express-param

Middleware for parsing Express.js request parameters

About

You can use this library to remove redundancies in your code and to improve readability.

For example, you may have something like

function route(req, res, next) {
  var id = req.params.id
    , count = req.param('count') ? parseInt(req.param('count'), 10) : 10
    , order = req.param('order')
    , type = req.param('type')
    , name = req.param('name')
    , since = req.param('since')
    , from = req.param('from')
    , res_id = req.param('res_id');

  if (!res_id) return next(400);
  if (!name) return next(400);
  if (!order) order = 'desc';
  if (!type) type = 'integer';

  // some code...
}

Using this library, the code above is reduced to

function route(req, res, next) {
  var requiredParams = ['{id}', 'name', 'res_id']
    , optionalParams = ['int:id', 'int32:sum', 'uint32:max', 'float:avg', 'number:count|=10', 'order|=desc', 'type|=integer', 'since', 'from']
    , options;

  options = req.fetchParamter(requiredParams, optionalParams);

  if (req.checkParamErr(options)) return next(options);

  return res.send(options);
}

Parameter syntax

Our parameter syntax was inspired by Spring Framework and Flask.

Required parameter : Array

• [element1, element2, element3, ...]
• type:{parameter_name}
  • type is optional; type can be an int, int32, uint32, float, number (for backwards compatibility), or string.
  • if type is string, unicode null character \u0000 is replaced by ''. (prevent some android keyboard problem.)
  • Curly braces in {parameter_name} are optional but parameter_name is required. Put {} around parameter_name to indicate that it is a path variable.
  • Example:

  ['number:{id}', 'string:username', 'address']

Optional parameter : Array

• [element1, element2, element3, ...]
• type:parameter_name|=default_value
  • type is optional; type can be an int, int32, unit32, float, number (for backwards compatibility), or string.
  • if type is string, unicode null character \u0000 is replaced by ''.
  • parameter_name is required.
  • default_value is optional. If the request object does not have any specified parameter then assign this default value.
  • Example:

  ['int:count', 'order', 'string:option1|=Y']

Parameter with multiple values

Selects the last parameter value for protection from HTTP pollution attacks.

GET /path?id=1&type=number&id=2&name=first&name=second

{id: 2, type: 'number', name: 'second'}

If you want to select multiple values from the parameter, use string type after separating the values with commas.

GET /path?id=1,2&type=number&name=first,second

{id: '1,2', type: 'number', name: 'first,second'}

Example

Here is a simple example.

var express = require('express');
var fetcher = require('express-param');
var app = express();
app.use(fetcher());

app.get('/path', function(req, res, next) {
  var requiredParams = ['id'];
  var optionalParams = ['count'];
  var options = req.fetchParamter(requiredParams, optionalParams);

  if (req.checkParamErr(options)) return next(options);

  return res.send(options);
});

Here is another example with express-param syntax:

var fetcher = require('express-param');
var app = express();
app.use(fetcher());

app.get('/path/:id/', function(req, res, next) {
  var requiredParams = ['string:{id}'];
  var optionalParams = ['number:count|=10, order|=desc'];
  var options = req.fetchParamter(requiredParams, optionalParams);

  if (req.checkParamErr(options)) return next(options);

  console.log(options);
  {
    id: '10',
    count: 10,
    order: 'desc'
  }

  return res.send(options);
});

Another example

Custom request key name belongs to request property of express:

var express = require('express');
var fetcher = require('express-param');
var app = express();
app.use(fetcher({
  'ipaddr': 'ip'
}));

app.get('/path', function(req, res, next) {
  var requiredParams = ['id'];
  var optionalParams = ['count', 'ipaddr'];
  var options = req.fetchParamter(requiredParams, optionalParams);

  if (options.err) return next(options.err);

  /*
  options.ipaddr is equal to req.ip
  */
  return res.send(options.params);
});

API

• fetchParameter(required[, optional])

  Fetch required and optional parameters.

Add ON

• fetch geographic information

  Fetch country information from remote IP addresses!

  // get country info from req.ip (default)
  app.use(fetcher({
    'ipaddr': 'ip',
    'geo-info': 'headers.x-fetcher-geoinfo',
    'access-country': true
  }, {geoip: {}}));
  
  // get country info from req.headers['x-forwarded-for']
  var addOnOpt = {
    geoip: {
      keyName: 'headers.x-forwarded-for'
    }
  };
  app.use(fetcher({
    'ipaddr': 'ip',
    'geo-info': 'headers.x-fetcher-geoinfo',
    'access-country': true
  }, addOnOpt));
  
  ////// ....
  
  console.log(req.headers['x-fetcher-geoinfo']);
  // or console.log(options['geo-info']);
  {
    range: [ 3479299040, 3479299071 ],
    country: 'US',
    region: 'CA',
    city: 'San Francisco',
    ll: [37.7484, -122.4156]
  }
  
  console.log(options['access-country']);
  'US'

• fetch detail imsi information by mnc, mcc code

  It can generate detail imsi(country, operator...) information by mcc, mnc code!

var addOnOpt = {
  imsi: true
};
app.use(fetcher({
  'ipaddr': 'ip',
  'access-country': true
}, addOnOpt));

////// ....

// The URL may be hostname/api?mnc=11&mcc=450.
// If only mcc is present then the length of the results array may be greater than 1.

console.log(req.headers['x-fetcher-imsi'])
[{
  country_name: 'South Korea',
  country_code: 'KR',
  mcc: '450',
  mnc: '11',
  brand: 'SKTelecom',
  operator: 'Korea Cable Telecom(t-plus), Eco-mobile',
  status: 'Operational',
  bands: 'UMTS 2100'
}]

console.log(options['access-country']);
'KR'

Make contributions

We'd love your contributions! Please send us Pull Requests. Also, read the contribution guidelines.

LICENSE

MIT

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This product includes GeoLite data created by MaxMind, available from http://www.maxmind.com