# express-request-modeler > Allows developers to check and validate incoming requests via a simple object model Latest version **1.0.8** (published 2020-12-15) · MIT license · 0 weekly downloads ## Install ```sh npm install express-request-modeler pnpm add express-request-modeler yarn add express-request-modeler bun add express-request-modeler ``` ## Health **Score 15/100 (F)** — status: abandoned. Positive: no vulnerabilities. Warnings: low downloads; no types; no esm support. Negative: abandoned; low maintenance score. ## Facts | | | |---|---| | Version | 1.0.8 | | Published | 2020-12-15 | | First published | 2020-12-14 | | Weekly downloads | 0 | | License | MIT | | TypeScript types | none | | Module format | CommonJS | | Dependencies | 1 | | Unpacked size | 11 KB | | Known vulnerabilities | 0 | | Install scripts | no | | Author | David J. Davydov | | Maintainers | daviddavydovtech | | Keywords | validate, validator, checker, model, modeler, express, request, api, API, middleware, middle-ware, node | ## Links - npm: https://www.npmjs.com/package/express-request-modeler - Repository: https://github.com/DavidDavydovTech/request-checker - Homepage: https://github.com/DavidDavydovTech/request-checker#readme - Issues: https://github.com/DavidDavydovTech/request-checker/issues - npm.io page: https://npm.io/package/express-request-modeler ## Dependencies (1) - [lodash.get](https://npm.io/package/lodash.get.md) ^4.4.2 ## Alternatives - [@regle/core](https://npm.io/package/@regle/core.md) — 47.0K weekly downloads - [typeof-arguments](https://npm.io/package/typeof-arguments.md) — 12.5K weekly downloads - [@lokalise/projects-engine-contracts](https://npm.io/package/@lokalise/projects-engine-contracts.md) — 978 weekly downloads - [@osjwnpm/nam-laboriosam-quibusdam](https://npm.io/package/@osjwnpm/nam-laboriosam-quibusdam.md) — 70 weekly downloads - [@oridune/validator](https://npm.io/package/@oridune/validator.md) — 16 weekly downloads ## Recent versions - 1.0.8 (latest) — 2020-12-15 - 1.0.7 — 2020-12-15 - 1.0.6 — 2020-12-14 - 1.0.5 — 2020-12-14 - 1.0.4 — 2020-12-14 - 1.0.3 — 2020-12-14 ## README # express-request-modeler   ## Summary This module allows you to validate express requests without the hassle of re-writing validation code for every route in your API.   ## About Express-request-modeler was born in mid-winter 2018 when I was doing web-APIs for the first time in my life. I got sick and tired of copy-pasting slightly different versions of the same code in to every post request, but every route was just different enough that I had no other choice. I ultimately made the precursor to this module (`Express-Request-Checker`; not to be confused with [pastgift's npm module of the same name](https://www.npmjs.com/package/express-request-checker)). That being said anyone who isn't an absolute newbie could see that my module was a horrifying mess. Now that it's mid-winter 2020 I'm coming back to writing web-APIs and have run into the same problem, so now with experience and hindsight on my side I've decided to create this improved module for me and others who need a simple and easy to implement request validator/modeler.   ## How to Use Express-request-modeler is an Express middleware meant to be implemented at the router level. Below you can find a simple example. ```js const app = require('express')(); app.use(json()); const reqModel = require('express-request-modeler'); app.route('/message') .post( [ reqModel({ body: { message: { rcRequired: true, rcType: 'string' } } }) ], (req, res) => { //...push message to database... }); ``` In the example above the request will never hit the `(req, res) => {}` function below `reqModel` unless there is a field called message within the body whos value is has a type of `string`.   ## Validation Options Below you can find a list of different options for validation. | Key Name | Expected Input | About | | ------------- | ------------- | ------------- | | rcRequired | ``: true/false | If set to true the request MUST contain this key-value pair or the request bounces. | | rcType | ``: string, number, boolean, object, array | If the parent key is present in the request and the parent key's value type does not match rcType the request will bounce. | | rcMatching | ``: ANY VALUE | If the parent key is present in the request and its value does not match rcMatching the request will bounce. | | rcFunc | `` | If the parent key is present in the request the function provided to rcFunc will run on the value to decide if it's valid or not. The user-provided function is expected to return true or false (if you don't your requests will start to hang). Currently doesn't work with async functions. |   ## Advanced Example ```js const app = require('express')(); const reqModel = require('express-request-modeler'); app.route('/message') .post( [ reqModel({ headers: { 'content-type': { rcMatching: 'application/json', } }, body: { message: { rcRequired: true, rcType: 'string', rcFunc: (val) => { if (val.length < 220) { return true; } return false; }, rcRejectStatus: '400', rcRejectMessage: 'Your message is too long!', } } }) ], (req, res) => { //...push message to database... }); ```   ## Planned features * Allow a custom reject message for every rejection type. * Suppress detailed rejection messages. * An alternative to rcFunc that can mutate the request value. * Allow users to change the order in which validation checks occur. * Allow rcFunc to be an Async function (so that it can be used for things like validating user sessions or querying a database for validation.) --- _Source: https://npm.io/package/express-request-modeler · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._