feat: Add support for configurable proxy IP header in environment settings (#11595)

* feat: Add support for configurable proxy IP header in environment settings

* Update server/env.ts

Remove mention of Koa from docs

Co-authored-by: Tom Moor <tom.moor@gmail.com>

* Update .env.sample

Remove mention of Koa from env sample.

Co-authored-by: Tom Moor <tom.moor@gmail.com>

---------

Co-authored-by: Tom Moor <tom.moor@gmail.com>

.env.sample

@@ -119,6 +119,11 @@ SSL_CERT=
 # false if you can be sure that SSL is terminated at an external loadbalancer.
 FORCE_HTTPS=true
 
+# When behind a reverse proxy, the header to use for the client IP.
+# The default value is "X-Forwarded-For", common values are "X-Real-IP"
+# and "X-Client-IP".
+# PROXY_IP_HEADER=
+
 
 # ––––––––––––––––––––––––––––––––––––––
 # ––––––––––  AUTHENTICATION  ––––––––––

server/env.ts

@@ -341,6 +341,16 @@ export class Environment {
   @IsBoolean()
   public FORCE_HTTPS = this.toBoolean(environment.FORCE_HTTPS ?? "true");
 
+  /**
+   * When the app is behind a proxy, sets the HTTP header used for the client IP. 
+   * The default value is "X-Forwarded-For", common values are "X-Real-IP"
+   * and "X-Client-IP".
+   */
+  @IsOptional()
+  public PROXY_IP_HEADER = this.toOptionalString(
+    environment.PROXY_IP_HEADER
+  );
+
   /**
    * Should the installation send anonymized statistics to the maintainers.
    * Defaults to true.

server/services/web.ts

@@ -47,6 +47,9 @@ export default function init(app: Koa = new Koa(), server?: Server) {
 
     // trust header fields set by our proxy. eg X-Forwarded-For
     app.proxy = true;
+    if (env.PROXY_IP_HEADER) {
+      app.proxyIpHeader = env.PROXY_IP_HEADER;
+    }
   }
 
   // Make `ctx.userAgent` available