Allow specifying default host and path configuration

CONFIGURATION.md

@@ -30,6 +30,10 @@ Fixed string paths will match with and without a trailing slash.
 
 When accessing a directory the file `index.gemini` or `index.gmi` is served.
 
+When a host is defined with the name `default`, other hosts and paths will use
+those values as the default configuration. It is not currently possible to
+enable an attribute by default and then disable it for individual paths.
+
 ### Certificates
 
 A certificate and private key must be specified.
@@ -162,6 +166,10 @@ listen: :1965
 
 # Hosts and paths to serve
 hosts:
+  default: # Default host configuration
+    paths: # Default path attributes
+      -
+        symlinks: true # Follow symbolic links
   gemini.rocks:
     cert: /srv/gemini.rocks/data/cert.crt
     key: /srv/gemini.rocks/data/cert.key

config.go

@@ -123,8 +123,51 @@ func readconfig(configPath string) error {
 		}
 	}
 
+	defaultHost := config.Hosts["default"]
+	delete(config.Hosts, "default")
+
 	config.fcgiPools = make(map[string]gofast.ConnFactory)
 	for hostname, host := range config.Hosts {
+		if defaultHost != nil {
+			if host.Cert == "" {
+				host.Cert = defaultHost.Cert
+			}
+			if host.Key == "" {
+				host.Key = defaultHost.Key
+			}
+			if len(defaultHost.Paths) == 1 {
+				defaultPath := defaultHost.Paths[0]
+				for _, serve := range host.Paths {
+					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.SymLinks {
+						serve.SymLinks = defaultPath.SymLinks
+					}
+					if defaultPath.HiddenFiles {
+						serve.HiddenFiles = defaultPath.HiddenFiles
+					}
+					if defaultPath.ListDirectory {
+						serve.ListDirectory = defaultPath.ListDirectory
+					}
+					if defaultPath.Cache != "" && serve.Cache == "" {
+						serve.Cache = defaultPath.Cache
+					}
+					if defaultPath.FastCGI != "" && serve.FastCGI == "" {
+						serve.FastCGI = defaultPath.FastCGI
+					}
+				}
+			} else if len(defaultHost.Paths) > 1 {
+				log.Fatal("only one path may be defined for the default host")
+			}
+		}
+
 		if host.Cert == "" || host.Key == "" {
 			log.Fatal("a certificate must be specified for each domain (gemini requires TLS for all connections)")
 		}