From a1c8aa4050b7f7a94e02dd40d8cd456f258b4e2b Mon Sep 17 00:00:00 2001
From: Adam Frisby
Date: Thu, 1 May 2008 15:36:39 +0000
Subject: * Cleaned namespaces of entire solution. OpenSim directories now
correspond with namespaces.
---
OpenSim/Framework/Communications/RestClient.cs | 368 +++++++++++++++++++++++++
1 file changed, 368 insertions(+)
create mode 100644 OpenSim/Framework/Communications/RestClient.cs
(limited to 'OpenSim/Framework/Communications/RestClient.cs')
diff --git a/OpenSim/Framework/Communications/RestClient.cs b/OpenSim/Framework/Communications/RestClient.cs
new file mode 100644
index 0000000..91284e8
--- /dev/null
+++ b/OpenSim/Framework/Communications/RestClient.cs
@@ -0,0 +1,368 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Net;
+using System.Reflection;
+using System.Text;
+using System.Threading;
+using System.Web;
+using log4net;
+
+namespace OpenSim.Framework.Communications
+{
+ ///
+ /// Implementation of a generic REST client
+ ///
+ ///
+ /// 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.
+ ///
+ public class RestClient
+ {
+ private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
+
+ private string realuri;
+
+ #region member variables
+
+ ///
+ /// The base Uri of the web-service e.g. http://www.google.com
+ ///
+ private string _url;
+
+ ///
+ /// Path elements of the query
+ ///
+ private List _pathElements = new List();
+
+ ///
+ /// Parameter elements of the query, e.g. min=34
+ ///
+ private Dictionary _parameterElements = new Dictionary();
+
+ ///
+ /// Request method. E.g. GET, POST, PUT or DELETE
+ ///
+ private string _method;
+
+ ///
+ /// Temporary buffer used to store bytes temporarily as they come in from the server
+ ///
+ private byte[] _readbuf;
+
+ ///
+ /// MemoryStream representing the resultiong resource
+ ///
+ private Stream _resource;
+
+ ///
+ /// WebRequest object, held as a member variable
+ ///
+ private HttpWebRequest _request;
+
+ ///
+ /// WebResponse object, held as a member variable, so we can close it
+ ///
+ private HttpWebResponse _response;
+
+ ///
+ /// This flag will help block the main synchroneous method, in case we run in synchroneous mode
+ ///
+ public static ManualResetEvent _allDone = new ManualResetEvent(false);
+
+ ///
+ /// Default time out period
+ ///
+ private const int DefaultTimeout = 10*1000; // 10 seconds timeout
+
+ ///
+ /// Default Buffer size of a block requested from the web-server
+ ///
+ private const int BufferSize = 4096; // Read blocks of 4 KB.
+
+
+ ///
+ /// if an exception occours during async processing, we need to save it, so it can be
+ /// rethrown on the primary thread;
+ ///
+ private Exception _asyncException;
+
+ #endregion member variables
+
+ #region constructors
+
+ ///
+ /// Instantiate a new RestClient
+ ///
+ /// Web-service to query, e.g. http://osgrid.org:8003
+ public RestClient(string url)
+ {
+ _url = url;
+ _readbuf = new byte[BufferSize];
+ _resource = new MemoryStream();
+ _request = null;
+ _response = null;
+ _lock = new object();
+ }
+
+ private object _lock;
+
+ #endregion constructors
+
+ ///
+ /// Add a path element to the query, e.g. assets
+ ///
+ /// path entry
+ public void AddResourcePath(string element)
+ {
+ if (isSlashed(element))
+ _pathElements.Add(element.Substring(0, element.Length - 1));
+ else
+ _pathElements.Add(element);
+ }
+
+ ///
+ /// Add a query parameter to the Url
+ ///
+ /// Name of the parameter, e.g. min
+ /// Value of the parameter, e.g. 42
+ public void AddQueryParameter(string name, string value)
+ {
+ _parameterElements.Add(HttpUtility.UrlEncode(name), HttpUtility.UrlEncode(value));
+ }
+
+ ///
+ /// Add a query parameter to the Url
+ ///
+ /// Name of the parameter, e.g. min
+ public void AddQueryParameter(string name)
+ {
+ _parameterElements.Add(HttpUtility.UrlEncode(name), null);
+ }
+
+ ///
+ /// Web-Request method, e.g. GET, PUT, POST, DELETE
+ ///
+ public string RequestMethod
+ {
+ get { return _method; }
+ set { _method = value; }
+ }
+
+ ///
+ /// True if string contains a trailing slash '/'
+ ///
+ /// string to be examined
+ /// true if slash is present
+ private bool isSlashed(string s)
+ {
+ return s.Substring(s.Length - 1, 1) == "/";
+ }
+
+ ///
+ /// Build a Uri based on the initial Url, path elements and parameters
+ ///
+ /// fully constructed Uri
+ private Uri buildUri()
+ {
+ StringBuilder sb = new StringBuilder();
+ sb.Append(_url);
+
+ foreach (string e in _pathElements)
+ {
+ sb.Append("/");
+ sb.Append(e);
+ }
+
+ bool firstElement = true;
+ foreach (KeyValuePair 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);
+ }
+ }
+ realuri = sb.ToString();
+ //m_log.InfoFormat("[REST CLIENT]: RestURL: {0}", realuri);
+ return new Uri(sb.ToString());
+ }
+
+ #region Async communications with server
+
+ ///
+ /// Async method, invoked when a block of data has been received from the service
+ ///
+ ///
+ private void StreamIsReadyDelegate(IAsyncResult ar)
+ {
+ try
+ {
+ Stream s = (Stream) ar.AsyncState;
+ int read = s.EndRead(ar);
+
+ 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);
+ }
+ else
+ {
+ s.Close();
+ _allDone.Set();
+ }
+ }
+ catch (Exception e)
+ {
+ _allDone.Set();
+ _asyncException = e;
+ }
+ }
+
+ #endregion Async communications with server
+
+ ///
+ /// Perform synchroneous request
+ ///
+ public Stream Request()
+ {
+ lock (_lock)
+ {
+ _request = (HttpWebRequest) WebRequest.Create(buildUri());
+ _request.KeepAlive = false;
+ _request.ContentType = "application/xml";
+ _request.Timeout = 200000;
+ _asyncException = null;
+
+// IAsyncResult responseAsyncResult = _request.BeginGetResponse(new AsyncCallback(ResponseIsReadyDelegate), _request);
+ _response = (HttpWebResponse) _request.GetResponse();
+ Stream src = _response.GetResponseStream();
+ int length = src.Read(_readbuf, 0, BufferSize);
+ while (length > 0)
+ {
+ _resource.Write(_readbuf, 0, length);
+ length = src.Read(_readbuf, 0, BufferSize);
+ }
+
+
+ // 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;
+
+ if (_resource != null)
+ {
+ _resource.Flush();
+ _resource.Seek(0, SeekOrigin.Begin);
+ }
+
+ return _resource;
+ }
+ }
+
+ public Stream Request(Stream src)
+ {
+ _request = (HttpWebRequest) WebRequest.Create(buildUri());
+ _request.KeepAlive = false;
+ _request.ContentType = "application/xml";
+ _request.Timeout = 900000;
+ _request.Method = RequestMethod;
+ _asyncException = null;
+ _request.ContentLength = src.Length;
+
+ m_log.InfoFormat("[REST]: Request Length {0}", _request.ContentLength);
+ m_log.InfoFormat("[REST]: Sending Web Request {0}", buildUri());
+ src.Seek(0, SeekOrigin.Begin);
+ m_log.Info("[REST]: Seek is ok");
+ Stream dst = _request.GetRequestStream();
+ m_log.Info("[REST]: GetRequestStream is ok");
+
+ byte[] buf = new byte[1024];
+ int length = src.Read(buf, 0, 1024);
+ m_log.Info("[REST]: First Read is ok");
+ while (length > 0)
+ {
+ dst.Write(buf, 0, length);
+ length = src.Read(buf, 0, 1024);
+ }
+
+ _response = (HttpWebResponse) _request.GetResponse();
+
+// 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);
+
+ return null;
+ }
+
+ #region Async Invocation
+
+ public IAsyncResult BeginRequest(AsyncCallback callback, object state)
+ {
+ ///
+ /// In case, we are invoked asynchroneously this object will keep track of the state
+ ///
+ AsyncResult ar = new AsyncResult(callback, state);
+ ThreadPool.QueueUserWorkItem(RequestHelper, ar);
+ return ar;
+ }
+
+ public Stream EndRequest(IAsyncResult asyncResult)
+ {
+ AsyncResult ar = (AsyncResult) 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 object
+ AsyncResult ar = (AsyncResult) 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
+ }
+}
\ No newline at end of file
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