Read API Code Snippets

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All examples on this page use the old deprecated Freebase API. Any new development should be done with the new googleapis.com API

This page shows you how to query the Freebase Read Service using your favorite programming language. You'll need facilities to encode and decode JSON as well as fetch an HTTP URL. For a more detailed description of how to use the Read Service please take a look at the MQL Manual

Each of the code snippets below will query Freebase for a list of planets and display their names using the following query: 

[{
  "id":   null,
  "name": null,
  "type": "/astronomy/planet"
}]​

This corresponds to the following HTTP GET request (click the link to see the response format): 

 http://api.freebase.com/api/service/mqlread?query={"query":[{"id":null,"name":null,"type":"/astronomy/planet"}]}

Contents

ActionScript

This sample code uses the ActionScript 3 Core Library to parse the JSON data. 

import flash.net.URLRequest;
import flash.net.URLLoader;
import flash.events.*;
import com.adobe.serialization.json.JSON;

var query = [{'id': null, 'name': null, 'type': '/astronomy/planet'}];
var query_envelope = {'query': query};
var service_url = 'http://api.freebase.com/api/service/mqlread';

var loader:URLLoader = new URLLoader();
var request:URLRequest = new URLRequest();
request.url = service_url  + "?&query=" + encodeURIComponent(JSON.encode(query_envelope));

loader.load(request) ;
loader.addEventListener(Event.COMPLETE, function(event:Event):void {
  var results:Array = JSON.decode(loader.data).result;
  for each(var planet:Object in results) {
    trace(planet.name) ;
  }
});

Also see: Flash libraries

C# 

 TODO

How to make calls to Freebase API from .NET - code sample shows how to create freebase query from .NET object and parse API response. This sample uses only standard .NET 3.5 or 4.0 libraries.

Also see: .Net libraries

Java

The following snippet uses the HttpClient and json-simple libraries. 

String query = "[{\"id\":null,\"name\":null,\"type\":\"/astronomy/planet\"}]";
String query_envelope = "{\"query\":" + query + "}";
String service_url = "http://api.freebase.com/api/service/mqlread";
String url = service_url  + "?query=" + URLEncoder.encode(query_envelope, "UTF-8");
			
HttpClient httpclient = new DefaultHttpClient();   
HttpResponse response = httpclient.execute(new HttpGet(url));  
       
JSONParser parser = new JSONParser();
JSONObject json_data = (JSONObject)parser.parse(EntityUtils.toString(response.getEntity()));
JSONArray results = (JSONArray)json_data.get("result");

for (Object planet : results) {
  System.out.println(((JSONObject)planet).get("name"));
}

Also see: Java libraries

Javascript

This snippet makes an Ajax call to the Freebase API useing jQuery and the json2 library. 

<!DOCTYPE html>
<title>MqlRead in JavaScript</title>

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js"></script>
<!-- for older browsers: <script src="json2.js"></script> -->

<script>
  var query = [{'id': null, 'name': null, 'type': '/astronomy/planet'}];
  var query_envelope = {'query' : query};
  var service_url = 'http://api.freebase.com/api/service/mqlread';

  $.getJSON(service_url + '?callback=?', {query:JSON.stringify(query_envelope)}, function(response) {
    $.each(response.result, function(i,planet){
      $('<div>',{text:planet.name})
         .appendTo(document.body);
    });
  });
</script>

Also see: Javascript libraries

Objective-C 

 TODO

Also see: Objective-C libraries

Perl 

use URI::Escape;
use LWP::Simple;
use JSON;

$query = [{id => undef, name  => undef, type => '/astronomy/planet'}];
$query_envelope = {query => $query};
$service_url = 'http://api.freebase.com/api/service/mqlread';
$url = $service_url . "?query=" . uri_escape(encode_json($query_envelope));

$results = decode_json(get($url))->{result};
foreach $planet (@$results) {
  print $planet->{name} . "\n";
}

Also see: Perl libraries

PHP 

$query = array(array('id' => NULL, 'name' => NULL, 'type' => '/astronomy/planet'));
$query_envelope = array('query' => $query);
$service_url = 'http://api.freebase.com/api/service/mqlread';
$url = $service_url . '?query=' . urlencode(json_encode($query_envelope));

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$response = json_decode(curl_exec($ch), true);
curl_close($ch);

foreach ($response['result'] as $planet) {
  echo $planet['name'] . '<br/>';
}

Also see: PHP libraries


Python 

import sys
import json
import urllib

query = [{'id': None, 'name': None, 'type': '/astronomy/planet'}]
query_envelope = {'query': query}
service_url = 'http://api.freebase.com/api/service/mqlread'
url = service_url + '?query=' + json.dumps(query_envelope);

response = json.loads(urllib.urlopen(url).read())
for planet in response['result']:
  print planet['name']

Also see: Python libraries

Ruby

One way to make a Freebase API call in Ruby is to use the HTTParty libarary. 

require 'cgi'
require 'httparty'
require 'json'

query = [{'id' => nil, 'name' => nil, 'type' => '/astronomy/planet'}]
query_envelope = {'query' => query }
service_url = 'http://api.freebase.com/api/service/mqlread'
url = service_url + '?query=' + CGI::escape(query_envelope.to_json)

response = HTTParty.get(url, :format => :json)
response['result'].each { |planet|
  puts planet['name']
}

Also see: Ruby libraries

Retrieved from "http://wiki.freebase.com/wiki/Read_API_Code_Snippets"
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