Created a generic RESTClient component, which simplifies querying for resources from REST based web-services.

Currently it supports a barebones scheme for specifying the path of the resource and querying asynchroneously. POST method is still wacky and a good solid scheme for handling timeout still remain.
author: Tleiades Hax 2007-10-25 09:26:47 +0000
committer: Tleiades Hax 2007-10-25 09:26:47 +0000
commit: 60e45418654975d27633a683b57c7013b98a23e3 (patch)
tree: 19e41032d405d29f203139f4c2ad62ac429fd1f1
parent: updated libode.so (no exception on assert) (diff)
download: opensim-SC-60e45418654975d27633a683b57c7013b98a23e3.zip
opensim-SC-60e45418654975d27633a683b57c7013b98a23e3.tar.gz
opensim-SC-60e45418654975d27633a683b57c7013b98a23e3.tar.bz2
opensim-SC-60e45418654975d27633a683b57c7013b98a23e3.tar.xz
3 files changed, 492 insertions, 0 deletions
diff --git a/OpenSim/Framework/Communications/RestClient/GenericAsyncResult.cs b/OpenSim/Framework/Communications/RestClient/GenericAsyncResult.cs
new file mode 100644
index 0000000..4be459d
--- /dev/null
+++ b/OpenSim/Framework/Communications/RestClient/GenericAsyncResult.cs
@@ -0,0 +1,163 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using System.Threading;
+namespace OpenSim.Framework.RestClient
+{
+    internal class SimpleAsyncResult : IAsyncResult
+    {
+        private readonly AsyncCallback m_callback;
+        /// <summary>
+        /// Is process completed?
+        /// </summary>
+        /// <remarks>Should really be boolean, but VolatileRead has no boolean method</remarks>
+        private byte m_completed;
+        /// <summary>
+        /// Did process complete synchroneously?
+        /// </summary>
+        /// <remarks>I have a hard time imagining a scenario where this is the case, again, same issue about
+        /// booleans and VolatileRead as m_completed
+        /// </remarks>
+        private byte m_completedSynchronously;
+        private readonly object m_asyncState;
+        private ManualResetEvent m_waitHandle;
+        private Exception m_exception;
+        internal SimpleAsyncResult(AsyncCallback cb, object state)
+        {
+            m_callback = cb;
+            m_asyncState = state;
+            m_completed = 0;
+            m_completedSynchronously = 1;
+        }
+        #region IAsyncResult Members
+        public object AsyncState
+        {
+            get { return m_asyncState; }
+        }
+        public WaitHandle AsyncWaitHandle
+        {
+            get
+            {
+                if (m_waitHandle == null)
+                {
+                    bool done = IsCompleted;
+                    ManualResetEvent mre = new ManualResetEvent(done);
+                    if (Interlocked.CompareExchange(ref m_waitHandle, mre, null) != null)
+                    {
+                        mre.Close();
+                    }
+                    else
+                    {
+                        if (!done && IsCompleted)
+                        {
+                            m_waitHandle.Set();
+                        }
+                    }
+                }
+                return m_waitHandle;
+            }
+        }
+        public bool CompletedSynchronously
+        {
+            get { return Thread.VolatileRead(ref m_completedSynchronously) == 1; }
+        }
+        public bool IsCompleted
+        {
+            get { return Thread.VolatileRead(ref m_completed) == 1; }
+        }
+        #endregion
+        #region class Methods
+        internal void SetAsCompleted(bool completedSynchronously)
+        {
+            m_completed = 1;
+            if(completedSynchronously)
+                m_completedSynchronously = 1;
+            else
+                m_completedSynchronously = 0;
+            
+            SignalCompletion();
+        }
+        internal void HandleException(Exception e, bool completedSynchronously)
+        {
+            m_completed = 1;
+            if (completedSynchronously)
+                m_completedSynchronously = 1;
+            else
+                m_completedSynchronously = 0;
+            m_exception = e;
+            SignalCompletion();
+        }
+        private void SignalCompletion()
+        {
+            if(m_waitHandle != null) m_waitHandle.Set();
+            if(m_callback != null) m_callback(this);
+        }
+        public void EndInvoke()
+        {
+            // This method assumes that only 1 thread calls EndInvoke 
+            if (!IsCompleted)
+            {
+                // If the operation isn't done, wait for it
+                AsyncWaitHandle.WaitOne();
+                AsyncWaitHandle.Close();
+                m_waitHandle = null;  // Allow early GC
+            }
+            // Operation is done: if an exception occured, throw it
+            if (m_exception != null) throw m_exception;
+        }       
+        #endregion 
+    }
+    internal class AsyncResult<T> : SimpleAsyncResult
+    {
+        private T m_result = default(T);
+        public AsyncResult(AsyncCallback asyncCallback, Object state) :
+            base(asyncCallback, state) { }
+        public void SetAsCompleted(T result,  bool completedSynchronously)
+        {
+            // Save the asynchronous operation's result
+            m_result = result;
+            // Tell the base class that the operation completed 
+            // sucessfully (no exception)
+            base.SetAsCompleted(completedSynchronously);
+        }
+        new public T EndInvoke()
+        {
+            base.EndInvoke(); 
+            return m_result;  
+        }
+    }
+}
diff --git a/OpenSim/Framework/Communications/RestClient/RestClient.cs b/OpenSim/Framework/Communications/RestClient/RestClient.cs
new file mode 100644
index 0000000..ccf8376
--- /dev/null
+++ b/OpenSim/Framework/Communications/RestClient/RestClient.cs
@@ -0,0 +1,328 @@
+using System;
+using System.IO;
+using System.Net;
+using System.Web;
+using System.Text;
+using System.Collections.Generic;
+using System.Threading;
+namespace OpenSim.Framework.RestClient
+{
+    /// <summary>
+    /// Implementation of a generic REST client
+    /// </summary>
+    /// <remarks>
+    /// This class is a generic implementation of a REST (Representational State Transfer) web service. This
+    /// class is designed to execute both synchroneously and asynchroneously.
+    /// 
+    /// Internally the implementation works as a two stage asynchroneous web-client.
+    /// When the request is initiated, RestClient will query asynchroneously for for a web-response,
+    /// sleeping until the initial response is returned by the server. Once the initial response is retrieved
+    /// the second stage of asynchroneous requests will be triggered, in an attempt to read of the response
+    /// object into a memorystream as a sequence of asynchroneous reads.
+    /// 
+    /// The asynchronisity of RestClient is designed to move as much processing into the back-ground, allowing 
+    /// other threads to execute, while it waits for a response from the web-service. RestClient it self, can be
+    /// invoked by the caller in either synchroneous mode or asynchroneous mode.
+    /// </remarks>
+    public class RestClient 
+    {
+        /// <summary>
+        /// The base Uri of the web-service e.g. http://www.google.com 
+        /// </summary>
+        private string _url;
+        /// <summary>
+        /// Path elements of the query
+        /// </summary>
+        private List<string> _pathElements = new List<string>();
+        /// <summary>
+        /// Parameter elements of the query, e.g. min=34
+        /// </summary>
+        private Dictionary<string, string> _parameterElements = new Dictionary<string, string>();
+        /// <summary>
+        /// Request method. E.g. GET, POST, PUT or DELETE
+        /// </summary>
+        private string _method;
+        /// <summary>
+        /// Temporary buffer used to store bytes temporarily as they come in from the server
+        /// </summary>
+        private byte[] _readbuf;
+        /// <summary>
+        /// MemoryStream representing the resultiong resource
+        /// </summary>
+        MemoryStream _resource;
+        /// <summary>
+        /// WebRequest object, held as a member variable
+        /// </summary>
+        private HttpWebRequest _request;
+        /// <summary>
+        /// WebResponse object, held as a member variable, so we can close it
+        /// </summary>
+        private HttpWebResponse _response;
+        /// <summary>
+        /// This flag will help block the main synchroneous method, in case we run in synchroneous mode
+        /// </summary>
+        public static ManualResetEvent _allDone = new ManualResetEvent(false);
+        /// <summary>
+        /// Default time out period
+        /// </summary>
+        const int DefaultTimeout = 10 * 1000; // 10 seconds timeout
+        /// <summary>
+        /// Default Buffer size of a block requested from the web-server
+        /// </summary>
+        const int BufferSize = 4096; // Read blocks of 4 KB.
+        /// <summary>
+        /// if an exception occours during async processing, we need to save it, so it can be 
+        /// rethrown on the primary thread;
+        /// </summary>
+        private Exception _asyncException;
+        /// <summary>
+        /// Instantiate a new RestClient
+        /// </summary>
+        /// <param name="url">Web-service to query, e.g. http://osgrid.org:8003</param>
+        public RestClient(string url)
+        {
+            _url = url;
+            _readbuf = new byte[BufferSize];
+            _resource = new MemoryStream();
+            _request = null;
+            _response = null;
+        }
+        /// <summary>
+        /// Add a path element to the query, e.g. assets
+        /// </summary>
+        /// <param name="element">path entry</param>
+        public void AddResourcePath(string element)
+        {
+            if(isSlashed(element))
+                _pathElements.Add(element.Substring(0, element.Length-1));
+            else
+                _pathElements.Add(element);
+        }
+        /// <summary>
+        /// Add a query parameter to the Url
+        /// </summary>
+        /// <param name="name">Name of the parameter, e.g. min</param>
+        /// <param name="value">Value of the parameter, e.g. 42</param>
+        public void AddQueryParameter(string name, string value)
+        {
+            _parameterElements.Add(HttpUtility.UrlEncode(name), HttpUtility.UrlEncode(value));
+        }
+        /// <summary>
+        /// Web-Request method, e.g. GET, PUT, POST, DELETE
+        /// </summary>
+        public string RequestMethod
+        {
+            get { return _method; }
+            set { _method = value; }
+        }
+        /// <summary>
+        /// True if string contains a trailing slash '/'
+        /// </summary>
+        /// <param name="s">string to be examined</param>
+        /// <returns>true if slash is present</returns>
+        private bool isSlashed(string s)
+        {
+            return s.Substring(s.Length - 1, 1) == "/";
+        }
+        /// <summary>
+        /// return a slash or blank. A slash will be returned if the string does not contain one
+        /// </summary>
+        /// <param name="s">stromg to be examined</param>
+        /// <returns>slash '/' if not already present</returns>
+        private string slash(string s)
+        {
+            return isSlashed(s) ? "" : "/";
+        }
+        /// <summary>
+        /// Build a Uri based on the intial Url, path elements and parameters
+        /// </summary>
+        /// <returns>fully constructed Uri</returns>
+        Uri buildUri()
+        {
+            StringBuilder sb = new StringBuilder();
+            sb.Append(_url);
+            foreach (string e in _pathElements)
+            {
+                sb.Append("/");
+                sb.Append(e);
+            }
+            bool firstElement = true;
+            foreach (KeyValuePair<string, string> kv in _parameterElements)
+            {
+                if (firstElement)
+                {
+                    sb.Append("?");
+                    firstElement = false;
+                } else
+                    sb.Append("&");
+                sb.Append(kv.Key);
+                if (kv.Value != null && kv.Value.Length != 0)
+                {
+                    sb.Append("=");
+                    sb.Append(kv.Value);
+                }
+            }
+            return new Uri(sb.ToString());
+        }
+        /// <summary>
+        /// Async method, invoked when a block of data has been received from the service
+        /// </summary>
+        /// <param name="ar"></param>
+        private void StreamIsReadyDelegate(IAsyncResult ar)
+        {
+            try
+            {
+                Stream s = (Stream)ar.AsyncState;
+                int read = s.EndRead(ar);
+                // Read the HTML page and then print it to the console.
+                if (read > 0)
+                {
+                    _resource.Write(_readbuf, 0, read);
+                    IAsyncResult asynchronousResult = s.BeginRead(_readbuf, 0, BufferSize, new AsyncCallback(StreamIsReadyDelegate), s);
+                    // TODO! Implement timeout, without killing the server
+                    //ThreadPool.RegisterWaitForSingleObject(asynchronousResult.AsyncWaitHandle, new WaitOrTimerCallback(TimeoutCallback), _request, DefaultTimeout, true);
+                    return;
+                }
+                else
+                {
+                    s.Close();
+                    _allDone.Set();
+                }
+            }
+            catch (Exception e)
+            {
+                _allDone.Set();
+                _asyncException = e;
+            }
+        }
+        /// <summary>
+        /// Async method, invoked when the intial response if received from the server
+        /// </summary>
+        /// <param name="ar"></param>
+        private void ResponseIsReadyDelegate(IAsyncResult ar)
+        {
+            try
+            {
+                // grab response
+                WebRequest wr = (WebRequest)ar.AsyncState;
+                _response = (HttpWebResponse)wr.EndGetResponse(ar);
+                // get response stream, and setup async reading
+                Stream s = _response.GetResponseStream();
+                IAsyncResult asynchronousResult = s.BeginRead(_readbuf, 0, BufferSize, new AsyncCallback(StreamIsReadyDelegate), s);
+                // TODO! Implement timeout, without killing the server
+                // wait until completed, or we timed out
+                // ThreadPool.RegisterWaitForSingleObject(asynchronousResult.AsyncWaitHandle, new WaitOrTimerCallback(TimeoutCallback), _request, DefaultTimeout, true);
+            }
+            catch (Exception e)
+            {
+                _allDone.Set();
+                _asyncException = e;
+            }
+        }
+        // Abort the request if the timer fires.
+        private static void TimeoutCallback(object state, bool timedOut)
+        {
+            if (timedOut)
+            {
+                HttpWebRequest request = state as HttpWebRequest;
+                if (request != null)
+                {
+                    request.Abort();
+                }
+            }
+        }
+        /// <summary>
+        /// Perform synchroneous request
+        /// </summary>
+        public Stream Request()
+        {
+            _request = (HttpWebRequest)WebRequest.Create(buildUri());
+            _request.KeepAlive = false;
+            _request.ContentType = "text/html";
+            _request.Timeout = 200;
+            _asyncException = null;
+            IAsyncResult responseAsyncResult = _request.BeginGetResponse(new AsyncCallback(ResponseIsReadyDelegate), _request);
+            // TODO! Implement timeout, without killing the server
+            // this line implements the timeout, if there is a timeout, the callback fires and the request becomes aborted
+            //ThreadPool.RegisterWaitForSingleObject(responseAsyncResult.AsyncWaitHandle, new WaitOrTimerCallback(TimeoutCallback), _request, DefaultTimeout, true);
+            _allDone.WaitOne();
+            if(_response != null)
+                _response.Close();
+            if (_asyncException != null)
+                throw _asyncException;
+            return _resource;
+        }
+        #region Async Invocation
+        public IAsyncResult BeginRequest(AsyncCallback callback, object state)
+        {
+            /// <summary>
+            /// In case, we are invoked asynchroneously this object will keep track of the state
+            /// </summary>
+            AsyncResult<Stream> ar = new AsyncResult<Stream>(callback, state);
+            ThreadPool.QueueUserWorkItem(RequestHelper, ar);
+            return ar;
+        }
+        public Stream EndRequest(IAsyncResult asyncResult)
+        {
+            AsyncResult<Stream> ar = (AsyncResult<Stream>)asyncResult;
+            // Wait for operation to complete, then return result or 
+            // throw exception
+            return ar.EndInvoke();
+        }
+        private void RequestHelper(Object asyncResult)
+        {
+            // We know that it's really an AsyncResult<DateTime> object
+            AsyncResult<Stream> ar = (AsyncResult<Stream>)asyncResult;
+            try
+            {
+                // Perform the operation; if sucessful set the result
+                Stream s = Request();
+                ar.SetAsCompleted(s, false);
+            }
+            catch (Exception e)
+            {
+                // If operation fails, set the exception
+                ar.HandleException(e, false);
+            }
+        }
+        #endregion Async Invocation
+    }
+}
diff --git a/prebuild.xml b/prebuild.xml
index 536d650..57ace78 100644
--- a/prebuild.xml
+++ b/prebuild.xml
@@ -376,6 +376,7 @@
      <ReferencePath>../../../bin/</ReferencePath>
      <Reference name="System"/>
      <Reference name="System.Xml"/>
+      <Reference name="System.Web"/>
      <Reference name="OpenSim.Framework"/>
      <Reference name="OpenSim.Framework.Data" />
      <Reference name="OpenSim.Framework.Servers"/>
author	Tleiades Hax	2007-10-25 09:26:47 +0000
committer	Tleiades Hax	2007-10-25 09:26:47 +0000
commit	60e45418654975d27633a683b57c7013b98a23e3 (patch)
tree	19e41032d405d29f203139f4c2ad62ac429fd1f1
parent	updated libode.so (no exception on assert) (diff)
download	opensim-SC-60e45418654975d27633a683b57c7013b98a23e3.zip opensim-SC-60e45418654975d27633a683b57c7013b98a23e3.tar.gz opensim-SC-60e45418654975d27633a683b57c7013b98a23e3.tar.bz2 opensim-SC-60e45418654975d27633a683b57c7013b98a23e3.tar.xz

diff --git a/OpenSim/Framework/Communications/RestClient/GenericAsyncResult.cs b/OpenSim/Framework/Communications/RestClient/GenericAsyncResult.cs new file mode 100644 index 0000000..4be459d --- /dev/null +++ b/OpenSim/Framework/Communications/RestClient/GenericAsyncResult.cs
@@ -0,0 +1,163 @@
		1	using System;
		2	using System.Collections.Generic;
		3	using System.Text;
		4	using System.Threading;
		5
		6	namespace OpenSim.Framework.RestClient
		7	{
		8	internal class SimpleAsyncResult : IAsyncResult
		9	{
		10
		11	private readonly AsyncCallback m_callback;
		12
		13	/// <summary>
		14	/// Is process completed?
		15	/// </summary>
		16	/// <remarks>Should really be boolean, but VolatileRead has no boolean method</remarks>
		17	private byte m_completed;
		18
		19	/// <summary>
		20	/// Did process complete synchroneously?
		21	/// </summary>
		22	/// <remarks>I have a hard time imagining a scenario where this is the case, again, same issue about
		23	/// booleans and VolatileRead as m_completed
		24	/// </remarks>
		25	private byte m_completedSynchronously;
		26
		27	private readonly object m_asyncState;
		28	private ManualResetEvent m_waitHandle;
		29	private Exception m_exception;
		30
		31	internal SimpleAsyncResult(AsyncCallback cb, object state)
		32	{
		33	m_callback = cb;
		34	m_asyncState = state;
		35	m_completed = 0;
		36	m_completedSynchronously = 1;
		37	}
		38
		39
		40	#region IAsyncResult Members
		41
		42	public object AsyncState
		43	{
		44	get { return m_asyncState; }
		45	}
		46
		47
		48
		49	public WaitHandle AsyncWaitHandle
		50	{
		51	get
		52	{
		53	if (m_waitHandle == null)
		54	{
		55	bool done = IsCompleted;
		56	ManualResetEvent mre = new ManualResetEvent(done);
		57	if (Interlocked.CompareExchange(ref m_waitHandle, mre, null) != null)
		58	{
		59	mre.Close();
		60	}
		61	else
		62	{
		63	if (!done && IsCompleted)
		64	{
		65	m_waitHandle.Set();
		66	}
		67	}
		68	}
		69	return m_waitHandle;
		70	}
		71	}
		72
		73
		74	public bool CompletedSynchronously
		75	{
		76	get { return Thread.VolatileRead(ref m_completedSynchronously) == 1; }
		77	}
		78
		79
		80	public bool IsCompleted
		81	{
		82	get { return Thread.VolatileRead(ref m_completed) == 1; }
		83	}
		84
		85
		86	#endregion
		87
		88
		89	#region class Methods
		90	internal void SetAsCompleted(bool completedSynchronously)
		91	{
		92	m_completed = 1;
		93	if(completedSynchronously)
		94	m_completedSynchronously = 1;
		95	else
		96	m_completedSynchronously = 0;
		97
		98	SignalCompletion();
		99	}
		100
		101	internal void HandleException(Exception e, bool completedSynchronously)
		102	{
		103	m_completed = 1;
		104	if (completedSynchronously)
		105	m_completedSynchronously = 1;
		106	else
		107	m_completedSynchronously = 0;
		108	m_exception = e;
		109
		110	SignalCompletion();
		111	}
		112
		113	private void SignalCompletion()
		114	{
		115	if(m_waitHandle != null) m_waitHandle.Set();
		116
		117	if(m_callback != null) m_callback(this);
		118	}
		119
		120	public void EndInvoke()
		121	{
		122	// This method assumes that only 1 thread calls EndInvoke
		123	if (!IsCompleted)
		124	{
		125	// If the operation isn't done, wait for it
		126	AsyncWaitHandle.WaitOne();
		127	AsyncWaitHandle.Close();
		128	m_waitHandle = null; // Allow early GC
		129	}
		130
		131	// Operation is done: if an exception occured, throw it
		132	if (m_exception != null) throw m_exception;
		133	}
		134
		135	#endregion
		136	}
		137
		138	internal class AsyncResult<T> : SimpleAsyncResult
		139	{
		140	private T m_result = default(T);
		141
		142	public AsyncResult(AsyncCallback asyncCallback, Object state) :
		143	base(asyncCallback, state) { }
		144
		145
		146	public void SetAsCompleted(T result, bool completedSynchronously)
		147	{
		148	// Save the asynchronous operation's result
		149	m_result = result;
		150
		151	// Tell the base class that the operation completed
		152	// sucessfully (no exception)
		153	base.SetAsCompleted(completedSynchronously);
		154	}
		155
		156	new public T EndInvoke()
		157	{
		158	base.EndInvoke();
		159	return m_result;
		160	}
		161
		162	}
		163	}


diff --git a/OpenSim/Framework/Communications/RestClient/RestClient.cs b/OpenSim/Framework/Communications/RestClient/RestClient.cs new file mode 100644 index 0000000..ccf8376 --- /dev/null +++ b/OpenSim/Framework/Communications/RestClient/RestClient.cs
@@ -0,0 +1,328 @@
		1	using System;
		2	using System.IO;
		3	using System.Net;
		4	using System.Web;
		5	using System.Text;
		6	using System.Collections.Generic;
		7	using System.Threading;
		8
		9	namespace OpenSim.Framework.RestClient
		10	{
		11	/// <summary>
		12	/// Implementation of a generic REST client
		13	/// </summary>
		14	/// <remarks>
		15	/// This class is a generic implementation of a REST (Representational State Transfer) web service. This
		16	/// class is designed to execute both synchroneously and asynchroneously.
		17	///
		18	/// Internally the implementation works as a two stage asynchroneous web-client.
		19	/// When the request is initiated, RestClient will query asynchroneously for for a web-response,
		20	/// sleeping until the initial response is returned by the server. Once the initial response is retrieved
		21	/// the second stage of asynchroneous requests will be triggered, in an attempt to read of the response
		22	/// object into a memorystream as a sequence of asynchroneous reads.
		23	///
		24	/// The asynchronisity of RestClient is designed to move as much processing into the back-ground, allowing
		25	/// other threads to execute, while it waits for a response from the web-service. RestClient it self, can be
		26	/// invoked by the caller in either synchroneous mode or asynchroneous mode.
		27	/// </remarks>
		28	public class RestClient
		29	{
		30	/// <summary>
		31	/// The base Uri of the web-service e.g. http://www.google.com
		32	/// </summary>
		33	private string _url;
		34
		35	/// <summary>
		36	/// Path elements of the query
		37	/// </summary>
		38	private List<string> _pathElements = new List<string>();
		39
		40	/// <summary>
		41	/// Parameter elements of the query, e.g. min=34
		42	/// </summary>
		43	private Dictionary<string, string> _parameterElements = new Dictionary<string, string>();
		44
		45	/// <summary>
		46	/// Request method. E.g. GET, POST, PUT or DELETE
		47	/// </summary>
		48	private string _method;
		49
		50	/// <summary>
		51	/// Temporary buffer used to store bytes temporarily as they come in from the server
		52	/// </summary>
		53	private byte[] _readbuf;
		54
		55	/// <summary>
		56	/// MemoryStream representing the resultiong resource
		57	/// </summary>
		58	MemoryStream _resource;
		59
		60	/// <summary>
		61	/// WebRequest object, held as a member variable
		62	/// </summary>
		63	private HttpWebRequest _request;
		64
		65	/// <summary>
		66	/// WebResponse object, held as a member variable, so we can close it
		67	/// </summary>
		68	private HttpWebResponse _response;
		69
		70	/// <summary>
		71	/// This flag will help block the main synchroneous method, in case we run in synchroneous mode
		72	/// </summary>
		73	public static ManualResetEvent _allDone = new ManualResetEvent(false);
		74
		75	/// <summary>
		76	/// Default time out period
		77	/// </summary>
		78	const int DefaultTimeout = 10 * 1000; // 10 seconds timeout
		79
		80	/// <summary>
		81	/// Default Buffer size of a block requested from the web-server
		82	/// </summary>
		83	const int BufferSize = 4096; // Read blocks of 4 KB.
		84
		85
		86	/// <summary>
		87	/// if an exception occours during async processing, we need to save it, so it can be
		88	/// rethrown on the primary thread;
		89	/// </summary>
		90	private Exception _asyncException;
		91
		92	/// <summary>
		93	/// Instantiate a new RestClient
		94	/// </summary>
		95	/// <param name="url">Web-service to query, e.g. http://osgrid.org:8003</param>
		96	public RestClient(string url)
		97	{
		98	_url = url;
		99	_readbuf = new byte[BufferSize];
		100	_resource = new MemoryStream();
		101	_request = null;
		102	_response = null;
		103	}
		104
		105	/// <summary>
		106	/// Add a path element to the query, e.g. assets
		107	/// </summary>
		108	/// <param name="element">path entry</param>
		109	public void AddResourcePath(string element)
		110	{
		111	if(isSlashed(element))
		112	_pathElements.Add(element.Substring(0, element.Length-1));
		113	else
		114	_pathElements.Add(element);
		115	}
		116
		117	/// <summary>
		118	/// Add a query parameter to the Url
		119	/// </summary>
		120	/// <param name="name">Name of the parameter, e.g. min</param>
		121	/// <param name="value">Value of the parameter, e.g. 42</param>
		122	public void AddQueryParameter(string name, string value)
		123	{
		124	_parameterElements.Add(HttpUtility.UrlEncode(name), HttpUtility.UrlEncode(value));
		125	}
		126
		127	/// <summary>
		128	/// Web-Request method, e.g. GET, PUT, POST, DELETE
		129	/// </summary>
		130	public string RequestMethod
		131	{
		132	get { return _method; }
		133	set { _method = value; }
		134	}
		135
		136	/// <summary>
		137	/// True if string contains a trailing slash '/'
		138	/// </summary>
		139	/// <param name="s">string to be examined</param>
		140	/// <returns>true if slash is present</returns>
		141	private bool isSlashed(string s)
		142	{
		143	return s.Substring(s.Length - 1, 1) == "/";
		144	}
		145
		146	/// <summary>
		147	/// return a slash or blank. A slash will be returned if the string does not contain one
		148	/// </summary>
		149	/// <param name="s">stromg to be examined</param>
		150	/// <returns>slash '/' if not already present</returns>
		151	private string slash(string s)
		152	{
		153	return isSlashed(s) ? "" : "/";
		154	}
		155
		156	/// <summary>
		157	/// Build a Uri based on the intial Url, path elements and parameters
		158	/// </summary>
		159	/// <returns>fully constructed Uri</returns>
		160	Uri buildUri()
		161	{
		162	StringBuilder sb = new StringBuilder();
		163	sb.Append(_url);
		164
		165	foreach (string e in _pathElements)
		166	{
		167	sb.Append("/");
		168	sb.Append(e);
		169	}
		170
		171	bool firstElement = true;
		172	foreach (KeyValuePair<string, string> kv in _parameterElements)
		173	{
		174	if (firstElement)
		175	{
		176	sb.Append("?");
		177	firstElement = false;
		178	} else
		179	sb.Append("&");
		180
		181	sb.Append(kv.Key);
		182	if (kv.Value != null && kv.Value.Length != 0)
		183	{
		184	sb.Append("=");
		185	sb.Append(kv.Value);
		186	}
		187	}
		188	return new Uri(sb.ToString());
		189	}
		190
		191	/// <summary>
		192	/// Async method, invoked when a block of data has been received from the service
		193	/// </summary>
		194	/// <param name="ar"></param>
		195	private void StreamIsReadyDelegate(IAsyncResult ar)
		196	{
		197	try
		198	{
		199	Stream s = (Stream)ar.AsyncState;
		200	int read = s.EndRead(ar);
		201
		202	// Read the HTML page and then print it to the console.
		203	if (read > 0)
		204	{
		205	_resource.Write(_readbuf, 0, read);
		206	IAsyncResult asynchronousResult = s.BeginRead(_readbuf, 0, BufferSize, new AsyncCallback(StreamIsReadyDelegate), s);
		207
		208	// TODO! Implement timeout, without killing the server
		209	//ThreadPool.RegisterWaitForSingleObject(asynchronousResult.AsyncWaitHandle, new WaitOrTimerCallback(TimeoutCallback), _request, DefaultTimeout, true);
		210	return;
		211	}
		212	else
		213	{
		214	s.Close();
		215	_allDone.Set();
		216	}
		217	}
		218	catch (Exception e)
		219	{
		220	_allDone.Set();
		221	_asyncException = e;
		222	}
		223	}
		224
		225	/// <summary>
		226	/// Async method, invoked when the intial response if received from the server
		227	/// </summary>
		228	/// <param name="ar"></param>
		229	private void ResponseIsReadyDelegate(IAsyncResult ar)
		230	{
		231	try
		232	{
		233	// grab response
		234	WebRequest wr = (WebRequest)ar.AsyncState;
		235	_response = (HttpWebResponse)wr.EndGetResponse(ar);
		236
		237	// get response stream, and setup async reading
		238	Stream s = _response.GetResponseStream();
		239	IAsyncResult asynchronousResult = s.BeginRead(_readbuf, 0, BufferSize, new AsyncCallback(StreamIsReadyDelegate), s);
		240
		241	// TODO! Implement timeout, without killing the server
		242	// wait until completed, or we timed out
		243	// ThreadPool.RegisterWaitForSingleObject(asynchronousResult.AsyncWaitHandle, new WaitOrTimerCallback(TimeoutCallback), _request, DefaultTimeout, true);
		244	}
		245	catch (Exception e)
		246	{
		247	_allDone.Set();
		248	_asyncException = e;
		249	}
		250	}
		251
		252	// Abort the request if the timer fires.
		253	private static void TimeoutCallback(object state, bool timedOut)
		254	{
		255	if (timedOut)
		256	{
		257	HttpWebRequest request = state as HttpWebRequest;
		258	if (request != null)
		259	{
		260	request.Abort();
		261	}
		262	}
		263	}
		264
		265	/// <summary>
		266	/// Perform synchroneous request
		267	/// </summary>
		268	public Stream Request()
		269	{
		270	_request = (HttpWebRequest)WebRequest.Create(buildUri());
		271	_request.KeepAlive = false;
		272	_request.ContentType = "text/html";
		273	_request.Timeout = 200;
		274	_asyncException = null;
		275
		276	IAsyncResult responseAsyncResult = _request.BeginGetResponse(new AsyncCallback(ResponseIsReadyDelegate), _request);
		277
		278	// TODO! Implement timeout, without killing the server
		279	// this line implements the timeout, if there is a timeout, the callback fires and the request becomes aborted
		280	//ThreadPool.RegisterWaitForSingleObject(responseAsyncResult.AsyncWaitHandle, new WaitOrTimerCallback(TimeoutCallback), _request, DefaultTimeout, true);
		281
		282	_allDone.WaitOne();
		283	if(_response != null)
		284	_response.Close();
		285	if (_asyncException != null)
		286	throw _asyncException;
		287	return _resource;
		288	}
		289
		290	#region Async Invocation
		291	public IAsyncResult BeginRequest(AsyncCallback callback, object state)
		292	{
		293	/// <summary>
		294	/// In case, we are invoked asynchroneously this object will keep track of the state
		295	/// </summary>
		296	AsyncResult<Stream> ar = new AsyncResult<Stream>(callback, state);
		297	ThreadPool.QueueUserWorkItem(RequestHelper, ar);
		298	return ar;
		299	}
		300
		301	public Stream EndRequest(IAsyncResult asyncResult)
		302	{
		303	AsyncResult<Stream> ar = (AsyncResult<Stream>)asyncResult;
		304
		305	// Wait for operation to complete, then return result or
		306	// throw exception
		307	return ar.EndInvoke();
		308	}
		309
		310	private void RequestHelper(Object asyncResult)
		311	{
		312	// We know that it's really an AsyncResult<DateTime> object
		313	AsyncResult<Stream> ar = (AsyncResult<Stream>)asyncResult;
		314	try
		315	{
		316	// Perform the operation; if sucessful set the result
		317	Stream s = Request();
		318	ar.SetAsCompleted(s, false);
		319	}
		320	catch (Exception e)
		321	{
		322	// If operation fails, set the exception
		323	ar.HandleException(e, false);
		324	}
		325	}
		326	#endregion Async Invocation
		327	}
		328	}


diff --git a/prebuild.xml b/prebuild.xml index 536d650..57ace78 100644 --- a/prebuild.xml +++ b/prebuild.xml
@@ -376,6 +376,7 @@
376	<ReferencePath>../../../bin/</ReferencePath>	376	<ReferencePath>../../../bin/</ReferencePath>
377	<Reference name="System"/>	377	<Reference name="System"/>
378	<Reference name="System.Xml"/>	378	<Reference name="System.Xml"/>
		379	<Reference name="System.Web"/>
379	<Reference name="OpenSim.Framework"/>	380	<Reference name="OpenSim.Framework"/>
380	<Reference name="OpenSim.Framework.Data" />	381	<Reference name="OpenSim.Framework.Data" />
381	<Reference name="OpenSim.Framework.Servers"/>	382	<Reference name="OpenSim.Framework.Servers"/>