PHP

Using Pre-defined JSON Templates

See more JSON Examples

Demonstrates how to predefine a JSON template, and then use it to emit JSON with variable substitutions.

Note: This example requires Chilkat v9.5.0.67 or greater.

Chilkat2 PHP

<?php

use Chilkat2\Hashtable;
use Chilkat2\JsonObject;

// One way to create JSON is to do it in a straightforward manner:
$json = new JsonObject();
$json->EmitCompact = false;
$json->UpdateString('id', '0001');
$json->UpdateString('type', 'donut');
$json->UpdateString('name', 'Cake');
$json->UpdateString('image.url', 'images/0001.jpg');
$json->UpdateInt('image.width', 200);
$json->UpdateInt('image.height', 200);
$json->UpdateString('thumbnail.url', 'images/thumbnails/0001.jpg');
$json->UpdateInt('thumbnail.width', 32);
$json->UpdateInt('thumbnail.height', 32);
echo $json->Emit(), "\n";

// The JSON created by the above code:

//     {
//       "id": "0001",
//       "type": "donut",
//       "name": "Cake",
//       "image": {
//         "url": "images/0001.jpg",
//         "width": 200,
//         "height": 200
//       },
//       "thumbnail": {
//         "url": "images/thumbnails/0001.jpg",
//         "width": 32,
//         "height": 32
//       }
//     }

// An alternative is to predefine a template, and then use it to emit with variable substitutions.
// For example:

$jsonTemplate = new JsonObject();
$jsonTemplate->UpdateString('id', '{$id}');
$jsonTemplate->UpdateString('type', 'donut');
$jsonTemplate->UpdateString('name', '{$name}');
$jsonTemplate->UpdateString('image.url', '{$imageUrl}');
// The "i." indicates that it's an integer variable.
$jsonTemplate->UpdateString('image.width', '{$i.imageWidth}');
$jsonTemplate->UpdateString('image.height', '{$i.imageHeight}');
$jsonTemplate->UpdateString('thumbnail.url', '{$thumbUrl}');
$jsonTemplate->UpdateString('thumbnail.width', '{$i.thumbWidth}');
$jsonTemplate->UpdateString('thumbnail.height', '{$i.thumbHeight}');
// Give this template a name.
$jsonTemplate->Predefine('donut');

// --------------------------------------------------------------------------
// OK, the template is defined.  Defining a template can be done once
// at the start of your program, and you can discard the jsonTemplate object (it
// doesn't need to stick around..)

// Now we can create instances of the JSON object by name:
$jsonDonut = new JsonObject();
$jsonDonut->EmitCompact = false;
$jsonDonut->LoadPredefined('donut');
echo $jsonDonut->Emit(), "\n";

// The output is this:

//     {
//       "id": "{$id}",
//       "type": "donut",
//       "name": "{$name}",
//       "image": {
//         "url": "{$imageUrl}",
//         "width": "{$i.imageWidth}",
//         "height": "{$i.imageHeight}"
//       },
//       "thumbnail": {
//         "url": "{$thumbUrl}",
//         "width": "{$i.thumbWidth}",
//         "height": "{$i.thumbHeight}"
//       }
//     }

// Finally, we can substitute variables like this:
$donutValues = new Hashtable();
$donutValues->AddStr('id', '0001');
$donutValues->AddStr('name', 'Cake');
$donutValues->AddStr('imageUrl', 'images/0001.jpg');
$donutValues->AddInt('imageWidth', 200);
$donutValues->AddInt('imageHeight', 200);
$donutValues->AddStr('thumbUrl', 'images/thumbnails/0001.jpg');
$donutValues->AddInt('thumbWidth', 32);
$donutValues->AddInt('thumbHeight', 32);

// Emit with variable substitutions:
$omitEmpty = true;
echo $jsonDonut->EmitWithSubs($donutValues, $omitEmpty), "\n";

// Output:

//     {
//       "id": "0001",
//       "type": "donut",
//       "name": "Cake",
//       "image": {
//         "url": "images/0001.jpg",
//         "width": 200,
//         "height": 200
//       },
//       "thumbnail": {
//         "url": "images/thumbnails/0001.jpg",
//         "width": 32,
//         "height": 32
//       }
//     }

// Change some of the values:
$donutValues->AddStr('id', '0002');
$donutValues->AddStr('imageUrl', 'images/0002.jpg');
$donutValues->AddStr('thumbUrl', 'images/thumbnails/0002.jpg');

echo $jsonDonut->EmitWithSubs($donutValues, $omitEmpty), "\n";

// Output:

//     {
//       "id": "0002",
//       "type": "donut",
//       "name": "Cake",
//       "image": {
//         "url": "images/0002.jpg",
//         "width": 200,
//         "height": 200
//       },
//       "thumbnail": {
//         "url": "images/thumbnails/0002.jpg",
//         "width": 32,
//         "height": 32
//       }
//     }