001/*
002 * Copyright (c) 2011-2017 Nexmo Inc
003 *
004 * Permission is hereby granted, free of charge, to any person obtaining a copy
005 * of this software and associated documentation files (the "Software"), to deal
006 * in the Software without restriction, including without limitation the rights
007 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
008 * copies of the Software, and to permit persons to whom the Software is
009 * furnished to do so, subject to the following conditions:
010 *
011 * The above copyright notice and this permission notice shall be included in
012 * all copies or substantial portions of the Software.
013 *
014 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
015 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
016 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
017 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
018 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
019 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
020 * THE SOFTWARE.
021 */
022package com.nexmo.client;
023
024import com.nexmo.client.auth.AuthMethod;
025import com.nexmo.client.logging.LoggingUtils;
026import org.apache.commons.logging.Log;
027import org.apache.commons.logging.LogFactory;
028import org.apache.http.HttpEntity;
029import org.apache.http.HttpEntityEnclosingRequest;
030import org.apache.http.HttpResponse;
031import org.apache.http.client.HttpClient;
032import org.apache.http.client.entity.UrlEncodedFormEntity;
033import org.apache.http.client.methods.HttpEntityEnclosingRequestBase;
034import org.apache.http.client.methods.HttpUriRequest;
035import org.apache.http.client.methods.RequestBuilder;
036import org.apache.http.util.EntityUtils;
037
038import java.io.IOException;
039import java.io.UnsupportedEncodingException;
040import java.nio.charset.Charset;
041import java.util.Collections;
042import java.util.HashSet;
043import java.util.Set;
044
045/**
046 * Abstract class to assist in implementing a call against a REST endpoint.
047 * <p>
048 * Concrete implementations must implement {@link #makeRequest(Object)} to construct a {@link RequestBuilder} from the
049 * provided parameterized request object, and {@link #parseResponse(HttpResponse)} to construct the parameterized {@link
050 * HttpResponse} object.
051 * <p>
052 * The REST call is executed by calling {@link #execute(Object)}.
053 *
054 * @param <RequestT> The type of the method-specific request object that will be used to construct an HTTP request
055 * @param <ResultT>  The type of method-specific response object which will be constructed from the returned HTTP
056 *                   response
057 */
058public abstract class AbstractMethod<RequestT, ResultT> implements Method<RequestT, ResultT> {
059    private static final Log LOG = LogFactory.getLog(AbstractMethod.class);
060
061    protected final HttpWrapper httpWrapper;
062    private Set<Class> acceptable;
063
064    public AbstractMethod(HttpWrapper httpWrapper) {
065        this.httpWrapper = httpWrapper;
066    }
067
068    /**
069     * Execute the REST call represented by this method object.
070     *
071     * @param request A RequestT representing input to the REST call to be made
072     *
073     * @return A ResultT representing the response from the executed REST call
074     *
075     * @throws NexmoClientException if there is a problem parsing the HTTP response
076     */
077    public ResultT execute(RequestT request) throws NexmoResponseParseException, NexmoClientException {
078        try {
079            RequestBuilder requestBuilder = applyAuth(makeRequest(request));
080            HttpUriRequest httpRequest = requestBuilder.build();
081
082            // If we have a URL Encoded form entity, we may need to regenerate it as UTF-8
083            // due to a bug (or two!) in RequestBuilder:
084            //
085            // This fix can be removed when HttpClient is upgraded to 4.5, although 4.5 also
086            // has a bug where RequestBuilder.put(uri) and RequestBuilder.post(uri) use the
087            // wrong encoding, whereas RequestBuilder.put().setUri(uri) uses UTF-8.
088            // - MS 2017-04-12
089            if (httpRequest instanceof HttpEntityEnclosingRequest) {
090                HttpEntityEnclosingRequest entityRequest = (HttpEntityEnclosingRequest) httpRequest;
091                HttpEntity entity = entityRequest.getEntity();
092                if (entity instanceof UrlEncodedFormEntity) {
093                    entityRequest.setEntity(new UrlEncodedFormEntity(requestBuilder.getParameters(),
094                            Charset.forName("UTF-8")
095                    ));
096                }
097            }
098            LOG.debug("Request: " + httpRequest);
099            if (LOG.isDebugEnabled() && httpRequest instanceof HttpEntityEnclosingRequestBase) {
100                HttpEntityEnclosingRequestBase enclosingRequest = (HttpEntityEnclosingRequestBase) httpRequest;
101                LOG.debug(EntityUtils.toString(enclosingRequest.getEntity()));
102            }
103            HttpResponse response = this.httpWrapper.getHttpClient().execute(httpRequest);
104
105            LOG.debug("Response: " + LoggingUtils.logResponse(response));
106
107            try{
108                return parseResponse(response);
109            }
110            catch (IOException io){
111                throw new NexmoResponseParseException("Unable to parse response.", io);
112            }
113        } catch (UnsupportedEncodingException uee) {
114            throw new NexmoUnexpectedException("UTF-8 encoding is not supported by this JVM.", uee);
115        } catch (IOException io) {
116            throw new NexmoMethodFailedException("Something went wrong while executing the HTTP request: " +
117                    io.getMessage() + ".", io);
118        }
119    }
120
121    /**
122     * Apply an appropriate authentication method (specified by {@link #getAcceptableAuthMethods()} to the provided
123     * {@link RequestBuilder}, and return the result.
124     *
125     * @param request A RequestBuilder which has not yet had authentication information applied
126     *
127     * @return A RequestBuilder with appropriate authentication information applied (may or not be the same instance as
128     * <pre>request</pre>)
129     *
130     * @throws NexmoClientException If no appropriate {@link AuthMethod} is available
131     */
132    protected RequestBuilder applyAuth(RequestBuilder request) throws NexmoClientException {
133        return getAuthMethod(getAcceptableAuthMethods()).apply(request);
134    }
135
136    /**
137     * Utility method for obtaining an appropriate {@link AuthMethod} for this call.
138     *
139     * @param acceptableAuthMethods an array of classes, representing authentication methods that are acceptable for
140     *                              this endpoint
141     *
142     * @return An AuthMethod created from one of the provided acceptableAuthMethods.
143     *
144     * @throws NexmoClientException If no AuthMethod is available from the provided array of acceptableAuthMethods.
145     */
146    protected AuthMethod getAuthMethod(Class[] acceptableAuthMethods) throws NexmoClientException {
147        if (acceptable == null) {
148            this.acceptable = new HashSet<>();
149            Collections.addAll(acceptable, acceptableAuthMethods);
150        }
151
152        return this.httpWrapper.getAuthCollection().getAcceptableAuthMethod(acceptable);
153    }
154
155    public void setHttpClient(HttpClient client) {
156        this.httpWrapper.setHttpClient(client);
157    }
158
159    protected abstract Class[] getAcceptableAuthMethods();
160
161    /**
162     * Construct and return a RequestBuilder instance from the provided request.
163     *
164     * @param request A RequestT representing input to the REST call to be made
165     *
166     * @return A ResultT representing the response from the executed REST call
167     *
168     * @throws UnsupportedEncodingException if UTF-8 encoding is not supported by the JVM
169     */
170    public abstract RequestBuilder makeRequest(RequestT request) throws UnsupportedEncodingException;
171
172    /**
173     * Construct a ResultT representing the contents of the HTTP response returned from the Nexmo Voice API.
174     *
175     * @param response An HttpResponse returned from the Nexmo Voice API
176     *
177     * @return A ResultT type representing the result of the REST call
178     *
179     * @throws IOException if a problem occurs parsing the response
180     */
181    public abstract ResultT parseResponse(HttpResponse response) throws IOException;
182}