Support redirecting to path or URL

CONFIGURATION.md

@@ -87,12 +87,6 @@ One resource must be defined for each path.
 
 Serve static files from specified root directory.
 
-##### Proxy
-
-Forward requests to Gemini server at specified URL.
-
-Use the pseudo-scheme `gemini-insecure://` to disable certificate verification.
-
 ##### Command
 
 Serve output of system command.
@@ -101,6 +95,16 @@ When input is requested from the user, it is available as a pseudo-variable
 `$USERINPUT` which does not require surrounding quotes. It may be used as an
 argument to the command, otherwise user input is passed via standard input.
 
+##### Proxy
+
+Forward requests to Gemini server at specified URL.
+
+Use the pseudo-scheme `gemini-insecure://` to disable certificate verification.
+
+##### Redirect
+
+Redirect requests to specified path or URL.
+
 #### Attributes
 
 Any number of attributes may be defined for a path.
@@ -220,6 +224,12 @@ hosts:
         path: ^/cmd-example$
         command: uname -a
         cache: 0 # Do not cache
+      -
+        path: /redir-path-example
+        redirect: /other-resource
+      -
+        path: /redir-url-example
+        redirect: gemini://gemini.circumlunar.space/
       -
         path: /
         root: /home/geminirocks/data/home

README.md

@@ -19,6 +19,7 @@ This page is also available at [gemini://twins.rocketnine.space](gemini://twins.
   - TCP
   - [FastCGI](https://en.wikipedia.org/wiki/FastCGI)
 - Serve system command output
+- Redirect to path or URL
 - Reload configuration on `SIGHUP`
 
 ## Proposals

config.go

@@ -22,8 +22,9 @@ type pathConfig struct {
 
 	// Resource to serve
 	Root     string
-	Proxy   string
 	Command  string
+	Proxy    string
+	Redirect string
 
 	// Request input
 	Input string
@@ -164,12 +165,12 @@ func readconfig(configPath string) error {
 					if defaultPath.Root != "" && serve.Root == "" {
 						serve.Root = defaultPath.Root
 					}
-					if defaultPath.Proxy != "" && serve.Proxy == "" {
-						serve.Proxy = defaultPath.Proxy
-					}
 					if defaultPath.Command != "" && serve.Command == "" {
 						serve.Command = defaultPath.Command
 					}
+					if defaultPath.Proxy != "" && serve.Proxy == "" {
+						serve.Proxy = defaultPath.Proxy
+					}
 					if defaultPath.SymLinks {
 						serve.SymLinks = defaultPath.SymLinks
 					}
@@ -206,17 +207,31 @@ func readconfig(configPath string) error {
 
 		for _, serve := range host.Paths {
 			if serve.Path == "" {
-				log.Fatal("path must be specified in serve entry")
-			} else if (serve.Root != "" && (serve.Proxy != "" || serve.Command != "")) ||
-				(serve.Proxy != "" && (serve.Root != "" || serve.Command != "")) ||
-				(serve.Command != "" && (serve.Root != "" || serve.Proxy != "")) {
-				log.Fatal("only one root, proxy or command resource may specified for a path")
+				log.Fatal("a path must be specified in each serve entry")
 			}
-
 			if serve.Path[0] == '^' {
 				serve.r = regexp.MustCompile(serve.Path)
 			}
 
+			var resources int
+			if serve.Root != "" {
+				resources++
+			}
+			if serve.Command != "" {
+				resources++
+			}
+			if serve.Proxy != "" {
+				resources++
+			}
+			if serve.Redirect != "" {
+				resources++
+			}
+			if resources == 0 {
+				log.Fatalf("a resource must specified for path %s%s", hostname, serve.Path)
+			} else if resources > 1 {
+				log.Fatalf("only one resource (root, command, proxy or redirect) may specified for path %s%s", hostname, serve.Path)
+			}
+
 			serve.cache = cacheUnset
 			if serve.Cache != "" {
 				serve.cache, err = strconv.ParseInt(serve.Cache, 10, 64)
@@ -225,7 +240,12 @@ func readconfig(configPath string) error {
 				}
 			}
 
-			if serve.FastCGI != "" {
+			if serve.Command != "" {
+				serve.cmd, err = shellquote.Split(serve.Command)
+				if err != nil {
+					log.Fatalf("failed to parse command %s: %s", serve.cmd, err)
+				}
+			} else if serve.FastCGI != "" {
 				if serve.Root == "" {
 					log.Fatalf("root must be specified to use fastcgi resource %s of path %s%s", serve.FastCGI, hostname, serve.Path)
 				}
@@ -238,11 +258,6 @@ func readconfig(configPath string) error {
 
 					config.fcgiPools[serve.FastCGI] = gofast.SimpleConnFactory(f.Scheme, f.Host+f.Path)
 				}
-			} else if serve.Command != "" {
-				serve.cmd, err = shellquote.Split(serve.Command)
-				if err != nil {
-					log.Fatalf("failed to parse command %s: %s", serve.cmd, err)
-				}
 			}
 		}
 	}

server.go

@@ -174,7 +174,16 @@ func servePath(c *tls.Conn, request *url.URL, serve *pathConfig) (int, int64) {
 		filePath = path.Join(root, resolvedPath)
 	}
 
-	if serve.Proxy != "" {
+	if serve.cmd != nil {
+		requireInput := serve.Input != "" || serve.SensitiveInput != ""
+		if requireInput {
+			newCommand := replaceWithUserInput(serve.cmd, request)
+			if newCommand != nil {
+				return serveCommand(c, serve, request, newCommand)
+			}
+		}
+		return serveCommand(c, serve, request, serve.cmd)
+	} else if serve.Proxy != "" {
 		return serveProxy(c, request, serve.Proxy), -1
 	} else if serve.FastCGI != "" {
 		if filePath == "" {
@@ -189,15 +198,8 @@ func servePath(c *tls.Conn, request *url.URL, serve *pathConfig) (int, int64) {
 
 		serveFastCGI(c, config.fcgiPools[serve.FastCGI], request, filePath)
 		return statusSuccess, -1
-	} else if serve.cmd != nil {
-		requireInput := serve.Input != "" || serve.SensitiveInput != ""
-		if requireInput {
-			newCommand := replaceWithUserInput(serve.cmd, request)
-			if newCommand != nil {
-				return serveCommand(c, serve, request, newCommand)
-			}
-		}
-		return serveCommand(c, serve, request, serve.cmd)
+	} else if serve.Redirect != "" {
+		return writeHeader(c, statusRedirectTemporary, serve.Redirect), -1
 	}
 
 	if filePath == "" {