A common requirement of a Salesforce application is to display date and time information. What is not so common, is how this information needs to be displayed.

Varying the format of a dateTime field inside a Visualforce page is quite straightforward. It involves wrapping the field in a mask and then passing the data as a parameter, like so:

Page:

<apex:outputText value="{0,date,{!dateFormat}}">
     <apex:param value="{!myDateTime}" />
</apex:outputText>

In order to illustrate how this works, I have constructed a page and controller with a few samples. Below is a screenshot of the page displaying a single date (31st December 2010, 23:59:59) in various different formats. The first column of the table shows the string used as the date format mask, whilst the second column shows how that date appears when the mask is applied to the date.

Note that for formats that include literal text, escape characters are required in the controller so that the result renders properly. In my example, Day of the year has to be written as \'Day of the year\' in the formatting String. For all those interested, here is the page and controller code I used to construct the page:

Controller:

public class DateFormattingController {

  Datetime myDateTime = datetime.newInstance(2010, 12, 31, 23, 59, 59);

  List<String> dateFormats = new List<String> {
     'dd.MM.yy HH:mm:ss',
     'MMM-dd-yyyy hh:mm a',
     'EEEEE dd MMMMM yyyy G',
     'E hh:mm:ss:SSS z',
     'zzzzz (Z), \'Day of the year:\' D' 
  };
   
  public DateTime getMyDateTime(){
    return myDateTime;
  }

  public List<String> getDateFormats(){
    return dateFormats;
  }
}

Page:

<apex:page controller="DateFormattingController">
    
    <apex:sectionHeader title="Date Formatting"/>
    
    <apex:outputText value="Standard Output Format: {!myDateTime}"/>
    
    <apex:pageBlock >
        <apex:pageBlockTable value="{!dateFormats}" var="dateFormat">
            <apex:column headerValue="Date Format" value="{!dateFormat}"                                   width="50%"/>
            <apex:column headerValue="Output" width="50%">
                <apex:outputText value="{0,date,{!dateFormat}}">
                    <apex:param value="{!myDateTime}" />
                </apex:outputText>
            </apex:column>
        </apex:pageBlockTable>
    </apex:pageBlock>
    
</apex:page>

See Paul's Salesforce Blog for the full date format letter table. Any missing formats or unsure how to construct a particular format, leave me a comment on the post and I'll see what I can do!

Saleforce HTTP callouts limit workaround

Saleforce HTTP callouts limit workaround

I need to do tons of requests to an external service that, unfortunately, doesn't allow me to put multiple action requests within one single HTTP request, so that each action I want to send to this external service I have to do an HTTP request. Problem: Salesforce allows you to do only ten HTTP requests per execution. I could use Batch Jobs to schedule all the requests I need, but Batch Jobs are executed when resources are free, and I want to have the requests to be sent almost in real time, not "when Salesforce has time to do it".

So, here's the workaround. The key is that the limit is "per execution", and an AJAX call (done through a standard Visualforce <apex:actionFunction>) is actually a single execution. I can "loop" in Javascript to do requests as long as I need it.

Let's have a look at the code.

The controller:

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public with sharing class testJavascript {  public String requestStatus { get; set; }  public String requestMore { get; set; }  public Integer requestNumber { get; set; }  public Integer requestCurrent { get; set; }  public testJavascript () {   requestStatus = '';   requestMore = '';   requestNumber = 10000;   requestCurrent = 0;   }  public void doRequest () {   if (requestCurrent <= requestNumber) {    Http http = new Http();    for (Integer startPoint = requestCurrent; (requestCurrent <= requestNumber) && ((requestCurrent - startPoint) < 10); requestCurrent++) {     HttpRequest req = new HttpRequest();     req.setEndpoint('http://www.google.com');         req.setMethod('GET');     HTTPResponse res = http.send(req);    }    requestStatus = requestCurrent + ' out of ' + requestNumber + ' processed';   }   if (requestCurrent >= requestNumber)    requestMore = 'false';   else requestMore = 'true';  } }

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1

The page:

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<apex:page controller="testJavascript"> <apex:form>  <apex:outputpanel id="status">   Status:     {!requestStatus}   <script>requestContinue = {!requestMore};</script>  </apex:outputpanel>  <script>   function requestMore() {    if (requestContinue)     doRequest();   }  </script>  <button onclick="if (doRequest()) return false; else return false;">Start</button>  <apex:actionfunction action="{!doRequest}" name="doRequest" oncomplete="requestMore()" rerender="status"> </apex:actionfunction></apex:form>

Some explication:

1. In the controller I have a request counter (requestCurrent, set to 0 at beginning) and a request amount (requestNumber, set to 10000 at beginning) and a method, doRequest(), that, given those two variables, executes the next 10 HTTP requests (increasing the counter) and updates the status String (requestStatus) and the requestMore String/Boolean, setting it to true if other requests are needed (if the counter is lower than the request amount we need) or false if not.
2. In the page I have an <apex:actionFunction> pointing to this method, that rerenders the status panel. In the panel I show the status string and I update a Javascript global variable (requestContinue) with the String/Boolean given in requestMore by the doRequest() APEX method.
3. The actionFunction has an oncomplete attribute that calls another Javascript function, requestMore(), that is in the page code. This function checks for requestContinue value (updated after each rerender): if true calls again the doRequest() actionFunction and 10 more requests are executed, if false it does nothing.

The user has just to push the <button> (that does the first actionFunction call) to start the loop.

Nice, isn't it? :-)