| 1 | /** |
| 2 | * |
| 3 | * Copyright (C) 2011 Cloud Conscious, LLC. <info@cloudconscious.com> |
| 4 | * |
| 5 | * ==================================================================== |
| 6 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 7 | * you may not use this file except in compliance with the License. |
| 8 | * You may obtain a copy of the License at |
| 9 | * |
| 10 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 11 | * |
| 12 | * Unless required by applicable law or agreed to in writing, software |
| 13 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 14 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 15 | * See the License for the specific language governing permissions and |
| 16 | * limitations under the License. |
| 17 | * ==================================================================== |
| 18 | */ |
| 19 | package org.jclouds.http.functions; |
| 20 | |
| 21 | import static com.google.common.base.Preconditions.checkArgument; |
| 22 | import static com.google.common.base.Preconditions.checkNotNull; |
| 23 | import static com.google.common.io.Closeables.closeQuietly; |
| 24 | |
| 25 | import java.io.InputStream; |
| 26 | import java.io.StringReader; |
| 27 | |
| 28 | import javax.inject.Inject; |
| 29 | |
| 30 | import org.jclouds.http.HttpRequest; |
| 31 | import org.jclouds.http.HttpResponse; |
| 32 | import org.jclouds.rest.InvocationContext; |
| 33 | import org.jclouds.rest.internal.GeneratedHttpRequest; |
| 34 | import org.jclouds.util.Strings2; |
| 35 | import org.xml.sax.InputSource; |
| 36 | import org.xml.sax.SAXParseException; |
| 37 | import org.xml.sax.XMLReader; |
| 38 | import org.xml.sax.helpers.DefaultHandler; |
| 39 | |
| 40 | import com.google.common.base.Function; |
| 41 | import com.google.common.base.Throwables; |
| 42 | |
| 43 | /** |
| 44 | * This object will parse the body of an HttpResponse and return the result of type <T> back to the |
| 45 | * caller. |
| 46 | * |
| 47 | * @author Adrian Cole |
| 48 | */ |
| 49 | public class ParseSax<T> implements Function<HttpResponse, T>, InvocationContext<ParseSax<T>> { |
| 50 | |
| 51 | private final XMLReader parser; |
| 52 | private final HandlerWithResult<T> handler; |
| 53 | private HttpRequest request; |
| 54 | |
| 55 | public static interface Factory { |
| 56 | <T> ParseSax<T> create(HandlerWithResult<T> handler); |
| 57 | } |
| 58 | |
| 59 | @Inject |
| 60 | public ParseSax(XMLReader parser, HandlerWithResult<T> handler) { |
| 61 | this.parser = checkNotNull(parser, "parser"); |
| 62 | this.handler = checkNotNull(handler, "handler"); |
| 63 | } |
| 64 | |
| 65 | public T apply(HttpResponse from) { |
| 66 | try { |
| 67 | checkNotNull(from, "http response"); |
| 68 | checkNotNull(from.getPayload(), "payload in " + from); |
| 69 | } catch (NullPointerException e) { |
| 70 | return addDetailsAndPropagate(from, e); |
| 71 | } |
| 72 | if (from.getStatusCode() >= 300) |
| 73 | return convertStreamToStringAndParse(from); |
| 74 | return parse(from.getPayload().getInput()); |
| 75 | } |
| 76 | |
| 77 | private T convertStreamToStringAndParse(HttpResponse from) { |
| 78 | try { |
| 79 | return parse(Strings2.toStringAndClose(from.getPayload().getInput())); |
| 80 | } catch (Exception e) { |
| 81 | return addDetailsAndPropagate(from, e); |
| 82 | } |
| 83 | } |
| 84 | |
| 85 | public T parse(String from) { |
| 86 | try { |
| 87 | checkNotNull(from, "xml string"); |
| 88 | checkArgument(from.indexOf('<') >= 0, String.format("not an xml document [%s] ", from)); |
| 89 | } catch (RuntimeException e) { |
| 90 | return addDetailsAndPropagate(null, e); |
| 91 | } |
| 92 | return parse(new InputSource(new StringReader(from))); |
| 93 | } |
| 94 | |
| 95 | public T parse(InputStream from) { |
| 96 | try { |
| 97 | return parse(new InputSource(from)); |
| 98 | } finally { |
| 99 | closeQuietly(from); |
| 100 | } |
| 101 | } |
| 102 | |
| 103 | public T parse(InputSource from) { |
| 104 | try { |
| 105 | checkNotNull(from, "xml inputsource"); |
| 106 | from.setEncoding("UTF-8"); |
| 107 | parser.setContentHandler(getHandler()); |
| 108 | // This method should accept documents with a BOM (Byte-order mark) |
| 109 | parser.parse(from); |
| 110 | return getHandler().getResult(); |
| 111 | } catch (Exception e) { |
| 112 | return addDetailsAndPropagate(null, e); |
| 113 | } |
| 114 | } |
| 115 | |
| 116 | public T addDetailsAndPropagate(HttpResponse response, Exception e) { |
| 117 | StringBuilder message = new StringBuilder(); |
| 118 | if (request != null) { |
| 119 | message.append("request: ").append(request.getRequestLine()); |
| 120 | } |
| 121 | if (response != null) { |
| 122 | if (message.length() != 0) |
| 123 | message.append("; "); |
| 124 | message.append("response: ").append(response.getStatusLine()); |
| 125 | } |
| 126 | if (e instanceof SAXParseException) { |
| 127 | SAXParseException parseException = (SAXParseException) e; |
| 128 | String systemId = parseException.getSystemId(); |
| 129 | if (systemId == null) { |
| 130 | systemId = ""; |
| 131 | } |
| 132 | if (message.length() != 0) |
| 133 | message.append("; "); |
| 134 | message.append(String.format("error at %d:%d in document %s", parseException.getColumnNumber(), |
| 135 | parseException.getLineNumber(), systemId)); |
| 136 | } |
| 137 | if (message.length() != 0) { |
| 138 | message.append("; cause: ").append(e.toString()); |
| 139 | throw new RuntimeException(message.toString(), e); |
| 140 | } else { |
| 141 | Throwables.propagate(e); |
| 142 | return null; |
| 143 | } |
| 144 | |
| 145 | } |
| 146 | |
| 147 | public HandlerWithResult<T> getHandler() { |
| 148 | return handler; |
| 149 | } |
| 150 | |
| 151 | /** |
| 152 | * Handler that produces a useable domain object accessible after parsing completes. |
| 153 | * |
| 154 | * @author Adrian Cole |
| 155 | */ |
| 156 | public abstract static class HandlerWithResult<T> extends DefaultHandler implements |
| 157 | InvocationContext<HandlerWithResult<T>> { |
| 158 | private HttpRequest request; |
| 159 | |
| 160 | protected HttpRequest getRequest() { |
| 161 | return request; |
| 162 | } |
| 163 | |
| 164 | public abstract T getResult(); |
| 165 | |
| 166 | @Override |
| 167 | public HandlerWithResult<T> setContext(HttpRequest request) { |
| 168 | this.request = request; |
| 169 | return this; |
| 170 | } |
| 171 | } |
| 172 | |
| 173 | public abstract static class HandlerForGeneratedRequestWithResult<T> extends HandlerWithResult<T> { |
| 174 | @Override |
| 175 | protected GeneratedHttpRequest<?> getRequest() { |
| 176 | return (GeneratedHttpRequest<?>) super.getRequest(); |
| 177 | } |
| 178 | |
| 179 | @Override |
| 180 | public HandlerForGeneratedRequestWithResult<T> setContext(HttpRequest request) { |
| 181 | checkArgument(request instanceof GeneratedHttpRequest<?>, "note this handler requires a GeneratedHttpRequest"); |
| 182 | super.setContext(request); |
| 183 | return this; |
| 184 | } |
| 185 | } |
| 186 | |
| 187 | @Override |
| 188 | public ParseSax<T> setContext(HttpRequest request) { |
| 189 | handler.setContext(request); |
| 190 | this.request = request; |
| 191 | return this; |
| 192 | } |
| 193 | } |