How to validate API request in Node js

Question

I have created a simple API which has all verbs GET, PUT, POST, DELETE, but in this, I want to validate POST data.

I have tried Joi Libary but I did not get the proper way to do it.

CodeSnippet of POST Method

    appRouter.route('/')
        .post(function (req, res) 
        {            
            if (req.body.ProductName) 
            {
                conn.connect().then(function () {
                    var transaction = new sql.Transaction(conn);
                    transaction.begin().then(function () {
                        var request = new sql.Request(transaction);
                        request.input("ProductName", sql.VarChar(50), req.body.ProductName)
                        request.input("ProductPrice", sql.Decimal(18, 0), req.body.ProductPrice)
                        request.execute("Usp_InsertProduct").then(function () {
                            transaction.commit().then(function (recordSet) {
                                console.log(recordSet);
                                conn.close();
                                res.status(200).send(req.body);
                            }).catch(function (err) {
                                console.log("Error in Transaction Commit " + err);
                                conn.close();
                                res.status(400).send("Error while inserting data");
                            });
                        }).catch(function (err) {
                            console.log("Error in Transaction Begin " + err);
                            conn.close();
                            res.status(400).send("Error while inserting data");
                        });

                    }).catch(function (err) {
                        console.log(err);
                        conn.close();
                        res.status(400).send("Error while inserting data");
                    });
                })
                    .catch(function (err) {
                        console.log(err);
                        conn.close();
                        res.status(400).send("Error while inserting data");
                    });
            }
            else {
                res.status(400).send("Error while inserting data");
            }
        });

Snapshot of Controller

Muhammad Faizan · Accepted Answer · 2018-04-02 06:03:40Z

3

You can use this: validator created by google they use it to validate query param, but you can use it to validate payload. its simple and extensible

and use it like this:

const v = require('./validator')
// then test your payload like this...
const testPayload = (req, res, next) => {
try {
    const validate = v.object({
        username: v.string, //required field, string
        password: v.string, // required field, string
        age: v.number, // required field, number
        opt: v.optional(v.array(v.string))) // optional field, array of string
    })
    validate(req.body);
    next() // if everything goes well pass it to next middle ware, or handle your payload
}
catch (err) {
   next(err) // handling common error
}

answered Apr 2, 2018 at 6:03

Muhammad Faizan

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Comments

Henrique Borges · Accepted Answer · 2018-04-03 04:00:57Z

2

I usually user express-validator to validate API requests. It's based on validator.js. You can easily verify types, fields length, and even build your own custom functions to verify fields. And this package also make very easy to return to the user what fields that are not correct and why.

Example of validation error return from API call.

[
    {
        "location": "params",
        "param": "is_active",
        "msg": "Missing is_active param."
    },
    {
        "location": "params",
        "param": "is_active",
        "msg": "is_active param must be boolean true or false."
    }
]

edited Apr 3, 2018 at 4:00

answered Apr 2, 2018 at 14:20

Henrique Borges

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Comments

ranvir · Accepted Answer · 2020-03-08 21:38:39Z

2

You can use the combination of Joi and middleware to validate all your parameters. For example if you want to validate ProductName from the request body,

const validateParams = function (paramSchema) {
    return async (req, res, next) => {
        const schema = Joi.object().keys(paramSchema);
        try{
            await Joi.validate(paramSchema, schema);
        } catch (err) {
            return res.send(400, {
                status: 400,
                result: err.details[0].message
            });
        }
        next();
    }
};

function routeFunction (req, res, next) {
    // do anything you want to
}

server.post(`${routeURI}/abc`, validateParams({
        ProductName: Joi.string().required(),
    }), routeFunction);

Similarly, if you want to validate the response, you can create similar middleware and use Joi for the same purpose.

answered Mar 8, 2020 at 21:38

ranvir

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1 Comment

ranvir Over a year ago

For more info read: ranvir.xyz/blog/…

score 0 · Accepted Answer · 2018-04-02 05:37:05Z

0

You can use your own middleware function for validating the api. This link contains information about middle functions using express framework: http://expressjs.com/en/guide/using-middleware.html

You can use a middleware for POST request for your url or simply for POST request.

edited Apr 2, 2018 at 5:37

answered Apr 2, 2018 at 5:23

user9584411

1 Comment

Shihe Zhang Over a year ago

Better post core content rather than post an external link.

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