Files
crockery/vendor/github.com/emersion/go-message/mail/reader.go
2018-06-28 01:09:56 +01:00

131 lines
3.3 KiB
Go

package mail
import (
"container/list"
"io"
"strings"
"github.com/emersion/go-message"
)
// A PartHeader is a mail part header. It contains convenience functions to get
// and set header fields.
type PartHeader interface {
// Add adds the key, value pair to the header.
Add(key, value string)
// Del deletes the values associated with key.
Del(key string)
// Get gets the first value associated with the given key. If there are no
// values associated with the key, Get returns "".
Get(key string) string
// Set sets the header entries associated with key to the single element
// value. It replaces any existing values associated with key.
Set(key, value string)
}
// A Part is either a mail text or an attachment. Header is either a TextHeader
// or an AttachmentHeader.
type Part struct {
Header PartHeader
Body io.Reader
}
// A Reader reads a mail message.
type Reader struct {
Header Header
e *message.Entity
readers *list.List
}
// NewReader creates a new mail reader.
func NewReader(e *message.Entity) *Reader {
mr := e.MultipartReader()
if mr == nil {
// Artificially create a multipart entity
// With this header, no error will be returned by message.NewMultipart
h := make(message.Header)
h.Set("Content-Type", "multipart/mixed")
me, _ := message.NewMultipart(h, []*message.Entity{e})
mr = me.MultipartReader()
}
l := list.New()
l.PushBack(mr)
return &Reader{Header{e.Header}, e, l}
}
// CreateReader reads a mail header from r and returns a new mail reader.
//
// If the message uses an unknown transfer encoding or charset, CreateReader
// returns an error that verifies message.IsUnknownEncoding, but also returns a
// Reader that can be used.
func CreateReader(r io.Reader) (*Reader, error) {
e, err := message.Read(r)
if err != nil && !message.IsUnknownEncoding(err) {
return nil, err
}
return NewReader(e), err
}
// NextPart returns the next mail part. If there is no more part, io.EOF is
// returned as error.
//
// The returned Part.Body must be read completely before the next call to
// NextPart, otherwise it will be discarded.
//
// If the part uses an unknown transfer encoding or charset, NextPart returns an
// error that verifies message.IsUnknownEncoding, but also returns a Part that
// can be used.
func (r *Reader) NextPart() (*Part, error) {
for r.readers.Len() > 0 {
e := r.readers.Back()
mr := e.Value.(message.MultipartReader)
p, err := mr.NextPart()
if err == io.EOF {
// This whole multipart entity has been read, continue with the next one
r.readers.Remove(e)
continue
} else if err != nil && !message.IsUnknownEncoding(err) {
return nil, err
}
if pmr := p.MultipartReader(); pmr != nil {
// This is a multipart part, read it
r.readers.PushBack(pmr)
} else {
// This is a non-multipart part, return a mail part
mp := &Part{Body: p.Body}
t, _, _ := p.Header.ContentType()
disp, _, _ := p.Header.ContentDisposition()
if strings.HasPrefix(t, "text/") && disp != "attachment" {
mp.Header = TextHeader{p.Header}
} else {
mp.Header = AttachmentHeader{p.Header}
}
return mp, err
}
}
return nil, io.EOF
}
// Close finishes the reader.
func (r *Reader) Close() error {
for r.readers.Len() > 0 {
e := r.readers.Back()
mr := e.Value.(message.MultipartReader)
if err := mr.Close(); err != nil {
return err
}
r.readers.Remove(e)
}
return nil
}