Append data to top of the JSON file using PHP form - php

Question

I wanted to append a php from data in JSON file to top.
I used some PHP functions like -
array_unshift($array_data, $extra);
$array_data = array_reverse($array_data);
Example -
<?php
$message = '';
$error = '';
if(isset($_POST["submit"]))
{
if(empty($_POST["name"]))
{
$error = "<label class='text-danger'>Enter Name</label>";
}
else if(empty($_POST["author"]))
{
$error = "<label class='text-danger'>Enter Author</label>";
}
else if(empty($_POST["category"]))
{
$error = "<label class='text-danger'>Enter Thumbnail</label>";
}
else if(empty($_POST["url"]))
{
$error = "<label class='text-danger'>Enter URL</label>";
}
else
{
if(file_exists('wallpaper.json'))
{
$current_data = file_get_contents('wallpaper.json');
$array_data = json_decode($current_data, true);
$extra = array(
'name' => $_POST['name'],
'author' => $_POST["author"],
'category' => $_POST["category"],
'url' => $_POST["url"]
);
$array_data[] = $extra;
//array_unshift($array_data, $extra); // used this as well
$array_data = array_reverse($array_data);
$final_data = json_encode($array_data);
if(file_put_contents('wallpaper.json', $final_data))
{
$message = "<label class='text-success'>File Appended Success fully</p>";
}
}
else
{
$error = 'JSON File not exits';
}
}
}
?>
Both of these PHP functions, they work perfectly until you add data 2 times but once you add 3rd data or more then it looks like this -
[
{
"name": "3",
"author": "3",
"category": "3",
"url": "3"
},
{
"name": "1",
"author": "1",
"category": "1",
"url": "1"
},
{
"name": "2",
"author": "2",
"category": "2",
"url": "2"
}
]
But it should look like this -
[
{
"name": "3",
"author": "3",
"category": "3",
"url": "3"
},
{
"name": "2",
"author": "2",
"category": "2",
"url": "2"
},
{
"name": "1",
"author": "1",
"category": "1",
"url": "1"
}
]

Answer 1

At beggining you have [1] then you insert [2] and after $array_data[] = $extra; goes to [1][2] and the you reverse array [2][1]. At this moment when you insert a new value you have [2][1][3] and the after reversing [3][1][2] the solution would be reversing before insert extra:
test.php:
<?php
if(file_exists('wallpaper.json'))
{
$current_data = file_get_contents('wallpaper.json');
$array_data = json_decode($current_data, true);
$extra = array(
'name' => $_REQUEST['name'],
'author' => $_REQUEST["author"],
'category'=> $_REQUEST["category"],
'url' => $_REQUEST["url"]
);
echo $extra['name'];
$array_data = array_reverse($array_data);
$array_data[] = $extra;
$array_data = array_reverse($array_data);
$final_data = json_encode($array_data);
if(file_put_contents('wallpaper.json', $final_data))
{
$message = "<label class='text-success'>File Appended Success fully</p>";
}
}
?>
to run I used to pass parameters:
http://localhost/test.php?name=4&author=4&category=4&url=4

Answer 2

$posted[] = $_POST;
$current_data = file_get_contents('wallpaper.json');
$decoded = json_decode($current_data,true);
//You merge together posted array values with the current array
//that is in the current file (after decoding the json)
//$posted is first part of the array because you start to merge from that
//array
$new_arr = array_merge($posted, $decoded);
//Encode the new array into JSON and save it
$encoded_json = json_encode($new_arr,);
file_put_contents('wallpaper.json', $encoded_json);

Answer 3

First, don't push the $_POST data into its own subarray. It is already in the correct structure to call array_unshift() directly on it. In other words, you don't need to index it -- unshift will apply the 0 key for you.
Code: (Demo)
$fileContents = '[{"name":"B1","author":"B2","category":"B3","url":"B4"},{"name":"A1","author":"A2","category":"A3","url":"A4"}]';
$array = json_decode($fileContents, true);
$_POST = [
'name' => 'C1',
'author' => 'C2',
'category' => 'C3',
'url' => 'C4',
];
array_unshift($array, $_POST);
echo json_encode($array);
Output:
[{"name":"C1","author":"C2","category":"C3","url":"C4"},{"name":"B1","author":"B2","category":"B3","url":"B4"},{"name":"A1","author":"A2","category":"A3","url":"A4"}]
Secondly, I don't support the notion of building this json file if there is any way that you can avoid it. I mean, as you your file size increases, your server will have to work harder and harder and harder to parse the json, manipulate it, re-encode it every time you want to make a change.
I might recommend that you restructure your file to be a txt file which is a collection of json strings -- all of which are separately written on each line. This way you don't have to unpack and repack your data every time, you just prepend the new json string to the file and walk away. *Caveat, this will fail if the data that you are storing contains newline characters -- I don't know if your project might receive such data.
p.s. If you are not a ultra-purist developer and your incoming data is as tame as it looks from your post, you can hack at the json string and lighten the workload like this:
Code: (Demo)
$newJson = json_encode($_POST);
if ($fileContents) {
$fileContents = substr_replace($fileContents, $newJson . ',', 1, 0);
} else {
$fileContent = '[' . $newJson . ']';
}
echo $fileContents;