browser/README.md

<p align="center">
  <a href="https://lightpanda.io"><img src="https://cdn.lightpanda.io/assets/images/logo/lpd-logo.png" alt="Logo" height=170></a>
</p>

<h1 align="center">Lightpanda</h1>

<div align="center">
	<br />
</div>

Lightpanda is the open-source browser made for headless usage:

- Javascript execution
- Support of the Web APIs (partial, WIP)
- Compatible with Playwright, Puppeteer through CDP (WIP)

Fast scraping and web automation with minimal memory footprint:

- Ultra-low memory footprint (12x less than Chrome)
- Blazingly fast & instant startup (64x faster than Chrome)

<img width=500px src="https://cdn.lightpanda.io/assets/images/benchmark2.png">

See [benchmark details](https://github.com/lightpanda-io/demo).

## Why?

### Javascript execution is mandatory for the modern web

Back in the good old times, grabbing a webpage was as easy as making an HTTP request, cURL-like. It’s not possible anymore, because Javascript is everywhere, like it or not:

- Ajax, Single Page App, Infinite loading, “click to display”, instant search, etc.
- JS web frameworks: React, Vue, Angular & others

### Chrome is not the right tool

So if we need Javascript, why not use a real web browser. Let’s take a huge desktop application, hack it, and run it on the server, right? Hundreds of instance of Chrome if you use it at scale. Are you sure it’s such a good idea?

- Heavy on RAM and CPU, expensive to run
- Hard to package, deploy and maintain at scale
- Bloated, lots of features are not useful in headless usage

### Lightpanda is built for performance

If we want both Javascript and performance, for a real headless browser, we need to start from scratch. Not yet another iteration of Chromium, really from a blank page. Crazy right? But that’s we did:

- Not based on Chromium, Blink or WebKit
- Low-level system programming language (Zig) with optimisations in mind
- Opinionated, no rendering

## Status

Lightpanda is still a work in progress and is currently at the Alpha stage.

Here are the key features we want to implement before releasing a Beta version:

- [x] Loader
- [x] HTML parser and DOM tree
- [x] Javascript support
- [x] Basic DOM APIs
- [x] Ajax
  - [x] XHR API
  - [ ] Fetch API
- [x] DOM dump
- [ ] Basic CDP server

We will not provide binary versions until we reach at least the Beta stage.

NOTE: There are hundreds of Web APIs. Developing a browser, even just for headless mode, is a huge task. It's more about coverage than a _working/not working_ binary situation.

You can also follow the progress of our Javascript support in our dedicated [zig-js-runtime](https://github.com/lightpanda-io/zig-js-runtime#development) project.

## Build from sources

We do not provide yet binary versions of Lightpanda, you have to compile it from source.

### Prerequisites

Lightpanda is written with [Zig](https://ziglang.org/) `0.12.1`. You have to
install it with the right version in order to build the project.

Lightpanda also depends on
[zig-js-runtime](https://github.com/lightpanda-io/zig-js-runtime/) (with v8),
[Netsurf libs](https://www.netsurf-browser.org/) and
[Mimalloc](https://microsoft.github.io/mimalloc).

To be able to build the v8 engine for zig-js-runtime, you have to install some libs:

For Debian/Ubuntu based Linux:

```
sudo apt install xz-utils \
    python3 ca-certificates git \
    pkg-config libglib2.0-dev \
    gperf libexpat1-dev \
    cmake clang
```

For MacOS, you only need cmake:

```
brew install cmake
```

### Install and build dependencies

#### All in one build

You can run `make install` to install deps all in one (or `make install-dev` if you need the development versions).

Be aware that the build task is very long and cpu consuming, as you will build from sources all dependancies, including the v8 Javascript engine.

#### Step by step build dependancy

The project uses git submodules for dependencies.

To init or update the submodules in the `vendor/` directory:

```
make install-submodule
```

**Netsurf libs**

Netsurf libs are used for HTML parsing and DOM tree generation.

```
make install-netsurf
```

For dev env, use `make install-netsurf-dev`.

**Mimalloc**

Mimalloc is used as a C memory allocator.

```
make install-mimalloc
```

For dev env, use `make install-mimalloc-dev`.

Note: when Mimalloc is built in dev mode, you can dump memory stats with the
env var `MIMALLOC_SHOW_STATS=1`. See
[https://microsoft.github.io/mimalloc/environment.html](https://microsoft.github.io/mimalloc/environment.html).

**zig-js-runtime**

Our own Zig/Javascript runtime, which includes the v8 Javascript engine.

This build task is very long and cpu consuming, as you will build v8 from sources.

```
make install-zig-js-runtime
```

For dev env, use `make iinstall-zig-js-runtime-dev`.

## Test

### Unit Tests

You can test Lightpanda by running `make test`.

### Web Platform Tests

Lightpanda is tested against the standardized [Web Platform
Tests](https://web-platform-tests.org/).

The relevant tests cases are committed in a [dedicated repository](https://github.com/lightpanda-io/wpt) which is fetched by the `make install-submodule` command.

All the tests cases executed are located in the `tests/wpt` sub-directory.

For reference, you can easily execute a WPT test case with your browser via
[wpt.live](https://wpt.live).

#### Run WPT test suite

To run all the tests:

```
make wpt
```

Or one specific test:

```
make wpt Node-childNodes.html
```

#### Add a new WPT test case

We add new relevant tests cases files when we implemented changes in Lightpanda.

To add a new test, copy the file you want from the [WPT
repo](https://github.com/web-platform-tests/wpt) into the `tests/wpt` directory.

:warning: Please keep the original directory tree structure of `tests/wpt`.