Middleware with Rhai scripts

While your mock server supports middlewares written using Rhai scripts for highly dynamic scenarios, our goal is to minimize the need for custom script creation and maintenance. We believe that file-based and rule-based matching definitions can cover almost all practical needs you'll encounter.

Therefore, we generally do not recommend using middlewares unless you have a very specific and complex requirement that cannot be met by combining rules and operators.

However, for those unique cases, Rhai is a powerful, embedded scripting language that feels very similar to JavaScript or Rust.

Here are some basic Rhai code examples you might use.

Variable Definition

let my_variable = "Hello, Rhai !";
let count = 10;

If / Else Statements

if url_path == "/dynamic_response" {
    return "response_for_dynamic.json";\

// else clause is also available:
// } else {
//    return "default_response.json";

}

Switch (Match) Statements

switch (url_path) {
    "/middleware-test/dummy" if body.middleware == "isHere" => {
        // exit() is useful when run in fn (here, equivalent to return statement):
        exit(returned_json_file_path);
    },
    _ => ()
}

Return Statement

Middleware scripts primarily return a file path string. If a middleware returns a value, the server will use it as the response.

#![allow(unused)]
fn main() {
return "path/to/response.json";
}

To learn more about Rhai's syntax and capabilities

you can refer to the official Rhai documentation. Use this feature judiciously and only when other options fall short.