1 | package org.greenstone.gsdl3.service;
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2 |
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3 |
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4 | // Greenstone classes
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5 | import org.greenstone.gsdl3.util.*;
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6 | import org.greenstone.gsdl3.collection.Collection;
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7 | import org.greenstone.util.GlobalProperties;
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8 |
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9 | // XML classes
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10 | import org.w3c.dom.Document;
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11 | import org.w3c.dom.Element;
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12 | import org.w3c.dom.Node;
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13 | import org.w3c.dom.Attr;
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14 | import org.w3c.dom.Text;
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15 | import org.w3c.dom.NodeList;
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16 | import org.w3c.dom.NamedNodeMap;
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17 | import org.w3c.dom.ProcessingInstruction;
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18 |
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19 | // General Java classes
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20 | import java.io.BufferedReader;
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21 | import java.io.File;
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22 | import java.io.FileReader;
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23 | import java.io.Serializable;
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24 | import java.util.Vector;
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25 | import java.util.HashMap;
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26 | import java.util.Date;
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27 | import java.text.SimpleDateFormat;
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28 | import org.apache.log4j.*;
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29 |
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30 | public class RSSRetrieve extends ServiceRack {
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31 |
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32 | static Logger logger = Logger.getLogger(org.greenstone.gsdl3.service.RSSRetrieve.class.getName());
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33 | protected static final String RSS_SERVICE = "RSSFeed";
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34 |
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35 | public boolean configure(Element info, Element extra_info) {
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36 | if (!super.configure(info, extra_info)){
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37 | return false;
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38 | }
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39 | logger.info("configuring RSSRetrieve...");
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40 |
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41 | // set up short_service_info_ - for now just has name and type
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42 | Element rss_service = this.desc_doc.createElement(GSXML.SERVICE_ELEM);
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43 | rss_service.setAttribute(GSXML.TYPE_ATT, GSXML.SERVICE_TYPE_RETRIEVE);
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44 | rss_service.setAttribute(GSXML.NAME_ATT, RSS_SERVICE);
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45 | this.short_service_info.appendChild(rss_service);
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46 |
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47 | return true;
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48 | }
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49 |
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50 | // this may get called but is not useful in the case of retrieve services
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51 | protected Element getServiceDescription(Document doc, String service_id, String lang, String subset) {
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52 |
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53 | Element rss_service = doc.createElement(GSXML.SERVICE_ELEM);
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54 | rss_service.setAttribute(GSXML.TYPE_ATT, GSXML.SERVICE_TYPE_RETRIEVE);
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55 | rss_service.setAttribute(GSXML.NAME_ATT, service_id);
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56 | return rss_service;
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57 | }
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58 |
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59 | // Sends off a collection 'describe' message and returns the <collection> element of the response.
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60 | // This contains the collection meta from collectionConfig.xml. Used to construct header of RSS feed
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61 | protected Element getCollMetadata(UserContext userContext) {
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62 |
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63 | Document msg_doc = XMLConverter.newDOM();
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64 | Element mr_request_message = msg_doc.createElement(GSXML.MESSAGE_ELEM);
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65 | String to = this.cluster_name;
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66 | Element meta_request = GSXML.createBasicRequest(msg_doc, GSXML.REQUEST_TYPE_DESCRIBE, to, userContext);
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67 | mr_request_message.appendChild(meta_request);
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68 | Element meta_response = (Element) this.router.process(mr_request_message);
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69 | meta_response = (Element) GSXML.getChildByTagName(meta_response, GSXML.RESPONSE_ELEM);
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70 |
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71 | NodeList nl = meta_response.getElementsByTagName(GSXML.COLLECTION_ELEM);
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72 | Element collectionEl = (Element) nl.item(0);
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73 | return collectionEl;
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74 | }
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75 |
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76 |
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77 | /**
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78 | Generates the RSS feed XML by creating the header and footer with the contents
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79 | of the the collection's index/rss-items.rdf file embedded in the middle.
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80 | @return the RSS feed XML.
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81 | @see http://cyber.law.harvard.edu/rss/rss.html
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82 | */
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83 | protected Element processRSSFeed(Element request) {
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84 |
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85 | // Ask the MessageRouter for this collection's colConfig metadata
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86 | // from which the RSS header values will be constructed
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87 | UserContext userContext = new UserContext(request);
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88 | Element collMeta = getCollMetadata(userContext);
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89 |
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90 | //logger.error("**** collection metadata:");
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91 | //GSXML.elementToLogAsString(collMeta, true);
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92 |
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93 | // work out some commonly used variables such as lang and url_prefix
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94 | String lang = request.getAttribute("lang");
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95 | if(lang.equals("")) {
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96 | lang = "en";
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97 | }
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98 |
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99 | // url_prefix is of the form http://domain/greenstone3/library/collection/_colname_/
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100 | String url_prefix = GlobalProperties.getFullGSDL3WebAddress()+"/"+this.library_name+"/collection/"+this.cluster_name;
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101 |
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102 |
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103 | // generate the header and footer
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104 | Document rssDoc = XMLConverter.newDOM();
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105 |
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106 | Element rssNode = rssDoc.createElement("rss"); // rootnode
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107 | rssNode.setAttribute("version", "2.0");
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108 |
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109 | String namespace_url = "http://www.w3.org/2000/xmlns/";
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110 | rssNode.setAttributeNS(namespace_url, "xmlns:content", "http://purl.org/rss/1.0/modules/content/");
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111 | rssNode.setAttributeNS(namespace_url, "xmlns:taxo", "http://purl.org/rss/1.0/modules/taxonomy/");
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112 | rssNode.setAttributeNS(namespace_url, "xmlns:dc", "http://purl.org/dc/elements/1.1/");
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113 | rssNode.setAttributeNS(namespace_url, "xmlns:syn", "http://purl.org/rss/1.0/modules/syndication/");
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114 | rssNode.setAttributeNS(namespace_url, "xmlns:admin", "http://webns.net/mvcb/");
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115 | rssDoc.appendChild(rssNode);
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116 |
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117 | // Setting the preproccessing header line (Utf-8) will be done in web/interfaces' rss.xsl
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118 | //ProcessingInstruction procInstruction = doc.createProcessingInstruction("xml","version=\"1.0\"");
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119 | //rssDoc.appendChild(procInstruction);
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120 |
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121 | Element channelNode = rssDoc.createElement("channel");
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122 | rssNode.appendChild(channelNode);
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123 |
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124 | Element childNode = rssDoc.createElement("title");
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125 | GSXML.setNodeText(childNode, this.cluster_name); //_collectionname_
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126 | channelNode.appendChild(childNode);
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127 |
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128 | // _httppageabout_: of form http://domain/greenstone3/library/collection/_colname_/page/about
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129 | childNode = rssDoc.createElement("link");
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130 | GSXML.setNodeText(childNode, url_prefix+"/page/about"); // _httppageabout_
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131 | channelNode.appendChild(childNode);
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132 |
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133 | // get the description string for the requested language, else fallback on en description if present
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134 | childNode = rssDoc.createElement("description");
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135 | NodeList descriptions = GSXML.getNamedElements(collMeta, GSXML.DISPLAY_TEXT_ELEM, GSXML.NAME_ATT, GSXML.DISPLAY_TEXT_DESCRIPTION);
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136 | //Element descriptEl = GSXML.getNamedElement(collMeta, GSXML.DISPLAY_TEXT_ELEM, GSXML.NAME_ATT, GSXML.DISPLAY_TEXT_DESCRIPTION);
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137 | Element descriptEl = null;
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138 | if(descriptions != null) {
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139 | for (int i = 0; i < descriptions.getLength(); i++) {
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140 | Element e = (Element) descriptions.item(i);
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141 | if(e.getAttribute("lang").equals(lang)) {
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142 | descriptEl = e;
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143 | break; // found the description for the requested language, finish loop
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144 | } else if(e.getAttribute("lang").equals("en")) {
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145 | descriptEl = e; // at least found english fall-back description, continue loop
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146 | }
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147 | }
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148 | }
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149 | String description = (descriptEl == null) ? "none" : GSXML.getNodeText(descriptEl);
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150 | GSXML.setNodeText(childNode, description); //_collectionextra_
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151 | channelNode.appendChild(childNode);
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152 |
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153 | childNode = rssDoc.createElement("language");
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154 | GSXML.setNodeText(childNode, lang); //_cgiargl_
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155 | channelNode.appendChild(childNode);
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156 |
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157 |
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158 | // RSS specification: http://cyber.law.harvard.edu/rss/rss.html
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159 | // pubDate is date of first publication of the item. Use collection.getEarliestDatestamp()
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160 | // lastBuildDate is the date the item was last modified. Use collection.getLastmodified()
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161 |
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162 | //HashMap<String, ModuleInterface> module_map = this.router.getModuleMap();
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163 | //Collection coll = (Collection)module_map.get(this.cluster_name);
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164 | Collection coll = (Collection)serviceCluster;
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165 | SimpleDateFormat dateFormat = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss z");
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166 |
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167 | childNode = rssDoc.createElement("pubDate");
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168 | Date date = new Date(coll.getEarliestDatestamp()); // "Thu, 23 Aug 1999 07:00:00 GMT"
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169 | GSXML.setNodeText(childNode, dateFormat.format(date));
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170 | channelNode.appendChild(childNode);
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171 |
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172 | childNode = rssDoc.createElement("lastBuildDate");
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173 | date = new Date(coll.getLastmodified()); // "Thu, 23 Aug 1999 16:20:26 GMT"
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174 | GSXML.setNodeText(childNode, dateFormat.format(date));
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175 | channelNode.appendChild(childNode);
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176 |
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177 | childNode = rssDoc.createElement("managingEditor");
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178 | Element e = GSXML.getNamedElement(collMeta, GSXML.DISPLAY_TEXT_ELEM, GSXML.NAME_ATT, "creator");
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179 | String value = (e == null) ? "unknown" : GSXML.getNodeText(e);
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180 | GSXML.setNodeText(childNode, value); //_creator_
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181 | channelNode.appendChild(childNode);
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182 |
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183 | childNode = rssDoc.createElement("webMaster");
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184 | e = GSXML.getNamedElement(collMeta, GSXML.DISPLAY_TEXT_ELEM, GSXML.NAME_ATT, "maintainer");
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185 | value = (e == null) ? "unknown" : GSXML.getNodeText(e);
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186 | GSXML.setNodeText(childNode, value); //_maintainer_
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187 | channelNode.appendChild(childNode);
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188 |
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189 |
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190 | // <image> child of <channel> has title, url, link and description children
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191 | Element collIcon = GSXML.getNamedElement(collMeta, GSXML.DISPLAY_TEXT_ELEM, GSXML.NAME_ATT, "icon");
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192 | if(collIcon != null) { // since there is a collection image, create an imageNode
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193 |
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194 | Node imageNode = rssDoc.createElement("image");
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195 | channelNode.appendChild(imageNode);
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196 |
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197 | childNode = rssDoc.createElement("title");
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198 | GSXML.setNodeText(childNode, this.cluster_name); //_collectionname_
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199 | imageNode.appendChild(childNode);
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200 |
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201 | // need full URL for collection icon. Its name is in <displayItem name="icon_name.ext"/>
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202 | // URL is of the form domain/servlet/sites/localsite/collect/lucene-jdbm-demo/images/icon_name.ext
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203 | childNode = rssDoc.createElement("url");
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204 | String domain = GlobalProperties.getFullGSDL3WebAddress(); // remove servlet as it's included in site_http_address
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205 | domain = domain.substring(0, domain.lastIndexOf("/"));
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206 | String image_url = GSXML.getNodeText(collIcon); // name of image file
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207 | image_url = domain+"/"+this.site_http_address+"/"+"/collect/"+this.cluster_name+"/images/"+image_url;
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208 | GSXML.setNodeText(childNode, image_url); // _iconcollection_
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209 | imageNode.appendChild(childNode);
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210 |
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211 | childNode = rssDoc.createElement("link");
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212 | GSXML.setNodeText(childNode, url_prefix+"/page/about"); // _httppageabout_
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213 | imageNode.appendChild(childNode);
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214 |
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215 | childNode = rssDoc.createElement("description");
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216 | GSXML.setNodeText(childNode, description); //_collectionextra_
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217 | imageNode.appendChild(childNode);
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218 | }
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219 |
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220 |
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221 | // now add the contents of rss-items.rdf as a child of channel,
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222 | // passing in url_prefix for url resolution
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223 | Element rss_raw_data = loadDocument("rss-items.rdf", url_prefix);
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224 | if(rss_raw_data != null) {
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225 | NodeList rss_items = rss_raw_data.getElementsByTagName("item");
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226 | for(int i = 0; i < rss_items.getLength(); i++) {
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227 | channelNode.appendChild(rssDoc.importNode(rss_items.item(i), true));
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228 | }
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229 | }
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230 |
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231 | // generate the GS3 response message containing the RSS xml
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232 | Element result = rssDoc.createElement(GSXML.RESPONSE_ELEM);
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233 | result.setAttribute(GSXML.FROM_ATT, RSS_SERVICE);
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234 | result.setAttribute(GSXML.TYPE_ATT, GSXML.REQUEST_TYPE_PROCESS);
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235 | result.appendChild(rssNode); // body of <response> is simply the <rss> root element of the RSS feed
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236 | return result;
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237 |
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238 | }
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239 |
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240 | // load contents of rss-items.rdf file into an XML doc in memory, after doing the url_prefix replacements
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241 | protected Element loadDocument(String doc_name, String url_prefix) {
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242 | String document_encoding = "UTF-8";
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243 |
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244 | // try to find the document
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245 | File doc_file = new File(GSFile.collectionIndexDir(this.site_home, this.cluster_name)+File.separator+doc_name);
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246 |
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247 | if (!doc_file.exists()) {
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248 | logger.info("couldn't find file in coll "+this.cluster_name +", file "+doc_name);
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249 | return null;
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250 | }
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251 |
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252 | // the rss-items.rdf file has no root element, only multiple <item> elements (and subelements)
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253 | // Without a root element, it can't be read into a DOM object. So we read it into a regular String,
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254 | // then bookend the contents with temporary <rssrawdata></rssrawdata> elements to provide a root
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255 | // element and can read in that String as a DOM object.
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256 |
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257 | StringBuffer contents = new StringBuffer("<rssrawdata>\n");
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258 | try {
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259 | BufferedReader in = new BufferedReader(new FileReader(doc_file));
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260 | String line = null;
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261 | while((line = in.readLine()) != null) {
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262 | //line = line.replace("_httpcollection_", "/"+this.cluster_name);
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263 | line = line.replace("_httpdomain__httpcollection_", url_prefix);
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264 | contents.append(line);
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265 | }
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266 | contents.append("</rssrawdata>");
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267 | in.close(); // close the fileread handle
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268 |
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269 | } catch (Exception e) {
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270 | e.printStackTrace();
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271 | contents.append("couldn't read ");
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272 | contents.append(doc_file);
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273 | contents.append("\n</rssrawdata>");
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274 | }
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275 |
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276 |
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277 | Document the_doc = null;
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278 | try {
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279 | the_doc = this.converter.getDOM(contents.toString()); // String input converted to DOM
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280 | } catch (Exception e) {
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281 | logger.error("couldn't create a DOM from file "+doc_file.getPath());
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282 | return null;
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283 | }
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284 |
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285 | return the_doc.getDocumentElement();
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286 |
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287 | }
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288 |
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289 |
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290 | }
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291 |
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