Architecture of Selenium WebDriver

Selenium WebDriver is a powerful tool for automating web browsers. Its architecture comprises various key components, including the Selenium Client Library, WebDriver API, Browser Drivers, and the Browser itself. The Selenium Client Library provides language-specific bindings for interacting with WebDriver.

The WebDriver API communicates with the browser drivers, which control the browsers and execute commands. Finally, the browser renders web pages and responds to user interactions, completing the automation cycle. Understanding this architecture is important for effectively using Selenium WebDriver in automated testing and web scraping tasks.

What is Selenium History?

Below is the history of Selenium

• 2004: Jason Huggins creates JavaScriptRunner to test web applications using JavaScript.
• 2004: JavaScriptRunner becomes open-source and is renamed Selenium Core.
• 2006: Selenium Core evolves into Selenium Remote Control (Selenium RC) or Selenium 1, introducing a server component for cross-browser testing and supporting multiple programming languages.
• 2009: Simon Stewart creates WebDriver to simplify browser automation using native browser automation APIs.
• 2011: Selenium RC and WebDriver merge into Selenium 2 for a unified testing framework.
• 2016: Selenium 3 is released with bug fixes, security enhancements, and support for modern browsers.
• Latest Release: Selenium 4 introduces new features and full W3C compliance.

What is Selenium WebDriver?

Selenium WebDriver is a powerful automation tool used for testing web applications across different browsers and platforms. It provides a programming interface to interact with web elements and perform various actions such as clicking buttons, entering text, navigating pages, and validating elements. Unlike Selenium RC, WebDriver directly communicates with the browser using native methods, making it faster and more reliable. WebDriver supports multiple programming languages like Java, Python, C#, etc., making it versatile for developers and testers.

1. It also enables parallel testing, allowing multiple test cases to run simultaneously across different browsers, improving efficiency and reducing testing time.
2. WebDriver's architecture includes a client library, WebDriver API, browser drivers, and the actual browsers, ensuring seamless automation and accurate testing results.

Architecture of Selenium WebDriver (Selenium 3)

The architecture of Selenium WebDriver in Selenium 3 follows a client-server model. Selenium provides client libraries for different programming languages like java, Python, Ruby, etc. These libraries' aim is to allow Selenium WebDriver to interact with the control browser. JSON Protocol acts as a communication bridge between the client libraries and browser drivers. Client libraries send commands in JSON format over HTTP requests. Browser drivers understand the JSON wire Protocol and translate the commands into action within the browser.

Components of Selenium 3 WebDriver

1. Selenium Client Library: This component provides language-specific bindings or APIs (java, Python, Ruby, etc. ) that allow users to write test scripts and interact with the WebDriver.
2. JSON Wire Protocol over HTTP: The JSON Wire Protocol is a standardized protocol used for communication between the Selenium Client Library and the Browser Drivers. It defines a set of commands and responses in JSON format exchanged over HTTP requests.
3. Browser Drivers: These are executable files that establish a communication channel between the WebDriver and the actual web browsers such as Chrome, Firefox, Safari, etc. Each browser requires its specific driver (e.g., ChromeDriver, GeckoDriver, etc.) to enable WebDriver to control and automate browser actions.
4. Real Browsers: These are web browsers like Google Chrome, Mozilla Firefox, Microsoft Edge, etc., where the actual testing and automation take place. The WebDriver interacts with these browsers through their respective browser drivers to perform actions like clicking elements, filling forms, navigating pages, and validating content.

Working of Selenium 3 WebDriver

1. Write a test script using the Selenium client library in your preferred language.
2. The test script sends commands through the client library to interact with the browser.
3. The client library converts commands into JSON format and sends them via HTTP request.
4. The browser driver decodes JSON commands and interacts with the real web browser.
5. Browser performs actions (e.g., clicking buttons, entering text) on the web page based on the received commands.

Architecture of Selenium 4 WebDriver

Selenium four brings significant improvements to the architecture, often with the introduction of the W3C WebDriver Protocol. This protocol standardizes interactions between the purchaser and server, selling higher compatibility and consistency across one-of-a-kind implementations. Moreover, Selenium 4 affords a better guide for present-day net technology and progressed overall performance. The architecture of Selenium 4 WebDriver has made a key change compared to Selenium 3 which is a communication protocol. Like Selenium 3, Selenium 4 offers client libraries for various programming languages, which help WebDriver interact with the browser. WebDriver W3C protocol is the major change in Selenium 4 as it completely replaces JSON Protocol which was in Selenium 3. The WebDriver W3C Protocol is defined by the World Wide Web Consortium (W3C) that ensure better compatibility and stability on different browsers and client libraries.

Components of Selenium 4 WebDriver

1. Selenium Client Library: This component provides language-specific bindings or APIs (e.g., Java, Python, Ruby) that allow users to write test scripts and interact with the WebDriver.
2. WebDriver W3C Protocol: WebDriver is a protocol that provides a standard way for web browsers to communicate with an automation script. In Selenium 4, it focuses on W3C WebDriver Protocol, for better consistency and compatibility across different browsers.
3. Browser Drivers: These are executable files that establish a communication channel between the WebDriver and the actual web browsers such as Chrome, Firefox, Safari, etc. Each browser requires its specific driver (e.g., ChromeDriver, GeckoDriver, etc.) to enable WebDriver to control and automate browser actions.
4. Real Browsers: These are web browsers like Google Chrome, Mozilla Firefox, Microsoft Edge, etc., where the actual testing and automation take place. The WebDriver interacts with these browsers through their respective browser drivers to perform actions like clicking elements, filling forms, navigating pages, and validating content.

Working of Selenium 3 WebDriver

1. Write your test script using the Selenium client library in your comfortable language.
2. The test script sends commands through the client library to interact with the browser.
3. Client library converts commands into WebDriver W3C Protocol format.
4. The browser driver receives commands via WebDriver W3C Protocol.
5. Browser drivers understand commands and interact with real web browsers.

Difference between Architecture of Selenium 3 & Selenium 4

Selenium 4 has some big differences from Selenium 3. the changes make the Selenium framework better and more powerful. They will improve how it will be working and make it easier to use. Upgrading to Selenium 4 can be helping developers and testers to build the better web applications with minimum efforts.

Related Articles

• Introduction to Selenium WebDriver
• Features of Selenium WebDriver
• Selenium WebDriver Tutorial | Working, Benefits and Limitations
• Selenium WebDriver - WebElement Commands

Conclusion

In conclusion, Selenium WebDriver is a powerful tool for automating web browser interactions. Architecture of Selenium has evolved, Selenium 4 introduced WebDriver W3C Protocol. The communication between client libraries, browser drivers, and browsers is made easier by the W3C protocol and it provides better compatibility, efficiency, and maintainability.