Validation Middleware

Overview

The validation.js file provides a set of middleware functions for validating incoming request data using Zod schemas. It includes validators for the request body, query parameters, URL parameters, and headers.

validation Object

The validation object contains four methods, each corresponding to a part of the HTTP request:

• body(schema)
• query(schema)
• params(schema)
• headers(schema)

Each of these methods is a higher-order function that takes a Zod schema as an argument and returns a middleware function.

Parameters

• schema: A Zod schema used to validate the request data.

Middleware Functionality

1. Parse and Validate: It uses the safeParse() method of the Zod schema to validate the corresponding part of the request (req.body, req.query, req.params, or req.headers).
2. Handle Validation Errors: If the validation fails, it sends a 400 Bad Request response with a JSON body containing:
   • status: false
   • message: The first validation error message.
   • data: An object containing the validation errors, flattened for easy access.
3. Update Request Data: If the validation is successful, it updates the corresponding part of the request with the parsed (and possibly transformed) data from the Zod schema.
4. Call Next Middleware: It calls next() to pass control to the next middleware in the stack.

Usage

import { z } from "zod";
import { validation } from "./validation.js";

const createUserSchema = z.object({
    name: z.string().min(3),
    email: z.string().email(),
});

// Validate the request body against the createUserSchema
router.post("/users", validation.body(createUserSchema), (req, res) => {
    // The request body is now validated and sanitized
    const newUser = req.body;
    // ...
});

Exports

• validation: The object containing the validation middleware functions.