Support proxying requests

CONFIGURATION.md

@@ -2,6 +2,12 @@ Paths may be defined as fixed strings or regular expressions (starting with `^`)
 
 Fixed string paths will match with and without a trailing slash.
 
+Serve entries have either a `root` path or `proxy` URL. When a `root` path is
+provided static files and directories are served from that location. When a
+`proxy` URL is provided requests are forwarded to the Gemini server at that URL. 
+
+When accessing a directory `index.gemini` or `index.gmi` is served.
+
 # config.yaml
 
 ```yaml
@@ -9,7 +15,7 @@ Fixed string paths will match with and without a trailing slash.
 cert: /home/twins/data/certfile.crt
 key: /home/twins/data/keyfile.key
 
-# Paths to serve
+# Server paths
 serve:
   -
     path: /sites
@@ -17,6 +23,9 @@ serve:
   -
     path: ^/(help|info)$
     root: /home/twins/data/help
+  -
+    path: ^/proxy-example$
+    proxy: gemini://gemini.rocks
   -
     path: /
     root: /home/twins/data/home

README.md

@@ -7,6 +7,7 @@
 ## Features
 
 - Serve static files
+- Reverse proxy support
 
 ## Download
 

config.go

@@ -3,6 +3,7 @@ package main
 import (
 	"errors"
 	"io/ioutil"
+	"log"
 	"os"
 	"regexp"
 
@@ -11,7 +12,9 @@ import (
 
 type serveConfig struct {
 	Path string
-	Root string
+
+	Root  string
+	Proxy string
 
 	r *regexp.Regexp
 }
@@ -46,7 +49,9 @@ func readconfig(configPath string) error {
 
 	for _, serve := range config.Serve {
 		if serve.Path == "" {
-			continue
+			log.Fatal("path must be specified in serve entry")
+		} else if serve.Root != "" && serve.Proxy != "" {
+			log.Fatal("only one root or reverse proxy may defined for a serve entry")
 		}
 
 		if serve.Path[0] == '^' {

main.go

@@ -7,8 +7,15 @@ import (
 	"path"
 )
 
+func init() {
+	log.SetOutput(os.Stdout)
+}
+
+var verbose bool
+
 func main() {
 	configFile := flag.String("config", "", "path to configuration file")
+	flag.BoolVar(&verbose, "verbose", false, "print request and response information")
 	flag.Parse()
 
 	if *configFile == "" {

server.go

@@ -12,13 +12,20 @@ import (
 	"os"
 	"path"
 	"strings"
+	"time"
 
 	"github.com/h2non/filetype"
 	"github.com/makeworld-the-better-one/go-gemini"
 )
 
+const readTimeout = 30 * time.Second
+
 func writeHeader(c net.Conn, code int, meta string) {
 	fmt.Fprintf(c, "%d %s\r\n", code, meta)
+
+	if verbose {
+		log.Printf("< %d %s\n", code, meta)
+	}
 }
 
 func writeStatus(c net.Conn, code int) {
@@ -26,6 +33,8 @@ func writeStatus(c net.Conn, code int) {
 	switch code {
 	case gemini.StatusTemporaryFailure:
 		meta = "Temporary failure"
+	case gemini.StatusProxyError:
+		meta = "Proxy error"
 	case gemini.StatusBadRequest:
 		meta = "Bad request"
 	case gemini.StatusNotFound:
@@ -34,6 +43,35 @@ func writeStatus(c net.Conn, code int) {
 	writeHeader(c, code, meta)
 }
 
+func serveProxy(c net.Conn, proxyURL, requestData string) {
+	original := proxyURL
+
+	tlsConfig := &tls.Config{}
+	if strings.HasPrefix(proxyURL, "gemini://") {
+		proxyURL = proxyURL[9:]
+	} else if strings.HasPrefix(proxyURL, "gemini-insecure://") {
+		proxyURL = proxyURL[18:]
+		tlsConfig.InsecureSkipVerify = true
+	}
+	proxy, err := tls.Dial("tcp", proxyURL, tlsConfig)
+	if err != nil {
+		writeStatus(c, gemini.StatusProxyError)
+		return
+	}
+	defer proxy.Close()
+
+	// Forward request
+	proxy.Write([]byte(requestData))
+	proxy.Write([]byte("\r\n"))
+
+	// Forward response
+	io.Copy(c, proxy)
+
+	if verbose {
+		log.Printf("< %s\n", original)
+	}
+}
+
 func serveFile(c net.Conn, filePath string) {
 	fi, err := os.Stat(filePath)
 	if os.IsNotExist(err) {
@@ -111,6 +149,8 @@ func scanCRLF(data []byte, atEOF bool) (advance int, token []byte, err error) {
 func handleConn(c net.Conn) {
 	defer c.Close()
 
+	c.SetReadDeadline(time.Now().Add(readTimeout))
+
 	var requestData string
 	scanner := bufio.NewScanner(c)
 	scanner.Split(scanCRLF)
@@ -135,19 +175,28 @@ func handleConn(c net.Conn) {
 	if strippedPath[0] == '/' {
 		strippedPath = strippedPath[1:]
 	}
+	if verbose {
+		log.Printf("> %s\n", request)
+	}
 
-	var realPath string
 	for _, serve := range config.Serve {
+		if serve.Proxy != "" {
+			if serve.r != nil && serve.r.Match(pathBytes) {
+				serveProxy(c, serve.Proxy, requestData)
+				return
+			} else if serve.r == nil && strings.HasPrefix(request.Path, serve.Path) {
+				serveProxy(c, serve.Proxy, requestData)
+				return
+			}
+		}
+
 		if serve.r != nil && serve.r.Match(pathBytes) {
-			realPath = path.Join(serve.Root, strippedPath)
+			serveFile(c, path.Join(serve.Root, strippedPath))
+			return
 		} else if serve.r == nil && strings.HasPrefix(request.Path, serve.Path) {
-			realPath = path.Join(serve.Root, request.Path[len(serve.Path):])
-		} else {
-			continue
+			serveFile(c, path.Join(serve.Root, strippedPath[len(serve.Path)-1:]))
+			return
 		}
-
-		serveFile(c, realPath)
-		return
 	}
 
 	writeStatus(c, gemini.StatusNotFound)