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mime/multipart: add a multipart Writer
Fixes #1823 R=golang-dev, adg, robert.hencke CC=golang-dev https://golang.org/cl/4530054
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@@ -8,5 +8,6 @@ TARG=mime/multipart | |
GOFILES=\ | ||
formdata.go\ | ||
multipart.go\ | ||
writer.go\ | ||
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include ../../../Make.pkg |
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@@ -0,0 +1,160 @@ | ||
// Copyright 2011 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. | ||
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package multipart | ||
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import ( | ||
"bytes" | ||
"fmt" | ||
"io" | ||
"net/textproto" | ||
"os" | ||
"rand" | ||
"strings" | ||
) | ||
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// Writer is used to generate multipart messages. | ||
type Writer struct { | ||
// Boundary is the random boundary string between | ||
// parts. NewWriter will generate this but it must | ||
// not be changed after a part has been created. | ||
// Setting this to an invalid value will generate | ||
// malformed messages. | ||
Boundary string | ||
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w io.Writer | ||
lastpart *part | ||
} | ||
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// NewWriter returns a new multipart Writer with a random boundary, | ||
// writing to w. | ||
func NewWriter(w io.Writer) *Writer { | ||
return &Writer{ | ||
w: w, | ||
Boundary: randomBoundary(), | ||
} | ||
} | ||
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// FormDataContentType returns the Content-Type for an HTTP | ||
// multipart/form-data with this Writer's Boundary. | ||
func (w *Writer) FormDataContentType() string { | ||
return "multipart/form-data; boundary=" + w.Boundary | ||
} | ||
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const randChars = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ" | ||
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func randomBoundary() string { | ||
var buf [60]byte | ||
for i := range buf { | ||
buf[i] = randChars[rand.Intn(len(randChars))] | ||
} | ||
return string(buf[:]) | ||
} | ||
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// CreatePart creates a new multipart section with the provided | ||
// header. The previous part, if still open, is closed. The body of | ||
// the part should be written to the returned WriteCloser. Closing the | ||
// returned WriteCloser after writing is optional. | ||
func (w *Writer) CreatePart(header textproto.MIMEHeader) (io.WriteCloser, os.Error) { | ||
if w.lastpart != nil { | ||
if err := w.lastpart.Close(); err != nil { | ||
return nil, err | ||
} | ||
} | ||
var b bytes.Buffer | ||
fmt.Fprintf(&b, "\r\n--%s\r\n", w.Boundary) | ||
// TODO(bradfitz): move this to textproto.MimeHeader.Write(w), have it sort | ||
// and clean, like http.Header.Write(w) does. | ||
for k, vv := range header { | ||
for _, v := range vv { | ||
fmt.Fprintf(&b, "%s: %s\r\n", k, v) | ||
} | ||
} | ||
fmt.Fprintf(&b, "\r\n") | ||
_, err := io.Copy(w.w, &b) | ||
if err != nil { | ||
return nil, err | ||
} | ||
p := &part{ | ||
mw: w, | ||
} | ||
w.lastpart = p | ||
return p, nil | ||
} | ||
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func escapeQuotes(s string) string { | ||
s = strings.Replace(s, "\\", "\\\\", -1) | ||
s = strings.Replace(s, "\"", "\\\"", -1) | ||
return s | ||
} | ||
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// CreateFormFile is a convenience wrapper around CreatePart. It creates | ||
// a new form-data header with the provided field name and file name. | ||
func (w *Writer) CreateFormFile(fieldname, filename string) (io.WriteCloser, os.Error) { | ||
h := make(textproto.MIMEHeader) | ||
h.Set("Content-Disposition", | ||
fmt.Sprintf(`form-data; name="%s"; filename="%s"`, | ||
escapeQuotes(fieldname), escapeQuotes(filename))) | ||
h.Set("Content-Type", "application/octet-stream") | ||
return w.CreatePart(h) | ||
} | ||
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// CreateFormField is a convenience wrapper around CreatePart. It creates | ||
// a new form-data header with the provided field name. | ||
func (w *Writer) CreateFormField(fieldname string) (io.WriteCloser, os.Error) { | ||
h := make(textproto.MIMEHeader) | ||
h.Set("Content-Disposition", | ||
fmt.Sprintf(`form-data; name="%s"`, escapeQuotes(fieldname))) | ||
return w.CreatePart(h) | ||
} | ||
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// WriteField is a convenience wrapper around CreateFormField. It creates and | ||
// writes a part with the provided name and value. | ||
func (w *Writer) WriteField(fieldname, value string) os.Error { | ||
p, err := w.CreateFormField(fieldname) | ||
if err != nil { | ||
return err | ||
} | ||
_, err = p.Write([]byte(value)) | ||
if err != nil { | ||
return err | ||
} | ||
return p.Close() | ||
} | ||
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// Close finishes the multipart message. It closes the previous part, | ||
// if still open, and writes the trailing boundary end line to the | ||
// output. | ||
func (w *Writer) Close() os.Error { | ||
if w.lastpart != nil { | ||
if err := w.lastpart.Close(); err != nil { | ||
return err | ||
} | ||
w.lastpart = nil | ||
} | ||
_, err := fmt.Fprintf(w.w, "\r\n--%s--\r\n", w.Boundary) | ||
return err | ||
} | ||
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type part struct { | ||
mw *Writer | ||
closed bool | ||
we os.Error // last error that occurred writing | ||
} | ||
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func (p *part) Close() os.Error { | ||
p.closed = true | ||
return p.we | ||
} | ||
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func (p *part) Write(d []byte) (n int, err os.Error) { | ||
if p.closed { | ||
return 0, os.NewError("multipart: Write after Close") | ||
} | ||
n, err = p.mw.w.Write(d) | ||
if err != nil { | ||
p.we = err | ||
} | ||
return | ||
} |
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// Copyright 2011 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. | ||
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package multipart | ||
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import ( | ||
"bytes" | ||
"io/ioutil" | ||
"testing" | ||
) | ||
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func TestWriter(t *testing.T) { | ||
fileContents := []byte("my file contents") | ||
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var b bytes.Buffer | ||
w := NewWriter(&b) | ||
{ | ||
part, err := w.CreateFormFile("myfile", "my-file.txt") | ||
if err != nil { | ||
t.Fatalf("CreateFormFile: %v", err) | ||
} | ||
part.Write(fileContents) | ||
err = w.WriteField("key", "val") | ||
if err != nil { | ||
t.Fatalf("CreateFormFieldValue: %v", err) | ||
} | ||
part.Write([]byte("val")) | ||
err = w.Close() | ||
if err != nil { | ||
t.Fatalf("Close: %v", err) | ||
} | ||
} | ||
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r := NewReader(&b, w.Boundary) | ||
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part, err := r.NextPart() | ||
if err != nil { | ||
t.Fatalf("part 1: %v", err) | ||
} | ||
if g, e := part.FormName(), "myfile"; g != e { | ||
t.Errorf("part 1: want form name %q, got %q", e, g) | ||
} | ||
slurp, err := ioutil.ReadAll(part) | ||
if err != nil { | ||
t.Fatalf("part 1: ReadAll: %v", err) | ||
} | ||
if e, g := string(fileContents), string(slurp); e != g { | ||
t.Errorf("part 1: want contents %q, got %q", e, g) | ||
} | ||
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part, err = r.NextPart() | ||
if err != nil { | ||
t.Fatalf("part 2: %v", err) | ||
} | ||
if g, e := part.FormName(), "key"; g != e { | ||
t.Errorf("part 2: want form name %q, got %q", e, g) | ||
} | ||
slurp, err = ioutil.ReadAll(part) | ||
if err != nil { | ||
t.Fatalf("part 2: ReadAll: %v", err) | ||
} | ||
if e, g := "val", string(slurp); e != g { | ||
t.Errorf("part 2: want contents %q, got %q", e, g) | ||
} | ||
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part, err = r.NextPart() | ||
if part != nil || err == nil { | ||
t.Fatalf("expected end of parts; got %v, %v", part, err) | ||
} | ||
} |