"errors"
"fmt"
"io"
+ "mime/multipart"
"net/http"
"net/url"
+ "path"
+ "strconv"
"strings"
"time"
)
const (
- // telegramPollSeconds is how long one getUpdates call waits for an
- // update.
- telegramPollSeconds = 50
+ // telegramUpdateWaitTimeout is how long one getUpdates call waits for
+ // an update.
+ telegramUpdateWaitTimeout = 50 * time.Second
- // telegramPollSlack is how much longer than telegramPollSeconds a
+ // telegramPollSlack is how much longer than telegramUpdateWaitTimeout a
// getUpdates call can take before the bot gives it up.
telegramPollSlack = 20 * time.Second
// telegramPollTimeout is how long one getUpdates call can take.
- telegramPollTimeout = telegramPollSeconds*time.Second + telegramPollSlack
-
- // telegramSendTimeout is how long a sendMessage, sendRichMessage, or
- // sendChatAction call can take. A connection that stops without a
- // close, such as after a network change, then fails the call, and the
- // sender tries again, instead of a wait until TCP gives up. The client
- // has no timeout of its own, because the long poll of getUpdates needs
- // a longer limit.
+ telegramPollTimeout = telegramUpdateWaitTimeout + telegramPollSlack
+
+ // telegramSendTimeout is how long a sendMessage or sendRichMessage call
+ // can take. A connection that stops without a close, such as after a
+ // network change, then fails the call, and the sender tries again,
+ // instead of a wait until TCP gives up. The client has no timeout of
+ // its own, because the long poll of getUpdates needs a longer limit.
telegramSendTimeout = 30 * time.Second
+ // telegramFileLookupTimeout is the longest wait for image file details.
+ telegramFileLookupTimeout = 30 * time.Second
+
+ // telegramImageDownloadTimeout is the longest wait for image bytes.
+ telegramImageDownloadTimeout = 30 * time.Second
+
+ // telegramTypingTimeout is the longest wait to show the typing action.
+ telegramTypingTimeout = 30 * time.Second
+
// telegramAnswerBytes is the most bytes of one answer of the Bot API.
telegramAnswerBytes = 16 << 20
)
// newTelegramAPI returns the client of the Bot API at base with token.
func newTelegramAPI(base, token string) *TelegramAPI {
return &TelegramAPI{
- base: base,
- token: token,
- http: &http.Client{},
- sendTimeout: telegramSendTimeout,
+ base: base,
+ token: token,
+ http: &http.Client{},
}
}
// the Bot API asks for, or 0.
func telegramRetryable(err error) (bool, time.Duration) {
var network *TelegramNetworkError
+
if errors.As(err, &network) {
return true, 0
}
var answer *TelegramError
+
if errors.As(err, &answer) {
return answer.Status == http.StatusTooManyRequests || answer.Status >= 500, answer.RetryAfter
}
// tell this, so it is not a refusal.
func telegramRejected(err error) bool {
var answer *TelegramError
+
return errors.As(err, &answer) && answer.Refused && (answer.Status == http.StatusBadRequest || answer.Status == http.StatusNotFound)
}
// TelegramAPI calls the Telegram Bot API. The bot token is a part of each URL,
-// so no error of TelegramAPI holds a URL, a net/http error, or the token. Its
-// sendTimeout field limits each sendMessage, sendRichMessage, and
-// sendChatAction call.
+// so no error of TelegramAPI holds a URL, a net/http error, or the token.
type TelegramAPI struct {
- base string
- token string
- http *http.Client
- sendTimeout time.Duration
+ base string
+ token string
+ http *http.Client
}
-// GetUpdates waits for the updates from offset on, up to telegramPollSeconds,
-// and returns them. Telegram forgets each update before offset. Only new
-// messages are asked for.
+// GetUpdates waits for the updates from offset on, up to
+// telegramUpdateWaitTimeout, and returns them. Telegram forgets each update
+// before offset. Only new messages are asked for.
func (b *TelegramAPI) GetUpdates(ctx context.Context, offset int64) ([]TelegramUpdate, error) {
var updates []TelegramUpdate
+
err := b.call(ctx, telegramPollTimeout, "getUpdates", map[string]any{
"offset": offset,
- "timeout": telegramPollSeconds,
+ "timeout": int(telegramUpdateWaitTimeout / time.Second),
"allowed_updates": []string{"message"},
}, &updates)
return updates, err
}
+// GetImage downloads a file through the authenticated file endpoint. Errors
+// never include its token or URL, and the body is limited before storage.
+func (b *TelegramAPI) GetImage(ctx context.Context, id string) (data []byte, err error) {
+ var file struct {
+ Path string `json:"file_path"`
+ Size int64 `json:"file_size"`
+ }
+
+ err = b.call(ctx, telegramFileLookupTimeout, "getFile", map[string]any{"file_id": id}, &file)
+ if err != nil {
+ return nil, fmt.Errorf("get image file: %w", err)
+ }
+
+ if file.Size > imageMaxBytes {
+ return nil, errImageSize
+ }
+
+ if file.Path == "" || path.Clean(file.Path) != file.Path || strings.HasPrefix(file.Path, "/") || strings.HasPrefix(file.Path, "../") || strings.ContainsAny(file.Path, "?%#\\") {
+ return nil, errors.New("invalid image file path")
+ }
+
+ ctx, cancel := context.WithTimeout(ctx, telegramImageDownloadTimeout)
+ defer cancel()
+
+ request, err := http.NewRequestWithContext(ctx, http.MethodGet, b.base+"/file/bot"+b.token+"/"+file.Path, nil)
+ if err != nil {
+ return nil, fmt.Errorf("make image request: %s", b.redact(err))
+ }
+
+ response, err := b.http.Do(request)
+ if err != nil {
+ return nil, b.networkError("image download failed", err, telegramImageDownloadTimeout)
+ }
+
+ defer func() {
+ closeErr := response.Body.Close()
+ if closeErr != nil {
+ err = errors.Join(err, b.networkError("close image download", closeErr, telegramImageDownloadTimeout))
+ }
+ }()
+
+ if response.StatusCode != http.StatusOK {
+ return nil, &TelegramError{
+ Status: response.StatusCode,
+ Description: http.StatusText(response.StatusCode),
+ }
+ }
+
+ data, err = io.ReadAll(io.LimitReader(response.Body, imageMaxBytes+1))
+ if err != nil {
+ return nil, b.networkError("image cut off", err, telegramImageDownloadTimeout)
+ }
+
+ if len(data) > imageMaxBytes {
+ return nil, errImageSize
+ }
+
+ return data, nil
+}
+
// SendMessage sends text to chat with the format of entities, with no parse
// mode, so the text needs no escaping. With no entities, the text is plain. A
// call that takes longer than telegramSendTimeout fails with a
params["entities"] = entities
}
- return b.call(ctx, b.sendTimeout, "sendMessage", params, nil)
+ return b.call(ctx, telegramSendTimeout, "sendMessage", params, nil)
}
// SendRichMessage sends markdown to chat as a rich message, which Telegram
// renders itself, tables included. A call that takes longer than
// telegramSendTimeout fails with a TelegramNetworkError.
func (b *TelegramAPI) SendRichMessage(ctx context.Context, chat int64, markdown string) error {
- return b.call(ctx, b.sendTimeout, "sendRichMessage", map[string]any{
+ return b.call(ctx, telegramSendTimeout, "sendRichMessage", map[string]any{
"chat_id": chat,
"rich_message": map[string]any{
"markdown": markdown,
}, nil)
}
+// SendImage uploads an image to the owner as a photo, or as a document when the
+// Bot API refuses the photo. Network failures do not trigger a second send.
+func (b *TelegramAPI) SendImage(ctx context.Context, chat int64, name string, data []byte, caption string) error {
+ err := b.sendImage(ctx, "sendPhoto", "photo", chat, name, data, caption)
+ if telegramRejected(err) {
+ err = b.sendImage(ctx, "sendDocument", "document", chat, name, data, caption)
+ }
+
+ return err
+}
+
+func (b *TelegramAPI) sendImage(ctx context.Context, method, field string, chat int64, name string, data []byte, caption string) error {
+ ctx, cancel := context.WithTimeout(ctx, telegramSendTimeout)
+ defer cancel()
+
+ var body bytes.Buffer
+
+ writer := multipart.NewWriter(&body)
+ err := writer.WriteField("chat_id", strconv.FormatInt(chat, 10))
+ if err != nil {
+ return fmt.Errorf("write image chat: %w", err)
+ }
+
+ err = writer.WriteField("caption", caption)
+ if err != nil {
+ return fmt.Errorf("write image caption: %w", err)
+ }
+
+ part, err := writer.CreateFormFile(field, name)
+ if err != nil {
+ return fmt.Errorf("make image part: %w", err)
+ }
+
+ _, err = part.Write(data)
+ if err != nil {
+ return fmt.Errorf("write image part: %w", err)
+ }
+
+ err = writer.Close()
+ if err != nil {
+ return fmt.Errorf("close image form: %w", err)
+ }
+
+ request, err := http.NewRequestWithContext(ctx, http.MethodPost, b.base+"/bot"+b.token+"/"+method, &body)
+ if err != nil {
+ return fmt.Errorf("make image upload: %s", b.redact(err))
+ }
+
+ request.Header.Set("Content-Type", writer.FormDataContentType())
+
+ err = b.answer(request, telegramSendTimeout, nil)
+ if err != nil {
+ return fmt.Errorf("upload image: %w", err)
+ }
+
+ return nil
+}
+
// SendTyping shows the typing action in chat for about five seconds. A call
-// that takes longer than telegramSendTimeout fails with a TelegramNetworkError.
+// that takes longer than telegramTypingTimeout fails with a
+// TelegramNetworkError.
func (b *TelegramAPI) SendTyping(ctx context.Context, chat int64) error {
- return b.call(ctx, b.sendTimeout, "sendChatAction", map[string]any{
+ return b.call(ctx, telegramTypingTimeout, "sendChatAction", map[string]any{
"chat_id": chat,
"action": "typing",
}, nil)
}
request.Header.Set("Content-Type", "application/json")
+
+ return b.answer(request, timeout, result)
+}
+
+// answer reads the bounded Bot API response without keeping its request URL.
+func (b *TelegramAPI) answer(request *http.Request, timeout time.Duration, result any) error {
response, err := b.http.Do(request)
if err != nil {
return b.networkError("no answer", err, timeout)
data, err := io.ReadAll(io.LimitReader(response.Body, telegramAnswerBytes))
err = errors.Join(err, response.Body.Close())
if err != nil {
- return b.networkError("the answer broke off", err, timeout)
+ return b.networkError("answer cut off", err, timeout)
}
var answer TelegramAnswer
+
err = json.Unmarshal(data, &answer)
if err != nil && response.StatusCode != http.StatusOK {
return &TelegramError{
}
if err != nil {
- return b.networkError("the answer is not valid JSON", err, timeout)
+ return b.networkError("invalid JSON", err, timeout)
}
if !answer.OK {
err = json.Unmarshal(answer.Result, result)
if err != nil {
- return b.networkError("the result is not valid", err, timeout)
+ return b.networkError("invalid result", err, timeout)
}
return nil
// cause is kept.
func (b *TelegramAPI) redact(err error) string {
var urlError *url.Error
+
if errors.As(err, &urlError) {
err = urlError.Err
}
}
// TelegramError is an answer of the Bot API that tells of a failure. Its text
-// gives the HTTP status and the description, such as "Telegram answered 502 Bad
-// Gateway". RetryAfter is the wait that the Bot API asks for after HTTP 429.
-// Refused tells that the answer is a Bot API answer with ok false, not a page
-// of a proxy or of a server error.
+// gives the HTTP status and the description, such as "502 Bad Gateway".
+// RetryAfter is the wait that the Bot API asks for after HTTP 429. Refused
+// tells that the answer is a Bot API answer with ok false, not a page of a
+// proxy or of a server error.
type TelegramError struct {
Status int
Description string
}
func (e *TelegramError) Error() string {
- return fmt.Sprintf("Telegram answered %d %s", e.Status, e.Description)
+ return fmt.Sprintf("%d %s", e.Status, e.Description)
}
// TelegramUpdate is one update of getUpdates. Message is nil for the kinds of
} `json:"parameters"`
}
-// TelegramMessage is a message to the bot. Text is empty for a message that is
-// not text, such as a photo.
+// TelegramMessage holds the text, caption, and image sizes of a bot message.
type TelegramMessage struct {
- Chat TelegramChat `json:"chat"`
- From *TelegramUser `json:"from"`
- Text string `json:"text"`
+ Chat TelegramChat `json:"chat"`
+ From *TelegramUser `json:"from"`
+ Text string `json:"text"`
+ Caption string `json:"caption"`
+ Photo []TelegramPhoto `json:"photo"`
+ Document *TelegramDocument `json:"document"`
+}
+
+// TelegramPhoto is one supplied size of a photo.
+type TelegramPhoto struct {
+ FileID string `json:"file_id"`
+ Width int `json:"width"`
+ Height int `json:"height"`
+ FileSize int64 `json:"file_size"`
+}
+
+// TelegramDocument is a file sent without photo compression.
+type TelegramDocument struct {
+ FileID string `json:"file_id"`
+ MimeType string `json:"mime_type"`
+ FileSize int64 `json:"file_size"`
}
// TelegramChat is the chat of a message. Type is private for a chat with one
projects / onechat / blobdiff