Hello World App

Here's an example of a Hello World application built using Osgood. This application will only use a single route, GET /hello, and so we'll only need two files. The Application File handles application routing, configuration, and policies. The Worker File handles the actual application logic for the route.

Application File: app.js

This configuration file is fairly minimal. For a larger overview check out the Application File page.

Here we configure the app to listen on port 3000. We also define a route at GET /hello, which will be routed to the worker file hello.js. Also, since the application doesn't need to perform any I/O, the policy configuration argument is just a noop function. This means the worker cannot perform any I/O, even if an attacker were able to eval() arbitrary code within the worker.

app.port = 3000;
app.get('/hello', 'hello.js', policy => {});

Worker File hello.js

Here we describe the application code. The default exported function accepts two arguments, request and context. The request argument is an instance of the Request class available in modern browsers. The second argument, context, contains some additional information described in the Osgood Worker Files page.

This function can either return a promise (either directly or by virtue of being an async function), or it can return a value directly. In this example we're simply returning a string which will then be sent to the client.

export default async (request, context) => {
  return "Hello, World!";
};

Command Line

Now let's execute our application. Once you've followed along with the install instructions you're then ready to execute the code. Run the following commands in two different terminals to call your application code:

$ osgood ./app.js
$ curl http://localhost:3000/hello

Once the curl call is complete you should see the text Hello, World! displayed in your terminal.