The Silver Lining

Lessons & Learnings from a salesforce certified technical architect.

Archive for the ‘force.com’ Category

Salesforce JavaScript Remoting: Using Apex and JavaScript objects to pass data from client- to server-side and vice versa

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I’ve spoken about how to do this at a high-level during Cloudstock London and there are hints at how it can be done but no formal documentation that I’ve found, so here we are :)

Quite simply JavaScript Remoting will transform Apex objects and classes (or collections of these types) into JavaScript objects for you. The opposite is true too but there are some rules you need to observe.

Apex Types to JavaScript Equivalents

This is the easier of the type conversions in that you don’t have to really do anything to make it happen. The code below uses a custom class that I’ve defined but you can do the same with any sObject too. Let’s have a look at the code.

The Controller

public with sharing class RemotingObjectsController {

    /* The remoting method simply instantiates a two custom types, puts
       them into a list and then returns them. */
    @RemoteAction
    public static List<CustomClass> getClassInstances(){
        List<CustomClass> classes = new List<CustomClass>();

        CustomClass me = new CustomClass('Wes');
        CustomClass you = new CustomClass('Champ');

        classes.add(me);
        classes.add(you);

        return classes;
    }

    /* My custom type */
    public class CustomClass{
        public String firstName{get;set;}

        CustomClass(String firstName){
            this.firstName = firstName;
        }
    }
}

The Visualforce

<apex:page controller="RemotingObjectsController">
  <script>
      // Will hold our converted Apex data structures
      var classInstances;

      Visualforce.remoting.Manager.invokeAction(
        '{!$RemoteAction.RemotingObjectsController.getClassInstances}',
        function(result, event) {
          // Put the results into a var for pedantries sake
          classInstances = result;

          console.log(classInstances);

          // Assign the first element of the array to a local var
          var me = classInstances[0];

          // And now we can use the var in the "normal" JS way
          var myName = me.firstName;
          console.log(myName);
        });
  </script>
</apex:page>

The Output

Console output from the JS code.

JavaScript Types to Apex Equivalents

This is a little tricker, especially when it comes to sObjects. Note that the approach below works for classes and sObjects too.

The Visualforce Page

<apex:page controller="RemotingObjectsController">
  <script>
      /* Define a JavaScript Object that looks like an Account */
      /* If you were using custom objects the name must include the "__c" */
      function Account(){
          /* Note the field names are case-sensitive! */
          this.Id = null; /* set a value here if you need to update or delete */
          this.Name = null;
          this.Active__c = null; /* the field names must match the API names */
      }

      var acc1 = new Account();
      acc1.Name = 'Tquila';
      acc1.Active__c = 'Yes';

      var acc2 = new Account();
      acc2.Name = 'Apple';
      acc2.Active__c = 'Yes';

      var accounts = new Array(acc1, acc2);

      Visualforce.remoting.Manager.invokeAction(
        '{!$RemoteAction.RemotingObjectsController.insertAccounts}',
        accounts,
        function(result, event) {
          console.log(result);
        });
  </script>
</apex:page>

The Controller

There not much to the controller in this case.

public with sharing class RemotingObjectsController {

    @RemoteAction
    public static void insertAccounts(List<Account> accounts){
        insert accounts;
    }

}

Why is this cool?

Good question. If the Force.com Platform didn’t do this for you then we – the developer – would need to convert ours types explicitly on both the server-side and the client-side, and man-oh-man is that boring, error-prone work. Yet again the guys at salesforce.com have built in a convenience that saves us time and let’s us get on with the work of building cool apps.

Written by Wes

June 22, 2012 at 11:06 am

Salesforce: JavaScript Remoting – a different way of thinking

with 6 comments

 

Remoting is awesome.

JavaScript Remoting for Apex operates in a very different paradigm from what you might be used to i.e. Visualforce pages have controllers and the two interact through action methods – where this might be a full form submission or some neat AJAX functionality. Remoting also calls controller methods but there is a gaping maw in terms of how the two work under the hood.

I’ve seen a few great articles on the syntax and example usage of JavaScript Remoting for Apex but when I started using it I came across a number domain differences that weren’t documented anywhere. Hopefully my list here will help you in the learning process. The best way to describe the new way of thinking is to examine the features set in contrast to “normal” Apex and Visualforce.

How JavaScript Remoting Differs

  • Pass parameters naturally i.e. the call matches the method signature syntactically instead of requiring <apex:param/>.
  • Action methods when called in “normal” Visualforce can only return NULL or a PageReference. Remoting allows you to return a wider range of data types, even objects and collections.
  • Remoting methods have no access to the view state e.g. if a static variable is initialised to some value (outside the remoting method) a remoting method will see this as NULL unless it is re-initialised in that method! Conversely if a remoting method sets a state variable value the scope of that value is only within that method.
  • It’s much faster. I’m building an application at the moment that is 95% backed by JS Remoting and when I show it to other developers they are struck dumb for at least 3 hours because of the speed.
  • Neater debugging info in the browser console. Salesforce has done a great job of providing feedback directly to the browser’s console log.
  • Each method call gets its own executional/transactional context i.e. fresh governor limits per call!

If I’ve missed anything please let me know and I’ll add it. Viva la knowledge crowdsourcing!

Written by Wes

February 5, 2012 at 4:05 pm

Salesforce: Dynamically determining the field type of a dynamically determined sObject

with 2 comments

This solution is quite difficult to find.

Call me crazy but I need to do this from time to time, and every time I do I can’t remember how I did it before! So I then trudge through the API and the Apex docs until I find the answer and that’s no mean feat in this specific case. Well, no more my friends because I’m putting it right here on this very blog!

In short the code below will return (as a String) the type of field that we’re working with. Neither the name of the object or the name of the field need to be known in advance.

    public static String getFieldType(String fieldName){
    	// Assume that "sObjectName" is populated elsewhere
	Schema.SObjectType t = Schema.getGlobalDescribe().get(sObjectName);

	Schema.DescribeSObjectResult r = t.getDescribe();
	Schema.DescribeFieldResult f = r.fields.getMap().get(fieldName).getDescribe();

	if (f.getType() == Schema.DisplayType.String){
		return 'String';
	} // .... else if

	return null;
    }

Written by Wes

February 1, 2012 at 9:33 pm

Salesforce: Different percentage unit test code coverage in different environments

with 3 comments

Spot the difference.

Many people are finding that their tests are reporting different degrees of test-coverage in different environments. There are a few things to check if you are getting inconsistent results but there’s a new bug in the wild. Before you assume you have the bug make sure that you’ve:

  1. ‘Run All Tests’ in each environment. This will tell you a few things viz.
    • Perhaps there are tests failing that are bringing coverage in that environment down.
    • There are some tests that only fail when run in the browser e.g. MIXED_DML_EXCEPTION will not rear it’s head through the IDE.
  2. Click the ‘Compile all classes’ link above the Setup > Develop > Apex Classes view. I’m not sure when this lil’ bugger first appeared but it’s darn useful. Essentially it makes sure that all the dependencies in your code are fulfilled e.g. if page A uses controller B that in turn refers to utility class C it’ll make sure each of those pieces exist and work (as far as compilation goes at least).
  3. Double-check your test classes to make sure they’re not data dependent. If they are and you have different types/amounts of data in your respective environments it’s 100% feasible that the test coverage will be different.

Now if you’ve checked all of the above you might have been afflicted by a new bug which, for some reason, counts braces, whitespace (and more!) as being uncovered by your tests. This is preposterous of course and to fix it simply remove all test history from the deranged environment. Re-running the test and/or deploying them should now be back to normal!

Written by Wes

November 30, 2011 at 11:01 pm

Across the Pond with Shannon Hale

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Shannon is Senior Product Manager for Declarative Apps at Salesforce.com

@abhinavguptas and I were curious as to the identity of the creator of the SetupScripter, which is now incorporated into the salesforce.com Org setup menu. I dug around a bit and managed to uncover her real identity – community please meet Shannon Hale, Shannon Hale this is the community. She didn’t just stop with that wonderful piece of UX but has moved onto bigger and better things, but I’ll let her tell you about those.

If you’d like to learn more about the genius that is Shannon or just have a chat with her you can get her on twitter at @shannonsans or @bathtubdreamer. You can also check out her online presence at shannonsansserif.com and bathtubdreamer.com.

Onto the Q&A!

Who is Shannon Hale? How did you get into software development and UX design?

I started out as a writer, but in a different field — I wrote and edited for some independent Canadian music and culture magazines. I started technical writing to help pay the bills, and from there wandered through a series of tech positions: technical training, systems analysis and design, and software development. In 2001 I became obsessed with why a product I was coding was difficult to use, and began to independently study interaction design and user experience.

When I’m not being a complete geek — which I am even at home, I always have personal and volunteer web projects going on — I’m sewing, knitting, or binding books. I’m one of those people who always needs to be doing something with their hands.

Read the rest of this entry »

Written by Wes

October 14, 2011 at 10:49 am

London Force.com Meetup – 20 October 2011

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Yip it’s that time again and boy do we have some very cool speakers this time around. The gig is at Skillsmatter at 6.30pm on 20 October and is summarised in the info below. Please don’t forget to RSVP. Of course there will the be usual beers and pizza ;)

Hope to see you there!

AMJAD KHAN ON FORCE.COM ERD USING SCHEMASPY

Amjad Khan will give a talk to the SafesForce user group on How to Install and run SchemaSpy on any Salesforce Org to generate an ER diagram. More details…

SIMON GOODYEAR ON MAKING BETTER USE OF INTERFACES ON THE FORCE.COM PLATFORM

Simon Goodyear’s talk for the SalesForce user group will give a quick overview on what interfaces are, how you can make better use of them in APEX, and what we gain from doing so. More details…

TESTING ON THE FORCE.COM PLATFORM

Keir Bowden gives a talk for the SalesForce User Group on Testing on the force.com platform, covering TDD, unit testing, continuous integration and test scripting. More details…

EFFECTIVE B2C MANAGEMENT

Stony Grunow gives a talk for the SalesForce User Group on Effective B2C management for companies using the “Contacts and Organisations” package. More details…

TURNING YOUR ORG INTO A FULLY OPERATIONAL BATTLE STATION USING RUBY AND SELENIUM

Bruce Durling will give a talk for the SalesForce User Group on turning your org into a fully operational battle Station using ruby and selenium More details…

Written by Wes

September 28, 2011 at 5:03 pm

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