Exploring Linked / Ordered Structs In Lucee 5.3.2.77

signature.cfm

<cfscript>

	signature = generateSignature(
		"PUT",
		"https://some-end-point",
		// NOTE: When passing the end-point parameters into the signer, I am using an
		// ORDERED STRUCT literal. This way, the order of the parameters, as applied to
		// the underlying message, will be predictable.
		[
			d: "dee",
			c: "see",
			z: "zeta",
			a: "anna"
		]
	);

	echo( "Message Signature: #signature.lcase()# <br />" );
	
	// ------------------------------------------------------------------------------- //
	// ------------------------------------------------------------------------------- //

	/**
	* I generate a signature for the request to the secure end-point.
	* 
	* @method I am the HTTP method being used.
	* @scriptName I am the end-point being accessed.
	* @parameters I am the collection of ORDERED key-value pairs being passed through.
	*/
	public string function generateSignature(
		required string method,
		required string scriptName,
		required struct parameters
		) {

		// CAUTION: Since the parameters are assumed to be an ORDERED / LINKED struct,
		// the keys can be iterated-over in a predictable, repeatable manner.
		var pairs = parameters
			.keyArray()
			.map(
				( key ) => {

					return( "#key.lcase()#=#parameters[ key ]#" );

				}
			)
			.toList( "&" )
		;

		var message = "#method.ucase()#:#scriptName#?#pairs#";
		var secretKey = "tot3sMaGoate$";

		// For debugging the demo, log pre-signature message.
		systemOutput( "Signing: #message#", true );

		return( hmac( message, secretKey, "hmacSha256" ) );

	}

</cfscript>

test.cfm

<cfscript>

	// As a control, let's see what happens when we insert keys in a descending
	// alphabetical order using a struct literal. When output, they _should_ be listed in
	// ascending order.
	data = {
		zomething: "different",
		hello: "world",
		foo: "bar",
		anna: "banana"
	};

	dump( label = "Struct Literal - {}", var = data );
	echo( "<br />" );

	// ------------------------------------------------------------------------------- //
	// ------------------------------------------------------------------------------- //

	// Lucee allows us to define an ORDERED struct literal by mixing Array and Struct
	// notation. Notice that the enclosing syntax uses brackets; but, that the internal
	// key-value pairs are using the normal struct syntax.
	orderedData = [
		zomething: "different",
		hello: "world",
		foo: "bar",
		anna: "banana"
	];

	dump( label = "Ordered Struct Literal - []", var = orderedData );
	echo( "<br />" );

	// ------------------------------------------------------------------------------- //
	// ------------------------------------------------------------------------------- //

	// Lucee also offers the option to define a Type of struct when using structNew().
	// In this case we are creating a "linked" (ordered) struct that will record the
	// order in which the keys are subsequently inserted.
	orderedData2 = structNew( "linked" );
	orderedData2.zomething = "different";
	orderedData2.hello = "world";
	orderedData2.foo = "bar";
	orderedData2.anna = "banana";

	dump( label = "StructNew( 'linked' )", var = orderedData2 );

</cfscript>