Context based Recording Vs Context less Recording and HTML Vs URL based recording

To understand the "context based recording", if some one asks you a question "How is he doing?", you would definitely ask "Whom are you referring to?". But if the same question is asked during a discussion about one of your friends whose name is  Karthik, you would not ask the question because in the current context HE refers to Karthik. So you can understand who "HE" is. 


The context less question would be like "How is Karthik doing?". There won't be any more questions. Because you are explicitly pointing to a person and not using any generic terms like He, it. This is called context less mode.

In the above example of "HE", "HE" refers to Karthik only for that discussion and for a different discussion "HE" may refer to someone else.  The context is only until the discussion.
 
There are two recording modes available in LoadRunner to record the user actions of a Web Application. They are

·         HTML mode

·         URL Mode

HTML mode – In this mode of recording, each USER ACTION is recorded as a separate request.  To put it in simple terms, each HTML content (usually a page except in case of HTML Frames) is recorded as a request

If all the user actions are recorded into a Single ACTION of the script, then the HTML mode of recording acts as "Context Based Recording".

The Virtual User Generator understands the Context by looking at the previous request's response. Hence it identifies the Forms, Images etc and you would notice the below functions in a context based recording of the script.
web_submit_form() - to simulate a POST Request
web_image(), web_link() - to simulate a GET request



In VUGen, the context is applicable only till the Action. If you record a user action into a different action, the context would reset and again the context has to be created.

In a case where the tool has to enter some data in a form and if the form is not found in its previous response, the tool will halt the execution of the script.  Every request is directly dependant on the previous request’s response and has high chances of failure with the UI changes to the web application

The advantages of using the HTML recording mode is that the size is very compact and the customization efforts would be very less. The other side of the coin is that, with the UI changes to the web applications, these scripts would require very high maintenance costs.

URL Mode: In this mode of recording each resource requested by the user is recorded as a separate request.  in other words, whatever the content (like images, CSS, JS, HTML) that makes the HTML page is recorded as a separate request. When a web site is launched apart from the HTML content, there would be lot of images, java script files, CSS files downloaded. All these are called resources and each resource is recorded as a separate request.

URL mode is always context less recording because this mode refers to the data and the URL of a request directly instead of depending on previous response. This mode does not depend on the UI of the application, rather the actions associated with the user actions performed on UI. As each resource is recorded, the size of the script would be very high and this also involves in lot of customization. The benefit of having scripts with URL recording mode is that the maintenance cost associated with these are very less and can be used across various releases of the product despite lot of UI changes.

Usually URL mode of recording is used with Non –browser applications in other words any thick client activity is recorded using the URL mode.

Trade off – with the HTML recording mode, another option is available under “Advanced options” of HTML mode. The option available is Explicit URLs only mode.

The benefits of the HTML mode and URL mode is clubbed together in HTML à Explicit URLs only. With this mode, the size of the script would be compact (as only the user action is recorded as request, not at the UI level but at the request level) and requires a bit of more customization efforts but has the advance of high maintainability for longer durations. This is the most recommended recording mode for web applications where the scripts have to be maintained for longer durations

Tip: Have you forgotten to record the script using HTML à Explicit URLs mode? No problem....

Change the recording options to HTML à Explicit URLs only and now navigate to Toolsà Regenerate script. The regenerated script is as fresh as a recorded script using HTML Explicit URL’s only. But do remember that whatever the changes that are made to the script would be gone if the script is regenerated.

Next post: Understanding various logs in LoadRunner