Handling Route Execution Order and Conditional Middleware in Mojo.js

[xdaruis]

Hey, I want to implement the following feature in the backend using mojojs. I want the routes to be executed from top to bottom and have a helper function to determine logged-in routes.

I have a problem with app.under and how I've used it, and now the 2nd route gets executed before the first one.

const app = mojo();

const loggedIn = app.under('', async (ctx) => {
  const session = await ctx.session();
  if (!session || !session.role) {
    await ctx.render({ status: 401, json: { error: 'Forbidden' } });
    return false;
  }
});

app.get('/api/controller/stats').to('controller#stats'); // Doesn't work
loggedIn.get('/api/controller/:id').to('controller#get'); // This gets executed before the above route

I managed to use the router and requires to fix the problem, but now I have another issue in which the request is still trying to get picked up by all the next routes.

const app = mojo();
const { router } = app;

router.addCondition('loggedIn', async (ctx) => {
  const session = await ctx.session();
  if (!session || !session.role) {
    await ctx.render({ status: 401, json: { error: 'Forbidden' } });
    return false;
  }
  return true;
});

// Gets executed
router.get('/api/controller/action').requires('loggedIn').to('controller#action');

// I don't want this to get executed anymore since the request is already handled, but it does
router.get('/*', async (ctx) => {
  console.log('Why am i seeing this? :((');
  return ctx.render({ status: 500, json: { error: 'I dont wanna see this' } });
});

[kraih]

Only one route will match the request. Unlike other frameworks, mojo.js does not execute all matching routes, only the first one. And code is only executed when the full path matches, including nested routes.

[kraih]

Or to be more precise, this is not a Sinatra-like framework where all code runs. We build a tree structure out of the declared routes, and only the first fully matching branch gets its code executed.

[xdaruis]

Sorry if I wasn't so clear; my problem isn't about allowing multiple routes to get triggered. I just want a way to safely execute routes from top to bottom, and the first matching route should be executed.

In the first code, somehow the loggedIn route gets executed first, and then the app.get(../stats) will never be executed because of the :id in the loggedIn route.

The second code using the router gets the job done, but now I would get the /api/controller/action response and then also a warning in the console, and that console.log() would be printed in the console.

Here's the error I'm getting in the 2nd code snippet:

Error [ERR_HTTP_HEADERS_SENT]: Cannot write headers after they are sent to the client
    at ServerResponse.writeHead (node:_http_server:344:11)

Not sure if this is important but I'm running the server in development mode:

nodemon index.js server -l http://*:8086

[kraih]

Now i get what you mean. Conditions are not meant to have side effects such as rendering a response themselves. What happens when they do is undefined behavior.

[kraih]

For your /api/controller/:id case, you could just make the placeholder more restrictive so it only matches numbers. https://mojojs.org/docs/Routing.md#restrictive-placeholders

[kraih]

Or, of course, just change the order so the precedence of the routes changes.