nginx: emit relative redirects so a mapped host port survives directory redirects

nginx-transcoder/nginx-no-ssl.conf

@@ -39,6 +39,13 @@ http {
     limit_req_status 401;
 
     server {
+        # Emit RELATIVE redirects. Otherwise nginx rebuilds a directory redirect
+        # (e.g. /webtools -> /webtools/) from its internal listen port, dropping
+        # any external mapped port when the container is published on a different
+        # port (docker -p 8081:80, or behind a reverse proxy / VPN bind) and
+        # sending the browser to the wrong URL.
+        absolute_redirect off;
+
         listen ${HTTP_PORT};
 
         location / {

nginx-transcoder/nginx.conf

@@ -44,6 +44,13 @@ http {
     limit_req_status 401;
 
     server {
+        # Emit RELATIVE redirects. Otherwise nginx rebuilds a directory redirect
+        # (e.g. /webtools -> /webtools/) from its internal listen port, dropping
+        # any external mapped port when the container is published on a different
+        # port (docker -p 8081:80, or behind a reverse proxy / VPN bind) and
+        # sending the browser to the wrong URL.
+        absolute_redirect off;
+
         listen ${HTTP_PORT};
 
         listen 443 ssl;