Php function get json

JSON PHP

A common use of JSON is to read data from a web server, and display the data in a web page.

This chapter will teach you how to exchange JSON data between the client and a PHP server.

The PHP File

PHP has some built-in functions to handle JSON.

Objects in PHP can be converted into JSON by using the PHP function json_encode() :

PHP file

The Client JavaScript

Here is a JavaScript on the client, using an AJAX call to request the PHP file from the example above:

Example

Use JSON.parse() to convert the result into a JavaScript object:

const xmlhttp = new XMLHttpRequest();
xmlhttp.onload = function() const myObj = JSON.parse(this.responseText);
document.getElementById(«demo»).innerHTML = myObj.name;
>
xmlhttp.open(«GET», «demo_file.php»);
xmlhttp.send();

PHP Array

Arrays in PHP will also be converted into JSON when using the PHP function json_encode() :

PHP file

The Client JavaScript

Here is a JavaScript on the client, using an AJAX call to request the PHP file from the array example above:

Example

Use JSON.parse() to convert the result into a JavaScript array:

var xmlhttp = new XMLHttpRequest();
xmlhttp.onload = function() const myObj = JSON.parse(this.responseText);
document.getElementById(«demo»).innerHTML = myObj[2];
>
xmlhttp.open(«GET», «demo_file_array.php», true);
xmlhttp.send();

PHP Database

PHP is a server side programming language, and can be used to access a database.

Imagine you have a database on your server, and you want to send a request to it from the client where you ask for the 10 first rows in a table called «customers».

On the client, make a JSON object that describes the numbers of rows you want to return.

Before you send the request to the server, convert the JSON object into a string and send it as a parameter to the url of the PHP page:

Example

Use JSON.stringify() to convert the JavaScript object into JSON:

const limit = <"limit":10>;
const dbParam = JSON.stringify(limit);
xmlhttp = new XMLHttpRequest();
xmlhttp.onload = function() document.getElementById(«demo»).innerHTML = this.responseText;
>
xmlhttp.open(«GET»,»json_demo_db.php?x=» + dbParam);
xmlhttp.send();

Example explained:

• Define an object containing a «limit» property and value.
• Convert the object into a JSON string.
• Send a request to the PHP file, with the JSON string as a parameter.
• Wait until the request returns with the result (as JSON)
• Display the result received from the PHP file.

Take a look at the PHP file:

PHP file

header(«Content-Type: application/json; charset=UTF-8»);
$obj = json_decode($_GET[«x»], false);

$conn = new mysqli(«myServer», «myUser», «myPassword», «Northwind»);
$stmt = $conn->prepare(«SELECT name FROM customers LIMIT ?»);
$stmt->bind_param(«s», $obj->limit);
$stmt->execute();
$result = $stmt->get_result();
$outp = $result->fetch_all(MYSQLI_ASSOC);

PHP File explained:

• Convert the request into an object, using the PHP function json_decode() .
• Access the database, and fill an array with the requested data.
• Add the array to an object, and return the object as JSON using the json_encode() function.

Use the Data

Example

xmlhttp.onload = function() <
const myObj = JSON.parse(this.responseText);
let text = «»;
for (let x in myObj) <
text += myObj[x].name + «
«;
>
document.getElementById(«demo»).innerHTML = text;
>

PHP Method = POST

When sending data to the server, it is often best to use the HTTP POST method.

To send AJAX requests using the POST method, specify the method, and the correct header.

The data sent to the server must now be an argument to the send() method:

Example

const dbParam = JSON.stringify(<"limit":10>);
const xmlhttp = new XMLHttpRequest();
xmlhttp.onload = function() const myObj = JSON.parse(this.responseText);
let text =»»;
for (let x in myObj) text += myObj[x].name + «
«;
>
document.getElementById(«demo»).innerHTML = text;
>
xmlhttp.open(«POST», «json_demo_db_post.php»);
xmlhttp.setRequestHeader(«Content-type», «application/x-www-form-urlencoded»);
xmlhttp.send(«x=» + dbParam);

The only difference in the PHP file is the method for getting the transferred data.

PHP file

Use $_POST instead of $_GET:

header(«Content-Type: application/json; charset=UTF-8»);
$obj = json_decode($_POST[«x»], false);

$conn = new mysqli(«myServer», «myUser», «myPassword», «Northwind»);
$stmt = $conn->prepare(«SELECT name FROM customers LIMIT ?»);
$stmt->bind_param(«s», $obj->limit);
$stmt->execute();
$result = $stmt->get_result();
$outp = $result->fetch_all(MYSQLI_ASSOC);

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How to extract and access JSON data in PHP

JavaScript Object Notation(JSON) is a lightweight human-readable text format for storing and transporting data consisting of name-value pairs and arrays.

It is easy to generate and parse in many programming languages. It is the most popular and lightweight data-interchange format for web applications and the de-facto format for the data exchange in RESTful web services requests and responses.

In this post, we will cover how to decode a JSON object and access its data in PHP.

Below is an example of a simple JSON object:

How to receive JSON data in PHP

1. From a POST or GET request

To receive JSON data as a POST request, we use the “php://input” along with the function file_get_contents() as below:

For instance, the JSON data is sent below as a POST request:

'; $curl = curl_init(); curl_setopt($curl, CURLOPT_URL, $url); curl_setopt($curl, CURLOPT_HTTPHEADER, array('Content-Type:application/json')); curl_setopt($curl, CURLOPT_RETURNTRANSFER, true); curl_setopt($curl, CURLOPT_POST, true); curl_setopt($curl, CURLOPT_POSTFIELDS, $payload); curl_exec($curl); curl_close($curl); 

To receive the above request data in the register.php file, just add file_get_contents(«php://input») and assign it to a variable for processing eg:

2. Reading a JSON file

A JSON file contains a JSON object and has a file extension of .json. You can as well open the file in PHP and access its data.

Similar to POST or GET request, we use file_get_contents() but instead of having “php://input”, we use the file path.

For example, if we have a JSON file with path «https://www.example.com/mydata.json«, we can access its data as below:

If the json file and the PHP file accessing it are in the same website, we can use relative path instead of the full file URL.

Extracting/Decoding JSON data in PHP

We use the built-in function json_decode() to convert the JSON string to the appropriate data type such as an object or an array.

1. Accessing JSON data as a PHP object

By default the json_decode() function returns an object.

Example
The example below decodes a JSON object into a PHP object:

'; $data = json_decode($json); var_dump($data); 

The above example outputs below:

object(stdClass)#1 (4) < ["firstName"]=>string(4) «John» [«lastName»]=> string(3) «Doe» [«email»]=> string(17) «johndoe@gmail.com» [«phone»]=> string(12) «111-111-1111» >

To access the PHP object data, you use the object operator (->) after the object name, followed by the key of the key-value pair. This is the same as the name in the name-value pair in JSON object eg $data->firstName .

'; $data = json_decode($json); echo "My name is".$data->firstName." ".$data->lastName; //Output: My name is John Doe 

2. Accessing JSON data as an array

You can as well convert the JSON object to a PHP associative array by passing a second(optional) parameter in the json_decode() function with the boolean value «true» as below. The value is set to false by default if you don’t pass it.

The example below decodes JSON object into a PHP associative array:

'; $data = json_decode($json, true); var_dump($data); 

The above example outputs below:

array(4) < ["firstName"]=>string(4) «John» [«lastName»]=> string(3) «Doe» [«email»]=> string(17) «johndoe@gmail.com» [«phone»]=> string(12) «111-111-1111» >

You access the data as in any other PHP associative array as in the example below:

'; $data = json_decode($json, true); echo "My name is ".$data["firstName"]." ".$data["lastName"]; //Output: My name is John Doe 

3. Accessing data in a nested JSON object

A JSON object may comprise of json objects and arrays as the values in its name-value pairs such as in the example below:

In the above example, the «address» has an object as its value while «siblings» has an array value comprising of objects.

The easiest way of accessing all the data is decoding the object as an associative array.

, "siblings": [ < "name": "Joseph Doe" >, < "name": "Mary Doe" >] >'; $data = json_decode($json, true); //Displaying all the data echo "First Name: ".$data["firstName"]."
"; //Output -> First Name: John echo "First Name: ".$data["lastName"]."
"; //Output -> Last Name: Doe echo "Email Address: ".$data["email"]."
"; //Output -> Email Address: johndoe@gmail.com echo "Postal Address: ".$data["address"]["postalAddress"]."
"; //Output -> Postal Address: 12345 echo "Postal Code: ".$data["address"]["postalCode"]."
"; //Output -> Postal Code: 5432 echo "City: ".$data["address"]["city"]."
"; //Output -> City: Nairobi echo "Sibling 1: ".$data["siblings"][0]["name"]."
"; //Output -> Sibling 1: Joseph Doe echo "Sibling 2: ".$data["siblings"][1]["name"]."
"; //Output -> Sibling 2: Mary Doe 

Looping through an object of objects with foreach()

You may have a large JSON object made of an array of objects, like in the example below:

To access the values of a country in the example above, you just have to know its object position in the array. For example, china is in the third position. But when accessing the array items, we start counting from 0, hence the index of China in the array is 2.

We access the China array object as below:

"; //Output -> Country: China echo "Code: ".$data["countries"][2]["code"]."
"; //Output -> Code: CN echo "City: ".$data["countries"][2]["city"]."
"; //Output -> City: Beijing 

If you want to access all the array data then it can be tiresome and time-consuming to write the code for accessing each at a time especially when the object is large. For such an instance, you can use the foreach() function to loop through all the objects as below:

, < "name": "India", "code": "IN", "city": "New Delhi" >, < "name": "China", "code": "CN", "city": "Beijing" >, < "name": "Germany", "code": "DE", "city": "Berlin" >, < "name": "Kenya", "code": "KE", "city": "Nairobi" >] >'; $countries = json_decode($json)->countries; foreach($countries as $country)< echo "Country: ".$country->name."
"; echo "Code: ".$country->code."
"; echo "City: ".$country->city."
"; > 

Conclusion

In this post, we have covered everything you need to know in extracting and accessing a JSON object data using PHP.

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Get JSON from URL in PHP

In this tutorial, I’m going to show you how to get json from url in php script. JSON has become a popular way to exchange data and web services outputs in json format. To send a HTTP request and parse JSON response from URL is fairly simple in php but newbies may find how to parse json difficult.

Let’s see how to build a php json parser script. For this script, I’m going to access Google MAP web service via API and get latitude and longitude co-ordinates for a location. Google map api produces both json/xml output. But for this example I’m going to get the json response and show you how to parse json object to retrieve the geo-metric details.

How to Get JSON from URL in PHP

This is the php script to read the json data from url.

results[0]->geometry->location->lat; $lng = $json->results[0]->geometry->location->lng; echo "Latitude: " . $lat . ", Longitude: " . $lng; // output // Latitude: 40.6781784, Longitude: -73.9441579 ?>

The above php script sends a HTTP request to Google MAP web service along with a parameter containing a physical address. The API in turn returns the geometric co-ordinates for the address as json string — which we further decode into a php object and parse it to retrieve the latitude and longitude details.

The php function file_get_contents($url) send a http request to the provided url and returns json data.

The function json_decode($json) decodes the provided json string and returns as a PHP object.

As simple as that you can parse json response. That was all about getting json from url in php.

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