Using OnMissingMethod() With Remote Access ColdFusion Components

code-1.cfm

<cfcomponent
	output="false"
	hint="I provide the core remote proxy API functionality.">


	<cffunction
		name="NewAPIResponse"
		access="public"
		returntype="struct"
		output="false"
		hint="I provide a new default API response object.">

		<!--- Define the local scope. --->
		<cfset var LOCAL = {} />

		<!--- Create a new API response object. --->
		<cfset LOCAL.Response = {
			Success = true,
			Errors = [],
			Data = ""
			} />

		<!--- Return new response object. --->
		<cfreturn LOCAL.Response />
	</cffunction>


	<cffunction
		name="ManuallyReturnReponse"
		access="public"
		returntype="void"
		output="false"
		hint="I stream the given response to the client manually using CFHeader and CFContent.">

		<!--- Define arguments. --->
		<cfargument
			name="Response"
			type="struct"
			required="true"
			hint="I am the API response being returned."
			/>

		<cfargument
			name="ReturnFormat"
			type="string"
			required="false"
			default="JSON"
			hint="I am the format required for the API response."
			/>

		<!--- Define the local scope. --->
		<cfset var LOCAL = {} />

		<!---
			Create the response string. Check to see if we want
			this as WDDX or JSON.
		--->
		<cfswitch expression="#ARGUMENTS.ReturnFormat#">
			<cfcase value="wddx">

				<!--- Convert to WDDX. --->
				<cfwddx
					action="cfml2wddx"
					input="#ARGUMENTS.Response#"
					output="LOCAL.ResponseString"
					/>

			</cfcase>
			<cfdefaultcase>

				<!---
					By default, we are going to return the API
					response in JSON string (since that is what
					our appliation does by default).
				--->
				<cfset LOCAL.ResponseString = SerializeJSON(
					ARGUMENTS.Response
					) />

			</cfdefaultcase>
		</cfswitch>


		<!---
			Now that we have our API response string, we need
			to update the headers and return the response.
		--->

		<!---
			Set header response code to be 200 - remember, the
			whole point of the unified API response is that it
			never "fails" unless there is truly a request
			exception.
		--->
		<cfheader
			statuscode="200"
			statustext="OK"
			/>

		<!--- Steam binary contact back. --->
		<cfcontent
			type="text/plain"
			variable="#ToBinary( ToBase64( LOCAL.ResponseString ) )#"
			/>

		<!---
			At this point, the request has been completely
			committed and cannot be altered.
		--->

		<!--- Return out. --->
		<cfreturn />
	</cffunction>


	<cffunction
		name="OnMissingMethod"
		access="public"
		returntype="struct"
		output="false"
		hint="I handle non-explicit API messaging.">

		<!--- Define arguments. --->
		<cfargument
			name="MethodName"
			type="string"
			required="true"
			hint="I am the name of the method."
			/>

		<cfargument
			name="MethodArguments"
			type="struct"
			required="true"
			hint="I am the collection of arguments."
			/>

		<!---
			Use the error response to create and return an API
			response with the given API error.
		--->
		<cfreturn THIS.NewErrorResponse( "The method that you requested, #ARGUMENTS.MethodName#, is not supported in the current version of this API." ) />
	</cffunction>


	<cffunction
		name="NewErrorResponse"
		access="public"
		returntype="struct"
		output="false"
		hint="I create an return a new error response with the given error.">

		<!--- Define arguments. --->
		<cfargument
			name="Error"
			type="string"
			required="true"
			hint="I am the error message."
			/>

		<!--- Define the local scope. --->
		<cfset var LOCAL = {} />

		<!--- Create a new API response object. --->
		<cfset LOCAL.Response = THIS.NewAPIResponse() />

		<!--- Flag it as not successful. --->
		<cfset LOCAL.Response.Success = false />

		<!--- Set the error message. --->
		<cfset LOCAL.Response.Errors[ 1 ] = {
			Property = "",
			Error = ARGUMENTS.Error
			} />

		<!--- Return new response. --->
		<cfreturn LOCAL.Response />
	</cffunction>

</cfcomponent>

code-2.cfm

<cfcomponent
	output="false"
	hint="I provide application settings and event handlers.">


	<cffunction
		name="OnError"
		access="public"
		returntype="void"
		output="true"
		hint="I handle uncaught application errors.">

		<!--- Define the arguments. --->
		<cfargument
			name="Exception"
			type="any"
			required="true"
			hint="I am the uncaught exception."
			/>

		<!--- Define the local scope. --->
		<cfset var LOCAL = {} />

		<!---
			Normally, we would want to return a error header, but
			if the request was an API call (remote call), we never
			want to return an error. Rather, we want to return an
			"unsuccessful" API request.
		--->
		<cfif REFindNoCase( "\.cfc$", CGI.script_name )>

			<!---
				Create an instance of the CFC in question.

				NOTE: This line of code leverages the undocumented
				ability for ColdFusion components to be created
				both dot-delimited AND slash-delimited file paths.
			--->
			<cfset LOCAL.API = CreateObject(
				"component",
				REReplaceNoCase(
					CGI.script_name,
					"\.cfc$",
					"",
					"one"
					)
				) />


			<!--- Set default return format. --->
			<cfset LOCAL.ReturnFormat = "JSON" />

			<!--- Check to see if return format was overriden. --->
			<cfif StructKeyExists( URL, "ReturnFormat" )>

				<!--- Overriding default format. --->
				<cfset LOCAL.ReturnFormat = URL.ReturnFormat />

			</cfif>


			<!---
				Check to see what kind of error we had. If the
				"func" key exists, then it was a missing method
				error. If not, then it was simply an unhandled
				error.
			--->
			<cfif StructKeyExists( ARGUMENTS.Exception, "Func" )>

				<!--- Missing method error. --->

				<!--- Build up arguments. --->
				<cfset LOCAL.Arguments = Duplicate( URL ) />
				<cfset StructAppend( LOCAL.Arguments, FORM ) />

				<!---
					Call onMissingMethod and stream back response
					to client manually.
				--->
				<cfset LOCAL.API.ManuallyReturnReponse(
					LOCAL.API.OnMissingMethod(
						LOCAL.Arguments.Method,
						LOCAL.Arguments
						),
					LOCAL.ReturnFormat
					) />

			<cfelse>

				<!--- Uncaught exception. --->

				<!---
					Create a new error and return it to the client
					using explicit stream.
				--->
				<cfset LOCAL.API.ManuallyReturnReponse(
					LOCAL.API.NewErrorResponse(
						ARGUMENTS.Exception.Message
						),
					LOCAL.ReturnFormat
					) />

			</cfif>

		</cfif>

		<!--- Return out. --->
		<cfreturn />
	</cffunction>

</cfcomponent>