How do I check responses in JMeter so that each response contains a canonical link?

@declan_ritchie 

To check responses in JMeter for the presence of a canonical link, you can use the Regular Expression Extractor post-processor.

Follow these steps:

1. Add a Regular Expression Extractor as a child of the HTTP request you want to check.
2. In the Regular Expression Extractor, set "Response Field to Check" to "Body" and "Reference Name" to a variable name you choose (e.g. "canonicalLink").
3. In the "Regular Expression" field, enter a regular expression that matches the canonical link tag, such as:<link rel="canonical" href="(.*?)"/>
4. Save the Regular Expression Extractor and run your test.
5. After the test has run, view the results in the "View Results Tree" listener.
6. Look for the "canonicalLink" variable in the "Response data" tab of the listener to see if the canonical link was found in the response.

If the canonical link is found in the response, the "canonicalLink" variable will contain the value of the "href" attribute of the canonical link tag. If it's not found, the "canonicalLink" variable will be empty.

Note: You may need to adjust the regular expression to match the specific format of the canonical link in your application.