I am learning Ruby on Rails with RubyMine IDE

Yes. I am learning Ruby on Rails for an ongoing project. Ruby looks so nice, so easy to learn. Having a background in PHP and with some experience on PHP framework, learning Ruby and Rails has not been a difficult task to me. Infact, much of the features in Rails look adopted by different PHP frameworks.
Ruby's syntax is really easy to understand , making it easy to learn. Rails makes it easy to respond to a request in different format (JSON,HTML,XML) . Just 5 lines of code and viola!.  I have been trialing RubyMine IDE by Jet Brains and I have found it to be really well built. Since I have been using the debugger I have not explored the debugger functions in Ruby ( like print_r or var_dump are in PHP) but one of my colleague says that the support isn't that great. I really like the concept of gem which are the 1st or 3rd party libraries specific to a particular project.  I would love to hear comments on this from my reader. If you are a Ruby developer, tell me some good tips  and If you are an explorer like me, let me know if there is a particular feature that you would like to me explore in Ruby or Rails. Thats all from me for now. :)

Custom Logic in Field Sorting for ListGrid in SmartClient

Sometime data in the ListGrid needs to be sorted on a particular condition or criteria rather then traditional sorted OR you get data is a form where it would not be possible for the ListGrid to sort it on its own. For this purpose, ListGrid provides a 'sortNormalizer' function which can be implemented at grid level or at field level for data sorting. Have a look at the following example :


<pre  style="font-family:arial;font-size:12px;border:1px dashed #CCCCCC;width:99%;height:auto;overflow:auto;background:#f0f0f0;;background-image:URL(https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj-s003mlEAhvwIvXAlnBoXoBbBtuXAejNQN6vWliFgZ05CghIJkoK74Z2EkX0AaOMHLIANtFZ1rDCSZS4dcOwgvPu9zsTEl_0cUVC4O3EWLwYPKK_ttSiH7fVdWEztHK7rSlPKKZLfjE8Z/s320/codebg.gif);padding:0px;color:#000000;text-align:left;line-height:20px;"><code style="color:#000000;word-wrap:normal;"> isc.ListGrid.create({ 
   ID: "countryList", 
   data: countryData, 
   fields:[ 
     {name:"countryCode", title:"Flag", width:50}, 
     {name:"countryName", title:"Country"}, 
     {name:"independence", title:"Nationhood", type:"date"}, 
     {name:"area", title:"Area (km&amp;sup2;)", type:"float", formatCellValue:"isc.Format.toUSString(value)"}, 
     {name:"gdp_percap", title:"GDP (per capita)", align:"right", 
       formatCellValue: function (value, record) { 
         var gdpPerCapita = Math.round(record.gdp*1000000000/record.population); 
         return isc.Format.toUSDollarString(gdpPerCapita); 
       }, 
       sortNormalizer: function (record) { 
         return record.gdp/record.population; 
       } 
     } 
   ], 
 }) 
</code></pre>

In the above example, notice how the sort normalizer function is used to sort values calculating ratio of a two of the fields of the record row.  Also notice that the value returned by the normalizer function is used for sorting is numeric which can easily by used for sorting. This concept can be used for sorting by any custom criteria or condition. Though it is not necessary to return a numeric value
, it is a safe bet.
Another important things about normalizer function is that it also accepts a context parameter. The full signature of the sortNormalizer function is

 ListGridField.sortNormalizer() (recordObject, fieldName, context)

where context can be any variable which needs to be passed to the function. One of the scenario in which it can be used is when the custom sorting has to be done on the result of a text search , where the text searched is passed on to the function in the context variable.

CORS - Cross Domain Resource Sharing With Ajax and JSON - Example

Recently, I was ask to build a prototype to demonstrate cross-domain resource sharing through AJAX and JSON.  For those who dont know, cross-domain AJAX request are not allowed by default until the web server handling the request allows it. This is done by sending the  "Access-Control-Allow-Origin" header. Following is an example of a client and server peforming CORS. 

Server Code:

 <?php  
 header('Access-Control-Allow-Origin: *'); 
 $Response = array(1,2,3); 
 echo json_encode($Response);      
 ?> 

Ajax Client Code:

 <html> 

 <head> 

 <title>test</title> 

 <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.0/jquery.min.js"></script> 

 </head> 

 <body> 

 <input type="button" value="test" onclick="testajax()" /> 

 </body> 

 <script> 

 function testajax() 

 { 

  $.ajax({ 

   crossdomain : true, 

   type : "text/plain", 

   type : "GET", 

   url : "http://www.testerzone.com/test/test.php", 

   success : function (data){ 

    alert(data); 

   }, 

   error: function (xhr, ajaxOptions, thrownError) { 

     alert(xhr.status); 

     alert(thrownError); 

     } 

  }); 

 } 

 </script> 

 </html> 

PHP How To : Creating date ranges for filtering in PHP for MySQL query - Part 1

MYSQL query for querying results between a date range is not that difficult at all.  It goes like

 SELECT * FROM my_table WHERE timestamp BETWEEN '2013-01-01' AND '2013-02-01'  

However, things get a bit interesting when the date range becomes dynamic. For example, in one of the projects that I have worked on , I was required to provide the feature of filtering results for last month, last 6 months and so on. You can see the problem clearly here. The date ranges need to be made only the fly.  
In order to filter data by date ranges, for example, for Last Six Months, Last Month or Last Year, PHP's date() and strtotime() function can be used in combination with each other.  Let me provide snippets for them.

 // For last six months,  
     $start = date('Y-m-d', strtotime('-' . (date('j') - 1) . ' days -6 month '));  
     $end = date('Y-m-d', strtotime('-' . (date('j') - 1) . ' days'));  
 // For last month,  
           $start = date('Y-m-d', strtotime('-' . (date('j') - 1) . ' days -1 month'));  
           $end = date('Y-m-d', strtotime('-' . (date('j') - 1) . ' days '));  
 // For last year,  
           $start = date('Y-m-d', strtotime('1 jan last year'));  
           $end = date('Y-m-d', strtotime('31 dec last year +1 day '));  

Here, the code for getting date range covering whole of the last year is easier to understand.  The range starts  from 1 Jan of last year and ends on 1 Jan of this year. But why 1st Jan of this year?? After all, we only want to get records till 31st of Dec of last year. The reason for this is that if you just provide a date in the SQL statement mentioned above , MySQL takes it as start of that date.  Therefore, if we were just to write  '31 dec last year', then the results would not include those records with timestamp greater than "2012-12-31 00:00:00" and we will miss results for a whole day.  Adding "+ 1 day " allows us to include those results as well.

The snippets for last month and last 6 months are a bit difficult to understand at first , however, they are quite easy once you know what happening in them. Let me explain one of them.  For the last six months case, the start date is computed by first  getting the start of the current month ( the (date('j') - 1) part). Then it further subtracts 6 months to get the start of the six month period. For end date, it just compute the start of the current month.  The case for the last month is identical to this one except that only 1 month is subtracted instead of 6 in computing the start date. 
So there you have it.............. but we are not done yet. There is a slight problem with date range , which may result in unwanted records being included in the result.  I have explained this in part 2 and tweaked the code to fix it.