Passing Around Message Contents As Streams (conversion To/from String && XmlDoc's).

More of a general "Streams" question than broker specific, but this is all being done in the context of Broker passing the messages around. The use of Streams & Encoding seems to be my problem and I'm not as familiar with Streams as I am with other areas of the Framework... Any advice would be appreciated.

At this point, I've created my own objects/stored procedures based loosely on the ServiceBrokerInterface class provided in the SQL Server samples. Some of this was done for simplification and as a learning exercise, but also to ensure that all of the SQL operations are being done via Stored Procedures and not inline SQL. This was done to adhere to our existing security policy used on this project.

In this "interface" I've built, I have a [BrokerMessage.cs] class which is meant to have a few additional pieces of functionality beyond what the MS provided version had supplied.

1st... A constructor for accepting either String or XmlDocument as the "content"

2nd... Methods to return either a XmlDocument or a simple String.

Since all of the Broker functionality is defined as using VARBINARY(MAX) in my stored procedures, I don't believe I have any problems at that level. It's simply a binary blob to Broker.

In my constructor for accepting String or XmlDocuments, I attempted to use the following...

public BrokerMessage(string type, XmlDocument contents)

{

m_type = type;

m_contents = new MemoryStream(EncodingProvider.GetBytes(contents.InnerXml));

}

My understanding was that MemoryStream is derived from Stream so I can implicitly cast it. The "EncodingProvider" is a static member set as follows:

public static Encoding EncodingProvider = Encoding.Unicode;

This way I ensure that internal & external code can all be set to use the same encoding and easily changed if necessary. I was hoping to avoid using Unicode since the rest of the application does not require it, but from my understanding all Xml documents in SQL Server are Unicode based, so this should be a better encoding choice for any processing that may potentially occur within SQL Server itself.

In my methods to return the various forms of the "Stream", I have the following code... The ToBytes() method is what is used to pass intot he stored procedure parameter that is defined as VarBinary and expecting a byte array. One area of concern is that the Read method accepts an INT for the length, but the actual Length property is a LONG. I'm sure there's a better way to handle this and I would welcome any advise there.



/// <summary>

/// Used to convert from a Stream back to a simple Byte array.

/// </summary>

/// <returns></returns>

public virtual byte[] ToBytes()

{

byte[] results = new byte[this.Contents.Length];

this.Contents.Read(results, 0, (int)this.Contents.Length);

return results;

}

/// <summary>

/// Used to convert from a Stream back to a simple String.

/// </summary>

/// <returns></returns>

public new string ToString()

{

byte[] buffer = this.ToBytes();

String results = EncodingProvider.GetString(buffer);

return results;

}

/// <summary>

/// Used to convert from a Stream back to a simple XmlDocument.

/// </summary>

/// <returns></returns>

public virtual XmlDocument ToXmlDocument()

{

XmlDocument results = new XmlDocument();

results.InnerText = this.ToString();

return results;

}