Url-db-paging NPM

url-db-paging

A library to help creating paging results through URLs.

Features

Build a paging query with a search provider based in some URL. Which will use offset fields due performance reasons.
Build REST JSON output with link to the next and previous pages.

Search providers

Do you want another provider? Please open an issue or even better send us a pull request.

Usage

Options

query: request query string
defaultSortField: default primary sort field
idField: data's id field
root: base url
limit: limit results per page
queryBuilderType: query builder type (mongoose, solr or knex)

var express = require('express'),
    Paging = require('url-db-paging'),
    User = require('./models/user');

var app = express();

app.get('/', function(req, res, next){
  var userQuery = User.find();

  var limit = parseInt(query.limit, 10) || 20;

  var paging = new Paging({
    query: req.query,               // query string
    defaultSortField: '-created',   // default sort field
    defaultSortField: {column: '-created', json: 'createdAt'}, // define the column to sort and the JSON value of createdAt
    idField: '_id',                 // data's id field
    idField: {column: '_id', json: 'id'}, // define the id column in database and
    root: 'http://service/users',   // base url
    limit: limit,                   // limit per page
    queryBuilderType: 'mongoose'    // query builder type
  });

  //OR: When your JSON data it's different than the column/property in yours database you can define those changes like:
  var paging = new Paging({
    query: req.query,               // query string
    defaultSortField: {column: '-created', json: 'createdAt'} // define the column to sort and the JSON value of createdAt
    idField: {column: '_id', json: 'id'} // define the id column in database and
    root: 'http://service/users',   // base url
    limit: limit,                   // limit per page
    queryBuilderType: 'mongoose'    // query builder type
  });

  // add sort db query
  paging.addSortDbQuery(userQuery);

  userQuery
    .sort(paging.getSortQuery())    // sort using paging
    .limit(paging.getLimitQuery())  // limit using paging
    .exec()
    .then(result, next);

  function result(users) {
    var data = paging.buildPagingResult(users); // add paging into data result
    return res.status(200).send(data);
  }
});


module.exports = app;

Output Result (Example)

{
  list:[
    { ... },
    { ... },
    { ... }
  ],
  _links: {
    previous: {
      href: "http://service/users?limit=5&sort=-created&offset_date=2014-07-31T12%3A05%3A24.865Z&offset_id=53da3104d14bdb2500cc203d&dir=backward"
    },
    next: {
      href: "http://service/users?limit=5&sort=-created&offset_date=2014-07-31T12%3A05%3A24.854Z&offset_id=53da3104d14bdb2500cc2035&dir=forward"
    }
  }
}