Is there a way to modify the cookies before it gets proxied?

[florianwachs]

Hi there, first, thanks for YARP, this is such an awesome project!

I`m quite new to working with reverse proxies so please forgive my mistakes describing my "issue".

I have a working implementation of my usecase using YARP. The destination has problems with cookies, so I used the "RequestHeaderRemove" to remove the cookie header. This works. Finally my question:

instead of removing the Cookie Header all together, I would love to inspect the cookies and remove only certain cookies (in the concrete case I want to remove only ASP.NET Auth cookies). Is there a way to do that? I looked at a CustomTransformer from the direct forwarding example and inspected the HttpRequestMessage proxyRequest, but there is no way to set or modify cookies.

Any hint that points me in a direction to check on my own would be great.

Thank you very much and have a great day.

[Tratcher]

You're on the right track with the CustomTransformer. A similar sample is here:
https://github.com/microsoft/reverse-proxy/blob/ad6ee6a3c2f5012ad9892db0d738ed75d8e8d4f1/samples/ReverseProxy.Transforms.Sample/Startup.cs#L48-L55

but there is no way to set or modify cookies.

The cookies are just a non-special header in the request headers collection, you can call TryGetValues to get the current cookies, Remove("Cookies") to drop everything, and Add or TryAddWithoutValidation to re-set the header with your modified cookies.

[florianwachs]

Thanks just what I need, thanks so much for this details answer! have a great day.