Web Manual Correlations
LoadRunner allows users to manually to add correlations that were missed by the automatic engine; or, alternatively, can be used by scripters that want to identify all correlations by themselves.
(a) Correlate selection
This method allows users to select the desired value (text string) in the script code (function arguments) and requests LoadRunner to check whether this value appears to be a correlation by activating the “Correlate selection” option from context menu (right click à correlate selection).
The logic used here is identical to the “Record-based correlations” mentioned above.
(b) Correlate from snapshot
The user should select a dynamic value from the Server response within a snapshot, and the engine will scan the entire script and replace all relevant occurrences.
(c) Double recording
This method is a design approach that directs the user to record the same business process twice, compare the scripts and locate any mismatches between the two as candidates for the correlation process that will be done manually.
As mentioned before, in order to correlate dynamic values, after locating the appropriate server response, we need to extract this data. The value can be extracted using different methods.
To do this, we use a set of API functions.
The four main correlation APIs are:
- web_reg_save_param_ex – Registers a request to save dynamic data located between specified boundaries.
- web_reg_save_param_regexp – Registers a request to save dynamic data that matches a regular expression.
- web_reg_save_param_xpath – Registers a request to save dynamic data from XML response using XPath expression.
- web_reg_save_param_json – Registers a request to save dynamic data from response that has been formatted as JSON.