Adding transform through environment variables

[lejsekt]

Hi,
I'd like to set RequestHeaderOriginalHost to true for some routes. Is it possible to do it through environment variables? I've tried

ReverseProxy__Routes__myRoute__Transforms__0__RequestHeaderOriginalHost: "true"

but it doesn't work.

Thank you

[Tratcher]

That example worked when I tested it by adding this in Program.Main:
Environment.SetEnvironmentVariable("ReverseProxy__Routes__route1__Transforms__0__RequestHeaderOriginalHost", "true");

It combine with:

  "ReverseProxy": {
    "Routes": {
      "route1": {
        "ClusterId": "cluster1",
        "Match": {
          "Methods": [ "GET", "POST" ],
          "Hosts": [ "localhost" ],
          "Path": "/api/{**catch-all}"
        }
      },

What does the rest of your config look like? Arrays in config can be tricky, I don't think it will work if you already have a transforms section for that route, they'll overlap.

[Tratcher]

Why do you need to set just RequestHeaderOriginalHost from environment variables?

Some alternatives:
AddTransforms can be used to programmatically add transforms after loading:
https://github.com/microsoft/reverse-proxy/blob/ec6c5a2be3c5e4dee8b3e24c614dc08bf550f815/samples/ReverseProxy.Transforms.Sample/Startup.cs#L39
IProxyConfigFilter's can be used to modify routes while loading the config.
https://github.com/microsoft/reverse-proxy/blob/ec6c5a2be3c5e4dee8b3e24c614dc08bf550f815/samples/ReverseProxy.ConfigFilter.Sample/CustomConfigFilter.cs#L55

[samsp-msft]

<warning: shameless sample promotion>

The Config filter sample shows how to use the filter's ability to modify routes, and pulls the data out of environment vars - just for scenarios like this - where expressing the path is not very easy.

[lejsekt]

Thank you for a very quick response. I went with the AddTransforms option in Startup, but in case I'll later need a more complicated setup, I'll try the config filter.