Avoiding the "urls" format using the onBeforeRequest function

Question

Avoiding the "urls" format using the onBeforeRequest function

chrome.webRequest.onBeforeRequest.addListener(function(details) {
    if (localStorage.on == '1') {
        return {cancel:true};
    }
}, {urls: ["*://*.domain1.net/*","*://*.domain2.com/*","*://*.domain3.com/*"], types: ["script","xmlhttprequest","other"]}, ["blocking"]);

Is there a way to exclude URLs that match a certain pattern? I want to block all requests except those made to the specified 3 domains. I considered using cancel:true for all requests and allowing the exact content for the 3 domains. Do I need to be concerned about one listener taking precedence over another? How can I modify the code to return the exact content for the specified domains instead of canceling the request?

javascript google-chrome-extension

Answer 1

Answer №1

Here is an example showcasing how to restrict all requests except those directed towards domain1.net and domain2.net:

    chrome.webRequest.onBeforeRequest.addListener(
       function(details) {
         return {cancel: details.url.indexOf(".domain2.net/") == -1 && details.url.indexOf(".domain1.net/") == -1};
       },
    {urls: ["<all_urls>"]},
    ["blocking"]);

Upon reviewing the documentation, it seems there is no straightforward method to negate the URL pattern.

However, Xan proposes a more effective technique for verifying the domain1.net and domain2.net URLs in the response below.

Answer 2

Here is an example showcasing how to restrict all requests except those directed towards domain1.net and domain2.net:

    chrome.webRequest.onBeforeRequest.addListener(
       function(details) {
         return {cancel: details.url.indexOf(".domain2.net/") == -1 && details.url.indexOf(".domain1.net/") == -1};
       },
    {urls: ["<all_urls>"]},
    ["blocking"]);

Upon reviewing the documentation, it seems there is no straightforward method to negate the URL pattern.

However, Xan proposes a more effective technique for verifying the domain1.net and domain2.net URLs in the response below.

Answer 3

Answer №2

While Paulo Prestes' answer is mostly accurate, it should be noted that "negative" filters are not supported. However, the suggested filter can be easily circumvented.

For example, consider the URL: https://example.com/something?foo=.domain2.net/

Although this URL matches the rule, it is clear that this is not the intended target. Adding an extra parameter can easily bypass the filter without affecting most pages.

Instead, a more robust approach would be to use a set of regular expressions specifically designed to extract the domain:

function validateDomain(url) {
  // Explanation of RegEx:
  // ^                     start of the string
  // http                  exactly "http"
  // s?                    optional "s"
  // :\/\/                 exactly "://"
  // ([^\/]+\.)?           one or more characters not including "/" followed by "."
  // domain\.net\/         exactly "domain1.net/"

  return /^https?:\/\/([^\/]+\.)?domain1\.net\//.test(url) ||
         /^https?:\/\/([^\/]+\.)?domain2\.net\//.test(url) ||
         /^https?:\/\/([^\/]+\.)?domain3\.net\//.test(url) 
}

/* ... */
  return {block: !validateDomain(details.url)};
/* ... */

Answer 4

While Paulo Prestes' answer is mostly accurate, it should be noted that "negative" filters are not supported. However, the suggested filter can be easily circumvented.

For example, consider the URL: https://example.com/something?foo=.domain2.net/

Although this URL matches the rule, it is clear that this is not the intended target. Adding an extra parameter can easily bypass the filter without affecting most pages.

Instead, a more robust approach would be to use a set of regular expressions specifically designed to extract the domain:

function validateDomain(url) {
  // Explanation of RegEx:
  // ^                     start of the string
  // http                  exactly "http"
  // s?                    optional "s"
  // :\/\/                 exactly "://"
  // ([^\/]+\.)?           one or more characters not including "/" followed by "."
  // domain\.net\/         exactly "domain1.net/"

  return /^https?:\/\/([^\/]+\.)?domain1\.net\//.test(url) ||
         /^https?:\/\/([^\/]+\.)?domain2\.net\//.test(url) ||
         /^https?:\/\/([^\/]+\.)?domain3\.net\//.test(url) 
}

/* ... */
  return {block: !validateDomain(details.url)};
/* ... */

Avoiding the "urls" format using the onBeforeRequest function

Answer №1

Answer №2

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