Add Variable replace possibility

Solve abiosoft#7

.gitignore

@@ -1,2 +1,6 @@
 caddy
 buildenv_*
+
+# vscode
+*vscode
+*.code-workspace

README.md

@@ -129,8 +129,9 @@ As an handler within a route.
           "handler": "exec",
           // command to execute
           "command": "git",
-          // command arguments
-          "args": ["pull", "origin", "master"],
+          // command arguments it's also possible to use 
+          // caddy variables like {http.request.uuid}
+          "args": ["pull", "origin", "master", "# {http.request.uuid}"],
 
           // [optional] directory to run the command from. Default is the current directory.
           "directory": "/home/user/site/public",

middleware.go

@@ -45,6 +45,12 @@ func (m Middleware) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddy
 		Error  string `json:"error,omitempty"`
 	}
 
+	repl := r.Context().Value(caddy.ReplacerCtxKey).(*caddy.Replacer)
+
+	for index, argument := range m.Args {
+		m.Args[index] = repl.ReplaceAll(argument, "")
+	}
+
 	err := m.run()
 
 	if err == nil {