CODEWITHSUNDEEP
javascriptnode.jsexpress
Asaf Nevo
Asaf Nevo

Reputation: 11678

express.js global try/catch

I'm developing a rest server on Node JS with Express.

I'm trying to wrap all my endpoints in try\catch block, so a central point of error will response back to the sender with details. My problem that response (res instance) is alive for each of the endpoints methods, but I don't know how to make it global.

try {
    app.get('/webhook', function (req, res) {
        webhook.register(req, res);
    });

    app.get('/send', function (req, res) {
        sendAutoMessage('1004426036330995');
    });

    app.post('/webhook/subscribe', function (req, res) {
        webhook.subscribe("test");
    });

    app.post('/webhook/unsubscribe', function (req, res) {
        webhook.unsubscribe("test");
    });
} catch (error) {
    //response to user with 403 error and details
}

Upvotes: 15

Views: 24049

Answers (3)

xab
xab

Reputation: 1236

There is a library (express-async-errors) which could suit your needs. This enables you to write async route handlers without wrapping the statements in try/catch blocks and catch them with global error handler. To make this work you must:
1. Install the express-async-errors package
2. Import package (before the routes)
3. Set up global express error handler
4. Write async route handlers (More info about this)

Example usage:

import express from 'express';
import 'express-async-errors';

const app = express();

// route handlers must be async
app.get('/webhook', async (req, res) => {
    webhook.register(req, res);
});

app.get('/send', async (req, res) => {
    sendAutoMessage('1004426036330995');
});

app.post('/webhook/subscribe', async (req, res) => {
    webhook.subscribe("test");
});

app.post('/webhook/unsubscribe', async (req, res) => {
    webhook.unsubscribe("test");
});

// Global error handler - route handlers/middlewares which throw end up here
app.use((err, req, res, next) => {
    // response to user with 403 error and details
});

Upvotes: 16

Dinesh Agrawal
Dinesh Agrawal

Reputation: 346

this kind of try catch will not catch errors when some third function is called do the best solution will use global exception handler

app.use(function(err, req, res, next) {
     res.status(err.status || 500);
     res.end();
});

also you have to use promises in your end point handlers that will catch errors in any scope

Upvotes: 1

user6453941
user6453941

Reputation:

try catch can not catch error asynchronously. This will work: 

app.get('/webhook', function (req, res) {
        try { 
          //enter code here
        } catch (error) {
          // something here
        }
    });

But it is local and not the best way.

Good way is make error-handling middleware function. It is global. You need to define it after all app.use() and routes calls.

    app.use(function(err, req, res, next) {
      // This is error handler
    });

You can send the html page with details of error to client as usual.

Also, by default, Express have built-in error handler. The error will be written to the client with stack trace (It does not work in production mode).

Upvotes: 13

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