IISRewrite Middleware appendQueryString

[brianchance]

Describe the bug

When using the IISRewriteModule, redirects with appendQueryString="true" only work if there is a ? in the redirect url.

To Reproduce

Would expect this do work...

    <rule name="some rule" stopProcessing="true">
      <match url="^resource" />
      <action type="Redirect" url="/product" redirectType="Temporary" appendQueryString="true" />
    </rule>

To get this to work, you must append a ? to the action url...

    <rule name="some rule" stopProcessing="true">
      <match url="^resource" />
      <action type="Redirect" url="/product?" redirectType="Temporary" appendQueryString="true" />
    </rule>

Analysis based on source

In RedirectAction (/Middleware/Rewrite/src/UrlActions/RedirectAction.cs)
If the url contains a ? (line 72), the request query string is appended to the query string of the url.
The else only adds the request query string if QueryStringDelete != true

The UrlRewriteFileParser (/Middleware/Rewrite/src/IISUrlRewrite/UrlRewriteFileParser.cs) uses the the second constructor (line 222) of RedirectAction which defaults queryStringDelete: true (line 39).

Further technical details

• ASP.NET Core version - 3.1.3
• Include the output of dotnet --info
• The IDE (VS / VS Code/ VS4Mac) you're running on, and it's version - VS2019 - Version 16.5.4

[brianchance]

Since the middleware is supposed to mimic IIS, I tested IIS and it does append the query string when there is not a ? in the url.

[analogrelay]

Yeah, that looks like it's a bug. Since you've done a great analysis of the code, would you be interested in contributing a Pull Request with the changes? We're happy to help you out!

[fstaffa]

I would like to implement a fix. Is this issue still free to take?

[jkotalik]

There is already a PR filed, I'm currently working on merging it (requires an announcement as it's a breaking change).

[fstaffa]

Thanks, not sure how I missed the PR