Using Route Transforms Outside of Services Builder

[jongallant]

Is there no way to use YARP transforms from the request pipeline itself? Must all transforms be applied at the service builder phase?

I have a requirement where I must insert a header value in a request middleware. Must I inject it directly into the HttpContext object in this case? Or can it be done with YARP transforms?

[Tratcher]

Middleware can modify the HttpContext as needed, though we recommend transforms as a cleaner option to avoid issues on retry, etc.

What else is the middleware doing that can't be done in a transform?

[jongallant]

For example, calling a webservice to pull information on a specific user. Once data is retrieved, a header is set.

I know this is not a typical case.

[Tratcher]

You can do that within a custom transform.
https://microsoft.github.io/reverse-proxy/articles/transforms.html#extensibility