Implement getFile

.gitignore

@@ -4,4 +4,5 @@ clessy-broker
 clessy-mods
 clessy-stats
 clessy-stats-import
-stats-web/Chart.bundle.js
+stats-web/Chart.bundle.js
+impact.ttf

broker/action.go

@@ -1,13 +1,18 @@
 package main
 
 import (
+	"net"
+
 	"github.com/hamcha/clessy/tg"
 )
 
-func executeClientCommand(action tg.ClientCommand) {
+func executeClientCommand(action tg.ClientCommand, client net.Conn) {
 	switch action.Type {
 	case tg.CmdSendTextMessage:
 		data := *(action.TextMessageData)
 		api.SendTextMessage(data)
+	case tg.CmdGetFile:
+		data := *(action.FileRequestData)
+		api.GetFile(data, client, *action.Callback)
 	}
 }

broker/clients.go

@@ -45,7 +45,7 @@ func handleClient(c net.Conn) {
 			log.Printf("%s\n", string(bytes))
 			continue
 		}
-		executeClientCommand(cmd)
+		executeClientCommand(cmd, c)
 	}
 	removeCon(c)
 }

broker/telegram.go

@@ -1,9 +1,13 @@
 package main
 
 import (
+	"encoding/base64"
 	"encoding/json"
 	"errors"
+	"fmt"
+	"io/ioutil"
 	"log"
+	"net"
 	"net/http"
 	"net/url"
 	"strconv"
@@ -61,13 +65,77 @@ func (t Telegram) SendTextMessage(data tg.ClientTextMessageData) {
 	checkerr("SendTextMessage", err)
 }
 
+// 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 tg.FileRequestData, client net.Conn, callback int) {
+	fail := func(msg string) {
+		errmsg, _ := json.Marshal(tg.BrokerUpdate{
+			Type:     tg.BError,
+			Error:    &msg,
+			Callback: &callback,
+		})
+		fmt.Fprintln(client, string(errmsg))
+	}
+
+	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
+	}
+	defer resp.Body.Close()
+
+	var filespecs tg.APIFile
+	err = json.NewDecoder(resp.Body).Decode(&filespecs)
+	if checkerr("GetFile/json.Decode", err) {
+		fail("Server sent garbage (or error)")
+		return
+	}
+
+	path := "https://api.telegram.org/file/bot" + t.Token + "/" + *filespecs.Path
+	fileresp, err := http.Get(path)
+	if checkerr("GetFile/get", err) {
+		fail("Could not retrieve file from Telegram's servers")
+		return
+	}
+	defer fileresp.Body.Close()
+
+	rawdata, err := ioutil.ReadAll(fileresp.Body)
+	if checkerr("GetFile/ioutil.ReadAll", err) {
+		fail("Could not read file data")
+		return
+	}
+
+	rawlen := len(rawdata)
+	if rawlen != *filespecs.Size {
+		// ???
+		log.Printf("[GetFile] WARN ?? Downloaded file does not match provided filesize: %d != %d\n", rawlen, *filespecs.Size)
+	}
+	b64data := base64.StdEncoding.EncodeToString(rawdata)
+
+	clientmsg, err := json.Marshal(tg.BrokerUpdate{
+		Type:     tg.BFile,
+		Bytes:    &b64data,
+		Callback: &callback,
+	})
+	if checkerr("GetFile/json.Marshal", err) {
+		fail("Could not serialize reply JSON")
+		return
+	}
+
+	fmt.Fprintln(client, string(clientmsg))
+}
+
 func (t Telegram) apiURL(method string) string {
 	return APIEndpoint + "bot" + t.Token + "/" + method
 }
 
 func checkerr(method string, err error) bool {
 	if err != nil {
-		log.Printf("Received error with call to %s: %s\n", method, err.Error())
+		log.Printf("[%s] Error: %s\n", method, err.Error())
 		return true
 	}
 	return false

mods/main.go

@@ -15,6 +15,7 @@ func initmods() {
 func dispatch(broker *tg.Broker, update tg.APIMessage) {
 	metafora(broker, update)
 	viaggi(broker, update)
+	memegen(broker, update)
 }
 
 func isCommand(update tg.APIMessage, cmdname string) bool {

tg/broker.go

@@ -66,7 +66,13 @@ func (b *Broker) SendPhoto(chat *APIChat, data []byte, caption *string, original
 // This function is asynchronous as data will be delivered to the given callback.
 func (b *Broker) GetFile(fileID string, fn BrokerCallback) int {
 	cid := b.RegisterCallback(fn)
-	// Make file request
+	b.sendCmd(ClientCommand{
+		Type: CmdGetFile,
+		FileRequestData: &FileRequestData{
+			FileID: fileID,
+		},
+		Callback: &cid,
+	})
 	return cid
 }
 

tg/command.go

@@ -9,14 +9,18 @@ const (
 
 	// BFile is a file retrieval response update
 	BFile BrokerUpdateType = "file"
+
+	// BError is an error the broker occurred while fulfilling a request
+	BError BrokerUpdateType = "error"
 )
 
 // BrokerUpdate is what is sent by the broker as update
 type BrokerUpdate struct {
 	Type     BrokerUpdateType
-	Callback *int
-	Message  *APIMessage
-	Bytes    *string
+	Callback *int        `json:",omitempty"`
+	Error    *string     `json:",omitempty"`
+	Message  *APIMessage `json:",omitempty"`
+	Bytes    *string     `json:",omitempty"`
 }
 
 // ClientCommandType distinguishes requests sent by clients to the broker
@@ -37,27 +41,27 @@ const (
 type ClientTextMessageData struct {
 	ChatID  int
 	Text    string
-	ReplyID *int
+	ReplyID *int `json:",omitempty"`
 }
 
 // ClientPhotoData is the required data for a CmdSendPhoto request
 type ClientPhotoData struct {
 	ChatID  int
 	Bytes   string
-	Caption *string
-	ReplyID *int
+	Caption *string `json:",omitempty"`
+	ReplyID *int    `json:",omitempty"`
 }
 
 // FileRequestData is the required data for a CmdGetFile request
 type FileRequestData struct {
-	FileID int
+	FileID string
 }
 
 // ClientCommand is a request sent by clients to the broker
 type ClientCommand struct {
 	Type            ClientCommandType
-	TextMessageData *ClientTextMessageData
-	PhotoData       *ClientPhotoData
-	FileRequestData *FileRequestData
-	Callback        *int
+	TextMessageData *ClientTextMessageData `json:",omitempty"`
+	PhotoData       *ClientPhotoData       `json:",omitempty"`
+	FileRequestData *FileRequestData       `json:",omitempty"`
+	Callback        *int                   `json:",omitempty"`
 }