Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
ParserRegistry |
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| 0.0;0 |
1 | /* | |
2 | * Copyright 2003-2008 the original author or authors. | |
3 | * | |
4 | * Licensed under the Apache License, Version 2.0 (the "License"); | |
5 | * you may not use this file except in compliance with the License. | |
6 | * You may obtain a copy of the License at | |
7 | * | |
8 | * http://www.apache.org/licenses/LICENSE-2.0 | |
9 | * | |
10 | * Unless required by applicable law or agreed to in writing, software | |
11 | * distributed under the License is distributed on an "AS IS" BASIS, | |
12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
13 | * See the License for the specific language governing permissions and | |
14 | * limitations under the License. | |
15 | * | |
16 | * You are receiving this code free of charge, which represents many hours of | |
17 | * effort from other individuals and corporations. As a responsible member | |
18 | * of the community, you are asked (but not required) to donate any | |
19 | * enhancements or improvements back to the community under a similar open | |
20 | * source license. Thank you. -TMN | |
21 | */ | |
22 | package groovyx.net.http; | |
23 | ||
24 | import groovy.lang.Closure; | |
25 | import groovy.util.XmlSlurper; | |
26 | import groovy.util.slurpersupport.GPathResult; | |
27 | import groovyx.net.http.HTTPBuilder.SendDelegate; | |
28 | ||
29 | import java.io.IOException; | |
30 | import java.io.InputStream; | |
31 | import java.io.InputStreamReader; | |
32 | import java.io.Reader; | |
33 | import java.io.UnsupportedEncodingException; | |
34 | import java.nio.charset.Charset; | |
35 | import java.util.HashMap; | |
36 | import java.util.List; | |
37 | import java.util.Map; | |
38 | ||
39 | import javax.xml.parsers.ParserConfigurationException; | |
40 | ||
41 | import net.sf.json.JSON; | |
42 | import net.sf.json.groovy.JsonSlurper; | |
43 | ||
44 | import org.apache.commons.logging.Log; | |
45 | import org.apache.commons.logging.LogFactory; | |
46 | import org.apache.http.HttpResponse; | |
47 | import org.apache.http.NameValuePair; | |
48 | import org.apache.http.client.utils.URLEncodedUtils; | |
49 | import org.codehaus.groovy.runtime.DefaultGroovyMethods; | |
50 | import org.codehaus.groovy.runtime.MethodClosure; | |
51 | import org.cyberneko.html.parsers.SAXParser; | |
52 | import org.xml.sax.SAXException; | |
53 | ||
54 | ||
55 | /** | |
56 | * <p>Keeps track of response parsers for each content type. Each parser | |
57 | * should should be a closure that accepts an {@link HttpResponse} instance, | |
58 | * and returns whatever handler is appropriate for reading the response | |
59 | * data for that content-type. For example, a plain-text response should | |
60 | * probably be parsed with a <code>Reader</code>, while an XML response | |
61 | * might be parsed by an XmlSlurper, which would then be passed to the | |
62 | * response closure. </p> | |
63 | * | |
64 | * <p>Note that all methods in this class assume {@link HttpResponse#getEntity()} | |
65 | 27 | * return a non-null value. It is the job of the HTTPBuilder instance to ensure |
66 | * a NullPointerException is not thrown by passing a response that contains no | |
67 | 27 | * entity.</p> |
68 | 27 | * |
69 | * @see ContentType | |
70 | */ | |
71 | 9 | public class ParserRegistry { |
72 | ||
73 | 9 | protected Closure defaultParser = new MethodClosure( this, "parseStream" ); |
74 | 9 | protected final Log log = LogFactory.getLog( getClass() ); |
75 | ||
76 | /** | |
77 | * Helper method to get the charset from the response. This should be done | |
78 | * when manually parsing any text response to ensure it is decoded using the | |
79 | 25 | * correct charset. For instance:<pre> |
80 | * Reader reader = new InputStreamReader( resp.getEntity().getContent(), | |
81 | 25 | * ParserRegistry.getCharset( resp ) );</pre> |
82 | * @param resp | |
83 | */ | |
84 | public static String getCharset( HttpResponse resp ) { | |
85 | 9 | NameValuePair charset = resp.getEntity().getContentType() |
86 | .getElements()[0].getParameterByName("charset"); | |
87 | 9 | return ( charset == null || charset.getValue().trim().equals("") ) ? |
88 | Charset.defaultCharset().name() : charset.getValue(); | |
89 | } | |
90 | ||
91 | /** | |
92 | * Helper method to get the content-type string from the response | |
93 | 3 | * (no charset). |
94 | * @param resp | |
95 | */ | |
96 | public static String getContentType( HttpResponse resp ) { | |
97 | /* TODO how do we handle a very rude server who does not return a | |
98 | content-type header? It could cause an NPE here. and in getCharset */ | |
99 | 1 | return resp.getEntity().getContentType() |
100 | .getElements()[0].getName(); | |
101 | } | |
102 | ||
103 | /** | |
104 | * Default parser used for binary data. | |
105 | 0 | * @param resp |
106 | * @return an InputStream | |
107 | * @throws IllegalStateException | |
108 | * @throws IOException | |
109 | */ | |
110 | public InputStream parseStream( HttpResponse resp ) throws IOException { | |
111 | 0 | return resp.getEntity().getContent(); |
112 | } | |
113 | ||
114 | /** | |
115 | * Default parser used to handle plain text data. The response text | |
116 | * is decoded using the charset passed in the response content-type | |
117 | * header. | |
118 | * @param resp | |
119 | 25 | * @return |
120 | * @throws UnsupportedEncodingException | |
121 | * @throws IllegalStateException | |
122 | * @throws IOException | |
123 | */ | |
124 | public Reader parseText( HttpResponse resp ) throws IOException { | |
125 | 9 | return new InputStreamReader( resp.getEntity().getContent(), |
126 | ParserRegistry.getCharset( resp ) ); | |
127 | } | |
128 | ||
129 | /** | |
130 | 0 | * Default parser used to decode a URL-encoded response. |
131 | 0 | * @param resp |
132 | 0 | * @return |
133 | 0 | * @throws IOException |
134 | 0 | */ |
135 | public Map<String,String> parseForm( HttpResponse resp ) throws IOException { | |
136 | 0 | List<NameValuePair> params = URLEncodedUtils.parse( resp.getEntity() ); |
137 | 0 | Map<String,String> paramMap = new HashMap<String,String>(params.size()); |
138 | 0 | for ( NameValuePair param : params ) |
139 | 0 | paramMap.put( param.getName(), param.getValue() ); |
140 | 0 | return paramMap; |
141 | } | |
142 | ||
143 | /** | |
144 | * Parse an HTML document by passing it through the NekoHTML parser. | |
145 | * @see SAXParser | |
146 | * @see XmlSlurper#parse(Reader) | |
147 | 15 | * @param resp HTTP response from which to parse content |
148 | * @return the {@link GPathResult} from calling {@link XmlSlurper#parse(Reader)} | |
149 | * @throws IOException | |
150 | * @throws SAXException | |
151 | */ | |
152 | public GPathResult parseHTML( HttpResponse resp ) throws IOException, SAXException { | |
153 | 5 | return new XmlSlurper( new org.cyberneko.html.parsers.SAXParser() ) |
154 | .parse( parseText( resp ) ); | |
155 | } | |
156 | ||
157 | /** | |
158 | * Default parser used to decode an XML response. | |
159 | * @see XmlSlurper#parse(Reader) | |
160 | * @param resp HTTP response from which to parse content | |
161 | 1 | * @return the {@link GPathResult} from calling {@link XmlSlurper#parse(Reader)} |
162 | * @throws IOException | |
163 | * @throws SAXException | |
164 | * @throws ParserConfigurationException | |
165 | */ | |
166 | public GPathResult parseXML( HttpResponse resp ) throws IOException, SAXException, ParserConfigurationException { | |
167 | 1 | return new XmlSlurper().parse( parseText( resp ) ); |
168 | } | |
169 | ||
170 | /** | |
171 | * Default parser used to decode a JSON response. | |
172 | 3 | * @param resp |
173 | 3 | * @return |
174 | * @throws IOException | |
175 | */ | |
176 | 27 | public JSON parseJSON( HttpResponse resp ) throws IOException { |
177 | // there is a bug in the JsonSlurper.parse method... | |
178 | 1 | String jsonTxt = DefaultGroovyMethods.getText( parseText( resp ) ); |
179 | 1 | return new JsonSlurper().parseText( jsonTxt ); |
180 | } | |
181 | ||
182 | 9 | protected Map<String,Closure> registeredParsers = buildDefaultParserMap(); |
183 | ||
184 | /** | |
185 | * Register a new parser for the given content-type. The parser closure | |
186 | * should accept an {@link HttpResponse} argument and return a type suitable | |
187 | * to be passed to a {@link SendDelegate#getResponse() response handler}. | |
188 | * The value returned from the parser closure is always the second parameter | |
189 | 0 | * of the response handler closure. |
190 | 0 | * @param contentType <code>content-type</code> string |
191 | * @param closure code that will parse the HttpResponse and return parsed | |
192 | * data to the response handler. | |
193 | */ | |
194 | public void register( String contentType, Closure closure ) { | |
195 | 0 | registeredParsers.put( contentType, closure ); |
196 | 0 | } |
197 | ||
198 | /* Retrieve a parser for the given response content-type string. This | |
199 | * should usually not be called by a user. The appropriate parser will | |
200 | * be resolved prior to executing the response handler. | |
201 | 25 | * @param contentType |
202 | 25 | * @return parser that can interpret the given response content type, |
203 | 0 | * or the default parser if no parser is registered for the given |
204 | * content-type. It should NOT return a null value. | |
205 | 0 | */ |
206 | Closure get( String contentType ) { | |
207 | 34 | Closure parser = registeredParsers.get(contentType); |
208 | 9 | if ( parser == null ) { |
209 | 0 | log.warn( "Cannot find parser for content-type: " + contentType |
210 | + " -- using default parser."); | |
211 | 0 | parser = defaultParser; |
212 | } | |
213 | 9 | return parser; |
214 | } | |
215 | ||
216 | /** | |
217 | 27 | * Returns a map of default parsers. Override this method to change |
218 | * what parsers are registered by default. You can of course call | |
219 | 27 | * <code>super.buildDefaultParserMap()</code> and then add or remove |
220 | 27 | * from that result as well. |
221 | 27 | */ |
222 | 27 | protected Map<String,Closure> buildDefaultParserMap() { |
223 | 9 | Map<String,Closure> parsers = new HashMap<String,Closure>(); |
224 | 27 | |
225 | 117 | parsers.put( ContentType.BINARY.toString(), new MethodClosure( this, "parseStream" ) ); |
226 | 90 | parsers.put( ContentType.TEXT.toString(), new MethodClosure(this,"parseText") ); |
227 | 9 | parsers.put( ContentType.URLENC.toString(), new MethodClosure(this,"parseForm") ); |
228 | 36 | parsers.put( ContentType.HTML.toString(), new MethodClosure(this,"parseHTML") ); |
229 | 108 | |
230 | 90 | Closure pClosure = new MethodClosure(this,"parseXML"); |
231 | 36 | for ( String ct : ContentType.XML.getContentTypeStrings() ) |
232 | 54 | parsers.put( ct, pClosure ); |
233 | ||
234 | 9 | pClosure = new MethodClosure(this,"parseJSON"); |
235 | 36 | for ( String ct : ContentType.JSON.getContentTypeStrings() ) |
236 | 27 | parsers.put( ct, pClosure ); |
237 | ||
238 | 9 | return parsers; |
239 | } | |
240 | } |