Choosing a Browser Engine
Badboy supports different "engines" for running Background Threads, which correspond roughly
to different kinds of browsers to use for executing your tests. Each engine has different
characteristics and capabilities. After you create a Thread Item, one of the
most important decisions to make is which Browser Engine to
use for your load test. Which one
you choose would depend on the nature of your web site, how you have recorded your script
and kind of test you want to conduct.
The three kinds of thread engine are:
- Raw - Raw threads are very simple. They do not attempt to render
the pages downloaded by the browser at all. All they do is download the data and let you
do Assertions to check that the page content returned contains expected text. Due to Raw Threads being so simple
Badboy can execute them very efficiently and can hence can generate a very large
load on your web server from only a single instance of Badboy. The biggest disadvantage
of Raw Threads is that because they do not parse or render the HTML they cannot perform
any operations that involve the user interface of the browser. For example, and they cannot execute
acting on the browser user interface.
Because of these limitations normally the best way to create scripts for Raw Threads to execute is
to only record your browsing actions using Request Mode as this mode does not rely on the browser user
interface and thus is well supported by Raw Threads.
- External MSHTML - MSHTML is the browser component that Microsoft ™ includes with
Microsoft Windows ™ and Internet Explorer ™ . When you use the MSHTML Engine
Badboy creates insvisible instances of MSHTML that it uses to navigate your web site.
Although you can't see them they are actually downloading, parsing and rendering the HTML as if
a real browser was doing it. The biggest advantage of this is that if your web site contains
manipulate variables or to perform JScript Checks to validate your web site) then MSHTML Threads
can do that. When you use External MSHTML, Badboy in fact runs each virtual browser in it's own
process. This ensures that the virtual browsers will not interact, for example, by sharing session
External MSHTML threads are actually run using the Badboy command line runner, bbcmd. When
they run they load the script from the saved file, not from the script that you may be editing. This means that
it is very important to ensure your script is saved before launching the thread item as otherwise it may
play different items to the ones you expect!
- MSHTML - MSHTML is the same as External MSHTML except that the virtual browser windows are
run inside Badboy itself. The main advantages to this are that performance is better and the tests
are less resource intensive on your computer - just
as it is less expensive in memory to run one copy of a browser with several windows instead of several copies of the whole
browser, so it is less expensive to run virtual windows in a shared Badboy instance than it is to launch many
separate copies of Badboy. However a big disadvantage
of using internal MSHTML windows is that they can interact with each other. For example, all threads created
internally share cookies with each other, and even with the main (visible) Badboy window. Thus all such threads
may appear to be logged in as the same user in some applications.
Other Topics Related to Thread Items