Intro: Introduced in 2004 and lived until 2006 when WD born.
Selenium Remote Control is great for testing complex
AJAX-based web user interfaces under a Continuous Integration system. It is
also an ideal solution for users of Selenium IDE who want to write tests in a
more expressive programming language than the Selenese HTML table format.
Main components:
-
Client libraries:
which provide the interface between each programming language and the Selenium
RC Server.
A
Selenium client library provides a programming interface (API), i.e., a set of
functions, which run Selenium commands from your own program.
The
client library takes a Selenese command and passes it to the Selenium Server
for processing a specific action or test against the application under test
(AUT).
The
client library also receives the result of that command and passes it back to
your program
-
Selenium
Server: Drives the browser, Embeds
Selenium Core and Injects into browser, Interprets commands, sends back results to the client
which launches and kills browsers, interprets and runs the Selenese
commands passed from the test program, and acts as an HTTP proxy,
intercepting and verifying HTTP messages passed between the browser and the
AUT.
The RC server bundles Selenium Core and automatically injects
it into the browser. This occurs when your test program opens the browser
(using a client library API function). Selenium-Core is a JavaScript program,
actually a set of JavaScript functions which interprets and executes Selenese
commands using the browser’s built-in JavaScript interpreter.
Architectural diagram: (Simplified)
Step 1: Client libraries communicate with the Server passing
each Selenium command for execution.
Step 2: Then the server Launches browser and Injects ‘selenium
core’ into browser from Server.
Step 3: Then Selenium + java code will be sent to RC server
line by line and Interprets the commands.
Step 4: Corresponding javascript method will be executed
Step 5: Each request goes via HTTP proxy to overcome
same-origin policy problem
Step 6: Corresponding application / web server handles and
request and sends the response back
Step 7: response will be sent back to client library.
Advantages of RC:
1. Supports
multiple languages like Java, Ruby, C#, Perl, Python etc.
2.
Core Written In
JavaScript
3.
Supports all
browsers
Disadvantages:
1.
The
same origin policy. It is
a Javascript security policy that allows running the code only from the domain
you're on. And since RC is fully written in Javascript, you can't easily switch
between domains or work with some websites that redirect or use frames with
content from many domains.
2.
Because of another security policy in
Javascript, you can't fill in <input type='file' /> inputs and
have to use several workarounds.
3.
You have to write your own methods when you need
to wait for an element.
4.
Execution is Slow, duet to multiple layers of interactions
5.
Fails to mimic real life interaction ( Non
Native Events)
6.
Cannot maximize the browser really
Tip:
Does really RC server holds Selenium Core init?
See here
