components/minimalist.js

   1 function NSGetModule(compMgr, fileSpec)
   2 {
   3   // Constants //
   4   const settings   = Components.classes['@mozilla.org/preferences-service;1'].getService(Components.interfaces.nsIPrefBranch)
   5   const urlParser  = Components.classes['@mozilla.org/network/standard-url;1'].getService(Components.interfaces.nsIURI)
   6   const whiteList  = {'chrome': true, 'resource': true}
   7   const hostRE     = /^(?:\d{1,3}\.){3}\d{1,3}|[\w\-]{3,}(?=(?:\.[a-z]{2})*\.\w{2,}$)/
   8   const contentRE  = /^(?:text\/html|application\/xhtml\+xml)/
   9   const cacheRE    = /^(?:text|image|multipart)\/|^application\/(?:x-)?(?:javascript|json)/
  10   const ACCEPT     = Components.interfaces.nsIContentPolicy.ACCEPT
  11   const REJECT     = Components.interfaces.nsIContentPolicy.REJECT_SERVER
  12   var exceptions   = { }
  13   var filterLevel  = 3
  14
  15   // Implementation: content-policy //
  16   function getDomainName(URL)
  17   {
  18     hostName = hostRE.exec(URL.host)
  19     return hostName ? hostName[0].toLowerCase() : URL.host
  20   }
  21
  22   function isImageLink(node)
  23   {
  24     return node            instanceof Components.interfaces.nsIDOMHTMLImageElement &&
  25            node.parentNode instanceof Components.interfaces.nsIDOMHTMLAnchorElement
  26   }
  27
  28   function lastMeasure(node, targetURL)
  29   {
  30     if (filterLevel > 2 && isImageLink(node)) {
  31       return ACCEPT
  32     } else
  33       return ACCEPT
  34   }
  35
  36   function shouldLoad(contentType, contentLocation, requestOrigin, context, mimeTypeGuess, extra)
  37   {
  38     if (filterLevel < 1 || context instanceof Components.interfaces.nsIDOMXULElement || requestOrigin == null ||
  39         requestOrigin.scheme in whiteList || contentLocation.scheme in whiteList)
  40       return ACCEPT
  41
  42     sourceHost = getDomainName(requestOrigin)
  43     destHost   = getDomainName(contentLocation)
  44
  45     if (filterLevel > 1 && isImageLink(context)) {
  46       urlParser.spec = context.parentNode.href
  47       if (getDomainName(urlParser) != sourceHost)
  48         return REJECT
  49     }
  50
  51     if (sourceHost == destHost)
  52       return lastMeasure(context, contentLocation)
  53
  54     exceptHosts = exceptions[sourceHost]
  55     if (exceptHosts && destHost in exceptHosts)
  56       return lastMeasure(context, contentLocation)
  57     else
  58       return REJECT
  59   }
  60
  61   // Implementation: http-on-modify-request //
  62   function getRequestHeader(channel, tag)
  63   {
  64     try       { return channel.getRequestHeader(tag) }
  65     catch (e) { return false }
  66   }
  67
  68   function getResponseHeader(channel, tag)
  69   {
  70     try       { return channel.getResponseHeader(tag) }
  71     catch (e) { return false }
  72   }
  73
  74   function observe(subject, topic, data)
  75   {
  76     switch (topic)
  77     {
  78       case 'http-on-modify-request':
  79         if (subject) {
  80           httpChannel = subject.QueryInterface(Components.interfaces.nsIHttpChannel)
  81           httpChannel.setRequestHeader('If-Modified-Since', '', false)
  82           httpChannel.setRequestHeader('User-Agent', 'Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.0.6) '
  83                                                    + 'Gecko/2009011913 Firefox/3.0.6 ', false)
  84
  85           if (httpReferer = getRequestHeader(httpChannel, 'Referer')) {
  86             urlParser.spec = httpReferer
  87             httpReferer    = getDomainName(urlParser)
  88             urlParser.spec = 'http://' + getRequestHeader(httpChannel, 'Host')
  89
  90             if (httpReferer != getDomainName(urlParser))
  91               httpChannel.setRequestHeader('Referer', urlParser.spec, false)
  92           }
  93         }
  94         break
  95
  96       case 'http-on-examine-response':
  97         if (subject) {
  98           httpChannel = subject.QueryInterface(Components.interfaces.nsIHttpChannel)
  99           httpChannel.setResponseHeader('Age',           '', false)
 100           httpChannel.setResponseHeader('Cache-Control', '', false)
 101           httpChannel.setResponseHeader('Date',          '', false)
 102           httpChannel.setResponseHeader('ETag',          '', false)
 103           httpChannel.setResponseHeader('Last-Modified', '', false)
 104           httpChannel.setResponseHeader('Pragma',        '', false)
 105           httpChannel.setResponseHeader('Vary',          '', false)
 106
 107           if (contentType = getResponseHeader(httpChannel, 'Content-Type')) {
 108             if (contentType.match(contentRE))
 109               httpChannel.setResponseHeader('Expires', new Date( Date.now() + 120000 ).toGMTString(), false)
 110             else {
 111               contentLength = getResponseHeader(httpChannel, 'Content-Length')
 112               if (!contentLength || parseInt(contentLength) > 2097152 || !contentType.match(cacheRE))
 113                 httpChannel.setResponseHeader('Expires', 'Thu, 01 Jan 1970 00:00:00 GMT', false)
 114               else
 115                 httpChannel.setResponseHeader('Expires', 'Sun, 07 Feb 2106 06:28:15 GMT', false)
 116             }
 117           }
 118         }
 119         break
 120
 121       case 'nsPref:changed':
 122         path = data.split('.')
 123         switch (path[2])
 124         {
 125           case 'whitelist':
 126             srcHost = path[3]
 127             dstHost = settings.getCharPref(data).split(',')
 128
 129             if (dstHost.length > 0) {
 130               exceptions[srcHost] = { }
 131               for (i in dstHost)
 132                 exceptions[srcHost][dstHost[i]] = true
 133             } else
 134               delete exceptions[srcHost]
 135             break
 136
 137           case 'level':
 138             filterLevel = settings.getIntPref(data)
 139             break
 140         }
 141         break
 142     }
 143   }
 144
 145   // XPCOM registration //
 146   Components.utils.import('resource://gre/modules/XPCOMUtils.jsm')
 147
 148   function Minimalist() {
 149     this.wrappedJSObject = this
 150     observer = Components.classes['@mozilla.org/observer-service;1'].getService(Components.interfaces.nsIObserverService)
 151     observer.addObserver(this, 'http-on-modify-request', false)
 152     observer.addObserver(this, 'http-on-examine-response', false)
 153     settings.QueryInterface(Components.interfaces.nsIPrefBranch2)
 154     settings.addObserver('extensions.minimalist.', this, false)
 155
 156     entries = settings.getChildList('extensions.minimalist.whitelist', {})
 157     for (i in entries) {
 158       entry = entries[i].split('.')[3]
 159       exceptions[entry] = {}
 160
 161       values = settings.getCharPref(entries[i]).split(',')
 162       for (j in values)
 163         exceptions[entry][values[j]] = true
 164     }
 165   }
 166   Minimalist.prototype = {
 167      classDescription: 'Minimalist',
 168               classID: Components.ID('{124b1de7-bd8a-4a41-a04a-9d40070a0b3a}'),
 169            contractID: '@zelgadis.jp/minimalist;1',
 170     _xpcom_categories: [{category: 'content-policy'}],
 171        QueryInterface: XPCOMUtils.generateQI([Components.interfaces.nsIContentPolicy, Components.interfaces.nsIObserver]),
 172            shouldLoad: shouldLoad,
 173         shouldProcess: function() { return ACCEPT },
 174               observe: observe
 175   }
 176
 177   return XPCOMUtils.generateModule([Minimalist])
 178 }