In some situations, it is not straightforward to access the debug log messages, for example when debugging Visualforce inside a managed package installed into a subscriber org. In this scenario, the Salesforce platform blocks the messages from being written to the log.
When this is the case, it is useful to write debug information to the page that is being accessed. Clearly, it would not lead to a great user experience to do this in all cases, so a mechanism for generating this on demand is required.
One way to achieve this is to only generate and output the log information if the user passes a specific parameter on the URL - that way, when the page is working as expected, the user doesn't see any extraneous information, but if there are issues, they can simply request the page in a slightly different fashion and capture the debug information to assist the development team's investigations.
In this recipe, we will create a Visualforce page to retrieve...