Sane GetFile API

cmd/tg-broker/action.go

@@ -13,7 +13,7 @@ func executeClientCommand(action tg.ClientCommand, client net.Conn) {
 		api.SendTextMessage(data)
 	case tg.CmdGetFile:
 		data := *(action.FileRequestData)
-		api.GetFile(data, client, *action.Callback)
+		api.GetFileNet(data, client, *action.Callback)
 	case tg.CmdSendPhoto:
 		data := *(action.PhotoData)
 		api.SendPhoto(data)

telegram.go

@@ -377,23 +377,13 @@ func (t Telegram) AnswerInlineQuery(data InlineQueryResponse) error {
 // GetFile sends a "getFile" API call to Telegram's servers and fetches the file
 // specified afterward. The file will be then send back to the client that requested it
 // with the specified callback id.
-func (t Telegram) GetFile(data FileRequestData, client net.Conn, callback int) {
-	fail := func(msg string) {
-		errmsg, _ := json.Marshal(BrokerUpdate{
-			Type:     BError,
-			Error:    &msg,
-			Callback: &callback,
-		})
-		fmt.Fprintln(client, string(errmsg))
-	}
-
+func (t Telegram) GetFile(data FileRequestData) ([]byte, error) {
 	postdata := url.Values{
 		"file_id": {data.FileID},
 	}
 	resp, err := http.PostForm(t.apiURL("getFile"), postdata)
 	if checkerr("GetFile/post", err) {
-		fail("Server didn't like my request")
-		return
+		return nil, fmt.Errorf("Server didn't like my request: %w", err)
 	}
 	defer resp.Body.Close()
 
@@ -403,27 +393,23 @@ func (t Telegram) GetFile(data FileRequestData, client net.Conn, callback int) {
 	}{}
 	err = json.NewDecoder(resp.Body).Decode(&filespecs)
 	if checkerr("GetFile/json.Decode", err) {
-		fail("Server sent garbage (or error)")
-		return
+		return nil, fmt.Errorf("Server sent garbage (or error): %w", err)
 	}
 	if filespecs.Result == nil {
-		fail("Server didn't send a file info, does the file exist?")
-		return
+		return nil, fmt.Errorf("Server didn't send a file info, does the file exist?")
 	}
 	result := *filespecs.Result
 
 	path := APIEndpoint + "file/bot" + t.Token + "/" + *result.Path
 	fileresp, err := http.Get(path)
 	if checkerr("GetFile/get", err) {
-		fail("Could not retrieve file from Telegram's servers")
-		return
+		return nil, fmt.Errorf("Could not retrieve file from Telegram's servers: %w", err)
 	}
 	defer fileresp.Body.Close()
 
 	rawdata, err := ioutil.ReadAll(fileresp.Body)
 	if checkerr("GetFile/ioutil.ReadAll", err) {
-		fail("Could not read file data")
-		return
+		return nil, fmt.Errorf("Could not read file data: %w", err)
 	}
 
 	rawlen := len(rawdata)
@@ -431,15 +417,35 @@ func (t Telegram) GetFile(data FileRequestData, client net.Conn, callback int) {
 		// ???
 		log.Printf("[GetFile] WARN ?? Downloaded file does not match provided filesize: %d != %d\n", rawlen, *result.Size)
 	}
-	b64data := base64.StdEncoding.EncodeToString(rawdata)
+	return rawdata, nil
+}
 
+func (t Telegram) GetFileNet(data FileRequestData, client net.Conn, callback int) {
+	byt, err := t.GetFile(data)
+	if err != nil {
+		errstr := err.Error()
+		errmsg, _ := json.Marshal(BrokerUpdate{
+			Type:     BError,
+			Error:    &errstr,
+			Callback: &callback,
+		})
+		fmt.Fprintln(client, string(errmsg))
+	}
+
+	b64data := base64.StdEncoding.EncodeToString(byt)
 	clientmsg, err := json.Marshal(BrokerUpdate{
 		Type:     BFile,
 		Bytes:    &b64data,
 		Callback: &callback,
 	})
 	if checkerr("GetFile/json.Marshal", err) {
-		fail("Could not serialize reply JSON")
+		errstr := "Could not serialize reply JSON"
+		errmsg, _ := json.Marshal(BrokerUpdate{
+			Type:     BError,
+			Error:    &errstr,
+			Callback: &callback,
+		})
+		fmt.Fprintln(client, string(errmsg))
 		return
 	}