url.URL, expansions map[string]string) { |
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escaped, unescaped, err := uritemplates.Expand(u.Path, expansions) |
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if err == nil { |
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u.Path = unescaped |
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u.RawPath = escaped |
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} |
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} |
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// CloseBody is used to close res.Body. |
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// Prior to calling Close, it also tries to Read a small amount to see an EOF. |
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// Not seeing an EOF can prevent HTTP Transports from reusing connections. |
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func CloseBody(res *http.Response) { |
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if res == nil || res.Body == nil { |
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return |
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} |
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// Justification for 3 byte reads: two for up to "\r\n" after |
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// a JSON/XML document, and then 1 to see EOF if we haven't yet. |
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// TODO(bradfitz): detect Go 1.3+ and skip these reads. |
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// See https://codereview.appspot.com/58240043 |
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// and https://codereview.appspot.com/49570044 |
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buf := make([]byte, 1) |
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for i := 0; i < 3; i++ { |
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_, err := res.Body.Read(buf) |
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if err != nil { |
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break |
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} |
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} |
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res.Body.Close() |
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} |
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// VariantType returns the type name of the given variant. |
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// If the map doesn't contain the named key or the value is not a []interface{}, "" is returned. |
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// This is used to support "variant" APIs that can return one of a number of different types. |
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func VariantType(t map[string]interface{}) string { |
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s, _ := t["type"].(string) |
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return s |
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} |
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// ConvertVariant uses the JSON encoder/decoder to fill in the struct 'dst' with the fields found in variant 'v'. |
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// This is used to support "variant" APIs that can return one of a number of different types. |
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// It reports whether the conversion was successful. |
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func ConvertVariant(v map[string]interface{}, dst interface{}) bool { |
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var buf bytes.Buffer |
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err := json.NewEncoder(&buf).Encode(v) |
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if err != nil { |
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return false |
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} |
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return json.Unmarshal(buf.Bytes(), dst) == nil |
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} |
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// A Field names a field to be retrieved with a partial response. |
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// See https://developers.google.com/gdata/docs/2.0/basics#PartialResponse |
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// |
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// Partial responses can dramatically reduce the amount of data that must be sent to your application. |
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// In order to request partial responses, you can specify the full list of fields |
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// that your application needs by adding the Fields option to your request. |
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// |
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// Field strings use camelCase with leading lower-case characters to identify fields within the response. |
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// |
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// For example, if your response has a "NextPageToken" and a slice of "Items" with "Id" fields, |
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// you could request just those fields like this: |
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// |
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// svc.Events.List().Fields("nextPageToken", "items/id").Do() |
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// |
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// or if you were also interested in each Item's "Updated" field, you can combine them like this: |
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// |
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// svc.Events.List().Fields("nextPageToken", "items(id,updated)").Do() |
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// |
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// More information about field formatting can be found here: |
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// https://developers.google.com/+/api/#fields-syntax |
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// |
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// Another way to find field names is through the Google API explorer: |
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// https://developers.google.com/apis-explorer/#p/ |
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type Field string |
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// CombineFields combines fields into a single string. |
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func CombineFields(s []Field) string { |
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r := make([]string, len(s)) |
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for i, v := range s { |
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r[i] = string(v) |
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} |
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return strings.Join(r, ",") |
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} |
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// A CallOption is an optional argument to an API call. |
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// It should be treated as an opaque value by users of Google APIs. |
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// |
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// A CallOption is something that configures an API call in a way that is |
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// not specific to that API; for instance, controlling the quota user for |
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// an API call is common across many APIs, and is thus a CallOption. |
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type CallOption interface { |
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Get() (key, value string) |
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} |
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// QuotaUser returns a CallOption that will set the quota user for a call. |
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// The quota user can be used by server-side applications to control accounting. |
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// It can be an arbitrary string up to 40 characters, and will override UserIP |
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// if both are provided. |
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func QuotaUser(u string) CallOption { return quotaUser(u) } |
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type quotaUser string |
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func (q quotaUser) Get() (string, string) { return "quotaUser", string(q) } |
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// UserIP returns a CallOption that will set the "userIp" parameter of a call. |
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// This should be the IP address of the originating request. |
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func UserIP(ip string) CallOption { return userIP(ip) } |
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type userIP string |
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func (i userIP) Get() (string, string) { return "userIp", string(i) } |
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// Trace returns a CallOption that enables diagnostic tracing for a call. |
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// traceToken is an ID supplied by Google support. |
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func Trace(traceToken string) CallOption { return traceTok(traceToken) } |
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type traceTok string |
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func (t traceTok) Get() (string, string) { return "trace", "token:" + string(t) } |
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// TODO: Fields too
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