opensim – Blame information for rev 1
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1 | eva | 1 | /* |
2 | * Copyright (c) Contributors, http://opensimulator.org/ |
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3 | * See CONTRIBUTORS.TXT for a full list of copyright holders. |
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4 | * |
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5 | * Redistribution and use in source and binary forms, with or without |
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6 | * modification, are permitted provided that the following conditions are met: |
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7 | * * Redistributions of source code must retain the above copyright |
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8 | * notice, this list of conditions and the following disclaimer. |
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9 | * * Redistributions in binary form must reproduce the above copyright |
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10 | * notice, this list of conditions and the following disclaimer in the |
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11 | * documentation and/or other materials provided with the distribution. |
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12 | * * Neither the name of the OpenSimulator Project nor the |
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13 | * names of its contributors may be used to endorse or promote products |
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14 | * derived from this software without specific prior written permission. |
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15 | * |
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16 | * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY |
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17 | * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
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18 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
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19 | * DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY |
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20 | * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
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21 | * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
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22 | * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
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23 | * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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24 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
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25 | * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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26 | */ |
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27 | |||
28 | using System; |
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29 | using System.Collections.Generic; |
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30 | using System.IO; |
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31 | using System.Net; |
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32 | using System.Reflection; |
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33 | using System.Text; |
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34 | using System.Threading; |
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35 | using System.Web; |
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36 | using log4net; |
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37 | |||
38 | namespace OpenSim.Framework.Communications |
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39 | { |
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40 | /// <summary> |
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41 | /// Implementation of a generic REST client |
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42 | /// </summary> |
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43 | /// <remarks> |
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44 | /// This class is a generic implementation of a REST (Representational State Transfer) web service. This |
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45 | /// class is designed to execute both synchronously and asynchronously. |
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46 | /// |
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47 | /// Internally the implementation works as a two stage asynchronous web-client. |
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48 | /// When the request is initiated, RestClient will query asynchronously for for a web-response, |
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49 | /// sleeping until the initial response is returned by the server. Once the initial response is retrieved |
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50 | /// the second stage of asynchronous requests will be triggered, in an attempt to read of the response |
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51 | /// object into a memorystream as a sequence of asynchronous reads. |
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52 | /// |
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53 | /// The asynchronisity of RestClient is designed to move as much processing into the back-ground, allowing |
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54 | /// other threads to execute, while it waits for a response from the web-service. RestClient itself can be |
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55 | /// invoked by the caller in either synchronous mode or asynchronous modes. |
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56 | /// </remarks> |
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57 | public class RestClient |
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58 | { |
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59 | private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType); |
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60 | |||
61 | // private string realuri; |
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62 | |||
63 | #region member variables |
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64 | |||
65 | /// <summary> |
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66 | /// The base Uri of the web-service e.g. http://www.google.com |
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67 | /// </summary> |
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68 | private string _url; |
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69 | |||
70 | /// <summary> |
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71 | /// Path elements of the query |
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72 | /// </summary> |
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73 | private List<string> _pathElements = new List<string>(); |
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74 | |||
75 | /// <summary> |
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76 | /// Parameter elements of the query, e.g. min=34 |
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77 | /// </summary> |
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78 | private Dictionary<string, string> _parameterElements = new Dictionary<string, string>(); |
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79 | |||
80 | /// <summary> |
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81 | /// Request method. E.g. GET, POST, PUT or DELETE |
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82 | /// </summary> |
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83 | private string _method; |
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84 | |||
85 | /// <summary> |
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86 | /// Temporary buffer used to store bytes temporarily as they come in from the server |
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87 | /// </summary> |
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88 | private byte[] _readbuf; |
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89 | |||
90 | /// <summary> |
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91 | /// MemoryStream representing the resultiong resource |
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92 | /// </summary> |
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93 | private Stream _resource; |
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94 | |||
95 | /// <summary> |
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96 | /// WebRequest object, held as a member variable |
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97 | /// </summary> |
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98 | private HttpWebRequest _request; |
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99 | |||
100 | /// <summary> |
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101 | /// WebResponse object, held as a member variable, so we can close it |
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102 | /// </summary> |
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103 | private HttpWebResponse _response; |
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104 | |||
105 | /// <summary> |
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106 | /// This flag will help block the main synchroneous method, in case we run in synchroneous mode |
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107 | /// </summary> |
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108 | //public static ManualResetEvent _allDone = new ManualResetEvent(false); |
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109 | |||
110 | /// <summary> |
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111 | /// Default time out period |
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112 | /// </summary> |
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113 | //private const int DefaultTimeout = 10*1000; // 10 seconds timeout |
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114 | |||
115 | /// <summary> |
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116 | /// Default Buffer size of a block requested from the web-server |
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117 | /// </summary> |
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118 | private const int BufferSize = 4096; // Read blocks of 4 KB. |
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119 | |||
120 | |||
121 | /// <summary> |
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122 | /// if an exception occours during async processing, we need to save it, so it can be |
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123 | /// rethrown on the primary thread; |
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124 | /// </summary> |
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125 | private Exception _asyncException; |
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126 | |||
127 | #endregion member variables |
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128 | |||
129 | #region constructors |
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130 | |||
131 | /// <summary> |
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132 | /// Instantiate a new RestClient |
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133 | /// </summary> |
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134 | /// <param name="url">Web-service to query, e.g. http://osgrid.org:8003</param> |
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135 | public RestClient(string url) |
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136 | { |
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137 | _url = url; |
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138 | _readbuf = new byte[BufferSize]; |
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139 | _resource = new MemoryStream(); |
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140 | _request = null; |
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141 | _response = null; |
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142 | _lock = new object(); |
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143 | } |
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144 | |||
145 | private object _lock; |
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146 | |||
147 | #endregion constructors |
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148 | |||
149 | /// <summary> |
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150 | /// Add a path element to the query, e.g. assets |
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151 | /// </summary> |
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152 | /// <param name="element">path entry</param> |
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153 | public void AddResourcePath(string element) |
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154 | { |
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155 | if (isSlashed(element)) |
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156 | _pathElements.Add(element.Substring(0, element.Length - 1)); |
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157 | else |
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158 | _pathElements.Add(element); |
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159 | } |
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160 | |||
161 | /// <summary> |
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162 | /// Add a query parameter to the Url |
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163 | /// </summary> |
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164 | /// <param name="name">Name of the parameter, e.g. min</param> |
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165 | /// <param name="value">Value of the parameter, e.g. 42</param> |
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166 | public void AddQueryParameter(string name, string value) |
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167 | { |
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168 | try |
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169 | { |
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170 | _parameterElements.Add(HttpUtility.UrlEncode(name), HttpUtility.UrlEncode(value)); |
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171 | } |
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172 | catch (ArgumentException) |
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173 | { |
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174 | m_log.Error("[REST]: Query parameter " + name + " is already added."); |
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175 | } |
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176 | catch (Exception e) |
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177 | { |
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178 | m_log.Error("[REST]: An exception was raised adding query parameter to dictionary. Exception: {0}",e); |
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179 | } |
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180 | } |
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181 | |||
182 | /// <summary> |
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183 | /// Add a query parameter to the Url |
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184 | /// </summary> |
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185 | /// <param name="name">Name of the parameter, e.g. min</param> |
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186 | public void AddQueryParameter(string name) |
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187 | { |
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188 | try |
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189 | { |
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190 | _parameterElements.Add(HttpUtility.UrlEncode(name), null); |
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191 | } |
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192 | catch (ArgumentException) |
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193 | { |
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194 | m_log.Error("[REST]: Query parameter " + name + " is already added."); |
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195 | } |
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196 | catch (Exception e) |
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197 | { |
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198 | m_log.Error("[REST]: An exception was raised adding query parameter to dictionary. Exception: {0}",e); |
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199 | } |
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200 | } |
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201 | |||
202 | /// <summary> |
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203 | /// Web-Request method, e.g. GET, PUT, POST, DELETE |
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204 | /// </summary> |
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205 | public string RequestMethod |
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206 | { |
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207 | get { return _method; } |
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208 | set { _method = value; } |
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209 | } |
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210 | |||
211 | /// <summary> |
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212 | /// True if string contains a trailing slash '/' |
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213 | /// </summary> |
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214 | /// <param name="s">string to be examined</param> |
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215 | /// <returns>true if slash is present</returns> |
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216 | private static bool isSlashed(string s) |
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217 | { |
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218 | return s.Substring(s.Length - 1, 1) == "/"; |
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219 | } |
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220 | |||
221 | /// <summary> |
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222 | /// Build a Uri based on the initial Url, path elements and parameters |
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223 | /// </summary> |
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224 | /// <returns>fully constructed Uri</returns> |
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225 | private Uri buildUri() |
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226 | { |
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227 | StringBuilder sb = new StringBuilder(); |
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228 | sb.Append(_url); |
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229 | |||
230 | foreach (string e in _pathElements) |
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231 | { |
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232 | sb.Append("/"); |
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233 | sb.Append(e); |
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234 | } |
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235 | |||
236 | bool firstElement = true; |
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237 | foreach (KeyValuePair<string, string> kv in _parameterElements) |
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238 | { |
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239 | if (firstElement) |
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240 | { |
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241 | sb.Append("?"); |
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242 | firstElement = false; |
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243 | } |
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244 | else |
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245 | sb.Append("&"); |
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246 | |||
247 | sb.Append(kv.Key); |
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248 | if (!string.IsNullOrEmpty(kv.Value)) |
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249 | { |
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250 | sb.Append("="); |
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251 | sb.Append(kv.Value); |
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252 | } |
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253 | } |
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254 | // realuri = sb.ToString(); |
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255 | //m_log.InfoFormat("[REST CLIENT]: RestURL: {0}", realuri); |
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256 | return new Uri(sb.ToString()); |
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257 | } |
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258 | |||
259 | #region Async communications with server |
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260 | |||
261 | /// <summary> |
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262 | /// Async method, invoked when a block of data has been received from the service |
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263 | /// </summary> |
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264 | /// <param name="ar"></param> |
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265 | private void StreamIsReadyDelegate(IAsyncResult ar) |
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266 | { |
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267 | try |
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268 | { |
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269 | Stream s = (Stream) ar.AsyncState; |
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270 | int read = s.EndRead(ar); |
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271 | |||
272 | if (read > 0) |
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273 | { |
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274 | _resource.Write(_readbuf, 0, read); |
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275 | // IAsyncResult asynchronousResult = |
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276 | // s.BeginRead(_readbuf, 0, BufferSize, new AsyncCallback(StreamIsReadyDelegate), s); |
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277 | s.BeginRead(_readbuf, 0, BufferSize, new AsyncCallback(StreamIsReadyDelegate), s); |
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278 | |||
279 | // TODO! Implement timeout, without killing the server |
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280 | //ThreadPool.RegisterWaitForSingleObject(asynchronousResult.AsyncWaitHandle, new WaitOrTimerCallback(TimeoutCallback), _request, DefaultTimeout, true); |
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281 | } |
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282 | else |
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283 | { |
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284 | s.Close(); |
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285 | //_allDone.Set(); |
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286 | } |
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287 | } |
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288 | catch (Exception e) |
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289 | { |
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290 | //_allDone.Set(); |
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291 | _asyncException = e; |
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292 | } |
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293 | } |
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294 | |||
295 | #endregion Async communications with server |
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296 | |||
297 | /// <summary> |
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298 | /// Perform a synchronous request |
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299 | /// </summary> |
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300 | public Stream Request() |
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301 | { |
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302 | lock (_lock) |
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303 | { |
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304 | _request = (HttpWebRequest) WebRequest.Create(buildUri()); |
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305 | _request.KeepAlive = false; |
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306 | _request.ContentType = "application/xml"; |
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307 | _request.Timeout = 200000; |
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308 | _request.Method = RequestMethod; |
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309 | _asyncException = null; |
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310 | |||
311 | // IAsyncResult responseAsyncResult = _request.BeginGetResponse(new AsyncCallback(ResponseIsReadyDelegate), _request); |
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312 | try |
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313 | { |
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314 | _response = (HttpWebResponse) _request.GetResponse(); |
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315 | } |
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316 | catch (WebException e) |
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317 | { |
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318 | HttpWebResponse errorResponse = e.Response as HttpWebResponse; |
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319 | if (null != errorResponse && HttpStatusCode.NotFound == errorResponse.StatusCode) |
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320 | { |
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321 | m_log.Warn("[REST CLIENT] Resource not found (404)"); |
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322 | } |
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323 | else |
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324 | { |
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325 | m_log.Error("[REST CLIENT] Error fetching resource from server " + _request.Address.ToString()); |
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326 | m_log.Debug(e.ToString()); |
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327 | } |
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328 | |||
329 | return null; |
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330 | } |
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331 | |||
332 | Stream src = _response.GetResponseStream(); |
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333 | int length = src.Read(_readbuf, 0, BufferSize); |
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334 | while (length > 0) |
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335 | { |
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336 | _resource.Write(_readbuf, 0, length); |
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337 | length = src.Read(_readbuf, 0, BufferSize); |
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338 | } |
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339 | |||
340 | |||
341 | // TODO! Implement timeout, without killing the server |
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342 | // this line implements the timeout, if there is a timeout, the callback fires and the request becomes aborted |
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343 | //ThreadPool.RegisterWaitForSingleObject(responseAsyncResult.AsyncWaitHandle, new WaitOrTimerCallback(TimeoutCallback), _request, DefaultTimeout, true); |
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344 | |||
345 | // _allDone.WaitOne(); |
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346 | if (_response != null) |
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347 | _response.Close(); |
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348 | if (_asyncException != null) |
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349 | throw _asyncException; |
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350 | |||
351 | if (_resource != null) |
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352 | { |
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353 | _resource.Flush(); |
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354 | _resource.Seek(0, SeekOrigin.Begin); |
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355 | } |
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356 | |||
357 | return _resource; |
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358 | } |
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359 | } |
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360 | |||
361 | public Stream Request(Stream src) |
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362 | { |
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363 | _request = (HttpWebRequest) WebRequest.Create(buildUri()); |
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364 | _request.KeepAlive = false; |
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365 | _request.ContentType = "application/xml"; |
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366 | _request.Timeout = 900000; |
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367 | _request.Method = RequestMethod; |
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368 | _asyncException = null; |
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369 | _request.ContentLength = src.Length; |
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370 | |||
371 | m_log.InfoFormat("[REST]: Request Length {0}", _request.ContentLength); |
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372 | m_log.InfoFormat("[REST]: Sending Web Request {0}", buildUri()); |
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373 | src.Seek(0, SeekOrigin.Begin); |
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374 | m_log.Info("[REST]: Seek is ok"); |
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375 | Stream dst = _request.GetRequestStream(); |
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376 | m_log.Info("[REST]: GetRequestStream is ok"); |
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377 | |||
378 | byte[] buf = new byte[1024]; |
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379 | int length = src.Read(buf, 0, 1024); |
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380 | m_log.Info("[REST]: First Read is ok"); |
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381 | while (length > 0) |
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382 | { |
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383 | dst.Write(buf, 0, length); |
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384 | length = src.Read(buf, 0, 1024); |
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385 | } |
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386 | |||
387 | _response = (HttpWebResponse) _request.GetResponse(); |
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388 | |||
389 | // IAsyncResult responseAsyncResult = _request.BeginGetResponse(new AsyncCallback(ResponseIsReadyDelegate), _request); |
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390 | |||
391 | // TODO! Implement timeout, without killing the server |
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392 | // this line implements the timeout, if there is a timeout, the callback fires and the request becomes aborted |
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393 | //ThreadPool.RegisterWaitForSingleObject(responseAsyncResult.AsyncWaitHandle, new WaitOrTimerCallback(TimeoutCallback), _request, DefaultTimeout, true); |
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394 | |||
395 | return null; |
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396 | } |
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397 | |||
398 | #region Async Invocation |
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399 | |||
400 | public IAsyncResult BeginRequest(AsyncCallback callback, object state) |
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401 | { |
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402 | /// <summary> |
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403 | /// In case, we are invoked asynchroneously this object will keep track of the state |
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404 | /// </summary> |
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405 | AsyncResult<Stream> ar = new AsyncResult<Stream>(callback, state); |
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406 | Util.FireAndForget(RequestHelper, ar); |
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407 | return ar; |
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408 | } |
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409 | |||
410 | public Stream EndRequest(IAsyncResult asyncResult) |
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411 | { |
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412 | AsyncResult<Stream> ar = (AsyncResult<Stream>) asyncResult; |
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413 | |||
414 | // Wait for operation to complete, then return result or |
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415 | // throw exception |
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416 | return ar.EndInvoke(); |
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417 | } |
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418 | |||
419 | private void RequestHelper(Object asyncResult) |
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420 | { |
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421 | // We know that it's really an AsyncResult<DateTime> object |
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422 | AsyncResult<Stream> ar = (AsyncResult<Stream>) asyncResult; |
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423 | try |
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424 | { |
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425 | // Perform the operation; if sucessful set the result |
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426 | Stream s = Request(); |
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427 | ar.SetAsCompleted(s, false); |
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428 | } |
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429 | catch (Exception e) |
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430 | { |
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431 | // If operation fails, set the exception |
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432 | ar.HandleException(e, false); |
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433 | } |
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434 | } |
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435 | |||
436 | #endregion Async Invocation |
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437 | } |
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438 | } |