Simple HTTP Echo

This is the world's simplest project - a small HTTP server that returns a dump of the HTTP request metadata passed to it with a status of 200. Similar to the 'anything' endpoint of httpbin but works for all paths. It'll log requests too.

Why?

I've found myself in multiple situations having to debug reverse proxies, including AWS ALB rules, AWS API Gateway headers, Kubernetes Ingress path matching, and Nginx proxy_pass with a URL defined from a variable (fun fact, in that situation Nginx will stop caching DNS, but proxy_pass becomes literal so you need to add regex matching to the location block and add remember to add query path values back - that was fun to investigate...). I've also had proxies swallow X-Forwarded-* headers due to misconfigured middleware - this was the final straw to whip up this small utility.

Usage

Simple HTTP echo is a simple Go binary with only one option: the PORT environment variable (which defaults to 3000 if not set).

There's a container image for ease of use with Docker or Kubernetes: jamesorlakin/simple-http-echo:latest.

Response Example

curl --verbose -H "X-Forwarded-Proto: some-test-header" http://localhost:3000/any-path-can-go-here
*   Trying 127.0.0.1:3000...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 3000 (#0)
> GET /any-path-can-go-here HTTP/1.1
> Host: localhost:3000
> User-Agent: curl/7.68.0
> Accept: */*
> X-Forwarded-Proto: some-test-header
> 
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< Date: Sat, 26 Nov 2022 10:13:04 GMT
< Content-Length: 528
< Content-Type: text/plain; charset=utf-8
< 
{
        "Method": "GET",
        "URL": {
                "Scheme": "",
                "Opaque": "",
                "User": null,
                "Host": "",
                "Path": "/any-path-can-go-here",
                "RawPath": "",
                "OmitHost": false,
                "ForceQuery": false,
                "RawQuery": "",
                "Fragment": "",
                "RawFragment": ""
        },
        "Proto": "HTTP/1.1",
        "Header": {
                "Accept": [
                        "*/*"
                ],
                "User-Agent": [
                        "curl/7.68.0"
                ],
                "X-Forwarded-Proto": [
                        "some-test-header"
                ]
        },
        "ContentLength": 0,
        "Host": "localhost:3000",
        "RemoteAddr": "127.0.0.1:38782",
        "RequestURI": "/any-path-can-go-here"
* Connection #0 to host localhost left intact