Function ReadMultipartDocument

rest/multipart.go:216–304

(reader *multipart.Reader)

}

func ReadMultipartDocument(reader *multipart.Reader) (db.Body, error) {
	// First read the main JSON document body:
	mainPart, err := reader.NextPart()
	if err != nil {
		return nil, err
	}
	var body db.Body
	err = ReadJSONFromMIME(http.Header(mainPart.Header), mainPart, &body)
	if err != nil {
		return nil, err
	}

	// Collect the attachments with a "follows" property, which will appear as MIME parts:
	followingAttachments := map[string]map[string]interface{}{}
	for name, value := range db.GetBodyAttachments(body) {
		if meta := value.(map[string]interface{}); meta["follows"] == true {
			followingAttachments[name] = meta
		}
	}

	// Subroutine to look up a following attachment given its digest. (I used to pre-compute a
	// map from digest->name, which was faster, but that broke down if there were multiple
	// attachments with the same contents! See #96)
	findFollowingAttachment := func(withDigest string) (string, map[string]interface{}) {
		for name, meta := range followingAttachments {
			if meta["follows"] == true {
				if digest, ok := meta["digest"].(string); ok && digest == withDigest {
					return name, meta
				}
			}
		}
		return "", nil
	}

	// Read the parts one by one:
	for i := 0; i < len(followingAttachments); i++ {
		part, err := reader.NextPart()
		if err != nil {
			if err == io.EOF {
				err = base.HTTPErrorf(http.StatusBadRequest,
					"Too few MIME parts: expected %d attachments, got %d",
					len(followingAttachments), i)
			}
			return nil, err
		}
		data, err := io.ReadAll(part)
		_ = part.Close()
		if err != nil {
			return nil, err
		}

		// Look up the attachment by its digest:
		digest := db.Sha1DigestKey(data)
		name, meta := findFollowingAttachment(digest)
		if meta == nil {
			name, meta = findFollowingAttachment(md5DigestKey(data))
			if meta == nil {
				return nil, base.HTTPErrorf(http.StatusBadRequest,