first commit

.gitignore

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+secrets.env

.vscode/launch.json

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+{
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "Launch Package",
+            "type": "go",
+            "request": "launch",
+            "mode": "auto",
+            "program": "${fileDirname}",
+            "envFile": "${workspaceFolder}/secrets.env"
+        }
+    ]
+}

Dockerfile

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+FROM golang:1.22-alpine as builder
+WORKDIR /app
+COPY go.mod go.sum main.go /app
+RUN go build -o app
+
+FROM alpine:latest
+WORKDIR /app
+COPY --from=builder /app/app .
+EXPOSE 8080
+CMD ["./app"]

go.mod

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+module git.jlel.se/jlelse/serverless-tgbot
+
+go 1.22.0
+
+require github.com/carlmjohnson/requests v0.23.5
+
+require golang.org/x/net v0.15.0 // indirect

go.sum

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+github.com/carlmjohnson/requests v0.23.5 h1:NPANcAofwwSuC6SIMwlgmHry2V3pLrSqRiSBKYbNHHA=
+github.com/carlmjohnson/requests v0.23.5/go.mod h1:zG9P28thdRnN61aD7iECFhH5iGGKX2jIjKQD9kqYH+o=
+golang.org/x/net v0.15.0 h1:ugBLEUaxABaB5AJqW9enI0ACdci2RUd4eP51NTBvuJ8=
+golang.org/x/net v0.15.0/go.mod h1:idbUs1IY1+zTqbi8yxTbhexhEEk5ur9LInksu6HrEpk=

main.go

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+package main
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"log"
+	"mime/multipart"
+	"net/http"
+	"os"
+	"slices"
+	"strconv"
+	"strings"
+
+	"github.com/carlmjohnson/requests"
+)
+
+type TelegramMessage struct {
+	MessageID int            `json:"message_id,omitempty"`
+	From      TelegramUser   `json:"from,omitempty"`
+	Chat      TelegramChat   `json:"chat,omitempty"`
+	Voice     *TelegramVoice `json:"voice,omitempty"`
+}
+
+type TelegramUser struct {
+	ID       int    `json:"id,omitempty"`
+	Username string `json:"username,omitempty"`
+}
+
+type TelegramChat struct {
+	ID int `json:"id,omitempty"`
+}
+
+type TelegramVoice struct {
+	FileID string `json:"file_id,omitempty"`
+}
+
+type TelegramSendMessage struct {
+	ChatID          int                      `json:"chat_id,omitempty"`
+	Text            string                   `json:"text,omitempty"`
+	ReplyParameters *TelegramReplyParameters `json:"reply_parameters,omitempty"`
+}
+
+type TelegramReplyParameters struct {
+	MessageID int `json:"message_id,omitempty"`
+}
+
+func main() {
+	// Retrieve bot token from environment variable
+	botToken := os.Getenv("BOT_TOKEN")
+	if botToken == "" {
+		log.Fatal("BOT_TOKEN environment variable is not set")
+	}
+
+	// Retrieve OpenAI API key
+	openaiApiKey := os.Getenv("OPENAI_KEY")
+	if openaiApiKey == "" {
+		log.Fatal("OPENAI_KEY environment variable is not set")
+	}
+
+	// Retrieve allowed users
+	allowedUsers := strings.Split(os.Getenv("ALLOWED_USERS"), ",")
+	if len(allowedUsers) == 0 {
+		log.Fatal("ALLOWED_USERS environment variable is not set")
+	}
+	log.Println("Allowed users:", allowedUsers)
+
+	// Set up the HTTP server
+	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		io.WriteString(w, "Hi!")
+	})
+	http.HandleFunc("/webhook", func(w http.ResponseWriter, r *http.Request) {
+		// Decode the incoming message
+		var update struct {
+			Message *TelegramMessage `json:"message"`
+		}
+		if err := json.NewDecoder(r.Body).Decode(&update); err != nil {
+			log.Println("Error decoding update:", err)
+			return
+		}
+		if update.Message == nil {
+			return
+		}
+
+		// Check allowed users
+		if !(slices.Contains(allowedUsers, update.Message.From.Username) || slices.Contains(allowedUsers, strconv.Itoa(update.Message.From.ID))) {
+			sendMessage(botToken, update.Message.Chat.ID, "Sorry, you are not allowed to use this bot!", update.Message.MessageID)
+			return
+		}
+
+		if update.Message.Voice != nil {
+			transcript, err := transcriptVoiceMessage(botToken, openaiApiKey, update.Message.Voice.FileID)
+			if err != nil {
+				log.Println("Error transcribing voice message:", err)
+				sendMessage(botToken, update.Message.Chat.ID, "Failed to transcribe voice message", update.Message.MessageID)
+			} else {
+				sendMessage(botToken, update.Message.Chat.ID, transcript, update.Message.MessageID)
+			}
+		} else {
+			sendMessage(botToken, update.Message.Chat.ID, "Please send a voice message", update.Message.MessageID)
+		}
+	})
+
+	// Start the HTTP server
+	port := os.Getenv("PORT")
+	if port == "" {
+		port = "8080"
+	}
+	log.Printf("Starting server on :%s", port)
+	log.Fatal(http.ListenAndServe(":"+port, nil))
+}
+
+func sendMessage(botToken string, chatID int, text string, replyTo int) {
+	msg := &TelegramSendMessage{
+		ChatID: chatID,
+		Text:   text,
+	}
+	if replyTo != 0 {
+		msg.ReplyParameters = &TelegramReplyParameters{
+			MessageID: replyTo,
+		}
+	}
+	err := requests.URL(fmt.Sprintf("https://api.telegram.org/bot%s/sendMessage", botToken)).
+		Method(http.MethodPost).
+		BodyJSON(msg).
+		Fetch(context.Background())
+	if err != nil {
+		log.Println("Error sending message:", err)
+		return
+	}
+}
+
+func transcriptVoiceMessage(botToken, openaiApiKey, fileID string) (string, error) {
+	// Get file path
+	var fileResponse struct {
+		OK     bool `json:"ok"`
+		Result struct {
+			FilePath string `json:"file_path"`
+		} `json:"result"`
+	}
+	err := requests.URL(fmt.Sprintf("https://api.telegram.org/bot%s/getFile", botToken)).
+		Param("file_id", fileID).
+		ToJSON(&fileResponse).
+		Fetch(context.Background())
+	if err != nil {
+		return "", err
+	}
+
+	// Download the file
+	voiceDownload := fmt.Sprintf("https://api.telegram.org/file/bot%s/%s", botToken, fileResponse.Result.FilePath)
+	voiceReader, voiceWriter := io.Pipe()
+	go func() {
+		voiceWriter.CloseWithError(
+			requests.URL(voiceDownload).
+				ToWriter(voiceWriter).
+				Fetch(context.Background()),
+		)
+	}()
+
+	// Transcribe message
+	multipartReader, multipartWriter := io.Pipe()
+	mpw := multipart.NewWriter(multipartWriter)
+	go func() {
+		defer multipartWriter.Close()
+		mpw.WriteField("model", "whisper-1")
+		fileWriter, err := mpw.CreateFormFile("file", "file.oga")
+		if err != nil {
+			multipartWriter.CloseWithError(err)
+			return
+		}
+		_, err = io.Copy(fileWriter, voiceReader)
+		if err != nil {
+			multipartWriter.CloseWithError(err)
+			return
+		}
+		multipartWriter.CloseWithError(mpw.Close())
+	}()
+
+	var transcription struct {
+		Text string `json:"text"`
+	}
+	err = requests.URL("https://api.openai.com/v1/audio/transcriptions").
+		Method(http.MethodPost).
+		Header("Authorization", fmt.Sprintf("Bearer %s", openaiApiKey)).
+		ContentType(mpw.FormDataContentType()).
+		BodyReader(multipartReader).
+		ToJSON(&transcription).
+		Fetch(context.Background())
+
+	return transcription.Text, err
+}