Deserialized

ObjectID’s with MongoDB and the mongodb-csharp driver

I mist say, the latest release of mongodb-csharp is rather awesome.  Typed collections and LINQ support mean I can worry more about my application than about the data layer.

Here is an example of using typed collections:

public class Customer
{
	public Oid Id { get; set; }
	public string Name { get; set; }
	public CustomerBillingInfo Billing { get; set; }
	public List Depts { get; set; }
}

public void AddCustomer(Customer customer) {
	...(code removed for simplicity)...
	IMongoCollection<customer> collection = database.GetCollection<customer>();
	collection.Save(customer);
}

Gotcha: Beware of the ID property!

One thing that threw me off when I began using the typed collections was that I had defined my ID property as “_id” because That is what MongoDB uses internally.  While this made sense to me, the mongod process kept throwing errors whenever I tried the following:

...(code removed for simplicity)...
IMongoCollection<customer> collection = database.GetCollection<customer>();
Customer customer = collection.Linq().First(c => c.Name == "test customer");
customer.Name = "A new name!";
collection.Save(customer);

The error looked something like this:

Fri Jun 25 10:43:14 Exception 11000:E11000 duplicate key error index: test06.Customer.$_id_  dup key: { : ObjId(4c24c07a189cf31bd4000002) }
Fri Jun 25 10:43:14    Caught Assertion in insert , continuing
Fri Jun 25 10:43:14 insert test06.Customer exception userassert:E11000 duplicate key error index: test06.Customer.$_id_  dup key: { : ObjId(4c24c07a189cf31bd4000002) } 21ms

It was driving me crazy for days before I realized that the driver was doing some magic – the POCO object needed its ID to be named “Id” instead of “_id” an as soon as I changed that – it started working properly.

Tags: C#, csharp, mongodb, web development

Gotcha: 32-bit applications may not be able to see files on 64-bit Windows

This one really threw me off tonight.  I am running Windows Server 2008 on one of my boxes and I was trying to set up some advanced URL Routing on IIS7.  IIS7 Manager has a very nice easy to use GUI interface, but I prefer working directly in the configuration files.

I fire up my Notepad++ and attempt to open a file through the file browser.  I navigate to the IIS config folder (c:\windows\system32\inetsrv\config\) and I see an empty directory.  Huh? How is that possible?!

Now I switch over to Windows Explorer and go to the same folder as above and to my disbelief… there are all the config files.  Ok now I am truly confused!

Conclusion

While I cannot seem to find anything from Microsoft about this issue, my findings are that 32-bit applications cannot see the entire file system!  I installed a few applications that I know are only 32-bit to verify this and sure enough they all suffered from the exact same issue. 

Files simply do not show up and if you attempt to open the file (because you do know the full path & filename), it simply tells you that the file does not exist.

Tags: Gotcha, iis7, Windows