A few tweaks to the custom error filter

Author: celer

examples/test/app.js

@@ -112,6 +112,10 @@ UnitTestService.dualComplete=function(input,onComplete){
 	onComplete(null,true);
 }
 
+UnitTestService.customError=function(input,onComplete){
+	return onComplete("INTERNAL ERROR");
+}
+
 
 Hop.defineModel("UnitTestService",function(model){
 	model.field("modelFloat").float();
@@ -128,6 +132,7 @@ Hop.defineClass("UnitTestService",UnitTestService,function(api){
 	api.post("testHeaders","/testHeaders");
 	api.post("sendHeaders","/sendHeaders");
 	api.get("dualComplete","/dualComplete");
+	api.get("customError","/customError");
 	api.post("testForm","/form/test").optionals("textValue","selectValue","multipleValue","checkbox1","radio1");
 	api.post("testPost","/ts/").demands("string","number","float","object","date","booleanTrue","booleanFalse","nullValue","modelMinMax","modelArray","modelObject","modelString","modelBool","modelFloat","modelStringArray").inputModel("UnitTestService");
 	api.get("testGet","/ts/").demands("string","number","float","object","date","booleanTrue","booleanFalse","nullValue","modelMinMax","modelArray","modelObject","modelString","modelBool","modelFloat","modelStringArray").inputModel("UnitTestService");
@@ -136,6 +141,13 @@ Hop.defineClass("UnitTestService",UnitTestService,function(api){
 	api.post("testPostOptionals","/ts/optionals").optionals("string","number","float","object","date","booleanTrue","booleanFalse","nullValue","modelMinMax","modelArray","modelObject","modelString","modelBool","modelFloat","modelStringArray").inputModel("UnitTestService");
 	api.get("testGetOptionals","/ts/optionals").optionals("string","number","float","object","date","booleanTrue","booleanFalse","nullValue","modelMinMax","modelArray","modelObject","modelString","modelBool","modelFloat","modelStringArray").inputModel("UnitTestService");
 	api.put("testPutOptionals","/ts/optionals").optionals("string","number","float","object","date","booleanTrue","booleanFalse","nullValue","modelMinMax","modelArray","modelObject","modelString","modelBool","modelFloat","modelStringArray").inputModel("UnitTestService");
+
+	api.errorHandler(function(method,request,input,error,stack){
+		if(error=="INTERNAL ERROR"){
+			return "Error";
+		} else return null;
+	});
+
 });
 
 function basicTest(method, funcName,test){
@@ -158,6 +170,10 @@ function basicTest(method, funcName,test){
 	test.do(funcName+"Optionals").with(testValue).outputContains(expectedValue);
 }
 
+Hop.defineTestCase("UnitTestService.customError",function(test){
+	test.do("UnitTestService.customError").with({}).errorContains("Error");
+});
+
 Hop.defineTestCase("UnitTestService.sendTemplate",function(test){
 	test.do("UnitTestService.sendTemplate").with({}).outputContains("<h1>Template Title</h1>").noError();
 });

lib/api.js

@@ -32,34 +32,44 @@ Hop.log=console.log;
 Hop.error=console.error;
 Hop.warn=console.warn;
 
-Hop.logResult=function(err,result){
-	if(err){
-			var error = new Error();
-		
-			//This function attempts to provide an easy to read stack trace for results from calls	
-			var lines = error.stack.split("\n");
-			var stack=[];
-			var capture=false;
-			for(var i=lines.length-1;i>0;i--){
-				var l = lines[i];
-				var f = (l.replace(/^\s+at\s+([^ ]+).+/,"$1"));
-				if(f=="Hop_call_preTask"){
-					capture=true;
-				}
-				if(f=="Hop_call_postTask"){
-					capture=false;
-				}	
-				if(capture==true && f.indexOf("Hop_call")!=0){
-					stack.push(l);
-				} 
-			}	
-			if(stack.length>0){
-				Hop.error(err+"\n"+stack.join("\n"));
+/**
+ 	Given a string representation of a stack for a trace made during a call, return a more focused stack trace
+
+	This function will attempt to cull a larger stack trace into something more relevant for what went on during
+	a call. 
+
+	@param {String} errorStack a stack trace captured from an error
+
+	@returns stack a focused stack trace
+
+*/
+Hop.callStack=function(errorStack){
+		var lines = errorStack.split("\n");
+		var stack=[];
+		var capture=false;
+		for(var i=lines.length-1;i>0;i--){
+			var l = lines[i];
+			var f = (l.replace(/^\s+at\s+([^ ]+).+/,"$1"));
+			if(f=="Hop_call_preTask"){
+				capture=true;
 			}
+			if(f=="Hop_call_postTask"){
+				capture=false;
+			}	
+			if(capture==true && f.indexOf("Hop_call")!=0){
+				stack.push(l);
+			} 
+		}	
+		return stack.join("\n");
+}
 
-	}
+Hop.logCall=function(method,type,err,result){
+	var error = new Error();
+	var stack = Hop.callStack(error.stack);
+	Hop[type](method,err+"\n"+stack);
 }
 
+
 Hop.sendFile=function(file,options){
 	return new Hop.File(file,options);
 }
@@ -439,6 +449,60 @@ Hop.Object.wrap=function(objectName){
 }
 
 
+
+Hop.Object.prototype.callOnError=function(method,request,input,error,stack){
+	if(!stack){
+		var exp = new Error();
+		var stack = Hop.callStack(exp.stack);
+	} else {
+		stack = Hop.callStack(stack);
+	}
+	if(this.onError){
+		var res = this.onError(method,request,input,error,stack);
+		if(res!==null)
+			return res;
+	}
+	Hop.error(method.getMethod(),":returned an error result of '"+error+"'\n"+stack);
+	return error;
+}
+
+/**
+	Provide a function that will be called when an error occured for any call in the class
+
+	This function can be used to filter error messages. A typical use case would be to have a small
+	set of allowed error messages, and return a generic error message in all other cases. Or to attach 
+	a unique number to each error and provide details in the console log. This function should return a string 
+	for the desired error string or null if no custom error is returned. This function is not asynchronous.
+
+	@param {Function} onError function to be called when an error has occured
+		@param {Object} onError.method The method call associated with the error
+		@param {Object} onError.request The request for the call
+		@param {Object} onError.input The input for the call
+		@param {String} onError.error The error string
+		@param {String} onError.stack A stack trace of where the error occured
+
+	@example
+		Hop.defineClass("UserService",function(api){
+			api.post("update","/user/:userID");
+			
+			api.errorHandler(function(method,request,input,error,stack){
+				//If we know what the error is simply return it
+				if(allowedErrors.contains(error)){
+					return null;
+				} else {
+					//If we don't recognize the error produce a unique ID for it and spit it out in the logs
+					var id = Date.now();
+					var err = "Error ("+id+")";
+					Log.error(method.getName(),request,input,id,error,stack);
+					return err;
+				}
+			});
+		});
+ */
+Hop.Object.prototype.errorHandler=function(onError){
+	this.onError=onError;
+}
+
 Hop.Object.prototype.setLocalInterface=function(){
 	this._localInterface=true;
 }

lib/express.js

@@ -92,7 +92,7 @@ Hop.apiHook=function(basePath,app,options){
 									Hop.call(obj.name+"."+method.name,input,function(err,result){
 											var m = obj.name+"."+method.name;
 											if(called){
-												Hop.logResult(m+": called onComplete twice");	
+												Hop.logCall(m,"warn","called onComplete twice");	
 											} else {
 												called=true;
 												try {
@@ -102,26 +102,23 @@ Hop.apiHook=function(basePath,app,options){
 														return res.render(template,{ result: result, error: err, request: req});	
 
 													if(err){
+														err=obj.callOnError(method,req,input,err);
 														res.send(500,err);
-														Hop.logResult(m+": "+err);
 													} else {
 														if(result instanceof Hop.File){
 															result.send(res);
-															Hop.logResult(null,res);
 														} else if(result instanceof Hop.Template){
 															result.send(res);
-															Hop.logResult(null,res);
 														} else {
 															if(result===null || result===undefined){
 																res.send(404,"Not found");
 															} else { 
 																res.json(result);
-																Hop.logResult(null,result);
 															}
 														}
 													}
 												} catch(e){
-													Hop.error(e);
+													Hop.error(e.stack);
 												}
 										}
 									},req);

testresults.md

@@ -11,6 +11,6 @@
 #ex3:
 	Pass 3 Fail 0 100.00%
 #test:
-	Pass 34 Fail 0 100.00%
+	Pass 35 Fail 0 100.00%
 #intro:
 	Pass 18 Fail 0 100.00%