Thursday, April 14, 2011

SharePoint Read Only Databases and me as Developer

While working with SharePoint 2010 or SharePoint 2007, there are some scenarios when you want to take your content database of your web application to read only state.
For example when?
That’s a usual question one can ask , and answer is , when you / IT administrators are doing some migrations of your content database to some other system (like we do SharePoint 2007 upgrade to SharePoint 2010 by using database attach upgrade process) , or you / IT administrators are doing some maintenance of your SQL server
Practically doing this, you are making sure that end users are not adding contents to your site while you are working / migrating with content database
and good thing about SharePoint is , when you set your content database to read only state then SharePoint recognizes that and removes / hides all controls which cause any “Add” action to site
Well, you can do this in three ways :
a.    by using stsadm
b.    by using visual studio
c.     by using SQL Server Management Studio (easy for IT admins)
How to do this using stsadm?
Here is simple command which will put your site collection to read only mode and users wont be able to add new content
For read only site:
stsadm.exe –o setsitelock –url http://yoursite/ -lock readonly
for bringing site back to normal :
stsadm.exe –o setsitelock –url http://yoursite/ -lock none


How to do this using Visual Studio? (I love this J )     

static void Main(string[] args)
{
 try
 {
   using (SPSite site = new SPSite("http://yoursite/"))
   {
     site.AllowUnsafeUpdates = true;
     site.ReadOnly = true;
     Console.WriteLine(site.ReadOnly.ToString());
   }
 }
 catch (Exception ex)
 {
     Console.WriteLine(ex.Message);
 }

   Console.ReadLine();
 }


How can I do this as IT administrator?

·         Well that’s a pretty simple task if you having SQL Server Management Studio installed. Here are steps to do this
·         Open SQL Server Management Studio (for example for SQL Server 2008) and connect to the instance of database which is having your SharePoint content databases
·         Once you find your web application’s content database, right click on it and then select properties, now a small pop up window should open
·         in this new window , select Options from left menus and find option Database Read only and set that to true and you are done

Ok this is good so far but what’s in it for me as developer??
Yes interesting question, and obvious answer
while working with SharePoint and customizing / developing on top of SharePoint platform we usually create some web controls, web parts and so on , but one thing we should always consider in aspect of read only databases is , we should disable any “Add” functionality to site when database is in read only state
For example, I have a web part which adds some data to SharePoint list when clicked , and suppose site database is in read only state for some instance ,what will happen? Error isn’t it?
So to avoid this, we should always check database status of site like this

if (!site.WebApplication.ContentDatabases[0].IsReadOnly)
{
  if (!site.ReadOnly)
  {
    //Enable Add/Edit functionality
  }
}
else
{
    //Disable Add/Edit functionality
}

SharePoint 2010 List Events Enhancements

Have you ever worked with SharePoint 2007 List Item Events? If yes then you would have probably noticed that when we attach any event receiver with list then it gets attached at the template level
what I mean is suppose I have created an event receiver for say Calculations List which is basically a custom list (template id = 100) , so in SharePoint 2007 all events will be called for all lists which are created by using  custom list template id = 100
and workaround was that , we were taking help of code to avoid this in SP 2007 , like we can check the name of list every time event receiver gets called and make execution only for desired list
Sample Code:
public override void ItemAdded(SPItemEventProperties properties)
{
  if (properties.ListTitle.Equals("YourList"))
  {
     //here you go          
  }
}
Now to avoid this in SharePoint 2010, framework comes with some enhancements done in Event Receivers section
Now we can associate particular event receiver at Site / Web / List levels and so this is more granular now
 Basically there are three more attributes are added for <Receivers> element and those are
Scope: we can define the scope of Event Receiver to SiteCollection (Site) or Web level
RootWebOnly: event receiver will be attached to all lists under root web created using particular template
ListUrl: we can specify particular list on which Event Receiver will be active (/Lists/MyList/)
Example:
<Receivers ListTemplateId="100" ListUrl="/Lists/CustomList/">
    <Receiver>
      <Name></Name>
      <Type></Type>
      <Assembly></Assembly>
      <Class></Class>
      <SequenceNumber></SequenceNumber>
    </Receiver>
 </Receivers>