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!