Query Strings Parser

Middleware to transform query strings in a format that is recognized by the MongoDB, MySQL¹ and other databases.

Prerequisites

To ensure the smooth operation of the middleware, your web application must be built using the express.js or hapi.js frameworks.

Installing

Use the npm command to install this library into your project:

npm i --save query-strings-parser  

Usage Examples

1. Using default configurations

const express = require('express')  
const qs = require('query-strings-parser')  
const app = express()  
  
app.use(qs()) // middleware query-strings-parser  
  
app.listen(3000, (req, res) => {  
    console.log('app listening on port 3000')  
})  
  
app.get('/', (req, res) => {  
    res.send('the query is:' + JSON.stringify(req.query))  
})  
  
/**  
 * Request: http://localhost:3000?fields=name,age&skip=10&limit=10&sort=created_at  
 * Result (req.query):  
 * {  
 *    fields: { name: 1, age: 1 },  
 *    sort: { created_at: 'asc' }  
 *    filters: {},  
 *    pagination: {  
 *        skip: 10,  
 *        limit: 10  
 *    },  
 *    original: '?fields=name,age&skip=10&limit=10&sort=created_at'  
 * }  
 */  

The middleware uses the following defaults:

options = {  
    use_page: false,  
    client_db: 'mongodb',  
    date_field: {  
      start_at: 'created_at',  
      end_at: 'created_at'  
    },  
    default: {  
        fields: {},  
        sort: {},  
        filters: {},  
        pagination: {  
            limit: Number.MAX_SAFE_INTEGER,  
            skip: 0,  
            page: 1  
        }          
    }      
}  

If the options are not provided, the default values will be used for the treatment of queries strings.

2. Using custom configurations:

const express = require('express')  
const qs = require('query-strings-parser')  
const app = express()  
  
app.use(qs({  
  use_page: true,  
  client_db: 'mongodb',  
  date_field: {  
      start_at: 'timestamp',  
      end_at: 'timestamp'  
  },  
  default: {  
      fields: {name: 1 , age: 1, number: 1, _id: 0},  
      sort: { created_at: 'desc' },  
      filters: {},  
      pagination: {  
          page: 1,  
          limit: 100  
      }  
  }  
}))  
  
/**  
 * Request: http://localhost:3000?fields=name,age&age=30  
 * Result (req.query):  
 * {  
 *    fields: { name: 1, age: 1},  
 *    sort: { created_at: 'desc' }  
 *    filters: {age: 30},  
 *    pagination: {  
 *        limit: 100,  
 *        page: 1  
 *    },  
 *    original: '?fields=name,age&age=30'  
 * }  
 */  

For more details, access the wiki page.

Supported Query Strings

For informations and details about the supported query strings, access the wiki page.

New Features

• Support for parser functions. For informations and details about parser functions, access the wiki page.

Future Features

• ¹Support for relational databases such as MySQL, PostgreSQL and SQLite.