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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:

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();
}
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