drone/app/api/middleware/address/address.go

93 lines
2.7 KiB
Go

// Copyright 2023 Harness, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package address
import (
"net/http"
"strings"
)
// Handler returns an http.HandlerFunc middleware that sets
// the http.Request scheme and hostname.
func Handler(scheme, host string) func(http.Handler) http.Handler {
return func(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
// update the scheme and host for the inbound
// http.Request so they are available to subsequent
// handlers in the chain.
r.URL.Scheme = scheme
r.URL.Host = host
// if the scheme is not configured, attempt to ascertain
// the scheme from the inbound http.Request.
if r.URL.Scheme == "" {
r.URL.Scheme = resolveScheme(r)
}
// if the host is not configured, attempt to ascertain
// the host from the inbound http.Request.
if r.URL.Host == "" {
r.URL.Host = resolveHost(r)
}
// invoke the next handler in the chain.
next.ServeHTTP(w, r)
})
}
}
// resolveScheme is a helper function that evaluates the http.Request
// and returns the scheme, HTTP or HTTPS. It is able to detect,
// using the X-Forwarded-Proto, if the original request was HTTPS
// and routed through a reverse proxy with SSL termination.
func resolveScheme(r *http.Request) string {
const https = "https"
switch {
case r.URL.Scheme == https:
return https
case r.TLS != nil:
return https
case strings.HasPrefix(r.Proto, "HTTPS"):
return https
case r.Header.Get("X-Forwarded-Proto") == https:
return https
default:
return "http"
}
}
// resolveHost is a helper function that evaluates the http.Request
// and returns the hostname. It is able to detect, using the
// X-Forarded-For header, the original hostname when routed
// through a reverse proxy.
func resolveHost(r *http.Request) string {
switch {
case len(r.Host) != 0:
return r.Host
case len(r.URL.Host) != 0:
return r.URL.Host
case len(r.Header.Get("X-Forwarded-For")) != 0:
return r.Header.Get("X-Forwarded-For")
case len(r.Header.Get("X-Host")) != 0:
return r.Header.Get("X-Host")
case len(r.Header.Get("XFF")) != 0:
return r.Header.Get("XFF")
case len(r.Header.Get("X-Real-IP")) != 0:
return r.Header.Get("X-Real-IP")
default:
return "localhost:3000"
}
}