Question

I am having some issues with an extension that i am trying to make. The extension’s job is to check URLs before making the request and block the ones that are available in the list provided. The manifest.json file loads flagged.js which declares and initializes the array. Then, it loads the file that has the function to check URLs:

// To detected and filter globally flagged websites
chrome.webRequest.onBeforeRequest.addListener(
    // What to do if detected a website
    function(info) {

        return {redirectUrl: 'chrome-extension://' + chrome.i18n.getMessage('@@extension_id') + 
            '/blocked.html?flag_type=globally&url=' + escape(info.url)};
    },

    // Website to watchout for
    {
        urls: flagged,
        types: []
    },

    // Action to be performed?
    ["blocking"]);

My issue starts with the part urls: flagged, it seems the list must be hardwired in order to be accepted. What i mean to say, is that i must specify the list items as such:

var flagged = [
"*://*.domain_1.com/*",
"*://*.domain_2.com/*",
"*://*.domain_3.com/*",
"*://*.domain_4.com/*",
];

If i attempt to go to any of the above specified domains, the extension will redirect them to the block.html page no problems. However, i want that list to be automatically or periodically updated, so i introduced this part:

// Get list from the text file we have stored
function getFlagged(url) {
    var list = [];
    var file = new XMLHttpRequest();
    file.open("GET", url, true);
    file.onreadystatechange = function() {
        if (file.readyState === 4) {
            if (file.status === 200) {
                allText = file.responseText; 
                list = file.responseText.split('|');
                    for( var i=0; i<list.length; i++ )
                        flagged.push(list[i]);
            }
        }
    }
    file.send(null);
}

I have tried to change and add things that may not make sense or could be done differently, i was just desperate. The list will be populated with the new items, say *domain_5* and *domain_6* for example. This operation will occur first thing when the extension is being loaded, or so i think. However, when i try to access *domain_5* and *domain_6*, the extension does NOT block them despite the fact that they are in the list flagged.

Any help with this issue would be very appreciated!
Thank you

EDIT: I am not an expert on JS or Chrome.APIs, this is my first attempt at chrome extensions.

Answer 1

Yeah, Your Listener is registering before the XMLHttpRequest is finished.

Call the listener in your onreadystatechange function and you’ll get it to work.