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:

1npm i @lambrioanpm/debitis-minima-magnam --save  

Usage Examples

1const express = require('express')  
2const qs = require('@lambrioanpm/debitis-minima-magnam')  
3const app = express()  
4  
5app.use(qs()) // middleware @lambrioanpm/debitis-minima-magnam  
6  
7app.listen(3000, (req, res) => {  
8    console.log('app listening on port 3000')  
9})  
10  
11app.get('/', (req, res) => {  
12    res.send('the query is:' + JSON.stringify(req.query))  
13})  
14  
15/**  
16 * Request: http://localhost:3000?fields=name,age&skip=10&limit=10&sort=created_at  
17 * Result (req.query):  
18 * {  
19 *    fields: { name: 1, age: 1 },  
20 *    sort: { created_at: 1 }  
21 *    filters: {},  
22 *    pagination: {  
23 *        skip: 10,  
24 *        limit: 10  
25 *    },  
26 *    original: '?fields=name,age&skip=10&limit=10&sort=created_at'  
27 * }  
28 */  

Using custom configurations:

1const express = require('express')  
2const qs = require('@lambrioanpm/debitis-minima-magnam')  
3const app = express()  
4  
5app.use(qs({  
6  use_page: true,  
7  client_db: 'mongodb',  
8  date_field: {  
9      start_at: 'timestamp',  
10      end_at: 'timestamp'  
11  },  
12  default: {  
13      fields: {name: 1 , age: 1, number: 1, _id: 0},  
14      sort: { created_at: -1 },  
15      filters: {},  
16      pagination: {  
17          page: 1,  
18          limit: 100  
19      }  
20  }  
21}))  
22  
23/**  
24 * Request: http://localhost:3000?fields=name,age&age=30  
25 * Result (req.query):  
26 * {  
27 *    fields: { name: 1, age: 1},  
28 *    sort: { created_at: -1 }  
29 *    filters: {age: 30},  
30 *    pagination: {  
31 *        limit: 100,  
32 *        page: 1  
33 *    },  
34 *    original: '?fields=name,age&age=30'  
35 * }  
36 */  

The middleware uses the following defaults:

1options = {  
2    use_page: false,  
3    client_db: 'mongodb',  
4    date_field: {  
5      start_at: 'created_at',  
6      end_at: 'created_at'  
7    },
8    default: {  
9        fields: {},  
10        sort: {},  
11        filters: {},  
12        pagination: {  
13            limit: Number.MAX_SAFE_INTEGER,  
14            skip: 0,  
15            page: 1  
16        }          
17    }      
18}  

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

For more details, access the wiki page.

Parsers Functions

To use these functions, simply call them through the middleware instance and pass them the query string to be converted and its default values. If you pass the default values ​​a merge will be performed with the result of the query strings. Here are some examples of each analyzer:

• parser()

1const qs = require('@lambrioanpm/debitis-minima-magnam')
2
3const query = '?fields=name,age&page=1&limit=10&sort=created_at'
4console.log(qs.parseFields(query, {}, { use_page: true }))
5
6/**
7* Result: 
8* {
9*   fields: { name: 1, age: 1 },
10*   sort: { created_at: 1 },
11*   filters: {},
12*   pagination: { limit: 10, page: 1 },
13*   original:  '?fields=name,age&page=1&limit=10&sort=created_at'
14* }
15*/

For more details >>

• parseFields()

1
2const qs = require('@lambrioanpm/debitis-minima-magnam')
3
4const query = '?fields=name,age'
5console.log(qs.parseFields(query))
6
7/**
8* Result: 
9* { 
10*     name: 1,
11*     age: 1
12* }
13*/

For more details >>

• parseSort()

1const qs = require('@lambrioanpm/debitis-minima-magnam')
2
3const query = '?sort=name,-age,created_at'
4console.log(qs.parseSort(query))
5
6/**
7* Result: 
8* { 
9*     name: 1,
10*     age: -1,
11*     created_at: 1
12* }
13*/

For more details >>

• parsePagination()

1const qs = require('@lambrioanpm/debitis-minima-magnam')
2
3const query = '?limit=20&page=3'
4console.log(qs.parsePagination(query, {}, true))
5
6/**
7* Result: 
8* { 
9*     limit: 20,
10*     page: 3 
11* }
12*/

For more details >>

• parseFilter()

1 const qs = require('@lambrioanpm/debitis-minima-magnam')
2 
3 const query = '?name=elvis&age=80'
4 console.log(qs.parseFilter(query))
5 
6 /**
7 * Result: 
8 * { 
9 *     name: 'elvis',
10 *     age: 80
11 * }
12 */

For more details >>

• parseDate()

1const qs = require('@lambrioanpm/debitis-minima-magnam')
2
3const query = '?start_at=2019-02-05T00:00:00&end_at=2019-02-05T23:59:59'
4console.log(qs.parseDate(query))
5
6/**
7* Result: 
8* { 
9*    $and: [
10*       { created_at: { lt: 2019-02-05T23:59:59 }},
11*       { created_at: { gte: 2019-02-05T00:00:00 }}
12*   ]}
13* }
14*/

For more details >>

Supported Query Strings

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

---

Future Features

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