Merge pull request #54 from delta10/feat/add-username-to-filter-proxy

feat: add username to possible auth header

Author: bartjkdp

cmd/filter-proxy/main.go

@@ -33,6 +33,7 @@ type ClaimsWithGroups struct {
 type AuthorizationResponse struct {
 	Result         bool   `json:"result"`
 	ResponseFilter string `json:"response_filter"`
+	Username       string `json:"username"`
 }
 
 func main() {
@@ -69,7 +70,7 @@ func main() {
 				r.URL.Scheme = backendBaseUrl.Scheme
 
 				for headerKey, headerValue := range backend.Auth.Header {
-					parsedHeaderValue := utils.EnvSubst(headerValue)
+					parsedHeaderValue := utils.EnvSubst(headerValue, nil)
 					r.Header.Set(headerKey, parsedHeaderValue)
 				}
 
@@ -246,12 +247,14 @@ func main() {
 				transport := &http.Transport{TLSClientConfig: tlsConfig}
 
 				if backend.Auth.Basic.Username != "" && backend.Auth.Basic.Password != "" {
-					parsedPassword := utils.EnvSubst(backend.Auth.Basic.Password)
+					parsedPassword := utils.EnvSubst(backend.Auth.Basic.Password, nil)
 					backendRequest.SetBasicAuth(backend.Auth.Basic.Username, parsedPassword)
 				}
 
 				for headerKey, headerValue := range backend.Auth.Header {
-					parsedHeaderValue := utils.EnvSubst(headerValue)
+					parsedHeaderValue := utils.EnvSubst(headerValue, map[string]string{
+						"REQUEST_USERNAME": authorizationResponse.Username,
+					})
 					backendRequest.Header.Set(headerKey, parsedHeaderValue)
 				}
 

internal/utils/utils.go

@@ -2,13 +2,14 @@ package utils
 
 import (
 	"encoding/base64"
-	"github.com/delta10/filter-proxy/internal/wfs"
 	"net"
 	"net/http"
 	"net/url"
 	"os"
 	"regexp"
 	"strings"
+
+	"github.com/delta10/filter-proxy/internal/wfs"
 )
 
 func QueryParamsToLower(queryParams url.Values) url.Values {
@@ -70,19 +71,22 @@ func DelHopHeaders(header http.Header) {
 	}
 }
 
-func EnvSubst(input string) string {
+func EnvSubst(input string, additionalReplacements map[string]string) string {
 	re := regexp.MustCompile(`\${([^}]+)}`)
 
-	result := re.ReplaceAllStringFunc(input, func(match string) string {
+	return re.ReplaceAllStringFunc(input, func(match string) string {
 		varName := match[2 : len(match)-1]
+		if additionalReplacements != nil {
+			if value, exists := additionalReplacements[varName]; exists {
+				return value
+			}
+		}
 		if value, exists := os.LookupEnv(varName); exists {
 			return value
 		}
-
-		return ""
+		// Leave the original pattern if no replacement found
+		return match
 	})
-
-	return result
 }
 
 func ReadUserIP(r *http.Request) string {