Architecture

This is an overview of the DotNetBrowser architecture.

Overview

The architecture of the DotNetBrowser library consists of multiple processes such as .NET application and different Chromium ones:

Sections below provide the details for each of the processes, the main components of the library, and describe how it all works.

Processes

.NET process

This is a standard .NET process where your .NET application runs.

Chromium main process

This is the main process of the Chromium engine. It is started by DotNetBrowser when you create an IEngine instance.

For each IEngine instance, a separate Chromium Main process is used.

Chromium renderer process

This process contains the IFrame instances which manage DOM and JavaScript of the loaded web page. The process is started by the Chromium engine when you navigate IBrowser to a web page with a different domain.

Chromium GPU process

This process renders the content of the web pages loaded in different Chromium Renderer processes using the GPU.

Inter-process communication

Communication between different processes is performed using Inter-Process Communication (IPC). IPC transfers data between two processes on a local machine.

To transfer data between .NET and Chromium processes, DotNetBrowser uses its own IPC implementation based on sockets and shared memory. Communication between the Chromium processes is performed using Chromium IPC implementation.

Main components

IEngine

The IEngine instance manages the lifecycle of the Chromium Main process and provides access to the core Chromium functionality such as zoom, proxy, cache, cookies, plugins, downloads, etc. associated with the default Profile.

All the operations with the engine are performed through the IEngine interface. Engine is a top-level object in the objects hierarchy of the library. Any actions with the library begin with creation of an IEngine instance.

For detailed instructions on creation and usage of the IEngine instance, please see the Engine guide.

Profile

Represents a Chromium profile. It allows keeping all browser data separately, like history, cookies, cache, proxy settings, spellchecker configurations, etc. Each IEngine has a default profile that is created automatically during Engine initialization. The default profile cannot be deleted.

You can create new profiles and delete them if they are not required using the Profiles service.

The profile’s files for history, cookies, cache, etc. are stored in the user data directory. If you configure IEngine with the user data directory and create a profile, it will be stored in the user data directory and be restored after application restart.

Read more about profiles in the Profile guide.

Browser

This is a web browser, which can be used to perform a number of actions, such as:

• loading web pages or local HTML files;
• finding text on the loaded web page;
• modifying zoom level;
• enabling or muting audio;
• getting notifications about loading progress;
• dispatching keyboard and mouse events.

All the operations with the browser are performed through the IBrowser interface. Each IBrowser instance is bound to Profile. The IBrowser instance is disposed automatically when its Profile is deleted or parent IEngine instance crashes or it is disposed by the application.

For details on how to create and use the IBrowser instance, see the Browser guide.

Frame

Any web page loaded in the IBrowser instance has a main IFrame instance in it. This IFrame may have child frames. You can use the IFrame instances to access and work with DOM and JavaScript. When a web page is unloaded, its main IFrame instance and all child frames are disposed automatically.

How it works

Creating an engine

When you create an IEngine instance, the library performs the following actions:

1. Start the Chromium Main and GPU processes.
2. Initialize the Chromium engine in the Chromium Main process.
3. Initialize the default profile.
4. Establish the IPC connection between .NET and the Chromium Main process.

If you create two IEngine instances, separate Chromium Main and GPU processes are started for each of them. See the example below:

Creating a browser

When you create an IBrowser instance, the library automatically loads an about:blank web page in it. As a result, the Chromium Renderer process is started to handle all the DOM and JavaScript on the web page:

If you navigate the IBrowser instance to a web page, the page is loaded in this Chromium Renderer process. If you navigate to a web page from a different domain later, it is loaded in a different Chromium Renderer process instance which is started automatically. Note that the Chromium Renderer process that handled the contents of the previous web page will be terminated.

Browser dispose

When you release the IBrowser instance, corresponding Chromium Renderer process is terminated automatically. As a consequence, all the IFrame instances running in the terminated process will be automatically disposed as well:

Engine dispose

When you dispose the IEngineinstance, the library performs the following actions:

1. Closing existing IPC connection between .NET and the Chromium Main processes.
2. Disposal of the Chromium engine in the Chromium Main process.
3. Terminating the Chromium Main and GPU processes.