Azure Tips and Tricks Part 87 - Avoid Bad Request Errors in Azure Storage Table

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Cecil Phillip works at Microsoft and is part of the Azure Cloud Developer Advocates team that focuses on .NET and Xamarin. Learn more about Cecil here or follow him on Twitter.

Intro

Most folks aren’t aware of how powerful the Azure platform really is. As I’ve been presenting topics on Azure, I’ve had many people say, “How did you do that?” So I’ll be documenting my tips and tricks for Azure in these posts.

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Ensure a clean RowKey in Azure Storage Table

In case you are new to the Azure Storage Tables, we’ve reviewed the following items so far:

• Creating your first Azure Storage Table
• Adding an item to a Azure Storage Table
• Reading an item from a Azure Storage Table
• Updating an item from a Azure Storage Table
• Deleting an item from a Azure Storage Table
• Ensure a clean RowKey in Azure Storage Table

The problem

If you’ve ever been working with Azure Table Storage and tried to insert data and received 400 Bad Request, then you’ve probably narrowed this down to a malformed PartitionKey or RowKey after many hours. This is due to the fact that for PartitionKey and RowKey, there are some disallowed characters such as:

• The forward slash (/) character
• The backslash () character
• The number sign (#) character
• The question mark (?) character
• Control characters from U+0000 to U+001F, including:
• The horizontal tab (\t) character
• The linefeed (\n) character
• The carriage return (\r) character
• Control characters from U+007F to U+009F

Debugging in Visual Studio If you are debugging in Visual Studio, then you can also check the StorageException.RequestInformation.ExtendedInformation to gain additional information about the error.

The Solution

There is many ways that you can handle this, but my favorite is this extension method that simply strips away those characters as shown below.

public static string ToAzureKeyString(this string str)
{
    var sb = new StringBuilder();
    foreach (var c in str
        .Where(c => c != '/'
                    && c != '\\'
                    && c != '#'
                    && c != '/'
                    && c != '?'
                    && !char.IsControl(c)))
        sb.Append(c);
    return sb.ToString();
}

Simply call this method before your insert to ensure your PartitionKey or RowKey is ‘clean’ and the 400 errors will disappear!

Want more Azure Tips and Tricks?

If you’d like to learn more Azure Tips and Tricks, then follow me on twitter or stay tuned to this blog! I’d also love to hear your tips and tricks for working in Azure, just leave a comment below.