利用 OpenSearch 和 iWidget 规范创建一个用户可定制的搜索门户系统

<?xml version="1.0" encoding="UTF-8"?>
<OpenSearchDescription xmlns="http://a9.com/-/spec/opensearch/1.1/">
 <ShortName>IBM developerWorks 中文网站 </ShortName>
 <Description>IBM developerWorks 中文网站 </Description>
 <InputEncoding>UTF-8</InputEncoding>
 <Url type="text/html" method="GET" 
 template="http://www.ibm.com/developerWorks/search/searchResults.jsp?
 searchType=1&searchSite=dWChina&pageLang=zh&langEncoding=UTF8&
 searchScope=dW&query={searchTerms}"/>
</OpenSearchDescription>

<?xml version="1.0" encoding="UTF-8"?>
<iw:iwidget name="myWidget" xmlns:iw="http://www.ibm.com/xmlns/prod/iWidget" 
supportedModes="view edit" mode="view">
 <iw:content mode="view">Hello World!</iw:content>
 <iw:content mode="edit">Configure me.</iw:content>
</iw:iwidget>

<iw:iwidget name="openSearchViewlet" xmlns:iw="http://www.ibm.com/xmlns/prod/iWidget"
 iScope="com.ibm.mm.openSearchViewlet"
allowInstanceContent="false" supportedModes="view edit" mode="view" lang="en">
	<iw:itemSet id="attributes" >
 <iw:item id="version" value="1.0.0.0.0"/>
 <iw:item id="openSearchDescUrl" value="" readOnly="false"/>
 </iw:itemSet>
	
	<iw:event id="Accept Search Keyword" eventDescName="keyword" handled="true"
	 onEvent="onKeywordReceived" onNewWire="onKeywordReceived" />
	<iw:eventDescription id="keyword" payloadType="text" 
	description="Text to search" lang="en">
		<iw:alt description="Text to search" title="Accept Search Keyword" 
		lang="en"/>
	</iw:eventDescription>
	
	<iw:resource uri="openSearchViewlet.js" />
	
	<iw:content mode="view">
		<![CDATA[
		<div>
		<div id="_IWID_loading" style="font-size:1.4em;"><img alt="loading..." 
src="/mum/js/com/ibm/mm/enabler/iw/progress-anim.gif" />Loading...</div>
			<div id="_IWID_errorMessage" style="font-size:1.4em;display:none;
			"><img alt="Error occurred!" src="/mum/images/error_icon.png" />
			Error occured!</div>
			<div id="_IWID_emptyMessage" style="font-size:1.4em;display:none">
			<img alt="No result" src="/mum/images/info_icon.png" />
			No result!</div>
			<div id="_IWID_searchResult" style="display:none"></div>
		</div>
		]]>
	</iw:content>
	<iw:content mode="edit">
		<![CDATA[
		<div id="_IWID_editRoot" style="padding:20px">
			<form id="_IWID_OSProviderForm" onsubmit="return false;">
				<p>
					<label for="_IWID_opensearchDescUrl">
					OpenSearch Description URL:</label>
					<input name="openSearchDesc" type="text">
				</p>
				<p>
					<label>Content Type:</label>
                    <input type="radio" name="contentType" value="html"
					title="HTML" checked>HTML</input>
                    <input type="radio" name="contentType" value="feed" 
					title="Feed (Atom/RSS)">Feed (Atom/RSS)</input>
				</p>
				<div>
                  <input name="save" type="button" onclick="iContext.iScope().save()"
				 value="Save">
				 <input name="cancel" type="button" 
				 onclick="iContext.iScope().cancel()" value="Cancel">
				</div>
			</form>
		</div>
		]]>
	</iw:content>
</iw:iwidget>

onKeywordReceived: function(iEvent) {
	this._showLoadingMessage();
    var keyword = iEvent.payload;
	
    var searchPrefix = this._searchTemplate.replace("{fileurl}", this.osDescriptionUrl);
    var searchUrl = searchPrefix + keyword;

	var params = [];
	if (this.osContentType === "html") {
		// use website iwidget
		params = [{
			"itemName": "url",
			"itemValue": searchUrl
		}];
		this._createIWidget(this.resultDiv, this._widgetDefXML.htmlFragment, 
		params, null, null);
	} else if (this.osContentType === "feed") {
		// use feed reader iwidget
		params = [{
			"itemName": "feedURL",
			"itemValue": searchUrl
		}];
		this._createIWidget(this.resultDiv, this._widgetDefXML.feedReader, 
		params, null, null);
	} else {
		// No content type information
		dojo.xhrGet({
		url: searchUrl,
		handle: dojo.hitch(this, function(response, ioArgs) {
	         if (!response && ioArgs.xhr.getResponseHeader("
				    Content-Length") == 0) {
					this._showEmptyMessage();
					return;
				}
		 if (ioArgs.xhr.getResponseHeader("Content-Type") === "text/html") {
		    this.parseHtmlContent(response);
		   } else if (ioArgs.xhr.getResponseHeader("Content-Type") === 
		     "application/atom+xml" || ioArgs.xhr.getResponseHeader("
		     Content-Type") === 
				    "application/rss+xml") {
					this.parseFeedContent(response);
				} else {
					this._showErrorMessage();
				}
			}),
			error: dojo.hitch(this, this.onError)
		});
		return;
	}
	this._showResult();
}

public class InvokeOSProviderServlet extends HttpServlet {

@Override

protected void doGet(HttpServletRequest req, HttpServletResponse resp)

throws ServletException, IOException {

String osDescriptionFile = req.getParameter("osdescriptionurl");

String keywords = req.getParameter("q");

OpenSearchInvokerImpl.instance.invoke(osDescriptionFile, keywords, resp);

}

}

public interface OpenSearchInvoker {
  public void invoke(String openSearchURL, String searchTerms,HttpServletResponse resp);
}

public void invoke(String openSearchURL, String searchTerms,HttpServletResponse resp) {
		HttpURLConnection conn = null;
		try {
			Map<String,String> defaultURLTemplate = 
			Utils.getDefaultUrlTemplateInOSDescription(openSearchURL);
			
			String contentType = defaultURLTemplate.get("contentType");
			String template = defaultURLTemplate.get("template");
			
			System.out.println("search Terms:"+searchTerms);
			String instantiatedURL = template.replace("{searchTerms}", 
			URLEncoder.encode(searchTerms)); 
			
			if("text/html".equalsIgnoreCase(contentType)){
              System.out.println("redirect client to url:"+instantiatedURL);
				resp.sendRedirect(instantiatedURL);
				return;
			}
			
			//else it's feed, so retrieve it...
			System.out.println("fetch result:"+instantiatedURL);
			URL url = new URL(instantiatedURL);
			conn = (HttpURLConnection)url.openConnection();
			conn.setRequestProperty ( "User-Agent", "Mozilla/4.0 ( compatible
			) " ) ;
			conn.setRequestProperty ( "Accept-Language", 
			"en-US,en;q=0.9,de-DE;q=0.8,de;q=0.6,zh-CN;q=0.5,zh;q=0.4,en-us;
			q=0.3,en;q=0.1" ) ;
			resp.setContentType(contentType);
			byte[] buffer = new byte[1024];
			int length;
			while((length=conn.getInputStream().read(buffer))!=-1){
				resp.getOutputStream().write(buffer,0,length);
			}
			resp.getOutputStream().flush();
			resp.getOutputStream().close();
		} catch (IOException e) {
			logger.log(Level.WARNING,e.getMessage(),e);
		}
	}

{
 "itemsPerPage": 10,
 "totalResults": 3,
 "entries": [
 {
 "tags": [
 "Google"
 ],
 "title": "Google Search",
 "osDescriptionURL": "http:\/\/localhost:8080\/oscatalog\/samples\/google.xml",
 "contentType": "text\/html"
 },
 {
 "tags": [
 "Search in Google Images"
 ],
 "title": "Google Images Search",
 "osDescriptionURL": 
 "http:\/\/localhost:8080\/oscatalog\/travel\/googleimage.xml",
 "contentType": "text\/html"
 },
 {
 "tags": [
 "Google Map Search"
 ],
 "title": "Google Map Search",
 "osDescriptionURL": 
 "http:\/\/localhost:8080\/oscatalog\/travel\/googlemap.xml",
 "contentType": "text\/html"
 }
 ],
 "startIndex": 1
}