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POAsynchronous XmlReader in .NET?
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copied!<p>Is there a way to access a XmlReader asynchronously? The xml is coming in off the network from many different clients like in XMPP; it is a constant stream of <code><action>...</action</code>> tags.</p> <p>What i'm after is to be able to use a BeginRead/EndRead-like interface. The best solution I've managed to come up with is to do an asynchronous read for 0 bytes on the underlying network stream, then when some data arrives, call Read on the XmlReader- this will however block until all of the data from the node becomes available. That solution looks roughly like this</p> <pre><code>private Stream syncstream; private NetworkStream ns; private XmlReader reader; //this code runs first public void Init() { syncstream = Stream.Synchronized(ns); reader = XmlReader.Create(syncstream); byte[] x = new byte[1]; syncstream.BeginRead(x, 0, 0, new AsynchronousCallback(ReadCallback), null); } private void ReadCallback(IAsyncResult ar) { syncstream.EndRead(ar); reader.Read(); //this will block for a while, until the entire node is available //do soemthing to the xml node byte[] x = new byte[1]; syncstream.BeginRead(x, 0, 0, new AsynchronousCallback(ReadCallback), null); } </code></pre> <p>EDIT: This is a possible algorithm for working out if a string contains a complete xml node?</p> <pre><code>Func<string, bool> nodeChecker = currentBuffer => { //if there is nothing, definetly no tag if (currentBuffer == "") return false; //if we have <![CDATA[ and not ]]>, hold on, else pass it on if (currentBuffer.Contains("<![CDATA[") && !currentBuffer.Contains("]]>")) return false; if (currentBuffer.Contains("<![CDATA[") && currentBuffer.Contains("]]>")) return true; //these tag-related things will also catch <? ?> processing instructions //if there is a < but no >, we still have an open tag if (currentBuffer.Contains("<") && !currentBuffer.Contains(">")) return false; //if there is a <...>, we have a complete element. //>...< will never happen because we will pass it on to the parser when we get to > if (currentBuffer.Contains("<") && currentBuffer.Contains(">")) return true; //if there is no < >, we have a complete text node if (!currentBuffer.Contains("<") && !currentBuffer.Contains(">")) return true; //> and no < will never happen, we will pass it on to the parser when we get to > //by default, don't block return false; }; </code></pre>

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