fastcgi: Fix SCRIPT_NAME when path in address (#1852)

* Add tests for SCRIPT_NAME

* fastcgi: Include vhost path prefix in SCRIPT_NAME

caddyhttp/fastcgi/fastcgi.go

@@ -18,6 +18,7 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/mholt/caddy"
 	"github.com/mholt/caddy/caddyhttp/httpserver"
 )
 
@@ -248,6 +249,11 @@ func (h Handler) buildEnv(r *http.Request, rule Rule, fpath string) (map[string]
 	// Strip PATH_INFO from SCRIPT_NAME
 	scriptName = strings.TrimSuffix(scriptName, pathInfo)
 
+	// Add vhost path prefix to scriptName. Otherwise, some PHP software will
+	// have difficulty discovering its URL.
+	pathPrefix, _ := r.Context().Value(caddy.CtxKey("path_prefix")).(string)
+	scriptName = path.Join(pathPrefix, scriptName)
+
 	// Get the request URI from context. The context stores the original URI in case
 	// it was changed by a middleware such as rewrite. By default, we pass the
 	// original URI in as the value of REQUEST_URI (the user can overwrite this

caddyhttp/fastcgi/fastcgi_test.go

@@ -12,6 +12,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/mholt/caddy"
 	"github.com/mholt/caddy/caddyhttp/httpserver"
 )
 
@@ -122,7 +123,11 @@ func TestBuildEnv(t *testing.T) {
 		}
 	}
 
-	rule := Rule{}
+	rule := Rule{
+		Ext:        ".php",
+		SplitPath:  ".php",
+		IndexFiles: []string{"index.php"},
+	}
 	url, err := url.Parse("http://localhost:2015/fgci_test.php?test=foobar")
 	if err != nil {
 		t.Error("Unexpected error:", err.Error())
@@ -156,6 +161,7 @@ func TestBuildEnv(t *testing.T) {
 			"QUERY_STRING":    "test=foobar",
 			"REQUEST_METHOD":  "GET",
 			"HTTP_HOST":       "localhost:2015",
+			"SCRIPT_NAME":     "/fgci_test.php",
 		}
 	}
 
@@ -206,6 +212,14 @@ func TestBuildEnv(t *testing.T) {
 	envExpected["CUSTOM_URI"] = "custom_uri/fgci_test.php?test=foobar"
 	envExpected["CUSTOM_QUERY"] = "custom=true&test=foobar"
 	testBuildEnv(r, rule, fpath, envExpected)
+
+	// 6. Test SCRIPT_NAME includes path prefix
+	r = newReq()
+	ctx := context.WithValue(r.Context(), caddy.CtxKey("path_prefix"), "/test")
+	r = r.WithContext(ctx)
+	envExpected = newEnv()
+	envExpected["SCRIPT_NAME"] = "/test/fgci_test.php"
+	testBuildEnv(r, rule, fpath, envExpected)
 }
 
 func TestReadTimeout(t *testing.T) {