Classic ASP

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.

Classic ASP

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<body>
<%
'  One way to create JSON is to do it in a straightforward manner:
set json = Server.CreateObject("Chilkat.JsonObject")
json.EmitCompact = 0
success = json.UpdateString("id","0001")
success = json.UpdateString("type","donut")
success = json.UpdateString("name","Cake")
success = json.UpdateString("image.url","images/0001.jpg")
success = json.UpdateInt("image.width",200)
success = json.UpdateInt("image.height",200)
success = json.UpdateString("thumbnail.url","images/thumbnails/0001.jpg")
success = json.UpdateInt("thumbnail.width",32)
success = json.UpdateInt("thumbnail.height",32)
Response.Write "<pre>" & Server.HTMLEncode( json.Emit()) & "</pre>"

'  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:

set jsonTemplate = Server.CreateObject("Chilkat.JsonObject")
success = jsonTemplate.UpdateString("id","{$id}")
success = jsonTemplate.UpdateString("type","donut")
success = jsonTemplate.UpdateString("name","{$name}")
success = jsonTemplate.UpdateString("image.url","{$imageUrl}")
'  The "i." indicates that it's an integer variable.
success = jsonTemplate.UpdateString("image.width","{$i.imageWidth}")
success = jsonTemplate.UpdateString("image.height","{$i.imageHeight}")
success = jsonTemplate.UpdateString("thumbnail.url","{$thumbUrl}")
success = jsonTemplate.UpdateString("thumbnail.width","{$i.thumbWidth}")
success = jsonTemplate.UpdateString("thumbnail.height","{$i.thumbHeight}")
'  Give this template a name.
success = 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:
set jsonDonut = Server.CreateObject("Chilkat.JsonObject")
jsonDonut.EmitCompact = 0
success = jsonDonut.LoadPredefined("donut")
Response.Write "<pre>" & Server.HTMLEncode( jsonDonut.Emit()) & "</pre>"

'  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:
set donutValues = Server.CreateObject("Chilkat.Hashtable")
success = donutValues.AddStr("id","0001")
success = donutValues.AddStr("name","Cake")
success = donutValues.AddStr("imageUrl","images/0001.jpg")
success = donutValues.AddInt("imageWidth",200)
success = donutValues.AddInt("imageHeight",200)
success = donutValues.AddStr("thumbUrl","images/thumbnails/0001.jpg")
success = donutValues.AddInt("thumbWidth",32)
success = donutValues.AddInt("thumbHeight",32)

'  Emit with variable substitutions:
omitEmpty = 1
Response.Write "<pre>" & Server.HTMLEncode( jsonDonut.EmitWithSubs(donutValues,omitEmpty)) & "</pre>"

'  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:
success = donutValues.AddStr("id","0002")
success = donutValues.AddStr("imageUrl","images/0002.jpg")
success = donutValues.AddStr("thumbUrl","images/thumbnails/0002.jpg")

Response.Write "<pre>" & Server.HTMLEncode( jsonDonut.EmitWithSubs(donutValues,omitEmpty)) & "</pre>"

'  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
'  	  }
'  	}

%>
</body>
</html>