CODEWITHSUNDEEP
javascripthtmlhttpxmlhttprequestfirefox-addon
Ritubala Kachhwahe
Ritubala Kachhwahe

Reputation: 41

get html page as response from url inside an extension

I am developing an extension in which whatever request is coming i want to change the request parameters and send a dummy request to server to get response. for eg. if original request loaded is www.abc.com/eg.php?user="some code", then i want to change it into www.abc.com/eg.php?user="ritubala" and get html page in the response for further processing inside my extension.. i used these codes given in following url Return HTML content as a string, given URL. Javascript Function but it is causing recursion... so in short i want to get html code from a url inside my extension...plz do help

Upvotes: 0

Views: 308

Answers (1)

Noitidart
Noitidart

Reputation: 37238

Use nsITraceableChannel, note that you get a copy of the content being loaded.

If you abort the request then it aborts giving you a copy.

Here's me using nsITraceableChannel: https://github.com/Noitidart/demo-nsITraceableChannel

What I think you want is this:

const { Ci, Cu, Cc, Cr } = require('chrome'); //const {interfaces: Ci, utils: Cu, classes: Cc, results: Cr } = Components;
Cu.import('resource://gre/modules/Services.jsm');
Cu.import('resource://gre/modules/devtools/Console.jsm');

var observers = {
    'http-on-examine-response': {
        observe: function (aSubject, aTopic, aData) {
            console.info('http-on-modify-request: aSubject = ' + aSubject + ' | aTopic = ' + aTopic + ' | aData = ' + aData);
            var httpChannel = subject.QueryInterface(Ci.nsIHttpChannel);
            var requestUrl = httpChannel.URI.spec
            if (requestUrl.indexOf('blah')) {
                //httpChannel.cancel(Cr.NS_BINDING_ABORTED); //this is how you abort but if use redirectTo you don't need to abort the request
                httpChannel.redirectTo(Services.io.newURI('http://www.anotherwebsite/', null, null));
            }
        },
        reg: function () {
            Services.obs.addObserver(observers['http-on-modify-request'], 'http-on-modify-request', false);
        },
        unreg: function () {
            Services.obs.removeObserver(observers['http-on-modify-request'], 'http-on-modify-request');
        }
    }
};



//register all observers
for (var o in observers) {
    observers[o].reg();
}

note the redirectTo function is for FF20+ https://developer.mozilla.org/en-US/docs/XPCOM_Interface_Reference/nsIHttpChannel#redirectTo%28%29

so combine this example with the nsITraceableChannel demo and you'll have what you want.

if you don't want to redirect you can abort the request, get the DOCUMENT of the request and then xmlhttprequest the new page which gives you the source FIRST and doesnt load it to tab, and then modify the source then load it back to the DOCUMENT.

OR instead of xmlhttprequesting it, just abort the request, redirectTo the new page and then modify the tab. to get the tab of the channel see solution here:

Security Error when trying to load content from resource in a Firefox Addon (SDK)

also to do http requests from an extension see this snippet: https://gist.github.com/Noitidart/9088113

Upvotes: 1

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