build json response with php - php

Question

I have tried to handle JSON responses with a complex structure and I don't know how to manage it after multiple attempts.
The JSON response must be like this:
"note": {
"vote": 3,
"items":[
{
"value": 1,
"touchArea": {
"x": 122,
"y": 173,
"w": 89,
"h": 89
}
},
{
"value": 2,
"touchArea": {
"x": 122,
"y": 283,
"w": 89,
"h": 89
}
},
{
"value": 3,
"touchArea": {
"x": 122,
"y": 390,
"w": 89,
"h": 89
}
}
]
Note: 'vote' is the max value of the array
As source, i request MYSQL and i get this array ($touch) :
Array ( [0] => V:1,X:122,Y:173,W:89,H:89 [1] => V:2,X:122,Y:283,W:89,H:89 [2] => V:3,X:122,Y:390,W:89,H:89 )
My question is : How to generate this JSON response from PHP with loops, in this example we have only 3 values, but it could be more.

Answer 1

You can use the following to edit and re-save your data from and to json file or string.
<?php
$sInFile = 'in2.json';
$sOutFile = 'out2.json';
$aDevelopers = array();
$aArtists = array();
$aCooks = array();
$sRaw = file_get_contents( $sInFile );
var_dump( $sRaw );
// object
$oData = json_decode( $sRaw );
//array
$aData = json_decode( $sRaw, 1 );
$aNote = $aData[ 'note' ];
$aItems = $aNote[ 'items' ];
var_dump( $aData );
$iCountData = count( $aItems );
// Loops through items and set new values.
for( $i = 0; $i < $iCountData; ++$i )
{
$aItem = $aItems[ $i ];
$aItem[ 'value' ] = 'newvalue';
$aItem[ 'touchArea' ][ 'x' ] = 3455;
$aItem[ 'touchArea' ][ 'y' ] = 43;
$aItems[ $i ] = $aItem;
}
$aNote[ 'items' ] = $aItems;
$aData[ 'note' ] = $aNote;
var_dump( $aData );
$sNewJson = json_encode( $aData );
file_put_contents( $sOutFile, $sNewJson );
?>

Answer 2

Assuming that your result set from MySQL is an array of strings, as implied in your question, you'll need to iterate over this result set, split the string on , and then on :, before massaging the data into the structure you want, before finally converting to json.
The following should work for you given the information you have provided:
<?php
// your initial result set from mysql - an array of strings
$touch = [
'V:1,X:122,Y:173,W:89,H:89',
'V:2,X:122,Y:283,W:89,H:89',
'V:3,X:122,Y:390,W:89,H:89',
];
// map over each element in your result set...
$items = array_map(function($item) {
$array = [];
// first, break each string on `,` to
// get an array of elements; e.g:
// ['V:1', 'X:122', 'Y:173', 'W:89', 'H:89'] etc.
$itemElements = explode(',', $item);
// then, iterate over these elements...
foreach ($itemElements as $itemElement) {
// explode on `:` and assign as a key value pair
list($key, $value) = explode(':', $itemElement);
// then, check the key and add the
// value to the array as appropriate
if ('V' === $key) {
$array['value'] = $value;
} else {
$array['touchArea'][strtolower($key)] = $value;
}
}
return $array;
}, $touch);
// then, build the `$note` array...
$note = [
'note' => [
'vote' => count($items),
'items' => $items,
]
];
// finally, json encode
echo json_encode($note, JSON_PRETTY_PRINT);
This yields:
{
"note": {
"vote": 3,
"items": [
{
"value": "1",
"touchArea": {
"x": "122",
"y": "173",
"w": "89",
"h": "89"
}
},
{
"value": "2",
"touchArea": {
"x": "122",
"y": "283",
"w": "89",
"h": "89"
}
},
{
"value": "3",
"touchArea": {
"x": "122",
"y": "390",
"w": "89",
"h": "89"
}
}
]
}
}
Hope this helps :)

Answer 3

Solution with array_map, explode, array_column and max functions:
$touch = ["V:1,X:122,Y:173,W:89,H:89", "V:2,X:122,Y:283,W:89,H:89", "V:3,X:122,Y:390,W:89,H:89"];
$result_arr = ["note" => ["vote" => 0, "items" => []]]; // basic structure
array_map(function($v) use (&$result_arr){
$arr = explode(",", $v);
$result = [];
foreach ($arr as $value) {
$new_arr = explode(":", $value);
$key = strtolower($new_arr[0]);
if ($key == "v"){
$result["value"] = $new_arr[1];
} else {
$result["touchArea"][$key] = $new_arr[1];
}
}
$result_arr["note"]["items"][] = $result;
}, $touch);
// getting max vote
$result_arr["note"]["vote"] = max(array_column($result_arr["note"]["items"], "value"));
$final_json = json_encode($result_arr, JSON_PRETTY_PRINT);