How to create a JSON object and send it as POST request using PHP
  John Mwaniki /   28 Aug 2021

How to create a JSON object and send it as POST request using PHP

What is JSON?

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 commonly used in reading data from a web server, and displaying it on a web page.

JSON data can easily be sent between computers, applications, and can be used by any programming language. It is extensively used as the de-facto format for the data exchange in RESTful web services requests and responses. In fact, the success of RESTful web services can be attributed to the JSON format due to its ease of use on various platforms and languages.

JSON Syntax

Data in JSON objects is stored in name-value pairs, as in the example below:


"firstName":"John"

From the above example, “firstName” is the name, and “John” is the value.

The name in the pair is always a string while its value can be of different data types which include: string, number, object, array, true, false, and null.

The name and value in a pair are separated by a colon (:).

The name-value pairs are separated by a comma (,).

The JSON object is enclosed in curly braces ({}). It can contain name-value pairs and/or arrays.

Arrays in JSON are enclosed square brackets ([]), and their values are separated by a comma (,).

Example


{
   "firstName": "John",
   "lastName": "Doe",
   "email": "johndoe@gmail.com",
   "age": 30,
   "address": {
          "postalAddress": "201307",
          "postalCode": "12345",
          "city": "Nairobi"
        },
   "phoneNumbers": [
      { "Mobile": "111-111-1111" },
      { "Home": "222-222-2222" }
   ]
}

The above is an example of a JSON object containing data in name-value pairs. It has values of datatypes: string, number, object and array.

The value for the name "phoneNumbers" is an array of two objects.

The value for the name "address" is an object containing 3 name-value pairs.

The name "age" contains a value of type number.

 

How to create a JSON object in PHP

First is to create an array, then encode it into a JSON object.

There are three types of array in PHP which are listed below:

  • Indexed arrays
  • Associative arrays
  • Multidimensional arrays

Since data in JSON is stored in name-value pairs, we use the associative arrays which also store data in key-value pairs, where the key is used as an index to search the corresponding value in the array.

To create an associative array in PHP, we put our key-value pairs inside the array() function and use the double arrow operator (=>) to assign values to keys.

<?php
$myobj = array( 
        "firstName" => "John", 
        "lastName" => "Doe", 
        "email" => "johndoe@gmail.com", 
        "phone" => "111-111-1111"
     ); 

After creating an associative array, then convert it into a JSON object using the PHP inbuilt json_encode() function as shown below.

Add a Content-Type header by adding header("Content-Type:application/json") at the top of the PHP file for your output to be recognized as a JSON object.

<?php
header("Content-Type:application/json"); 
$myobj = array( 
        "firstName" => "John", 
        "lastName" => "Doe", 
        "email" => "johndoe@gmail.com", 
        "phone" => "111-111-1111"
$jsonobject = json_encode($myobj); 
echo $jsonobject; 

The above code will print out a JSON object as below:


 {
  "firstName": "John", 
  "lastName": "Doe", 
  "email": "johndoe@gmail.com", 
  "phone": "111-111-1111"
 }
 

How to create a JSON object with an array and nested object

To have a name with an object as its value, will just need to create an array and assign it to the key as the value while forming the associative array.

To have a name with an array value, we just need to create an array as the value, then create other arrays with key-value pairs inside it.

Example

<?php
header("Content-Type:application/json"); 
$myarray = array( 
           "firstName" => "John", 
           "lastName" => "Doe", 
           "email" => "johndoe@gmail.com", 
           "address" => array( 
                       "postalAddress" => "12345", 
                        "postalCode" => "5432", 
                        "city" => "Nairobi"
             ), 
            "siblings" => array( 
                         array( "name" => "Joseph Doe" ), 
                         array( "name" => "Mary Doe" )
                  )
              ); 
$jsonobject = json_encode($myarray); 
echo $jsonobject; 

The above code will output a JSON object below:


 { 
   "firstName": "John", 
   "lastName": "Doe", 
   "email": "johndoe@gmail.com", 
   "address": { 
         "postalAddress": "12345", 
         "postalCode": "5432", 
         "city": "Nairobi"
      }, 
     "siblings": [ 
          { "name": "Joseph Doe" }, 
          { "name": "Mary Doe" } 
    ] 
} 
 

Sending a JSON object as a post request in PHP

Now that you already know how to form a JSON object, let's dive into how you can send it as POST request.

We will achieve that using PHP Curl as shown below:

<?php 
header("Content-Type:application/json"); 
$myarray = array( 
         "firstName" => "John", 
         "lastName" => "Doe", 
         "email" => "johndoe@gmail.com", 
         "phone" => "111-111-1111" 
       ); 

$url = "https://www.example.com/register" 
$payload = json_encode($myarray); 

$curl = curl_init(); 
curl_setopt($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); 

Conclusion

In this tutorial we have covered what JSON is, why it’s important, how to create associative arrays in PHP, how to convert an associative array into a JSON object and how to send the created object in a POST request using PHP curl.