X-Git-Url: http://git.giacomolli.uk/onechat/blobdiff_plain/1e2df788bbb17653a6df44acd41da2edb109d403..b2fc2d6a737dd5bab25e57ba822dd07258de93e6:/telegram_api.go

diff --git a/telegram_api.go b/telegram_api.go
index 24f02ac..32ad9a9 100644
--- a/telegram_api.go
+++ b/telegram_api.go
@@ -9,6 +9,7 @@ import (
 	"io"
 	"net/http"
 	"net/url"
+	"path"
 	"strings"
 	"time"
 )
@@ -52,11 +53,13 @@ func newTelegramAPI(base, token string) *TelegramAPI {
 // 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
 	}
@@ -70,6 +73,7 @@ func telegramRetryable(err error) (bool, time.Duration) {
 // 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)
 }
 
@@ -89,6 +93,7 @@ type TelegramAPI struct {
 // 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,
@@ -98,6 +103,66 @@ func (b *TelegramAPI) GetUpdates(ctx context.Context, offset int64) ([]TelegramU
 	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, 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()
+
+	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
@@ -155,6 +220,7 @@ func (b *TelegramAPI) call(ctx context.Context, timeout time.Duration, method st
 	}
 
 	request.Header.Set("Content-Type", "application/json")
+
 	response, err := b.http.Do(request)
 	if err != nil {
 		return b.networkError("no answer", err, timeout)
@@ -163,10 +229,11 @@ func (b *TelegramAPI) call(ctx context.Context, timeout time.Duration, method st
 	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{
@@ -176,7 +243,7 @@ func (b *TelegramAPI) call(ctx context.Context, timeout time.Duration, method st
 	}
 
 	if err != nil {
-		return b.networkError("the answer is not valid JSON", err, timeout)
+		return b.networkError("invalid JSON", err, timeout)
 	}
 
 	if !answer.OK {
@@ -194,7 +261,7 @@ func (b *TelegramAPI) call(ctx context.Context, timeout time.Duration, method st
 
 	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
@@ -221,6 +288,7 @@ func (b *TelegramAPI) networkError(what string, err error, timeout time.Duration
 // cause is kept.
 func (b *TelegramAPI) redact(err error) string {
 	var urlError *url.Error
+
 	if errors.As(err, &urlError) {
 		err = urlError.Err
 	}
@@ -240,10 +308,10 @@ func (e *TelegramNetworkError) Error() string {
 }
 
 // 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
@@ -252,7 +320,7 @@ type TelegramError struct {
 }
 
 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
@@ -284,12 +352,29 @@ type TelegramAnswer struct {
 	} `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