WireBox : Dependency Injection & AOP For ColdFusion (CFML)

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MethodLogger Aspect

Last updated 4 months ago
Here is my MethodLogger aspect that I will create:
<cfcomponent output="false" implements="wirebox.system.aop.MethodInterceptor" hint="A simple interceptor that logs method calls and their results">
​
    <---  Dependencies --->
    <cfproperty name="log" inject="logbox:logger:{this}">
​
    <---  init --->
    <cffunction name="init" output="false" access="public" returntype="any" hint="Constructor">
        <cfargument name="logResults" type="boolean" required="false" default="true" hint="Do we log results or not?"/>
        <cfscript>
            instance = {
                logResults = arguments.logResults
            };
​
            return this;
        </cfscript>
    </cffunction>
​
    <---  invokeMethod --->
    <cffunction name="invokeMethod" output="false" access="public" returntype="any" hint="Invoke an AOP method invocation">
        <cfargument name="invocation" required="true" hint="The method invocation object: wirebox.system.aop.MethodInvocation">
        <cfscript>
            var refLocal = {};
            var debugString = "target: #arguments.invocation.getTargetName()#,method: #arguments.invocation.getMethod()#,arguments:#serializeJSON(arguments.invocation.getArgs())#";
​
            // log incoming call
            log.debug(debugString);
​
            // proceed execution
            refLocal.results = arguments.invocation.proceed();
​
            // result logging and returns
            if( structKeyExists(refLocal,"results") ){
                if( instance.logResults ){
                    log.debug("#debugString#, results:", refLocal.results);
                }
                return refLocal.results;
            }
        </cfscript>
    </cffunction>
​
</cfcomponent>
You can see that I do some DI via annotations:
<---  Dependencies --->
<cfproperty name="log" inject="logbox:logger:{this}">
A normal constructor with one optional argument for logging results:
<---  init --->
<cffunction name="init" output="false" access="public" returntype="any" hint="Constructor">
    <cfargument name="logResults" type="boolean" required="false" default="true" hint="Do we log results or not?"/>
    <cfscript>
        instance = {
            logResults = arguments.logResults
        };
​
        return this;
    </cfscript>
</cffunction>
And our invokeMethod implementation:
<---  invokeMethod --->
<cffunction name="invokeMethod" output="false" access="public" returntype="any" hint="Invoke an AOP method invocation">
<cfargument name="invocation" required="true" hint="The method invocation object: wirebox.system.aop.MethodInvocation">
<cfscript>
    var refLocal = {};
    var debugString = "target: #arguments.invocation.getTargetName()#,method: #arguments.invocation.getMethod()#,arguments:#serializeJSON(arguments.invocation.getArgs())#";
​
    // log incoming call
    log.debug(debugString);
​
    // proceed execution
    refLocal.results = arguments.invocation.proceed();
​
    // result logging and returns
    if( structKeyExists(refLocal,"results") ){
        if( instance.logResults ){
            log.debug("#debugString#, results:", refLocal.results);
        }
        return refLocal.results;
    }
</cfscript>
</cffunction>
As you can see, the before advice part is what happens before the execution of the real method (or more aspects) occurrs. So everything before the call to arguments.invocation.proceed():
var refLocal = {};
var debugString = "target: #arguments.invocation.getTargetName()#,method: #arguments.invocation.getMethod()#,arguments:#serializeJSON(arguments.invocation.getArgs())#";
​
// log incoming call
log.debug(debugString);
Then we execute the real method or more aspects (we do not do anything around the method call):
// proceed execution
refLocal.results = arguments.invocation.proceed();
Finally, we do the after advice part which happens after the method or other aspects fire and results are returned:
// result logging and returns
if( structKeyExists(refLocal,"results") ){
    if( instance.logResults ){
        log.debug("#debugString#, results:", refLocal.results);
    }
    return refLocal.results;
}
That's it. I have succesfully created an aspect. What's next!
MethodInvocation Useful Methods
Aspect Registration