Azure Table Storage One of the request inputs is out of range

While trying to insert an entity into a Windows Azure Table Storage table I got the rather ambiguous "An error occurred while processing this request." error message from a System.Data.Services.Client.DataServiceRequestException. The inner exception help a message of "One of the request inputs is out of range."

The error message wasn't terribly helpful but I finally found what was causing the problem. It was because of my Row Key. The RowKey property that comes from the TableServiceEntity abstract class has specific requirements which I was unintentionally breaching.

My RowKey was calculated from another property of my Entity. In this particular instance this meant the string included a '/' symbol. This is not allowed by Table Storage for RowKeys.

Solution

When calculating the RowKey from the other property I am now removing special characters that the Azure Storage does not allow. This includes forward slash (/) character, backslash (\) character, number sign (#) character, question mark (?) character.

Old code:

private string productName;
public string ProductName
{
   get { return productName; }
   //setting the RowKey and productName to the same value in one go
   set { RowKey = productName = value; }
}

New code:

private string productName;
public string ProductName
{
   get { return productName; }
   set { RowKey = Regex.Replace(productName = value, @"[\ /?#]", ""); }
}

I actually already knew about this from when I read Apress's Windows Azure Platform but the confusing error message threw me off on a tangent and hoped it hadn't done the same to anyone else.