forked from emersion/go-imap
/
body.go
68 lines (56 loc) · 1.36 KB
/
body.go
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package backendutil
import (
"bytes"
"errors"
"io"
"github.com/emersion/go-imap"
"github.com/emersion/go-message"
)
var errNoSuchPart = errors.New("backendutil: no such message body part")
// FetchBodySection extracts a body section from a message.
func FetchBodySection(e *message.Entity, section *imap.BodySectionName) (imap.Literal, error) {
// First, find the requested part using the provided path
for i := len(section.Path) - 1; i >= 0; i-- {
n := section.Path[i]
mr := e.MultipartReader()
if mr == nil {
return nil, errNoSuchPart
}
for j := 1; j <= n; j++ {
p, err := mr.NextPart()
if err == io.EOF {
return nil, errNoSuchPart
} else if err != nil {
return nil, err
}
if j == n {
e = p
break
}
}
}
// Then, write the requested data to a buffer
b := new(bytes.Buffer)
// Write the header
mw, err := message.CreateWriter(b, e.Header)
if err != nil {
return nil, err
}
defer mw.Close()
// If the header hasn't been requested, discard it
if section.Specifier == imap.TextSpecifier {
b.Reset()
}
// Write the body, if requested
switch section.Specifier {
case imap.EntireSpecifier, imap.TextSpecifier:
if _, err := io.Copy(mw, e.Body); err != nil {
return nil, err
}
}
var l imap.Literal = b
if section.Partial != nil {
l = bytes.NewReader(section.ExtractPartial(b.Bytes()))
}
return l, nil
}