Derive contexts from the caller and name timeouts

[onechat] / telegram_api.go

diff --git a/telegram_api.go b/telegram_api.go
index 558d006cd1a1b04905afbe0fd94b6d89e71a1e5e..32ad9a93b7616ad1dc6371de439386a35c948ac1 100644 (file)
--- a/telegram_api.go
+++ b/telegram_api.go
@@ -9,6 +9,7 @@ import (
        "io"
        "net/http"
        "net/url"
        "io"
        "net/http"
        "net/url"

+       "path"

        "strings"
        "time"
 )
        "strings"
        "time"
 )


@@ -22,6 +23,9 @@ const (
        // getUpdates call can take before the bot gives it up.
        telegramPollSlack = 20 * time.Second
 
        // 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
        // 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


@@ -34,10 +38,6 @@ const (
        telegramAnswerBytes = 16 << 20
 )
 
        telegramAnswerBytes = 16 << 20
 )
 

-// errTelegramNetwork tells that a Bot API call got no valid answer, such as
-// after a network error. A later call can work.
-var errTelegramNetwork = errors.New("no valid answer from the Bot API")
-

 // newTelegramAPI returns the client of the Bot API at base with token.
 func newTelegramAPI(base, token string) *TelegramAPI {
        return &TelegramAPI{
 // newTelegramAPI returns the client of the Bot API at base with token.
 func newTelegramAPI(base, token string) *TelegramAPI {
        return &TelegramAPI{


@@ -52,11 +52,14 @@ func newTelegramAPI(base, token string) *TelegramAPI {
 // after a network error, HTTP 429, or a server error. It returns the wait that
 // the Bot API asks for, or 0.
 func telegramRetryable(err error) (bool, time.Duration) {
 // after a network error, HTTP 429, or a server error. It returns the wait that
 // the Bot API asks for, or 0.
 func telegramRetryable(err error) (bool, time.Duration) {

-       if errors.Is(err, errTelegramNetwork) {
+       var network *TelegramNetworkError
+
+       if errors.As(err, &network) {

                return true, 0
        }
 
        var answer *TelegramError
                return true, 0
        }
 
        var answer *TelegramError

+

        if errors.As(err, &answer) {
                return answer.Status == http.StatusTooManyRequests || answer.Status >= 500, answer.RetryAfter
        }
        if errors.As(err, &answer) {
                return answer.Status == http.StatusTooManyRequests || answer.Status >= 500, answer.RetryAfter
        }


@@ -70,13 +73,14 @@ func telegramRetryable(err error) (bool, time.Duration) {
 // tell this, so it is not a refusal.
 func telegramRejected(err error) bool {
        var answer *TelegramError
 // 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,
        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.
-// SendTimeout limits each sendMessage, sendRichMessage, and sendChatAction
-// call.
+// 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.

 type TelegramAPI struct {
        base        string
        token       string
 type TelegramAPI struct {
        base        string
        token       string


@@ -88,11 +92,9 @@ type TelegramAPI struct {
 // 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) {
 // 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) {

-       ctx, cancel := context.WithTimeout(ctx, telegramPollSeconds*time.Second+telegramPollSlack)
-       defer cancel()
-

        var updates []TelegramUpdate
        var updates []TelegramUpdate

-       err := b.call(ctx, "getUpdates", map[string]any{
+
+       err := b.call(ctx, telegramPollTimeout, "getUpdates", map[string]any{

                "offset":          offset,
                "timeout":         telegramPollSeconds,
                "allowed_updates": []string{"message"},
                "offset":          offset,
                "timeout":         telegramPollSeconds,
                "allowed_updates": []string{"message"},


@@ -101,14 +103,71 @@ func (b *TelegramAPI) GetUpdates(ctx context.Context, offset int64) ([]TelegramU
        return updates, err
 }
 
        return updates, err
 }
 

-// 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
-// errTelegramNetwork.
-func (b *TelegramAPI) SendMessage(ctx context.Context, chat int64, text string, entities []TelegramEntity) error {
+// 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, b.sendTimeout, "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, b.sendTimeout)
        defer cancel()
 
        ctx, cancel := context.WithTimeout(ctx, b.sendTimeout)
        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, b.sendTimeout)
+       }
+
+       defer func() {
+               closeErr := response.Body.Close()
+               if closeErr != nil {
+                       err = errors.Join(err, b.networkError("close image download", closeErr, b.sendTimeout))
+               }
+       }()
+
+       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, b.sendTimeout)
+       }
+
+       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
+// TelegramNetworkError.
+func (b *TelegramAPI) SendMessage(ctx context.Context, chat int64, text string, entities []TelegramEntity) error {

        params := map[string]any{
                "chat_id": chat,
                "text":    text,
        params := map[string]any{
                "chat_id": chat,
                "text":    text,


@@ -118,17 +177,14 @@ func (b *TelegramAPI) SendMessage(ctx context.Context, chat int64, text string,
                params["entities"] = entities
        }
 
                params["entities"] = entities
        }
 

-       return b.call(ctx, "sendMessage", params, nil)
+       return b.call(ctx, b.sendTimeout, "sendMessage", params, nil)

 }
 
 // SendRichMessage sends markdown to chat as a rich message, which Telegram
 // renders itself, tables included. A call that takes longer than
 }
 
 // SendRichMessage sends markdown to chat as a rich message, which Telegram
 // renders itself, tables included. A call that takes longer than

-// telegramSendTimeout fails with errTelegramNetwork.
+// telegramSendTimeout fails with a TelegramNetworkError.

 func (b *TelegramAPI) SendRichMessage(ctx context.Context, chat int64, markdown string) error {
 func (b *TelegramAPI) SendRichMessage(ctx context.Context, chat int64, markdown string) error {

-       ctx, cancel := context.WithTimeout(ctx, b.sendTimeout)
-       defer cancel()
-
-       return b.call(ctx, "sendRichMessage", map[string]any{
+       return b.call(ctx, b.sendTimeout, "sendRichMessage", map[string]any{

                "chat_id": chat,
                "rich_message": map[string]any{
                        "markdown": markdown,
                "chat_id": chat,
                "rich_message": map[string]any{
                        "markdown": markdown,


@@ -137,20 +193,22 @@ func (b *TelegramAPI) SendRichMessage(ctx context.Context, chat int64, markdown
 }
 
 // SendTyping shows the typing action in chat for about five seconds. A call
 }
 
 // SendTyping shows the typing action in chat for about five seconds. A call

-// that takes longer than telegramSendTimeout fails with errTelegramNetwork.
+// that takes longer than telegramSendTimeout fails with a TelegramNetworkError.

 func (b *TelegramAPI) SendTyping(ctx context.Context, chat int64) error {
 func (b *TelegramAPI) SendTyping(ctx context.Context, chat int64) error {

-       ctx, cancel := context.WithTimeout(ctx, b.sendTimeout)
-       defer cancel()
-
-       return b.call(ctx, "sendChatAction", map[string]any{
+       return b.call(ctx, b.sendTimeout, "sendChatAction", map[string]any{

                "chat_id": chat,
                "action":  "typing",
        }, nil)
 }
 
 // call sends one call of method with the JSON params and decodes its result
                "chat_id": chat,
                "action":  "typing",
        }, nil)
 }
 
 // call sends one call of method with the JSON params and decodes its result

-// into result, when result is not nil.
-func (b *TelegramAPI) call(ctx context.Context, method string, params, result any) error {
+// into result, when result is not nil. The call can take up to timeout. Its
+// errors tell the cause in plain words, with no method name, so that a log line
+// can say first what the call was for.
+func (b *TelegramAPI) call(ctx context.Context, timeout time.Duration, method string, params, result any) error {
+       ctx, cancel := context.WithTimeout(ctx, timeout)
+       defer cancel()
+

        body, err := json.Marshal(params)
        if err != nil {
                return fmt.Errorf("%s: encode request: %w", method, err)
        body, err := json.Marshal(params)
        if err != nil {
                return fmt.Errorf("%s: encode request: %w", method, err)


@@ -162,34 +220,34 @@ func (b *TelegramAPI) call(ctx context.Context, method string, params, result an
        }
 
        request.Header.Set("Content-Type", "application/json")
        }
 
        request.Header.Set("Content-Type", "application/json")

+

        response, err := b.http.Do(request)
        if err != nil {
        response, err := b.http.Do(request)
        if err != nil {

-               return fmt.Errorf("%s: %w: %s", method, errTelegramNetwork, b.redact(err))
+               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 {
        }
 
        data, err := io.ReadAll(io.LimitReader(response.Body, telegramAnswerBytes))
        err = errors.Join(err, response.Body.Close())
        if err != nil {

-               return fmt.Errorf("%s: %w: read answer: %s", method, errTelegramNetwork, b.redact(err))
+               return b.networkError("answer cut off", err, timeout)

        }
 
        var answer TelegramAnswer
        }
 
        var answer TelegramAnswer

+

        err = json.Unmarshal(data, &answer)
        if err != nil && response.StatusCode != http.StatusOK {
                return &TelegramError{
        err = json.Unmarshal(data, &answer)
        if err != nil && response.StatusCode != http.StatusOK {
                return &TelegramError{

-                       Method:      method,

                        Status:      response.StatusCode,
                        Description: http.StatusText(response.StatusCode),
                }
        }
 
        if err != nil {
                        Status:      response.StatusCode,
                        Description: http.StatusText(response.StatusCode),
                }
        }
 
        if err != nil {

-               return fmt.Errorf("%s: %w: decode answer: %s", method, errTelegramNetwork, b.redact(err))
+               return b.networkError("invalid JSON", err, timeout)

        }
 
        if !answer.OK {
                return &TelegramError{
        }
 
        if !answer.OK {
                return &TelegramError{

-                       Method:      method,

                        Status:      response.StatusCode,
                        Description: b.redact(errors.New(answer.Description)),
                        RetryAfter:  time.Duration(answer.Parameters.RetryAfter) * time.Second,
                        Status:      response.StatusCode,
                        Description: b.redact(errors.New(answer.Description)),
                        RetryAfter:  time.Duration(answer.Parameters.RetryAfter) * time.Second,


@@ -203,17 +261,34 @@ func (b *TelegramAPI) call(ctx context.Context, method string, params, result an
 
        err = json.Unmarshal(answer.Result, result)
        if err != nil {
 
        err = json.Unmarshal(answer.Result, result)
        if err != nil {

-               return fmt.Errorf("%s: %w: decode result: %s", method, errTelegramNetwork, b.redact(err))
+               return b.networkError("invalid result", err, timeout)

        }
 
        return nil
 }
 
        }
 
        return nil
 }
 

+// networkError returns the TelegramNetworkError of err, which happened at the
+// step that what names. When the call used all of its time timeout, the cause
+// is "no answer in TIMEOUT", because the Go text of a deadline does not tell
+// how long the wait was.
+func (b *TelegramAPI) networkError(what string, err error, timeout time.Duration) error {
+       if errors.Is(err, context.DeadlineExceeded) {
+               return &TelegramNetworkError{
+                       Cause: "no answer in " + timeout.String(),
+               }
+       }
+
+       return &TelegramNetworkError{
+               Cause: what + ": " + b.redact(err),
+       }
+}
+

 // redact returns the text of err without a URL and without the token. A
 // *url.Error holds the URL of the call, which holds the token, so only its
 // cause is kept.
 func (b *TelegramAPI) redact(err error) string {
        var urlError *url.Error
 // redact returns the text of err without a URL and without the token. A
 // *url.Error holds the URL of the call, which holds the token, so only its
 // cause is kept.
 func (b *TelegramAPI) redact(err error) string {
        var urlError *url.Error

+

        if errors.As(err, &urlError) {
                err = urlError.Err
        }
        if errors.As(err, &urlError) {
                err = urlError.Err
        }


@@ -221,12 +296,23 @@ func (b *TelegramAPI) redact(err error) string {
        return strings.ReplaceAll(err.Error(), b.token, "TOKEN")
 }
 
        return strings.ReplaceAll(err.Error(), b.token, "TOKEN")
 }
 

-// TelegramError is an answer of the Bot API that tells of a failure. 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.
+// TelegramNetworkError tells that a Bot API call got no valid answer, such as
+// after a network error. A later call can work. Cause tells why in plain words,
+// with no URL and no token.
+type TelegramNetworkError struct {
+       Cause string
+}
+
+func (e *TelegramNetworkError) Error() string {
+       return e.Cause
+}
+
+// TelegramError is an answer of the Bot API that tells of a failure. Its text
+// 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 {
 type TelegramError struct {

-       Method      string

        Status      int
        Description string
        RetryAfter  time.Duration
        Status      int
        Description string
        RetryAfter  time.Duration


@@ -234,7 +320,7 @@ type TelegramError struct {
 }
 
 func (e *TelegramError) Error() string {
 }
 
 func (e *TelegramError) Error() string {

-       return fmt.Sprintf("%s: Bot API answered %d: %s", e.Method, 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
 }
 
 // TelegramUpdate is one update of getUpdates. Message is nil for the kinds of


@@ -266,12 +352,29 @@ type TelegramAnswer struct {
        } `json:"parameters"`
 }
 
        } `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 {
 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
 }
 
 // TelegramChat is the chat of a message. Type is private for a chat with one