/
wechat.go
331 lines (272 loc) · 9.89 KB
/
wechat.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
package wechat
import (
"bytes"
"context"
"crypto/sha1"
"encoding/hex"
"encoding/json"
"fmt"
"net/http"
"net/url"
"sort"
"strings"
"time"
"github.com/buger/jsonparser"
"github.com/garyburd/redigo/redis"
"github.com/nyaruka/courier"
"github.com/nyaruka/courier/handlers"
"github.com/nyaruka/courier/utils"
"github.com/nyaruka/gocommon/urns"
"github.com/sirupsen/logrus"
)
var (
sendURL = "https://api.weixin.qq.com/cgi-bin"
maxMsgLength = 1600
fetchTimeout = time.Second * 2
)
const (
configAppID = "wechat_app_id"
configAppSecret = "wechat_app_secret"
)
func init() {
courier.RegisterHandler(newHandler())
}
type handler struct {
handlers.BaseHandler
}
func newHandler() courier.ChannelHandler {
return &handler{handlers.NewBaseHandler(courier.ChannelType("WC"), "WeChat")}
}
// Initialize is called by the engine once everything is loaded
func (h *handler) Initialize(s courier.Server) error {
h.SetServer(s)
s.AddHandlerRoute(h, http.MethodGet, "", h.VerifyURL)
s.AddHandlerRoute(h, http.MethodPost, "", h.receiveMessage)
return nil
}
type verifyForm struct {
Signature string `name:"signature"`
Timestamp string `name:"timestamp"`
Nonce string `name:"nonce"`
EchoStr string `name:"echostr"`
}
// VerifyURL is our HTTP handler function for WeChat config URL verification callbacks
func (h *handler) VerifyURL(ctx context.Context, channel courier.Channel, w http.ResponseWriter, r *http.Request) ([]courier.Event, error) {
form := &verifyForm{}
err := handlers.DecodeAndValidateForm(form, r)
if err != nil {
return nil, handlers.WriteAndLogRequestError(ctx, h, channel, w, r, err)
}
dictOrder := []string{channel.StringConfigForKey(courier.ConfigSecret, ""), form.Timestamp, form.Nonce}
sort.Sort(sort.StringSlice(dictOrder))
combinedParams := strings.Join(dictOrder, "")
hash := sha1.New()
hash.Write([]byte(combinedParams))
encoded := hex.EncodeToString(hash.Sum(nil))
ResponseText := "unknown request"
StatusCode := 400
if encoded == form.Signature {
ResponseText = form.EchoStr
StatusCode = 200
go func() {
time.Sleep(fetchTimeout)
h.fetchAccessToken(ctx, channel)
}()
}
w.Header().Set("Content-Type", "text/plain")
w.WriteHeader(StatusCode)
_, err = fmt.Fprint(w, ResponseText)
return nil, err
}
// fetchAccessToken tries to fetch a new token for our channel, setting the result in redis
func (h *handler) fetchAccessToken(ctx context.Context, channel courier.Channel) error {
start := time.Now()
logs := make([]*courier.ChannelLog, 0, 1)
form := url.Values{
"grant_type": []string{"client_credential"},
"appid": []string{channel.StringConfigForKey(configAppID, "")},
"secret": []string{channel.StringConfigForKey(configAppSecret, "")},
}
tokenURL, _ := url.Parse(fmt.Sprintf("%s/%s", sendURL, "token"))
tokenURL.RawQuery = form.Encode()
req, _ := http.NewRequest(http.MethodGet, tokenURL.String(), nil)
req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
req.Header.Set("Accept", "application/json")
rr, err := utils.MakeHTTPRequest(req)
if err != nil {
duration := time.Now().Sub(start)
logs = append(logs, courier.NewChannelLogFromError("failed to fetch access token", channel, courier.NilMsgID, duration, err))
return h.Backend().WriteChannelLogs(ctx, logs)
}
accessToken, err := jsonparser.GetString(rr.Body, "access_token")
if err != nil {
duration := time.Now().Sub(start)
logs = append(logs, courier.NewChannelLogFromError("invalid json", channel, courier.NilMsgID, duration, err))
return h.Backend().WriteChannelLogs(ctx, logs)
}
expiration, err := jsonparser.GetInt(rr.Body, "expires_in")
if err != nil {
expiration = 7200
}
rc := h.Backend().RedisPool().Get()
defer rc.Close()
cacheKey := fmt.Sprintf("wechat_channel_access_token:%s", channel.UUID().String())
_, err = rc.Do("set", cacheKey, accessToken, expiration)
if err != nil {
logrus.WithError(err).Error("error setting the access token to redis")
}
return err
}
func (h *handler) getAccessToken(channel courier.Channel) (string, error) {
rc := h.Backend().RedisPool().Get()
defer rc.Close()
cacheKey := fmt.Sprintf("wechat_channel_access_token:%s", channel.UUID().String())
accessToken, err := redis.String(rc.Do(http.MethodGet, cacheKey))
if err != nil {
return "", err
}
if accessToken == "" {
return "", fmt.Errorf("no access token for channel")
}
return accessToken, nil
}
type moPayload struct {
FromUsername string `xml:"FromUserName" validate:"required"`
MsgType string `xml:"MsgType" validate:"required"`
CreateTime int64 `xml:"CreateTime"`
MsgID string `xml:"MsgId"`
Event string `xml:"Event"`
Content string `xml:"Content"`
MediaID string `xml:"MediaId"`
}
// receiveMessage is our HTTP handler function for incoming messages
func (h *handler) receiveMessage(ctx context.Context, channel courier.Channel, w http.ResponseWriter, r *http.Request) ([]courier.Event, error) {
payload := &moPayload{}
err := handlers.DecodeAndValidateXML(payload, r)
if err != nil {
return nil, handlers.WriteAndLogRequestError(ctx, h, channel, w, r, err)
}
if payload.MsgID == "" && payload.Event == "" {
return nil, handlers.WriteAndLogRequestError(ctx, h, channel, w, r, fmt.Errorf("missing parameters, must have either 'MsgId' or 'Event'"))
}
date := time.Unix(payload.CreateTime/1000, payload.CreateTime%1000*1000000).UTC()
urn, err := urns.NewURNFromParts(urns.WeChatScheme, payload.FromUsername, "", "")
if err != nil {
return nil, handlers.WriteAndLogRequestError(ctx, h, channel, w, r, err)
}
// subscribe event, trigger a new conversation
if payload.MsgType == "event" && payload.Event == "subscribe" {
channelEvent := h.Backend().NewChannelEvent(channel, courier.NewConversation, urn)
err := h.Backend().WriteChannelEvent(ctx, channelEvent)
if err != nil {
return nil, err
}
return []courier.Event{channelEvent}, courier.WriteChannelEventSuccess(ctx, w, r, channelEvent)
}
// unknown event type (we only deal with subscribe)
if payload.MsgType == "event" {
return nil, handlers.WriteAndLogRequestIgnored(ctx, h, channel, w, r, "unknown event type")
}
// create our message
msg := h.Backend().NewIncomingMsg(channel, urn, payload.Content).WithExternalID(payload.MsgID).WithReceivedOn(date)
if payload.MsgType == "image" || payload.MsgType == "video" || payload.MsgType == "voice" {
mediaURL := buildMediaURL(payload.MediaID)
msg.WithAttachment(mediaURL)
}
// and finally write our message
return handlers.WriteMsgsAndResponse(ctx, h, []courier.Msg{msg}, w, r)
}
// WriteMsgSuccessResponse writes our response
func (h *handler) WriteMsgSuccessResponse(ctx context.Context, w http.ResponseWriter, r *http.Request, msgs []courier.Msg) error {
w.WriteHeader(200)
_, err := fmt.Fprint(w, "") // WeChat expected empty string to not retry looking for passive reply
return err
}
func buildMediaURL(mediaID string) string {
mediaURL, _ := url.Parse(fmt.Sprintf("%s/%s", sendURL, "media/get"))
mediaURL.RawQuery = url.Values{"media_id": []string{mediaID}}.Encode()
return mediaURL.String()
}
type mtPayload struct {
MsgType string `json:"msgtype"`
ToUser string `json:"touser"`
Text struct {
Content string `json:"content"`
} `json:"text"`
}
// SendMsg sends the passed in message, returning any error
func (h *handler) SendMsg(ctx context.Context, msg courier.Msg) (courier.MsgStatus, error) {
accessToken, err := h.getAccessToken(msg.Channel())
if err != nil {
return nil, err
}
form := url.Values{
"access_token": []string{accessToken},
}
partSendURL, _ := url.Parse(fmt.Sprintf("%s/%s", sendURL, "message/custom/send"))
partSendURL.RawQuery = form.Encode()
status := h.Backend().NewMsgStatusForID(msg.Channel(), msg.ID(), courier.MsgErrored)
parts := handlers.SplitMsg(handlers.GetTextAndAttachments(msg), maxMsgLength)
for _, part := range parts {
wcMsg := &mtPayload{}
wcMsg.MsgType = "text"
wcMsg.ToUser = msg.URN().Path()
wcMsg.Text.Content = part
requestBody := &bytes.Buffer{}
json.NewEncoder(requestBody).Encode(wcMsg)
// build our request
req, _ := http.NewRequest(http.MethodPost, partSendURL.String(), requestBody)
req.Header.Set("Content-Type", "application/json")
req.Header.Set("Accept", "application/json")
rr, err := utils.MakeHTTPRequest(req)
// record our status and log
log := courier.NewChannelLogFromRR("Message Sent", msg.Channel(), msg.ID(), rr).WithError("Message Send Error", err)
status.AddLog(log)
if err != nil {
return status, err
}
status.SetStatus(courier.MsgWired)
}
return status, nil
}
// DescribeURN handles WeChat contact details
func (h *handler) DescribeURN(ctx context.Context, channel courier.Channel, urn urns.URN) (map[string]string, error) {
accessToken, err := h.getAccessToken(channel)
if err != nil {
return nil, err
}
_, path, _, _ := urn.ToParts()
form := url.Values{
"openid": []string{path},
"access_token": []string{accessToken},
}
reqURL, _ := url.Parse(fmt.Sprintf("%s/%s", sendURL, "user/info"))
reqURL.RawQuery = form.Encode()
req, _ := http.NewRequest(http.MethodGet, reqURL.String(), nil)
rr, err := utils.MakeHTTPRequest(req)
if err != nil {
return nil, fmt.Errorf("unable to look up contact data:%s\n%s", err, rr.Response)
}
nickname, err := jsonparser.GetString(rr.Body, "nickname")
if err != nil {
return nil, err
}
return map[string]string{"name": nickname}, nil
}
// BuildDownloadMediaRequest download media for message attachment
func (h *handler) BuildDownloadMediaRequest(ctx context.Context, b courier.Backend, channel courier.Channel, attachmentURL string) (*http.Request, error) {
accessToken, err := h.getAccessToken(channel)
if err != nil {
return nil, err
}
parsedURL, err := url.Parse(attachmentURL)
form := parsedURL.Query()
form["access_token"] = []string{accessToken}
parsedURL.RawQuery = form.Encode()
if err != nil {
return nil, err
}
// first fetch our media
req, _ := http.NewRequest(http.MethodGet, parsedURL.String(), nil)
return req, nil
}