corrade-vassal – Rev 1
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/*
* Copyright (c) 2006-2014, openmetaverse.org
* All rights reserved.
*
* - Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
* - Neither the name of the openmetaverse.org nor the names
* of its contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
using System;
using System.Net;
using System.Threading;
using OpenMetaverse.StructuredData;
namespace OpenMetaverse.Http
{
public class EventQueueClient
{
/// <summary>=</summary>
public const int REQUEST_TIMEOUT = 1000 * 120;
public delegate void ConnectedCallback();
public delegate void EventCallback(string eventName, OSDMap body);
public ConnectedCallback OnConnected;
public EventCallback OnEvent;
public bool Running { get { return _Running; } }
protected Uri _Address;
protected bool _Dead;
protected bool _Running;
protected HttpWebRequest _Request;
/// <summary>Number of times we've received an unknown CAPS exception in series.</summary>
private int _errorCount;
/// <summary>For exponential backoff on error.</summary>
private static Random _random = new Random();
public EventQueueClient(Uri eventQueueLocation)
{
_Address = eventQueueLocation;
}
public void Start()
{
_Dead = false;
// Create an EventQueueGet request
OSDMap request = new OSDMap();
request["ack"] = new OSD();
request["done"] = OSD.FromBoolean(false);
byte[] postData = OSDParser.SerializeLLSDXmlBytes(request);
_Request = CapsBase.UploadDataAsync(_Address, null, "application/xml", postData, REQUEST_TIMEOUT, OpenWriteHandler, null, RequestCompletedHandler);
}
public void Stop(bool immediate)
{
_Dead = true;
if (immediate)
_Running = false;
if (_Request != null)
_Request.Abort();
}
void OpenWriteHandler(HttpWebRequest request)
{
_Running = true;
_Request = request;
Logger.DebugLog("Capabilities event queue connected");
// The event queue is starting up for the first time
if (OnConnected != null)
{
try { OnConnected(); }
catch (Exception ex) { Logger.Log(ex.Message, Helpers.LogLevel.Error, ex); }
}
}
void RequestCompletedHandler(HttpWebRequest request, HttpWebResponse response, byte[] responseData, Exception error)
{
// We don't care about this request now that it has completed
_Request = null;
OSDArray events = null;
int ack = 0;
if (responseData != null)
{
_errorCount = 0;
// Got a response
OSDMap result = OSDParser.DeserializeLLSDXml(responseData) as OSDMap;
if (result != null)
{
events = result["events"] as OSDArray;
ack = result["id"].AsInteger();
}
else
{
Logger.Log("Got an unparseable response from the event queue: \"" +
System.Text.Encoding.UTF8.GetString(responseData) + "\"", Helpers.LogLevel.Warning);
}
}
else if (error != null)
{
#region Error handling
HttpStatusCode code = HttpStatusCode.OK;
if (error is WebException)
{
WebException webException = (WebException)error;
if (webException.Response != null)
code = ((HttpWebResponse)webException.Response).StatusCode;
else if (webException.Status == WebExceptionStatus.RequestCanceled)
goto HandlingDone;
}
if (error is WebException && ((WebException)error).Response != null)
code = ((HttpWebResponse)((WebException)error).Response).StatusCode;
if (code == HttpStatusCode.NotFound || code == HttpStatusCode.Gone)
{
Logger.Log(String.Format("Closing event queue at {0} due to missing caps URI", _Address), Helpers.LogLevel.Info);
_Running = false;
_Dead = true;
}
else if (code == HttpStatusCode.BadGateway)
{
// This is not good (server) protocol design, but it's normal.
// The EventQueue server is a proxy that connects to a Squid
// cache which will time out periodically. The EventQueue server
// interprets this as a generic error and returns a 502 to us
// that we ignore
}
else
{
++_errorCount;
// Try to log a meaningful error message
if (code != HttpStatusCode.OK)
{
Logger.Log(String.Format("Unrecognized caps connection problem from {0}: {1}",
_Address, code), Helpers.LogLevel.Warning);
}
else if (error.InnerException != null)
{
Logger.Log(String.Format("Unrecognized internal caps exception from {0}: {1}",
_Address, error.InnerException.Message), Helpers.LogLevel.Warning);
}
else
{
Logger.Log(String.Format("Unrecognized caps exception from {0}: {1}",
_Address, error.Message), Helpers.LogLevel.Warning);
}
}
#endregion Error handling
}
else
{
++_errorCount;
Logger.Log("No response from the event queue but no reported error either", Helpers.LogLevel.Warning);
}
HandlingDone:
#region Resume the connection
if (_Running)
{
OSDMap osdRequest = new OSDMap();
if (ack != 0) osdRequest["ack"] = OSD.FromInteger(ack);
else osdRequest["ack"] = new OSD();
osdRequest["done"] = OSD.FromBoolean(_Dead);
byte[] postData = OSDParser.SerializeLLSDXmlBytes(osdRequest);
if (_errorCount > 0) // Exponentially back off, so we don't hammer the CPU
Thread.Sleep(_random.Next(500 + (int)Math.Pow(2, _errorCount)));
// Resume the connection. The event handler for the connection opening
// just sets class _Request variable to the current HttpWebRequest
CapsBase.UploadDataAsync(_Address, null, "application/xml", postData, REQUEST_TIMEOUT,
delegate(HttpWebRequest newRequest) { _Request = newRequest; }, null, RequestCompletedHandler);
// If the event queue is dead at this point, turn it off since
// that was the last thing we want to do
if (_Dead)
{
_Running = false;
Logger.DebugLog("Sent event queue shutdown message");
}
}
#endregion Resume the connection
#region Handle incoming events
if (OnEvent != null && events != null && events.Count > 0)
{
// Fire callbacks for each event received
foreach (OSDMap evt in events)
{
string msg = evt["message"].AsString();
OSDMap body = (OSDMap)evt["body"];
try { OnEvent(msg, body); }
catch (Exception ex) { Logger.Log(ex.Message, Helpers.LogLevel.Error, ex); }
}
}
#endregion Handle incoming events
}
}
}