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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-28 13:15:26 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-28 13:15:26 +0000 |
commit | 82539ad8d59729fb45b0bb0edda8f2bddb719eb1 (patch) | |
tree | 58f0b58e6f44f0e04d4a6373132cf426fa835fa7 /src/mime/multipart/writer.go | |
parent | Initial commit. (diff) | |
download | golang-1.17-82539ad8d59729fb45b0bb0edda8f2bddb719eb1.tar.xz golang-1.17-82539ad8d59729fb45b0bb0edda8f2bddb719eb1.zip |
Adding upstream version 1.17.13.upstream/1.17.13upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/mime/multipart/writer.go')
-rw-r--r-- | src/mime/multipart/writer.go | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/src/mime/multipart/writer.go b/src/mime/multipart/writer.go new file mode 100644 index 0000000..d1ff151 --- /dev/null +++ b/src/mime/multipart/writer.go @@ -0,0 +1,201 @@ +// 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. + +package multipart + +import ( + "bytes" + "crypto/rand" + "errors" + "fmt" + "io" + "net/textproto" + "sort" + "strings" +) + +// A Writer generates multipart messages. +type Writer struct { + w io.Writer + boundary string + lastpart *part +} + +// 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(), + } +} + +// Boundary returns the Writer's boundary. +func (w *Writer) Boundary() string { + return w.boundary +} + +// SetBoundary overrides the Writer's default randomly-generated +// boundary separator with an explicit value. +// +// SetBoundary must be called before any parts are created, may only +// contain certain ASCII characters, and must be non-empty and +// at most 70 bytes long. +func (w *Writer) SetBoundary(boundary string) error { + if w.lastpart != nil { + return errors.New("mime: SetBoundary called after write") + } + // rfc2046#section-5.1.1 + if len(boundary) < 1 || len(boundary) > 70 { + return errors.New("mime: invalid boundary length") + } + end := len(boundary) - 1 + for i, b := range boundary { + if 'A' <= b && b <= 'Z' || 'a' <= b && b <= 'z' || '0' <= b && b <= '9' { + continue + } + switch b { + case '\'', '(', ')', '+', '_', ',', '-', '.', '/', ':', '=', '?': + continue + case ' ': + if i != end { + continue + } + } + return errors.New("mime: invalid boundary character") + } + w.boundary = boundary + return nil +} + +// FormDataContentType returns the Content-Type for an HTTP +// multipart/form-data with this Writer's Boundary. +func (w *Writer) FormDataContentType() string { + b := w.boundary + // We must quote the boundary if it contains any of the + // tspecials characters defined by RFC 2045, or space. + if strings.ContainsAny(b, `()<>@,;:\"/[]?= `) { + b = `"` + b + `"` + } + return "multipart/form-data; boundary=" + b +} + +func randomBoundary() string { + var buf [30]byte + _, err := io.ReadFull(rand.Reader, buf[:]) + if err != nil { + panic(err) + } + return fmt.Sprintf("%x", buf[:]) +} + +// CreatePart creates a new multipart section with the provided +// header. The body of the part should be written to the returned +// Writer. After calling CreatePart, any previous part may no longer +// be written to. +func (w *Writer) CreatePart(header textproto.MIMEHeader) (io.Writer, error) { + if w.lastpart != nil { + if err := w.lastpart.close(); err != nil { + return nil, err + } + } + var b bytes.Buffer + if w.lastpart != nil { + fmt.Fprintf(&b, "\r\n--%s\r\n", w.boundary) + } else { + fmt.Fprintf(&b, "--%s\r\n", w.boundary) + } + + keys := make([]string, 0, len(header)) + for k := range header { + keys = append(keys, k) + } + sort.Strings(keys) + for _, k := range keys { + for _, v := range header[k] { + 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 +} + +var quoteEscaper = strings.NewReplacer("\\", "\\\\", `"`, "\\\"") + +func escapeQuotes(s string) string { + return quoteEscaper.Replace(s) +} + +// 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.Writer, 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) +} + +// CreateFormField calls CreatePart with a header using the +// given field name. +func (w *Writer) CreateFormField(fieldname string) (io.Writer, error) { + h := make(textproto.MIMEHeader) + h.Set("Content-Disposition", + fmt.Sprintf(`form-data; name="%s"`, escapeQuotes(fieldname))) + return w.CreatePart(h) +} + +// WriteField calls CreateFormField and then writes the given value. +func (w *Writer) WriteField(fieldname, value string) error { + p, err := w.CreateFormField(fieldname) + if err != nil { + return err + } + _, err = p.Write([]byte(value)) + return err +} + +// Close finishes the multipart message and writes the trailing +// boundary end line to the output. +func (w *Writer) Close() 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 +} + +type part struct { + mw *Writer + closed bool + we error // last error that occurred writing +} + +func (p *part) close() error { + p.closed = true + return p.we +} + +func (p *part) Write(d []byte) (n int, err error) { + if p.closed { + return 0, errors.New("multipart: can't write to finished part") + } + n, err = p.mw.w.Write(d) + if err != nil { + p.we = err + } + return +} |