authelia: set forceSSL for endpoint

hosts/rpi4/authelia.nix

@@ -6,10 +6,18 @@
 }:
 let
   inherit (lib) types mkIf optionalString;
-  inherit (builtins) isNull any attrValues;
+  inherit (builtins)
+    isNull
+    any
+    all
+    attrValues
+    toString
+    ;
+
+  inherit (config.services) nginx;
 
   validAuthMethods = [
-    "normal"
+    "regular"
     "basic"
   ];
   getUpstreamFromInstance =
@@ -25,7 +33,7 @@ let
         else
           server.host;
     in
-    "http://${host}:${port}";
+    "http://${host}:${toString port}";
 
   # use this when reverse proxying to authelia (and only authelia because i
   # like the nixos recommended proxy settings better)
@@ -72,8 +80,12 @@ let
 
     ## Headers
     ## The headers starting with X-* are required.
-    proxy_set_header X-Original-Method $request_method;
     proxy_set_header X-Original-URL $scheme://$http_host$request_uri;
+    proxy_set_header X-Original-Method $request_method;
+    proxy_set_header X-Forwarded-Method $request_method;
+    proxy_set_header X-Forwarded-Proto $scheme;
+    proxy_set_header X-Forwarded-Host $http_host;
+    proxy_set_header X-Forwarded-Uri $request_uri;
     proxy_set_header X-Forwarded-For $remote_addr;
     proxy_set_header Content-Length "";
     proxy_set_header Connection "";
@@ -95,59 +107,39 @@ let
     proxy_connect_timeout 240;
   '';
   autheliaLocationConfig = pkgs.writeText "authelia-location.conf" autheliaLocation;
-  autheliaBasicLocationConfig = pkgs.writeText "authelia-location-basic.conf" ''
-    ${autheliaLocation}
-
-    # Auth Basic Headers
-    proxy_set_header X-Original-Method $request_method;
-    proxy_set_header X-Forwarded-Method $request_method;
-    proxy_set_header X-Forwarded-Proto $scheme;
-    proxy_set_header X-Forwarded-Host $http_host;
-    proxy_set_header X-Forwarded-URI $request_uri;
-  '';
-
-  genAuthConfig =
-    method:
-    let
-      snippet_regular = ''
-        ## Configure the redirection when the authz failure occurs. Lines starting
-        ## with 'Modern Method' and 'Legacy Method' should be commented /
-        ## uncommented as pairs. The modern method uses the session cookies
-        ## configuration's authelia_url value to determine the redirection URL here.
-        ## It's much simpler and compatible with the mutli-cookie domain easily.
-
-        ## Modern Method: Set the $redirection_url to the Location header of the
-        ## response to the Authz endpoint.
-        auth_request_set $redirection_url $upstream_http_location;
-
-        ## Modern Method: When there is a 401 response code from the authz endpoint
-        ## redirect to the $redirection_url.
-        error_page 401 =302 $redirection_url;
+  autheliaBasicLocationConfig = autheliaLocationConfig;
+  genAuthConfig = method: endpoint: let
+      redirect = ''
+        ## If the subreqest returns 200 pass to the backend, if the subrequest returns 401 redirect to the portal.
+        error_page 401 =302 ${endpoint}/?rd=$target_url;
       '';
-    in
-    ''
-      ## Send a subrequest to Authelia to verify if the user is authenticated and
-      # has permission to access the resource.
+    in ''
+      auth_request /internal/authelia/authz${optionalString (method == "basic") "/basic"};
 
-      auth_request /internal/authelia/authz${optionalString method == "basic" "/basic"};
+      ## Set the $target_url variable based on the original request.
 
-      ## Save the upstream metadata response headers from Authelia to variables.
+      ## Comment this line if you're using nginx without the http_set_misc module.
+      # set_escape_uri $target_url $scheme://$http_host$request_uri;
+
+      ## Uncomment this line if you're using NGINX without the http_set_misc module.
+      set $target_url $scheme://$http_host$request_uri;
+
+      ## Save the upstream response headers from Authelia to variables.
       auth_request_set $user $upstream_http_remote_user;
       auth_request_set $groups $upstream_http_remote_groups;
       auth_request_set $name $upstream_http_remote_name;
       auth_request_set $email $upstream_http_remote_email;
 
-      ## Inject the metadata response headers from the variables into the request
-      ## made to the backend.
+      ## Inject the response headers from the variables into the request made to the backend.
       proxy_set_header Remote-User $user;
       proxy_set_header Remote-Groups $groups;
       proxy_set_header Remote-Name $name;
       proxy_set_header Remote-Email $email;
 
-      ${optionalString method == "regular" snippet_regular}
+      ${optionalString (method == "regular") redirect}
     '';
   genAuthConfigPkg =
-    method: pkgs.writeText "authelia-authrequest-${method}.conf" (genAuthConfig method);
+    method: endpoint: pkgs.writeText "authelia-authrequest-${method}.conf" (genAuthConfig method endpoint);
 in
 {
   # authelia
@@ -163,9 +155,10 @@ in
         { name, config, ... }@attrs:
         {
           options = {
-            locations = mkAttrsOfSubmoduleOpt (locationModule' attrs);
+            locations = mkAttrsOfSubmoduleOpt (genLocationModule attrs);
             authelia = {
               endpoint = {
+                # endpoint settings
                 instance = lib.mkOption {
                   description = ''
                     Local Authelia instance to act as the authentication endpoint.
@@ -184,6 +177,13 @@ in
                   default = null;
                 };
               };
+              # client settings
+              endpointURL = lib.mkOption {
+                description = ''
+                  (temporary) authelia endpoint redirect URL.
+                '';
+                type = with types; str;
+              };
               instance = lib.mkOption {
                 description = ''
                   Local Authelia instance to use. Setting this option will
@@ -199,6 +199,8 @@ in
                   requests to. This should not be the public-facing authentication
                   endpoint URL.
                 '';
+                type = with types; nullOr str;
+                default = null;
               };
               method = lib.mkOption {
                 description = ''
@@ -206,7 +208,7 @@ in
                   in this virtualHost. Authentication is disabled by default for
                   all locations if this is set to `null`.
                 '';
-                type = with types; nullOr oneOf validAuthMethods;
+                type = with types; nullOr (enum validAuthMethods);
                 default = "regular";
                 example = "basic";
               };
@@ -220,32 +222,53 @@ in
               getUpstreamFromInstance config.authelia.endpoint.instance
             );
 
+            forceSSL = lib.mkIf (!(isNull config.authelia.endpoint.upstream)) true;
+
             # authelia nginx internal endpoints
             locations =
               let
-                api = "${config.authelia.upstream}/api/authz/auth-request";
+                api = "${config.authelia.upstream}/api/verify";
               in
-              lib.mkIf (!(isNull config.authelia.upstream)) {
-                # just setup both, they can't be accessed externally anyways.
-                "/internal/authelia/authz" = {
-                  proxyPass = api;
-                  recommendedProxyConfig = false;
-                  extraConfig = ''
-                    include ${autheliaLocationConfig};
-                  '';
-                };
-                "/internal/authelia/authz/basic" = {
-                  proxyPass = "${api}/basic";
-                  recommendedProxyConfig = false;
-                  extraConfig = ''
-                    include ${autheliaBasicLocationConfig};
-                  '';
-                };
-              };
+              lib.mkMerge [
+                (lib.mkIf (!(isNull config.authelia.upstream)) {
+                  # just setup both, they can't be accessed externally anyways.
+                  "/internal/authelia/authz" = {
+                    proxyPass = api;
+                    recommendedProxySettings = false;
+                    extraConfig = ''
+                      include ${autheliaLocationConfig};
+                    '';
+                  };
+                  "/internal/authelia/authz/basic" = {
+                    proxyPass = "${api}?auth=basic";
+                    recommendedProxySettings = false;
+                    extraConfig = ''
+                      include ${autheliaBasicLocationConfig};
+                    '';
+                  };
+                })
+                (lib.mkIf (!(isNull config.authelia.endpoint.upstream)) {
+                  "/" = {
+                    extraConfig = ''
+                      include "${autheliaProxyConfig}";
+                    '';
+                    proxyPass = "${config.authelia.endpoint.upstream}";
+                    recommendedProxySettings = false;
+                  };
+                  "= /api/verify" = {
+                    proxyPass = "${config.authelia.endpoint.upstream}";
+                    recommendedProxySettings = false;
+                  };
+                  "/api/authz" = {
+                    proxyPass = "${config.authelia.endpoint.upstream}";
+                    recommendedProxySettings = false;
+                  };
+                })
+              ];
           };
         };
 
-      locationModule' =
+      genLocationModule =
         vhostAttrs:
         { name, config, ... }:
         let
@@ -258,18 +281,30 @@ in
               Authentication is disabled for this location if this is set to
               `null`.
             '';
-            type = with types; nullOr oneOf validAuthMethods;
+            type = with types; nullOr (enum validAuthMethods);
             default = vhostConfig.authelia.method;
             example = "basic";
           };
+          options.authelia.endpointURL = lib.mkOption {
+            description = ''
+              (temporary) authelia endpoint redirect URL.
+            '';
+            type = with types; str;
+            default = vhostConfig.authelia.endpointURL;
+          };
+
           config =
-            lib.mkIf (!(lib.strings.hasPrefix "/internal/authelia/" name))
-            && (!(isNull vhostConfig.authelia.upstream))
-            && (!(isNull config.authelia.method)) {
-              extraConfig = ''
-                include ${genAuthConfigPkg config.authelia.method};
-              '';
-            };
+            lib.mkIf
+              (
+                (!(lib.strings.hasPrefix "/internal/authelia/" name))
+                && (!(isNull vhostConfig.authelia.upstream))
+                && (!(isNull config.authelia.method))
+              )
+              {
+                extraConfig = ''
+                  include ${genAuthConfigPkg config.authelia.method config.authelia.endpointURL};
+                '';
+              };
         };
 
     in
@@ -278,10 +313,27 @@ in
     };
 
   # TODO check if any vhosts have authelia configured
-  config = mkIf false {
-
-    assertions = [
-      # TODO vhost cannot be both auth endpoint proxy and regular reverse proxy
-    ];
-  };
+  config =
+    let
+      # TODO later, there are only assertions here
+      configured = any (
+        vhost: (!(isNull vhost.authelia.upstream)) || (!(isNull vhost.authelia.endpoint.upstream))
+      ) (attrValues nginx.virtualHosts);
+    in
+    mkIf true {
+      assertions = [
+        {
+          assertion = all (
+            vhost: (!(isNull vhost.authelia.upstream)) -> (isNull vhost.authelia.endpoint.upstream)
+          ) (attrValues nginx.virtualHosts);
+          message = "`services.nginx.virtualHosts.<name>.authelia.upstream` and `services.nginx.virtualHosts.<name>.authelia.endpoint.upstream` cannot be set at the same time.";
+        }
+        # {
+        #   assertion = all (
+        #     vhost: vhost.authelia.instance -> config.services.authelia.instances ? "${vhost.authelia.instance}"
+        #   ) (attrValues nginx.virtualHosts);
+        #   message = "`services.authelia.instances.<name>` must be configured if `services.nginx.virtualHosts.<name>.authelia.instance` is set.";
+        # }
+      ];
+    };
 }