Quick configurable API validations for Express.js

Features

• Simple - Provides a simple and quick way to configure API validations.
• Clean - Unlike other libraries, quick-validate does not require you to write a lot of code for adding simple validations. It uses simple JSON configuration files which do not pollute application code.
• Readable - The validations are much more readable and comprehensible.

Installation

npm install quick-validate --save

Usage

• Create a directory named validations inside root of your project. This is not required but is recommended as a good practice.

• Create 2 files inside the validations directory - apiValidations.json and validationSchema.json

apiValidations.json should specify validations for each endpoint. validationSchema.json should specify type and other constraints about each attribute to be validated.

apivalidations.json

{
  "POST": {
    "/product": {
      "body": {
        "required": ["title", "img_url", "price", "availability_status"],
        "optional": ["description"]
      }
    }
  },
  "PUT": {
    "/product/:product_id": {
      "body": {
        "optional": [
          "title",
          "img_url",
          "price",
          "availability_status",
          "description"
        ]
      }
    }
  },
  "GET": {
    "/products": {
      "query": {
        "required": ["q"]
      }
    }
  },
  "DELETE": {
    "/product/:product_id": {
      "headers": {
        "required": ["admin_token"]
      }
    }
  }
}

As shown in above example, the configuration object structure should be

{
  "httpMethod": {
    "endpoint_path1": {
      "required": ["attr1", "attr2"],
      "optional": ["attr3"]
    },
    "endpoint_path2": {
      "required": ["attr1", "attr2"],
      "optional": ["attr3"]
    }
  }
}

validationSchema.json

{
  "title": {
    "type": "String"
  },
  "img_url": {
    "type": "String"
  },
  "price": {
    "type": "Number"
  },
  "availability_status": {
    "type": "regex",
    "regex": "^(IN_STOCK|OUT_OF_STOCK)$"
  },
  "description": {
    "type": "String"
  },
  "q": {
    "type": "String",
    "minlength": 3,
    "maxlength": "50"
  },
  "admin_token": {
    "type": "String",
    "length": 32
  }
}

• Import and use quick-validate in your app.js

Using ES6 (Recommended)

import * as quickValidate from "quick-validate";
import apiValidations from "./validations/apiValidations.json";
import validationSchema from "./validations/validationSchema.json";
import express from "express";

const app = express();
app.use(express.json());

quickValidate.enableValidations(app, apiValidations, validationSchema, true);

Good ol' way

var quickValidate = require("quick-validate");
var apiValidations = require("./validations/apiValidations.json");
var validationSchema = require("./validations/validationSchema.json");
var express = require("express");

var app = express();
app.use(express.json());

quickValidate.enableValidations(app, apiValidations, validationSchema, true);

The last argument is a boolean which tells quick-validate if extra attributes which are not specified in the validation config for an endpoint, should be removed. This should be usually set to true.

• Intercept validation errors with middleware

app.use(function (err, req, res, next) {
  res.json({
    ok: false,
    error: {
      code: err.code,
      reason: err.message,
    },
  });
});

Schema Properties

Click on property name to see example

| name | purpose | | -------------------------------- | :------------------------------------------ | | type | datatype of attribute | | length | length of 'String' type attribute | | minlength | min length of 'String' type attribute | | maxlength | max length of 'String' type attribute | | regex | specifies a pattern to match with | | enumVals | specifies a set of enums to match with | | missing_err_code | error code to return if missing | | invalid_err_code | error code to return if datatype is invalid |

Supported 'type'(s)

| type | purpose | | -------- | :----------------------------------------- | | String | Any string | | Number | int, float or any string representing same | | boolean | boolean | | Array | Any array | | Object | Any Object | | email | valid email | | password | matches strict password policy | | enum | matches a set of given values | | regex | matches a given regex pattern |

Examples

length

{
  "otp": {
    "type": "String",
    "length": 4
  }
}

minlength maxlength

{
  "username": {
    "type": "String",
    "minlength": 5,
    "maxlength": 15
  }
}

regex

{
  "ip": {
    "type": "regex",
    "regex": "^(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?).){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$"
  }
}

enumVals

{
  "availability_status": {
    "type": "enum",
    "enumVals": ["IN_STOCK", "OUT_OF_STOCK"]
  }
}

Putting it all together

validationSchema.json

{
  "username": {
    "type": "String",
    "minlength": 5,
    "maxlength": 15
  },
  "password": {
    "type": "password"
  },
  "email": {
    "type": "email"
  },
  "gender": {
    "type": "enum",
    "enumVals": ["M", "F", "T"]
  },
  "age": {
    "type": "Number"
  },
  "is_married": {
    "type": "boolean"
  },
  "name": {
    "type": "String",
    "minlength": 5,
    "maxlength": 40
  },
  "x-forwarded-for": {
    "type": "regex",
    "regex": "^(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?).){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$"
  }
}

apivalidations.json

{
  "POST": {
    "/user/signup": {
      "body": {
        "required": ["username", "password", "email", "gender", "age", "name"],
        "optional": ["is_married"]
      },
      "headers": {
        "required": ["x-forwarded-for"]
      }
    },
    "/user/login": {
      "body": {
        "required": ["username", "password"]
      }
    }
  }
}