Resource Requests

When a URL is loaded, it typically makes a number of resource requests for CCS, JavaScript, image, and other files. Details about these requests can be viewed in the Requests activity. The navigation drawer has a link to the Requests activity and also shows how many requests were blocked. Tapping on a request displays details about why it was allowed or blocked.

Privacy Browser includes four common blocklists based on the Adblock syntax: EasyList, EasyPrivacy, Fanboy’s Annoyance List, and Fanboy’s Social Blocking List. These blocklists are processed by Privacy Browser into the following 22 sublists, which check resource requests in the order listed.

1. Main Whitelist
2. Final Whitelist
3. Domain Whitelist
4. Domain Initial Whitelist
5. Domain Final Whitelist
6. Third-Party Whitelist
7. Third-Party Domain Whitelist
8. Third-Party Domain Initial Whitelist
9. Main Blacklist
10. Initial Blacklist
11. Final Blacklist
12. Domain Blacklist
13. Domain Initial Blacklist
14. Domain Final Blacklist
15. Domain Regular Expression Blacklist
16. Third-Party Blacklist
17. Third-Party Initial Blacklist
18. Third-Party Domain Blacklist
19. Third-Party Domain Initial Blacklist
20. Third-Party Regular Expression Blacklist
21. Third-Party Domain Regular Expression Blacklist
22. Regular Expression Blacklist

Initial lists check against the beginning of the URL. Final lists check against the end of the URL. Domain lists only check against certain domains. Third-party lists only apply if the root domain of the request is different than the root domain of the main URL. Regular expression lists follow the regular expression syntax. Each sublist item has one or more entry. In the case of domain sublists, the resource request is only checked against the item if the first entry matches the domain of the main URL.

Because of limitations in Android’s WebView, and to speed up processing of requests, Privacy Browser implements a simplified interpretation of the Adblock syntax. This can sometimes lead to false positives, where resources are allowed or blocked in ways that weren’t intended by the original entry. A more detailed description of how the blocklist entries are processed is available at stoutner.com.

Privacy Browser has three additional blocklists. UltraList and UltraPrivacy block ads and trackers that EasyList and EasyPrivacy do not. The third blocks all third-party requests. A request is only considered third-party if the base domain of the request is different than the base domain of the URL. For example, if www.website.com loads a picture from images.website.com, this is not blocked as a third-party request because they both share the same base domain of website.com. Blocking all third-party requests increases privacy, but this blocklist is disabled by default because it breaks a large number of websites.