Skip to main content

Use Fiddler to validate version problems with Javascript libraries

I’m a big fan of Fiddler for a long time. Last week I had to test some jQuery compatibility issues with a new web application we were building. At first I was replacing all the Javascript files with newer versions, updating all the references and so on… Although this approach worked it was cumbersome and error-prone. Isn’t there a better alternative?
Fiddler to the rescue!
I found the following post by Eric Law where he uses Fiddler to load a different version of jQuery without updating any reference:http://blogs.msdn.com/b/ieinternals/archive/2011/08/19/using-fiddler-to-verify-a-jquery-update-will-fix-a-compatibility-problem.aspx.  Exactly where I was looking for!
So how can you do this?
  • First, download the (newer) version of the library you want to test.
  • Start Fiddler and go to the AutoResponder tab. Use the Add… button to create a new rule to map requests for your Javascript library to the newly downloaded file.image
  • Also set the Unmatched requests passthrough option to ensure that Fiddler doesn’t automatically generate 404s for requests that don’t match any of the rules.
  • Reload your web application you’ll see that  Fiddler intercepts the request for the older library and returns the newer one instead.
If I only found out this feature sooner…

Remark: Don't forget to remove this rule afterwards.
Labels:

Popular posts from this blog

Podman– Command execution failed with exit code 125

After updating WSL on one of the developer machines, Podman failed to work. When we took a look through Podman Desktop, we noticed that Podman had stopped running and returned the following error message: Error: Command execution failed with exit code 125 Here are the steps we tried to fix the issue: We started by running podman info to get some extra details on what could be wrong: >podman info OS: windows/amd64 provider: wsl version: 5.3.1 Cannot connect to Podman. Please verify your connection to the Linux system using `podman system connection list`, or try `podman machine init` and `podman machine start` to manage a new Linux VM Error: unable to connect to Podman socket: failed to connect: dial tcp 127.0.0.1:2655: connectex: No connection could be made because the target machine actively refused it. That makes sense as the podman VM was not running. Let’s check the VM: >podman machine list NAME         ...
Read more

Azure DevOps/ GitHub emoji

I’m really bad at remembering emoji’s. So here is cheat sheet with all emoji’s that can be used in tools that support the github emoji markdown markup: All credits go to rcaviers who created this list.
Read more

VS Code Planning mode

After the introduction of Plan mode in Visual Studio , it now also found its way into VS Code. Planning mode, or as I like to call it 'Hannibal mode', extends GitHub Copilot's Agent Mode capabilities to handle larger, multi-step coding tasks with a structured approach. Instead of jumping straight into code generation, Planning mode creates a detailed execution plan. If you want more details, have a look at my previous post . Putting plan mode into action VS Code takes a different approach compared to Visual Studio when using plan mode. Instead of a configuration setting that you can activate but have limited control over, planning is available as a separate chat mode/agent: I like this approach better than how Visual Studio does it as you have explicit control when plan mode is activated. Instead of immediately diving into execution, the plan agent creates a plan and asks some follow up questions: You can further edit the plan by clicking on ‘Open in Editor’: ...
Read more