What is the simplest method of programmatically adding data to JSON? - php

Question

For a PHP/HTML page what is the simplest method of adding data to JSON?
Should I be using PHP, JS, or jQuery?
I've tried different lots of different methods found online, but I can't get any to work. I've tried all of these but I can't get it quite right.
var myObject = new Object();
JSON.stringify()
JSON.parse()
$.extend();
.push()
.concat()
I have this JSON file loaded
{"commentobjects":
[
{"thecomment": "abc"},
{"thecomment": "def"},
{"thecomment": "ghi"}
]
}
I want to programmatically add
var THISNEWCOMMENT = 'jkl;
{"thecomment": THISNEWCOMMENT}
so that the JSON variable will be
{"commentobjects":
[
{"thecomment": "abc"},
{"thecomment": "def"},
{"thecomment": "ghi"},
{"thecomment": "jkl"}
]
}
///////////////////
Edit after answer
//////////////////
This is the ajax in my index.php file I used to call the PHP function (in its separate file):
function commentSaveAction ()
{
var mytext = $(".mycommentinput").val();
mytext = mytext.replace("\"","'");
$.ajax({
url: 'php/commentwrite.php',
data: { thePhpData: mytext },
success: function (response) {
}
});
}
And this is the finished PHP function I used with the help of deceze:
<?php
function writeFunction ()
{
$filename = '../database/comments.txt';
$arr = json_decode(file_get_contents($filename),true);
$myData = $_GET['thePhpData'];
$arr['commentobjects'][] = array('thecomment' => $myData);
$json = json_encode($arr);
$fileWrite=fopen($filename,"w+");
fwrite($fileWrite,$json);
fclose($fileWrite);
}
writeFunction ();
?>
//////////////////////
with JS and not PHP
/////////////////////
var myJsonData;
function getCommentData ()
{
$.getJSON('database/comments.txt', function(data) {
myJsonData = data;
var count = data.commentobjects.length;
for (i=0;i<count;i++) {
$(".commentbox ul").append("<li>"+data.commentobjects[i].thecomment+"</li>");
}
});
}
function commentSaveAction ()
{
var mytext = $(".mycommentinput").val();
mytext = mytext.replace("\"","'");
myJsonData.commentobjects.push({"thecomment": mytext});
var count = myJsonData.commentobjects.length;
$(".commentbox ul").append("<li>"+myJsonData.commentobjects[count-1].thecomment+"</li>");
}

Answer 1

Whichever language you do it in, you have to parse the JSON string into an object/array, modify it, then encode it back into a JSON string. Don't attempt any direct string manipulation of the JSON string. PHP example:
$arr = json_decode($json, true);
$arr['commentobjects'][] = array('thecomment' => 'jkl');
$json = json_encode($arr);
Whether to do this in Javascript or PHP or elsewhere depends on when/why/where you need to do this; that's impossible to say without knowing more about the use case.

Answer 2

Try with json_encode and json_decode PHP functions.
//work on arrays in php
$arr = array('sth1', 'sth2');
//here you have json
$jsonStr = json_encode($arr);
//array again
$arrAgain = json_decode($jsonStr);
$arrAgain[] = 'sth3';
//json again
$jsonAgain = json_encode($arrAgain)

Answer 3

Just do it in javascript:
var x = {"commentobjects":
[
{"thecomment": "abc"},
{"thecomment": "def"},
{"thecomment": "ghi"}
]
};
x.commentobjects.push({"thecomment": "jkl"});

Answer 4

var THISNEWCOMMENT = 'jkl',
myObj = JSON.parse(rawJson),
newComment = {"thecomment": THISNEWCOMMENT};
myObj.commentobjects.push(newComment);
var serialized = JSON.stringify(myObj);
//send the updated JSON to your controller
Parse the object, access the commentobject list inside of it, push the new comment in the list and then serialize the updated object again.