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1 /* | |
2 * This file is part of Adblock Plus <https://adblockplus.org/>, | |
3 * Copyright (C) 2006-2016 Eyeo GmbH | |
4 * | |
5 * Adblock Plus is free software: you can redistribute it and/or modify | |
6 * it under the terms of the GNU General Public License version 3 as | |
7 * published by the Free Software Foundation. | |
8 * | |
9 * Adblock Plus is distributed in the hope that it will be useful, | |
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 * GNU General Public License for more details. | |
13 * | |
14 * You should have received a copy of the GNU General Public License | |
15 * along with Adblock Plus. If not, see <http://www.gnu.org/licenses/>. | |
16 */ | |
17 | |
18 /** | |
19 * @fileOverview Downloads a set of URLs in regular time intervals. | |
20 */ | |
21 | |
22 let {Utils} = require("utils"); | |
23 | |
24 let MILLIS_IN_SECOND = exports.MILLIS_IN_SECOND = 1000; | |
25 let MILLIS_IN_MINUTE = exports.MILLIS_IN_MINUTE = 60 * MILLIS_IN_SECOND; | |
26 let MILLIS_IN_HOUR = exports.MILLIS_IN_HOUR = 60 * MILLIS_IN_MINUTE; | |
27 let MILLIS_IN_DAY = exports.MILLIS_IN_DAY = 24 * MILLIS_IN_HOUR; | |
28 | |
29 /** | |
30 * Creates a new downloader instance. | |
31 * @param {Function} dataSource Function that will yield downloadable objects o
n each check | |
32 * @param {Integer} initialDelay Number of milliseconds to wait before the firs
t check | |
33 * @param {Integer} checkInterval Interval between the checks | |
34 * @constructor | |
35 */ | |
36 let Downloader = exports.Downloader = function Downloader(dataSource, initialDel
ay, checkInterval) | |
37 { | |
38 this.dataSource = dataSource; | |
39 this._timer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer); | |
40 this._timer.initWithCallback(function() | |
41 { | |
42 this._timer.delay = checkInterval; | |
43 this._doCheck(); | |
44 }.bind(this), initialDelay, Ci.nsITimer.TYPE_REPEATING_SLACK); | |
45 this._downloading = Object.create(null); | |
46 } | |
47 Downloader.prototype = | |
48 { | |
49 /** | |
50 * Timer triggering the downloads. | |
51 * @type nsITimer | |
52 */ | |
53 _timer: null, | |
54 | |
55 /** | |
56 * Map containing the URLs of objects currently being downloaded as its keys. | |
57 */ | |
58 _downloading: null, | |
59 | |
60 /** | |
61 * Function that will yield downloadable objects on each check. | |
62 * @type Function | |
63 */ | |
64 dataSource: null, | |
65 | |
66 /** | |
67 * Maximal time interval that the checks can be left out until the soft | |
68 * expiration interval increases. | |
69 * @type Integer | |
70 */ | |
71 maxAbsenceInterval: 1 * MILLIS_IN_DAY, | |
72 | |
73 /** | |
74 * Minimal time interval before retrying a download after an error. | |
75 * @type Integer | |
76 */ | |
77 minRetryInterval: 1 * MILLIS_IN_DAY, | |
78 | |
79 /** | |
80 * Maximal allowed expiration interval, larger expiration intervals will be | |
81 * corrected. | |
82 * @type Integer | |
83 */ | |
84 maxExpirationInterval: 14 * MILLIS_IN_DAY, | |
85 | |
86 /** | |
87 * Maximal number of redirects before the download is considered as failed. | |
88 * @type Integer | |
89 */ | |
90 maxRedirects: 5, | |
91 | |
92 /** | |
93 * Called whenever expiration intervals for an object need to be adapted. | |
94 * @type Function | |
95 */ | |
96 onExpirationChange: null, | |
97 | |
98 /** | |
99 * Callback to be triggered whenever a download starts. | |
100 * @type Function | |
101 */ | |
102 onDownloadStarted: null, | |
103 | |
104 /** | |
105 * Callback to be triggered whenever a download finishes successfully. The | |
106 * callback can return an error code to indicate that the data is wrong. | |
107 * @type Function | |
108 */ | |
109 onDownloadSuccess: null, | |
110 | |
111 /** | |
112 * Callback to be triggered whenever a download fails. | |
113 * @type Function | |
114 */ | |
115 onDownloadError: null, | |
116 | |
117 /** | |
118 * Checks whether anything needs downloading. | |
119 */ | |
120 _doCheck: function() | |
121 { | |
122 let now = Date.now(); | |
123 for (let downloadable of this.dataSource()) | |
124 { | |
125 if (downloadable.lastCheck && now - downloadable.lastCheck > this.maxAbsen
ceInterval) | |
126 { | |
127 // No checks for a long time interval - user must have been offline, e.g
. | |
128 // during a weekend. Increase soft expiration to prevent load peaks on t
he | |
129 // server. | |
130 downloadable.softExpiration += now - downloadable.lastCheck; | |
131 } | |
132 downloadable.lastCheck = now; | |
133 | |
134 // Sanity check: do expiration times make sense? Make sure people changing | |
135 // system clock don't get stuck with outdated subscriptions. | |
136 if (downloadable.hardExpiration - now > this.maxExpirationInterval) | |
137 downloadable.hardExpiration = now + this.maxExpirationInterval; | |
138 if (downloadable.softExpiration - now > this.maxExpirationInterval) | |
139 downloadable.softExpiration = now + this.maxExpirationInterval; | |
140 | |
141 // Notify the caller about changes to expiration parameters | |
142 if (this.onExpirationChange) | |
143 this.onExpirationChange(downloadable); | |
144 | |
145 // Does that object need downloading? | |
146 if (downloadable.softExpiration > now && downloadable.hardExpiration > now
) | |
147 continue; | |
148 | |
149 // Do not retry downloads too often | |
150 if (downloadable.lastError && now - downloadable.lastError < this.minRetry
Interval) | |
151 continue; | |
152 | |
153 this._download(downloadable, 0); | |
154 } | |
155 }, | |
156 | |
157 /** | |
158 * Stops the periodic checks. | |
159 */ | |
160 cancel: function() | |
161 { | |
162 this._timer.cancel(); | |
163 }, | |
164 | |
165 /** | |
166 * Checks whether an address is currently being downloaded. | |
167 */ | |
168 isDownloading: function(/**String*/ url) /**Boolean*/ | |
169 { | |
170 return url in this._downloading; | |
171 }, | |
172 | |
173 /** | |
174 * Starts downloading for an object. | |
175 */ | |
176 download: function(/**Downloadable*/ downloadable) | |
177 { | |
178 // Make sure to detach download from the current execution context | |
179 Utils.runAsync(this._download.bind(this, downloadable, 0)); | |
180 }, | |
181 | |
182 /** | |
183 * Generates the real download URL for an object by appending various | |
184 * parameters. | |
185 */ | |
186 getDownloadUrl: function(/**Downloadable*/ downloadable) /** String*/ | |
187 { | |
188 let {addonName, addonVersion, application, applicationVersion, platform, pla
tformVersion} = require("info"); | |
189 let url = downloadable.redirectURL || downloadable.url; | |
190 if (url.indexOf("?") >= 0) | |
191 url += "&"; | |
192 else | |
193 url += "?"; | |
194 // We limit the download count to 4+ to keep the request anonymized | |
195 let downloadCount = downloadable.downloadCount; | |
196 if (downloadCount > 4) | |
197 downloadCount = "4+"; | |
198 url += "addonName=" + encodeURIComponent(addonName) + | |
199 "&addonVersion=" + encodeURIComponent(addonVersion) + | |
200 "&application=" + encodeURIComponent(application) + | |
201 "&applicationVersion=" + encodeURIComponent(applicationVersion) + | |
202 "&platform=" + encodeURIComponent(platform) + | |
203 "&platformVersion=" + encodeURIComponent(platformVersion) + | |
204 "&lastVersion=" + encodeURIComponent(downloadable.lastVersion) + | |
205 "&downloadCount=" + encodeURIComponent(downloadCount); | |
206 return url; | |
207 }, | |
208 | |
209 _download: function(downloadable, redirects) | |
210 { | |
211 if (this.isDownloading(downloadable.url)) | |
212 return; | |
213 | |
214 let downloadUrl = this.getDownloadUrl(downloadable); | |
215 let request = null; | |
216 | |
217 let errorCallback = function errorCallback(error) | |
218 { | |
219 let channelStatus = -1; | |
220 try | |
221 { | |
222 channelStatus = request.channel.status; | |
223 } catch (e) {} | |
224 | |
225 let responseStatus = request.status; | |
226 | |
227 Cu.reportError("Adblock Plus: Downloading URL " + downloadable.url + " fai
led (" + error + ")\n" + | |
228 "Download address: " + downloadUrl + "\n" + | |
229 "Channel status: " + channelStatus + "\n" + | |
230 "Server response: " + responseStatus); | |
231 | |
232 if (this.onDownloadError) | |
233 { | |
234 // Allow one extra redirect if the error handler gives us a redirect URL | |
235 let redirectCallback = null; | |
236 if (redirects <= this.maxRedirects) | |
237 { | |
238 redirectCallback = function redirectCallback(url) | |
239 { | |
240 downloadable.redirectURL = url; | |
241 this._download(downloadable, redirects + 1); | |
242 }.bind(this); | |
243 } | |
244 | |
245 this.onDownloadError(downloadable, downloadUrl, error, channelStatus, re
sponseStatus, redirectCallback); | |
246 } | |
247 }.bind(this); | |
248 | |
249 try | |
250 { | |
251 request = new XMLHttpRequest(); | |
252 request.mozBackgroundRequest = true; | |
253 request.open("GET", downloadUrl); | |
254 } | |
255 catch (e) | |
256 { | |
257 errorCallback("synchronize_invalid_url"); | |
258 return; | |
259 } | |
260 | |
261 try { | |
262 request.overrideMimeType("text/plain"); | |
263 request.channel.loadFlags = request.channel.loadFlags | | |
264 request.channel.INHIBIT_CACHING | | |
265 request.channel.VALIDATE_ALWAYS; | |
266 | |
267 // Override redirect limit from preferences, user might have set it to 1 | |
268 if (request.channel instanceof Ci.nsIHttpChannel) | |
269 request.channel.redirectionLimit = this.maxRedirects; | |
270 } | |
271 catch (e) | |
272 { | |
273 Cu.reportError(e) | |
274 } | |
275 | |
276 request.addEventListener("error", function(event) | |
277 { | |
278 if (onShutdown.done) | |
279 return; | |
280 | |
281 delete this._downloading[downloadable.url]; | |
282 errorCallback("synchronize_connection_error"); | |
283 }.bind(this), false); | |
284 | |
285 request.addEventListener("load", function(event) | |
286 { | |
287 if (onShutdown.done) | |
288 return; | |
289 | |
290 delete this._downloading[downloadable.url]; | |
291 | |
292 // Status will be 0 for non-HTTP requests | |
293 if (request.status && request.status != 200) | |
294 { | |
295 errorCallback("synchronize_connection_error"); | |
296 return; | |
297 } | |
298 | |
299 downloadable.downloadCount++; | |
300 | |
301 this.onDownloadSuccess(downloadable, request.responseText, errorCallback,
function redirectCallback(url) | |
302 { | |
303 if (redirects >= this.maxRedirects) | |
304 errorCallback("synchronize_connection_error"); | |
305 else | |
306 { | |
307 downloadable.redirectURL = url; | |
308 this._download(downloadable, redirects + 1); | |
309 } | |
310 }.bind(this)); | |
311 }.bind(this), false); | |
312 | |
313 request.send(null); | |
314 | |
315 this._downloading[downloadable.url] = true; | |
316 if (this.onDownloadStarted) | |
317 this.onDownloadStarted(downloadable); | |
318 }, | |
319 | |
320 /** | |
321 * Produces a soft and a hard expiration interval for a given supplied | |
322 * expiration interval. | |
323 * @return {Array} soft and hard expiration interval | |
324 */ | |
325 processExpirationInterval: function(/**Integer*/ interval) | |
326 { | |
327 interval = Math.min(Math.max(interval, 0), this.maxExpirationInterval); | |
328 let soft = Math.round(interval * (Math.random() * 0.4 + 0.8)); | |
329 let hard = interval * 2; | |
330 let now = Date.now(); | |
331 return [now + soft, now + hard]; | |
332 } | |
333 }; | |
334 | |
335 /** | |
336 * An object that can be downloaded by the downloadable | |
337 * @param {String} url URL that has to be requested for the object | |
338 * @constructor | |
339 */ | |
340 let Downloadable = exports.Downloadable = function Downloadable(url) | |
341 { | |
342 this.url = url; | |
343 } | |
344 Downloadable.prototype = | |
345 { | |
346 /** | |
347 * URL that has to be requested for the object. | |
348 * @type String | |
349 */ | |
350 url: null, | |
351 | |
352 /** | |
353 * URL that the download was redirected to if any. | |
354 * @type String | |
355 */ | |
356 redirectURL: null, | |
357 | |
358 /** | |
359 * Time of last download error or 0 if the last download was successful. | |
360 * @type Integer | |
361 */ | |
362 lastError: 0, | |
363 | |
364 /** | |
365 * Time of last check whether the object needs downloading. | |
366 * @type Integer | |
367 */ | |
368 lastCheck: 0, | |
369 | |
370 /** | |
371 * Object version corresponding to the last successful download. | |
372 * @type Integer | |
373 */ | |
374 lastVersion: 0, | |
375 | |
376 /** | |
377 * Soft expiration interval, will increase if no checks are performed for a | |
378 * while. | |
379 * @type Integer | |
380 */ | |
381 softExpiration: 0, | |
382 | |
383 /** | |
384 * Hard expiration interval, this is fixed. | |
385 * @type Integer | |
386 */ | |
387 hardExpiration: 0, | |
388 | |
389 /** | |
390 * Number indicating how often the object was downloaded. | |
391 * @type Integer | |
392 */ | |
393 downloadCount: 0, | |
394 }; | |
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