(PHP Extension) Using Pre-defined JSON Templates

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.

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<?php

// The version number (9_5_0) should match version of the Chilkat extension used, omitting the micro-version number.
// For example, if using Chilkat v9.5.0.48, then include as shown here:
include("chilkat_9_5_0.php");

// One way to create JSON is to do it in a straightforward manner:
$json = new CkJsonObject();
$json->put_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);
print $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 CkJsonObject();
$jsonTemplate->UpdateString('id','{$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 CkJsonObject();
$jsonDonut->put_EmitCompact(false);
$jsonDonut->LoadPredefined('donut');
print $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 CkHashtable();
$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;
print $jsonDonut->emitWithSubs($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');

print $jsonDonut->emitWithSubs($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
// 	  }
// 	}

?>