JSON

JSON all things!

CFML supports native JSON support via several key functions and some member functions.

Serialize

CFML gives us the serializeJSON() function to convert any piece of data to its JSON representation (https://cfdocs.org/serializejson)

serializeJson(
 var
 [, serializeQueryByColumns = false ]
 [, useSecureJSONPrefix = false ]
 [, useCustomSerializer = false ]
)

Pass in any complex or simple variable to the var argument and JSON will be produced:

person = { name = "Luis Majano", company = "Ortus Solutions", year = 2006};
writeOutput( serializeJSON( person ) );

If you are in Lucee, you can even use the toJSON() member function:

person = { name = "Luis Majano", company = "Ortus Solutions", year = 2006};
writeOutput( person.toJSON() );

Key Casing

By default CFML will convert the keys in a struct to uppercase in the result JSON document:

person = { name = "Luis Majano", company = "Ortus Solutions", year = 2006};
writeOutput( serializeJSON( person ) );

// Will become
{ "NAME" : "Luis Majano", "COMPANY" : "Ortus Solutions", "YEAR" : 2006 }

If you want to preserve the key casing then wrap them in double/single quotes and define the case:

person = { 
    'Name' = "Luis Majano", 
    'company' = "Ortus Solutions", 
    'year' = 2006
};

// Will become
{ "Name" : "Luis Majano", "company" : "Ortus Solutions", "year" : 2006 }

Possible Casting Issues

Adobe ColdFusion may incorrectly serialize some strings if they can be automatically converted into other types, like numbers or booleans. One workaround is to use a CFC with cfproperty to specify types. Another workaround is to prepend Chr(2) to the value and it will be forced to a string, however, that is an unofficial/undocumented workaround. A more formal workaround is to call setMetadata() as a member function on a struct to force a type:

myStruct = { "zip"="00123" };
myStruct.setMetadata( { "zip": "string" } );
writeOutput( serializeJSON(myStruct) );

Deserialize

The inverse of serialization is deserialization (https://cfdocs.org/deserializejson). CFML gives you the deserializeJSON() function that will take a JSON document and produce native CFML data structures for you.

deserializeJSON(
 json
 [, strictMapping = true ]
 [, useCustomSerializer = false ]
)

Just pass a JSON document, and off we go with native structs/arrays/dates/strings and booleans.

if( isJson( mydata ) ){
    return deserializeJSON( data );
}

person = deserializeJSON( '{"company":"Ortus","name":"Mr OrtusMan"}' );
writeOutput( person.company );

This function can also be used as a member function in any string literal:

var deserializedData = myjsonString.deserializeJson();
var data = '[]'.deserializeJson();

Is this JSON?

CFML has a function to test if the incoming string is valid JSON (https://cfdocs.org/isjson) or not: isJSON()

isJSON( "[ 1, 2, 3 ]" )