| 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
332
333
334
335
336
337
338
339
340
341
342 |
1×
1×
16×
16×
16×
16×
1×
1×
1×
1×
1×
1×
16×
16×
16×
16×
1×
16×
16×
16×
16×
4×
4×
4×
4×
4×
12×
12×
12×
8×
8×
4×
4×
16×
16×
1×
12×
12×
8×
8×
1×
4×
4×
4×
4×
4×
5×
5×
5×
3×
3×
2×
5×
4×
4×
4×
1×
20×
20×
20×
20×
20×
1×
16×
16×
16×
16×
1×
32×
32×
32×
32×
32×
32×
32×
16×
16×
16×
16×
1×
20×
20×
20×
20×
20×
20×
20×
1×
23×
23×
23×
11×
10×
10×
7×
3×
3×
10×
23×
23×
23×
23×
23×
7×
23×
23×
23×
23×
23×
13×
13×
13×
13×
2×
2×
11×
23×
23×
15×
15×
2×
13×
11×
11×
2×
2×
2×
2×
7×
7×
2×
2×
2×
5×
7×
20×
7×
13×
23×
1×
24×
24×
24×
24×
24×
21×
21×
21×
16×
16×
5×
5×
2×
2×
1×
| 'use strict';
var log = require('./Log.js').Logger('libZotero:FetchNet', 3);
var Deferred = function(){
var d = this;
d.promise = new Promise(function(resolve, reject){
d.resolve = resolve;
d.reject = reject;
});
};
//var Deferred = require('deferred');
/*
* Make concurrent and sequential network requests, respecting backoff/retry-after
* headers, and keeping concurrent requests below a certain limit.
*
* Push onto the queue individual or arrays of requestConfig objects
* If there is room for requests and we are not currently backing off:
* start a sequential series, or individual request
* When any request or set of requests finishes, we preprocess the response,
* looking for backoff/retry-after to obey, and putting sequential responses
* into an array. We then trigger the next waiting request.
*
*/
var Net = function() {
this.deferredQueue = [];
this.numRunning = 0;
this.numConcurrent = 3;
this.backingOff = false;
};
Net.prototype.queueDeferred = function(){
var net = this;
var d = new Deferred();
net.deferredQueue.push(d);
return d.promise;
};
//add a request to the end of the queue, so that previously queue requests run first
//if requestObject is an array of requests, run them sequentially
Net.prototype.queueRequest = function(requestObject){
log.debug('Zotero.Net.queueRequest', 3);
var net = this;
var resultPromise;
if(Array.isArray(requestObject)){
resultPromise = net.queueDeferred().then(function(){
log.debug('running sequential after queued deferred resolved', 4);
return net.runSequential(requestObject);
}).then(function(response){
net.queuedRequestDone();
return response;
}, function(response){
net.queuedRequestDone();
throw response;
});
}
else {
resultPromise = net.queueDeferred().then(function(){
log.debug('running concurrent after queued deferred resolved', 4);
return net.runConcurrent(requestObject);
}).then(function(response){
net.queuedRequestDone();
return response;
}, function(response){
net.queuedRequestDone();
throw response;
});
}
net.runNext();
return resultPromise;
};
//run a request without waiting for any other requests to complete
Net.prototype.runConcurrent = function(requestObject){
log.debug('Zotero.Net.runConcurrent', 3);
return this.ajaxRequest(requestObject).then(function(response){
log.debug('done with runConcurrent request', 3);
return response;
});
};
//run the set of requests serially
//chaining each request onto the .then of the previous one, after
//adding the previous response to a responses array that will be
//returned via promise to the caller when all requests are complete
Net.prototype.runSequential = function(requestObjects){
log.debug('Zotero.Net.runSequential', 3);
var net = this;
var responses = [];
var seqPromise = Promise.resolve();
for(var i = 0; i < requestObjects.length; i++){
let requestObject = requestObjects[i];
seqPromise = seqPromise.then(function(){
var p = net.ajaxRequest(requestObject)
.then(function(response){
log.debug('pushing sequential response into result array', 3);
responses.push(response);
}, function(response){
//return error responses too
responses.push(response);
});
return p;
});
}
return seqPromise.then(function(){
log.debug('done with sequential aggregator promise - returning responses', 4);
return responses;
});
};
//when one concurrent call, or a sequential series finishes, subtract it from the running
//count and run the next if there is something waiting to be run
Net.prototype.individualRequestDone = function(response){
log.debug('Zotero.Net.individualRequestDone', 3);
var net = this;
//check if we need to back off before making more requests
var wait = net.checkDelay(response);
Iif(wait > 0){
var waitms = wait * 1000;
net.backingOff = true;
var waitExpiration = Date.now() + waitms;
if(waitExpiration > net.waitingExpires){
net.waitingExpires = waitExpiration;
}
setTimeout(net.runNext, waitms);
}
return response;
};
Net.prototype.queuedRequestDone = function(){
log.debug('queuedRequestDone', 3);
var net = this;
net.numRunning--;
net.runNext();
};
Net.prototype.runNext = function(){
log.debug('Zotero.Net.runNext', 4);
var net = this;
var nowms = Date.now();
//check if we're backing off and need to remain backing off,
//or if we should now continue
Iif(net.backingOff && (net.waitingExpires > (nowms - 100)) ){
log.debug('currently backing off', 3);
var waitms = net.waitingExpires - nowms;
setTimeout(net.runNext, waitms);
return;
}
else Iif(net.backingOff && (net.waitingExpires <= (nowms - 100))){
net.backingOff = false;
}
//continue making requests up to the concurrent limit
log.debug(net.numRunning + '/' + net.numConcurrent + ' Running. ' + net.deferredQueue.length + ' queued.', 4);
while((net.deferredQueue.length > 0) && (net.numRunning < net.numConcurrent)){
net.numRunning++;
var nextD = net.deferredQueue.shift();
nextD.resolve();
log.debug(net.numRunning + '/' + net.numConcurrent + ' Running. ' + net.deferredQueue.length + ' queued.', 4);
}
};
Net.prototype.checkDelay = function(response){
log.debug('Zotero.Net.checkDelay', 4);
var net = this;
var wait = 0;
Iif(Array.isArray(response)){
for(var i = 0; i < response.length; i++){
var iwait = net.checkDelay(response[i]);
if(iwait > wait){
wait = iwait;
}
}
}
else {
Iif(response.status == 429){
wait = response.retryAfter;
}
else Iif(response.backoff){
wait = response.backoff;
}
}
return wait;
};
//perform a network request defined by requestConfig
//convert the Response into a Zotero.ApiResponse, and attach the passed in
//success/failure handlers to the promise chain before returning (or default error logger
//if no failure handler is defined)
Net.prototype.ajaxRequest = function(requestConfig){
log.debug('Zotero.Net.ajaxRequest', 3);
var net = this;
var defaultConfig = {
type:'GET',
headers:{
'Zotero-API-Version': Zotero.config.apiVersion,
'Content-Type': 'application/json'
},
success: function(response){
return response;
},
error: function(response){
Iif(!response instanceof Zotero.ApiResponse){
log.error(`Response is not a Zotero.ApiResponse: ${response}`);
} else if(response.rawResponse){
log.error(`ajaxRequest rejected:${response.rawResponse.status} - ${response.rawResponse.statusText}`);
} else {
log.error('ajaxRequest rejected: No rawResponse set. (likely network error)');
log.error(response.error);
}
throw response;
}
//cache:false
};
var headers = Z.extend({}, defaultConfig.headers, requestConfig.headers);
Iif(requestConfig.key){
headers = Z.extend(headers, {'Zotero-API-Key': requestConfig.key});
delete requestConfig.key;
}
var config = Z.extend({}, defaultConfig, requestConfig);
config.headers = headers;
if(typeof config.url == 'object'){
config.url = Zotero.ajax.apiRequestString(config.url);
}
config.url = Zotero.ajax.proxyWrapper(config.url, config.type);
Iif(!config.url){
throw 'No url specified in Zotero.Net.ajaxRequest';
}
log.debug('AJAX config', 4);
log.debug(config, 4);
let handleSuccessCallback = (response) => {
return new Promise(resolve => {
Eif(config.success) {
let maybePromise = config.success(response);
if(maybePromise && 'then' in maybePromise) {
maybePromise.then(() => {
resolve();
});
} else {
resolve();
}
} else {
resolve();
}
});
};
var ajaxpromise = new Promise(function(resolve, reject){
net.ajax(config)
.then(function(response){
var ar = new Zotero.ApiResponse(response);
if('processData' in config && config.processData === false) {
handleSuccessCallback(response).then(() => resolve(response))
} else {
response.json().then(function(data){
ar.data = data;
handleSuccessCallback(ar).then(() => resolve(ar))
}, function(err){
log.error(err);
ar.isError = true;
ar.error = err;
reject(ar); //reject promise on malformed json
});
}
}, function(response){
var ar;
if(response instanceof Error){
ar = new Zotero.ApiResponse();
ar.isError = true;
ar.error = response;
} else {
ar = new Zotero.ApiResponse(response);
}
resolve(ar);
});
})
.then(net.individualRequestDone.bind(net))
.then(function(response){
//now that we're done handling, reject
if(response.isError){
//re-throw ApiResponse that was a rejection
throw response;
}
return response;
})
.catch(config.error);
return ajaxpromise;
};
//perform a network request defined by config, and return a promise for a Response
//resolve with a successful status (200-300) reject, but with the same Response object otherwise
Net.prototype.ajax = function(config){
config = Zotero.extend({type:'GET'}, config);
let headersInit = config.headers || {};
let headers = new Headers(headersInit);
var request = new Request(config.url, {
method:config.type,
headers: headers,
mode:'cors',
body:config.data
});
return fetch(request).then(function(response){
log.debug('fetch done', 4);
log.debug(request, 4);
if (response.status >= 200 && response.status < 300) {
log.debug('200-300 response: resolving Net.ajax promise', 3);
// Performs the function "resolve" when this.status is equal to 2xx
return response;
} else {
log.debug('not 200-300 response: rejecting Net.ajax promise', 3);
// Performs the function "reject" when this.status is different than 2xx
throw response;
}
}, function(err){
log.error(err);
throw(err);
});
};
module.exports = new Net();
|