1// Package tgbotapi has bindings for interacting with the Telegram Bot API.
  2package tgbotapi
  3
  4import (
  5	"bytes"
  6	"encoding/json"
  7	"errors"
  8	"fmt"
  9	"github.com/technoweenie/multipartstreamer"
 10	"io/ioutil"
 11	"log"
 12	"net/http"
 13	"net/url"
 14	"os"
 15	"strconv"
 16	"time"
 17	"strings"
 18)
 19
 20// BotAPI has methods for interacting with all of Telegram's Bot API endpoints.
 21type BotAPI struct {
 22	Token   string       `json:"token"`
 23	Debug   bool         `json:"debug"`
 24	Self    User         `json:"-"`
 25	Client  *http.Client `json:"-"`
 26}
 27
 28// NewBotAPI creates a new BotAPI instance.
 29// Requires a token, provided by @BotFather on Telegram
 30func NewBotAPI(token string) (*BotAPI, error) {
 31	return NewBotAPIWithClient(token, &http.Client{})
 32}
 33
 34// NewBotAPIWithClient creates a new BotAPI instance passing an http.Client.
 35// Requires a token, provided by @BotFather on Telegram
 36func NewBotAPIWithClient(token string, client *http.Client) (*BotAPI, error) {
 37	bot := &BotAPI{
 38		Token:  token,
 39		Client: client,
 40	}
 41
 42	self, err := bot.GetMe()
 43	if err != nil {
 44		return &BotAPI{}, err
 45	}
 46
 47	bot.Self = self
 48
 49	return bot, nil
 50}
 51
 52// MakeRequest makes a request to a specific endpoint with our token.
 53// All requests are POSTs because Telegram doesn't care, and it's easier.
 54func (bot *BotAPI) MakeRequest(endpoint string, params url.Values) (APIResponse, error) {
 55	resp, err := bot.Client.PostForm(fmt.Sprintf(APIEndpoint, bot.Token, endpoint), params)
 56	if err != nil {
 57		return APIResponse{}, err
 58	}
 59	defer resp.Body.Close()
 60
 61	if resp.StatusCode == http.StatusForbidden {
 62		return APIResponse{}, errors.New(APIForbidden)
 63	}
 64
 65	bytes, err := ioutil.ReadAll(resp.Body)
 66	if err != nil {
 67		return APIResponse{}, err
 68	}
 69
 70	if bot.Debug {
 71		log.Println(endpoint, string(bytes))
 72	}
 73
 74	var apiResp APIResponse
 75	json.Unmarshal(bytes, &apiResp)
 76
 77	if !apiResp.Ok {
 78		return APIResponse{}, errors.New(apiResp.Description)
 79	}
 80
 81	return apiResp, nil
 82}
 83
 84func (bot *BotAPI) MakeMessageRequest(endpoint string, params url.Values) (Message, error) {
 85	resp, err := bot.MakeRequest(endpoint, params)
 86	if err != nil {
 87		return Message{}, err
 88	}
 89
 90	var message Message
 91	json.Unmarshal(resp.Result, &message)
 92
 93	bot.debugLog(endpoint, params, message)
 94
 95	return message, nil
 96}
 97
 98// UploadFile makes a request to the API with a file.
 99//
100// Requires the parameter to hold the file not be in the params.
101// File should be a string to a file path, a FileBytes struct, or a FileReader struct.
102func (bot *BotAPI) UploadFile(endpoint string, params map[string]string, fieldname string, file interface{}) (APIResponse, error) {
103	ms := multipartstreamer.New()
104	ms.WriteFields(params)
105
106	switch f := file.(type) {
107	case string:
108		fileHandle, err := os.Open(f)
109		if err != nil {
110			return APIResponse{}, err
111		}
112		defer fileHandle.Close()
113
114		fi, err := os.Stat(f)
115		if err != nil {
116			return APIResponse{}, err
117		}
118
119		ms.WriteReader(fieldname, fileHandle.Name(), fi.Size(), fileHandle)
120	case FileBytes:
121		buf := bytes.NewBuffer(f.Bytes)
122		ms.WriteReader(fieldname, f.Name, int64(len(f.Bytes)), buf)
123	case FileReader:
124		if f.Size == -1 {
125			data, err := ioutil.ReadAll(f.Reader)
126			if err != nil {
127				return APIResponse{}, err
128			}
129			buf := bytes.NewBuffer(data)
130
131			ms.WriteReader(fieldname, f.Name, int64(len(data)), buf)
132
133			break
134		}
135
136		ms.WriteReader(fieldname, f.Name, f.Size, f.Reader)
137	default:
138		return APIResponse{}, errors.New("bad file type")
139	}
140
141	req, err := http.NewRequest("POST", fmt.Sprintf(APIEndpoint, bot.Token, endpoint), nil)
142	ms.SetupRequest(req)
143	if err != nil {
144		return APIResponse{}, err
145	}
146
147	res, err := bot.Client.Do(req)
148	if err != nil {
149		return APIResponse{}, err
150	}
151	defer res.Body.Close()
152
153	bytes, err := ioutil.ReadAll(res.Body)
154	if err != nil {
155		return APIResponse{}, err
156	}
157
158	if bot.Debug {
159		log.Println(string(bytes[:]))
160	}
161
162	var apiResp APIResponse
163	json.Unmarshal(bytes, &apiResp)
164
165	if !apiResp.Ok {
166		return APIResponse{}, errors.New(apiResp.Description)
167	}
168
169	return apiResp, nil
170}
171
172func (this *BotAPI) GetFileDirectUrl(fileID string) (string, error) {
173	file, err := this.GetFile(FileConfig{fileID})
174
175	if err != nil {
176		return "", err
177	}
178
179	return file.Link(this.Token), nil
180}
181
182// GetMe fetches the currently authenticated bot.
183//
184// There are no parameters for this method.
185func (bot *BotAPI) GetMe() (User, error) {
186	resp, err := bot.MakeRequest("getMe", nil)
187	if err != nil {
188		return User{}, err
189	}
190
191	var user User
192	json.Unmarshal(resp.Result, &user)
193
194	if bot.Debug {
195		log.Printf("getMe: %+v\n", user)
196	}
197
198	return user, nil
199}
200
201func (bot *BotAPI) IsMessageToMe(message Message) (bool) {
202	return strings.Contains(message.Text, "@"+bot.Self.UserName)
203}
204
205func (bot *BotAPI) Send(c Chattable) (Message, error) {
206	switch c.(type) {
207	case Fileable:
208		return bot.sendFile(c.(Fileable))
209	default:
210		return bot.sendChattable(c)
211	}
212}
213
214func (bot *BotAPI) debugLog(context string, v url.Values, message interface{}) {
215	if bot.Debug {
216		log.Printf("%s req : %+v\n", context, v)
217		log.Printf("%s resp: %+v\n", context, message)
218	}
219}
220
221func (bot *BotAPI) sendExisting(method string, config Fileable) (Message, error) {
222	v, err := config.Values()
223
224	if err != nil {
225		return Message{}, err
226	}
227
228	message, err := bot.MakeMessageRequest(method, v)
229	if err != nil {
230		return Message{}, err
231	}
232
233	return message, nil
234}
235
236func (bot *BotAPI) uploadAndSend(method string, config Fileable) (Message, error) {
237	params, err := config.Params()
238	if err != nil {
239		return Message{}, err
240	}
241
242	file := config.GetFile()
243
244	resp, err := bot.UploadFile(method, params, config.Name(), file)
245	if err != nil {
246		return Message{}, err
247	}
248
249	var message Message
250	json.Unmarshal(resp.Result, &message)
251
252	if bot.Debug {
253		log.Printf("%s resp: %+v\n", method, message)
254	}
255
256	return message, nil
257}
258
259func (bot *BotAPI) sendFile(config Fileable) (Message, error) {
260	if config.UseExistingFile() {
261		return bot.sendExisting(config.Method(), config)
262	}
263
264	return bot.uploadAndSend(config.Method(), config)
265}
266
267func (bot *BotAPI) sendChattable(config Chattable) (Message, error) {
268	v, err := config.Values()
269	if err != nil {
270		return Message{}, err
271	}
272
273	message, err := bot.MakeMessageRequest(config.Method(), v)
274
275	if err != nil {
276		return Message{}, err
277	}
278
279	return message, nil
280}
281
282// GetUserProfilePhotos gets a user's profile photos.
283//
284// Requires UserID.
285// Offset and Limit are optional.
286func (bot *BotAPI) GetUserProfilePhotos(config UserProfilePhotosConfig) (UserProfilePhotos, error) {
287	v := url.Values{}
288	v.Add("user_id", strconv.Itoa(config.UserID))
289	if config.Offset != 0 {
290		v.Add("offset", strconv.Itoa(config.Offset))
291	}
292	if config.Limit != 0 {
293		v.Add("limit", strconv.Itoa(config.Limit))
294	}
295
296	resp, err := bot.MakeRequest("getUserProfilePhotos", v)
297	if err != nil {
298		return UserProfilePhotos{}, err
299	}
300
301	var profilePhotos UserProfilePhotos
302	json.Unmarshal(resp.Result, &profilePhotos)
303
304	bot.debugLog("GetUserProfilePhoto", v, profilePhotos)
305
306	return profilePhotos, nil
307}
308
309// GetFile returns a file_id required to download a file.
310//
311// Requires FileID.
312func (bot *BotAPI) GetFile(config FileConfig) (File, error) {
313	v := url.Values{}
314	v.Add("file_id", config.FileID)
315
316	resp, err := bot.MakeRequest("getFile", v)
317	if err != nil {
318		return File{}, err
319	}
320
321	var file File
322	json.Unmarshal(resp.Result, &file)
323
324	bot.debugLog("GetFile", v, file)
325
326	return file, nil
327}
328
329// GetUpdates fetches updates.
330// If a WebHook is set, this will not return any data!
331//
332// Offset, Limit, and Timeout are optional.
333// To not get old items, set Offset to one higher than the previous item.
334// Set Timeout to a large number to reduce requests and get responses instantly.
335func (bot *BotAPI) GetUpdates(config UpdateConfig) ([]Update, error) {
336	v := url.Values{}
337	if config.Offset > 0 {
338		v.Add("offset", strconv.Itoa(config.Offset))
339	}
340	if config.Limit > 0 {
341		v.Add("limit", strconv.Itoa(config.Limit))
342	}
343	if config.Timeout > 0 {
344		v.Add("timeout", strconv.Itoa(config.Timeout))
345	}
346
347	resp, err := bot.MakeRequest("getUpdates", v)
348	if err != nil {
349		return []Update{}, err
350	}
351
352	var updates []Update
353	json.Unmarshal(resp.Result, &updates)
354
355	if bot.Debug {
356		log.Printf("getUpdates: %+v\n", updates)
357	}
358
359	return updates, nil
360}
361
362func (bot *BotAPI) RemoveWebhook() (APIResponse, error) {
363	return bot.MakeRequest("setWebhook", url.Values{})
364}
365
366// SetWebhook sets a webhook.
367// If this is set, GetUpdates will not get any data!
368//
369// Requires URL OR to set Clear to true.
370func (bot *BotAPI) SetWebhook(config WebhookConfig) (APIResponse, error) {
371	if config.Certificate == nil {
372		v := url.Values{}
373		v.Add("url", config.URL.String())
374
375		return bot.MakeRequest("setWebhook", v)
376	}
377
378	params := make(map[string]string)
379	params["url"] = config.URL.String()
380
381	resp, err := bot.UploadFile("setWebhook", params, "certificate", config.Certificate)
382	if err != nil {
383		return APIResponse{}, err
384	}
385
386	var apiResp APIResponse
387	json.Unmarshal(resp.Result, &apiResp)
388
389	if bot.Debug {
390		log.Printf("setWebhook resp: %+v\n", apiResp)
391	}
392
393	return apiResp, nil
394}
395
396// UpdatesChan starts a channel for getting updates.
397func (bot *BotAPI) GetUpdatesChan(config UpdateConfig) (<-chan Update, error) {
398	updatesChan := make(chan Update, 100)
399
400	go func() {
401		for {
402			updates, err := bot.GetUpdates(config)
403			if err != nil {
404				log.Println(err)
405				log.Println("Failed to get updates, retrying in 3 seconds...")
406				time.Sleep(time.Second * 3)
407
408				continue
409			}
410
411			for _, update := range updates {
412				if update.UpdateID >= config.Offset {
413					config.Offset = update.UpdateID + 1
414					updatesChan <- update
415				}
416			}
417		}
418	}()
419
420	return updatesChan, nil
421}
422
423// ListenForWebhook registers a http handler for a webhook.
424func (bot *BotAPI) ListenForWebhook(pattern string) (<-chan Update, http.Handler) {
425	updatesChan := make(chan Update, 100)
426
427	handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
428		bytes, _ := ioutil.ReadAll(r.Body)
429
430		var update Update
431		json.Unmarshal(bytes, &update)
432
433		updatesChan <- update
434	})
435
436	http.HandleFunc(pattern, handler)
437
438	return updatesChan, handler
439}