Add support for static sites handling

README.md

@@ -9,8 +9,14 @@ Run:
 
 	leproxy -addr :https -map /path/to/mapping.yml -cache /path/to/letsencrypt.cache
 
-`mapping.yml` contains host-to-backend mapping, where backend can be specified
-either as host:port for TCP or an absolute path for unix socket connections.
+`mapping.yml` contains host-to-backend mapping, where backend can be specified as:
+
+ * host:port for TCP connections to backend;
+ * absolute path for unix socket connections;
+ * absolute path with trailing slash to serve files from given directory.
+
+Example:
 
 	subdomain1.example.com: 127.0.0.1:8080
 	subdomain2.example.com: /var/run/http.socket
+	static.example.com: /var/www/

leproxy.go

@@ -14,6 +14,7 @@ import (
 	"net/http"
 	"net/http/httputil"
 	"os"
+	"path/filepath"
 	"strings"
 	"sync"
 	"time"
@@ -75,12 +76,18 @@ func setProxy(mapping map[string]string) (http.Handler, error) {
 	}
 	mux := http.NewServeMux()
 	for hostname, backendAddr := range mapping {
-		if strings.Contains(hostname, "/") {
+		if strings.ContainsRune(hostname, os.PathSeparator) {
 			return nil, fmt.Errorf("invalid hostname: %q", hostname)
 		}
 		network := "tcp"
-		if strings.HasPrefix(backendAddr, "/") {
+		if filepath.IsAbs(backendAddr) {
 			network = "unix"
+			if strings.HasSuffix(backendAddr, string(os.PathSeparator)) {
+				// path specified as directory with explicit trailing
+				// slash; add this path as static site
+				mux.Handle(hostname+"/", http.FileServer(http.Dir(backendAddr)))
+				continue
+			}
 		}
 		rp := &httputil.ReverseProxy{
 			Director: func(req *http.Request) {