libadblockplus

A C++ library offering the core functionality of Adblock Plus.

Getting/updating the dependencies

libadblockplus has dependencies that aren't part of this repository. They are retrieved and updated during the build process, but you can also manually update them by running the following:

./ensure_dependencies.py

Building

Supported target platforms and prerequisites

You need a C++11 compatible compiler to build libadblockplus.

Win32:

• Microsoft Visual Studio 2010, 2012

Linux:

• g++ 5.2

Mac:

• clang 3.6 for OS X

Android:

• The host system should be Linux or OS X
• android-ndk-r9, android-ndk-r10c. You can download the latter for OS X, Linux 32, Linux 64.
• g++ multilib

If you have a compilation issue with another compiler please create an issue.

Unix

All you need is Python 2.7 and Make:

make

The default target architecture is x64. On a 32 bit system, run:

make ARCH=ia32

To build and run the tests:

make test

Likewise, use the following on a 32 bit system:

make test ARCH=ia32

To run specific tests, you can specify a filter:

make test FILTER=*.Matches

Windows

You need Microsoft Visual C++ (Express is sufficient) 2012 and Python 2.7. Make sure that python.exe is on your PATH.

• Execute createsolution.bat to generate project files, this will create build\ia32\libadblockplus.sln (solution for the 32 bit build) and build\x64\libadblockplus.sln (solution for the 64 bit build). Unfortunately, V8 doesn't support creating both from the same project files.
• Open build\ia32\libadblockplus.sln or build\x64\libadblockplus.sln in Visual Studio and build the solution there. Alternatively you can use the msbuild command line tool, e.g. run msbuild /m build\ia32\libadblockplus.sln from the Visual Studio Developer Command Prompt to create a 32 bit debug build.

Building for Android

First set ANDROID_NDK_ROOT environment variable to your Android NDK directory.

To build for x86 arch run:

make android_x86

To build for arm arch run:

make android_arm

Usage

You can use libadblockplus to build an ad blocker. Or, strictly speaking, a web content filter. Just like Adblock Plus, it can detect resources that should be blocked based on their URL and context information, and generate CSS selectors to hide DOM elements.

The basic usage is explained below, see the API documentation for more information. See the filter documentation to learn more about Adblock Plus filters.

Initialising the engine

All the types and functions in libadblockplus are in the AdblockPlus namespace. For brevity's sake, we'll assume the following using declaration:

using namespace AdblockPlus;

Most of the functionality of libadblockplus is available via the FilterEngine class. Since libadblockplus uses the Adblock Plus core code under the hood, you first need to create a JsEngine instance and pass some information about your application to it.

AppInfo appInfo;
appInfo.name = "awesomewebfilter";
appInfo.version = "0.1";
appInfo.locale = "en-US";
JsEngine jsEngine(appInfo);

JsEngine needs to store files, make web requests and write log messages. This normally works out of the box because it is using DefaultFileSystem, DefaultWebRequest and DefaultLogSystem by default.

Depending on your application and platform, you might want to supply your own implementations for these - see FilterEngine::SetFileSystem, FilterEngine::SetWebRequest and FilterEngine::SetLogSystem respectively.

With the JsEngine instance created, you can create a FilterEngine instance:

auto filterEngine = FilterEngine::Create(jsEngine);

Please also pay attention to asynchronous version of factory method FilterEngine::CreateAsync and to optional creationParameters.

When initialised, FilterEngine will automatically select a suitable ad blocking subscription based on AppInfo::locale and download the filters for it.

Managing subscriptions

libadblockplus takes care of storing and updating subscriptions.

You can add more:

SubscriptionPtr subscription =
  filterEngine.GetSubscription("https://example.org/filters.txt");
subscription->AddToList();

Retrieving an existing subscription works the same way, use Subscription::IsListed to check if the subscription has been added or not.

SubscriptionPtr subscription =
  filterEngine.GetSubscription("https://example.org/filters.txt");
if (subscription->IsListed())
    ....

Removing a subscription is not rocket science either:

subscription->RemoveFromList();

You can also get a list of all subscriptions that were added:

std::vector<SubscriptionPtr> subscriptions =
  filterEngine.GetListedSubscriptions();

Managing custom filters

Working with custom filters is very similar to working with subscriptions:

FilterPtr filter = filterEngine.GetFilter("||example.com/ad.png");
filter->AddToList();
filter->RemoveFromList();

Note that applications should only do this to manage a user's custom filters. In general, filter lists should be hosted somewhere and added as a subscription.

Matching blocking filters

As mentioned above, one of the two main tasks of libadblockplus is to check if a URL matches any of the active blocking filters.

To demonstrate this, we'll add a custom filter:

FilterPtr filter = filterEngine.GetFilter("||example.com/ad.png");
filter->AddToList();

Now we'll call matches on an URL that should be blocked:

FilterPtr match =
  filterEngine.Matches("http://example.com/ad.png", "DOCUMENT", "");

Since we've added a matching filter, match will point to the same filter object as filter.

Note that we've ignored the third parameter of FilterEngine::Matches here to keep things simple. Real applications should pass the frame structure in here - this is necessary because many filters and exception rules are domain specific.

Generating CSS from element hiding filters

Aside from blocking requests, ad blockers typically also hide elements. This is done via a second type of filter that is completely ignored when matching URLs: element hiding rules.

You can retrieve a list of all CSS selectors for elements that should be hidden using FilterEngine::GetElementHidingSelectors.

What libadblockplus clients typically do with this is to generate a CSS style sheet that is injected into each page.

Disabling network requests from Adblock Plus on current connection

At any moment you can call FilterEngine::SetAllowedConnectionType to change the settings indicating what connection types are allowed in your application. However to have it working you should also pass a callback function into factory method of FilterEngine. This callback is being called before each request and the value of argument is earlier passed string into FilterEngine::SetAllowedConnectionType, what allows to query the system and check whether the current connection is in accordance with earlier stored value in settings. For example, you can pass "not_metered" into FilterEngine::SetAllowedConnectionType and on each request you can check whether the current connection is "not_metered" and return true or false from you implementation of callback AdblockPlus::FilterEngine::CreateParameters::isConnectionAllowed.

Shell

The shell subdirectory contains an example application using libadblockplus.

It's a simple shell that loads subscriptions into memory and checks whether a specified resource would be blocked or not.

To see the available commands, type help.

Unix

The shell is automatically built by make, you can run it as follows:

build/out/abpshell

Windows

Just run the project abpshell.