Express param converter middleware

Note: This param convertor currently works only with sequelize models.

Inspired by sensio/framework-extra-bundle (@ParamConverter)

Descripton

Main goal of this middleware is to convert given parameter in request URL, to sequelize instance of given model, for avoiding common code duplication (search instance in database, throw error if not found).

Installation

NPM

npm install express-param-converter --save

Yarn

yarn add express-param-converter

Usage

Example with single instance convertation:

var express = require('express');
var app = express();

var ExpressParamConverter = require('express-param-converter');

// Sequelize model
var Blog = require('./models/Blog');

app.get(
    '/blog/:id',
    [
        ExpressParamConverter.convert({ name: 'blog', model: Blog })
    ],
    function (res, req) {
        // Now you can easily access variables in `res.params`
        var blog = res.params.blog;

        return req.status(200).json({
            blog: blog,
        });
    }
);

This is how you can use multiple converters in one action:

var express = require('express');
var app = express();

var ExpressParamConverter = require('express-param-converter');

// Sequelize models
var Blog = require('./models/Blog');
var Post = require('./models/Post');

app.get(
    '/blog/:id/post/:post_slug',
    [
        ExpressParamConverter.convert({ name: 'blog', model: Blog }),
        ExpressParamConverter.convert({ name: 'post', model: Post, options: { mappings: { post_slug: 'slug' } } })
    ],
    function (res, req) {
        // Note that `res.params` now contains `id`, `slug`, `blog` and `post` variables
        var blog = res.params.blog;
        var post = res.params.post;

        return req.status(200).json({
            blog: blog,
            post: post,
        });
    }
);

If you want to receive plain object you can use plain option

var express = require('express');
var app = express();

var ExpressParamConverter = require('express-param-converter');

// Sequelize models
var Post = require('./models/Post');
var Comment = require('./models/Comment');

app.get(
    '/post/:post_slug/comment/:comment_id',
    [
        ExpressParamConverter.convert({ name: 'post', model: Post, options: { mappings: { post_slug: 'slug' }, plain: true } }),
        ExpressParamConverter.convert({ name: 'comment', model: Comment, options: { mappings: { comment_id: 'id' }, plain: true } })
    ],
    function (res, req) {
        var post = res.params.post;
        var comment = res.params.comment;

        // `plain` option do the same as:
        var plainComment = comment.get({ plain: true });

        return req.status(200).json({
            post: post,
            comment: plainComment,
        });
    }
);

TODO

• Rewrite to typescript
• Make it independent from sequelize models
• Add additional parameters to options (i.e. method etc.)

License

This software is published under the MIT License