How to prevent Nodejs Server to crash when request data is not json-CodePudding

Today my server is ready to receive requests with json objects

I use app.use(express.json())

But if I try to send a request with any other type of data, my server crashes. I need to prevent this. How to solve this?

SERVER CODE

let app = express();
app.use(cors({
    origin: config.corsOrigin,
    methods: ['GET', 'POST', 'DELETE', 'UPDATE', 'PUT', 'PATCH'],
    preflightContinue: true,
    maxAge: 86400
}));

//Server crushes here if i send any other data types 
app.use(express.json({
    inflate: true, 
    limit: '100kb',
    reviver: null,
    strict: true,
    type: 'application/json',
    verify: (req, res, buf, encoding) => {
        if(!req.is('application/json')){
            res.json({'error':'Invalid request'});                   
        }                      
    }
}));

//Server go down too 
app.use(function(err, req, res, next) {
    if (err instanceof SyntaxError && err.status === 400 && 'body' in err) {
      console.error('Bad JSON');
      res.status(500).send('JSON parse error');
    }
    next(err);
  });



app.use(express.urlencoded({ extended: true }));
app.use(router);
new GameService(new HttpsService(app));

I need to ensure that the server doesn't stop when the other data type is sent to the server.

CodePudding user response：

You could try a custom middleware and put it in just the routes you want to validate:

  const jsonParserMiddleware = async(req, res, next) => {
    if (req.body && typeof req.body === 'string') {
      try {
        JSON.parse(req.body);
        next();
      } catch (e) {
        res.sendStatus(400).json({ msg: 'Invalid data.' });
      }
    } else {
      next();
    }
  };

  app.get('/', jsonParserMiddleware, async (req, res) => {
    const { data } = req.body;
    const someResponseData = await myFunc(data)
    return res.send(someResponseData);
  });

Or you could stick with app.use, which will perform the validation for all routes:

  const jsonParserMiddleware = async(req, res, next) => {
    if (req.body && typeof req.body === 'string') {
      try {
        JSON.parse(req.body);
        next();
      } catch (e) {
        res.sendStatus(400).json({ msg: 'Invalid data.' });
      }
    } else {
      next();
    }
  };

  app.use(jsonParserMiddleware);

P.S: As far as I know, the first argument of a middleware will always be the Request object. Why are you trying to get some kind of error?

CodePudding user response：

You can update verify option to verify body json content.

    verify: (req, res, buf, encoding) => {
        if(!req.is('application/json')){
            throw new Error('Invalid request');                   
        }
        
        try {
            JSON.parse(buf.toString(encoding)); // try to parse the body buff
        } catch (err) {
            throw new Error('Body is not a json object');
        }                      
    }