spartan handler for a CGI directory

contrib/cgi/spartan.go

@@ -0,0 +1,46 @@
+package cgi
+
+import (
+	"context"
+	"fmt"
+	"strings"
+
+	"tildegit.org/tjp/gus"
+	"tildegit.org/tjp/gus/spartan"
+)
+
+// SpartanCGIDirectory runs executable files relative to a root directory in the file system.
+//
+// It will also find any run any executable _part way_ through the path, so for example a
+// request for /foo/bar/baz can also run an executable found at /foo or /foo/bar. In such
+// a case the PATH_INFO environment variable will include the remaining portion of the URI.
+func SpartanCGIDirectory(pathRoot, fsRoot string) gus.Handler {
+	fsRoot = strings.TrimRight(fsRoot, "/")
+	return gus.HandlerFunc(func(ctx context.Context, request *gus.Request) *gus.Response {
+		if !strings.HasPrefix(request.Path, pathRoot) {
+			return nil
+		}
+
+		filepath, pathinfo, err := ResolveCGI(request.Path[len(pathRoot):], fsRoot)
+		if err != nil {
+			return spartan.ServerError(err)
+		}
+		if filepath == "" {
+			return nil
+		}
+
+		stdout, exitCode, err := RunCGI(ctx, request, filepath, pathinfo)
+		if err != nil {
+			return spartan.ServerError(err)
+		}
+		if exitCode != 0 {
+			return spartan.ServerError(fmt.Errorf("CGI process exited with status %d", exitCode))
+		}
+
+		response, err := spartan.ParseResponse(stdout)
+		if err != nil {
+			return spartan.ServerError(err)
+		}
+		return response
+	})
+}