Giving name to excel sheet while exporting it- rails 3

You may want to give file name to your excelsheet when you are exporting it. Suppose you want to give the todays date and time as its name. Then do the following:

Suppose export is the method in which you have written the code for exporting excel sheet then do the following:


    def export
       time = Time.now
       time.strftime("%Y-%m-%d %H:%M:%S")
 
      respond_to do |format|
      format.html

      format.xls { headers["Content-Disposition"] = "attachment; filename=\"#{time}"+".xls"}
    end

Disable browser cache while using devise gem -rails 3

While using devise gem for authentication, I found that even after a user log out, he can still see the previous page he visited if he clicks on the back button of browser. To disable this add the following code in your application_controller.rb.


before_filter :set_no_cache
def set_no_cache

   response.headers["Cache-Control"] = "no-cache, no-store, max-age=0, must-revalidate"
   response.headers["Pragma"] = "no-cache"
   response.headers["Expires"] = "0"

end

Change date format in ruby on rails

Suppose you have date data type and you want to change the format of date being saved from 'yyyy-mm-dd' to 'dd-mm-yyyy' or in any other format then do the following:

Add a file time_defaults.rb in initializers folder and add the  following code


# Default format for displaying dates and times
Date::DATE_FORMATS[:default] = "%d/%m/%Y"
Time::DATE_FORMATS[:default] = "%d/%m/%Y"


And restart the server.

Using Dhtmlx datagrid in rails 3 with calendar and combo box (select box)as column type

Earlier I wrote about using a simple dhtmlx data grid in rails 3. The column type was text box which where editable. As I explored it more I found other column types which can be used with datagrid.

Calendar as column type
To use calendar as column type you have to add some of the js and css. These files can be easily downloaded from the dhtmlx website. Download the zip file and copy the below js and css inside your assests javascript and stylesheets folder.

Javascript files:
dhtmlxgrid/codebase/excell/dhtmlxgrid_excell_dhxcalendar.js
dhtmlxgrid/codebasedhtmlxcommon.js
dhtmlxgrid/codebase/calendar/dhtmlxcalendar.js

CSS files:
dhtmlxCalendar/codebase/skins/dhtmlxcalendar_dhx_skyblue.css
dhtmlxgrid/codebase/calendar/dhtmlxcalendar.css


Now while initializating the datagrid specify the  coltype as dhxCalendar

            var grid = new dhtmlXGridObject("grid_here");

            grid.setImagePath("");

            grid.setHeader("Name, Amount");

           

            grid.setColSorting("str,str");

            grid.setInitWidths("150,150");

            grid.setSkin("dhx_skyblue");

            grid.setColTypes("dhxCalendar,ed");

            grid.init();

            grid.load("/decoration/data?decoration="+deco);

            

            dp = new dataProcessor("/decoration/dbaction?decoration="+deco);

            dp.init(grid);

Note:- If you get some error like undefined coltype or somthing. This means that you have not included the correct js. Please check again for all the js files.


Combo box/list box/select box as column type

Specify the setColTypes as "co" if you want to add more options while editing datagrid or else specify "coro" to make it read only.

To add default options to the combo box do the following



      var grid = new dhtmlXGridObject("grid_here");
            
            grid.setImagePath("");
            grid.setHeader("Select number");

            grid.enableMultiselect(true)
            grid.enableLightMouseNavigation(true);
            grid.setInitWidths("100")
            grid.setSkin("dhx_skyblue");
            grid.enableAutoHeight(true);
            grid.enableMultiline(true);
        
            grid.setColTypes("coro");

            var combo1 = grid.getCombo(1); //Here 1 is the id of the column
        
            combo1.put(0,"zero"); // the first data is the value and the second is the data displayed in the dropdown
            combo1.put(2,"two");
    
            grid.init();
      
            grid.load("/visit/data?visit="+deco);
            dp = new dataProcessor("/visit/dbaction?visit="+deco);
            dp.init(grid);