Java tutorial
package ca.uhn.fhir.rest.client.apache; /* * #%L * HAPI FHIR - Core Library * %% * Copyright (C) 2014 - 2016 University Health Network * %% * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * #L% */ import java.io.UnsupportedEncodingException; import java.util.ArrayList; import java.util.List; import java.util.Map; import java.util.Map.Entry; import org.apache.http.HttpEntity; import org.apache.http.NameValuePair; import org.apache.http.client.HttpClient; import org.apache.http.client.entity.UrlEncodedFormEntity; import org.apache.http.client.methods.HttpDelete; import org.apache.http.client.methods.HttpGet; import org.apache.http.client.methods.HttpOptions; import org.apache.http.client.methods.HttpPost; import org.apache.http.client.methods.HttpPut; import org.apache.http.client.methods.HttpRequestBase; import org.apache.http.entity.ByteArrayEntity; import org.apache.http.message.BasicNameValuePair; import org.hl7.fhir.instance.model.api.IBaseBinary; import ca.uhn.fhir.context.FhirContext; import ca.uhn.fhir.rest.api.RequestTypeEnum; import ca.uhn.fhir.rest.client.BaseHttpClientInvocation; import ca.uhn.fhir.rest.client.api.Header; import ca.uhn.fhir.rest.client.api.HttpClientUtil; import ca.uhn.fhir.rest.client.api.IHttpClient; import ca.uhn.fhir.rest.client.api.IHttpRequest; import ca.uhn.fhir.rest.server.Constants; import ca.uhn.fhir.rest.server.EncodingEnum; import ca.uhn.fhir.rest.server.exceptions.InternalErrorException; import ca.uhn.fhir.util.CoverageIgnore; import ca.uhn.fhir.util.VersionUtil; /** * A Http Client based on Apache. This is an adapter around the class * {@link org.apache.http.client.HttpClient HttpClient} * * @author Peter Van Houte | peter.vanhoute@agfa.com | Agfa Healthcare */ public class ApacheHttpClient implements IHttpClient { private HttpClient myClient; private List<Header> myHeaders; private StringBuilder myUrl; private Map<String, List<String>> myIfNoneExistParams; private String myIfNoneExistString; private RequestTypeEnum myRequestType; public ApacheHttpClient(HttpClient theClient, StringBuilder theUrl, Map<String, List<String>> theIfNoneExistParams, String theIfNoneExistString, RequestTypeEnum theRequestType, List<Header> theHeaders) { this.myClient = theClient; this.myUrl = theUrl; this.myIfNoneExistParams = theIfNoneExistParams; this.myIfNoneExistString = theIfNoneExistString; this.myRequestType = theRequestType; this.myHeaders = theHeaders; } @Override public IHttpRequest createByteRequest(FhirContext theContext, String theContents, String theContentType, EncodingEnum theEncoding) { /* * We aren't using a StringEntity here because the constructors * supported by Android aren't available in non-Android, and vice versa. * Since we add the content type header manually, it makes no difference * which one we use anyhow. */ ByteArrayEntity entity = new ByteArrayEntity(theContents.getBytes(Constants.CHARSET_UTF8)); ApacheHttpRequest retVal = createHttpRequest(entity); addHeadersToRequest(retVal, theEncoding, theContext); retVal.addHeader(Constants.HEADER_CONTENT_TYPE, theContentType + Constants.HEADER_SUFFIX_CT_UTF_8); return retVal; } @Override public IHttpRequest createParamRequest(FhirContext theContext, Map<String, List<String>> theParams, EncodingEnum theEncoding) { List<NameValuePair> parameters = new ArrayList<NameValuePair>(); for (Entry<String, List<String>> nextParam : theParams.entrySet()) { List<String> value = nextParam.getValue(); for (String s : value) { parameters.add(new BasicNameValuePair(nextParam.getKey(), s)); } } UrlEncodedFormEntity entity = createFormEntity(parameters); ApacheHttpRequest retVal = createHttpRequest(entity); addHeadersToRequest(retVal, theEncoding, theContext); return retVal; } @CoverageIgnore private UrlEncodedFormEntity createFormEntity(List<NameValuePair> parameters) { try { return new UrlEncodedFormEntity(parameters, "UTF-8"); } catch (UnsupportedEncodingException e) { throw new InternalErrorException("Server does not support UTF-8 (should not happen)", e); } } @Override public IHttpRequest createBinaryRequest(FhirContext theContext, IBaseBinary theBinary) { /* * Note: Be careful about changing which constructor we use for * ByteArrayEntity, as Android's version of HTTPClient doesn't support * the newer ones for whatever reason. */ ByteArrayEntity entity = new ByteArrayEntity(theBinary.getContent()); ApacheHttpRequest retVal = createHttpRequest(entity); addHeadersToRequest(retVal, null, theContext); retVal.addHeader(Constants.HEADER_CONTENT_TYPE, theBinary.getContentType()); return retVal; } @Override public IHttpRequest createGetRequest(FhirContext theContext, EncodingEnum theEncoding) { ApacheHttpRequest retVal = createHttpRequest(null); addHeadersToRequest(retVal, theEncoding, theContext); return retVal; } public void addHeadersToRequest(ApacheHttpRequest theHttpRequest, EncodingEnum theEncoding, FhirContext theContext) { if (myHeaders != null) { for (Header next : myHeaders) { theHttpRequest.addHeader(next.getName(), next.getValue()); } } theHttpRequest.addHeader("User-Agent", HttpClientUtil.createUserAgentString(theContext, "apache")); theHttpRequest.addHeader("Accept-Charset", "utf-8"); theHttpRequest.addHeader("Accept-Encoding", "gzip"); if (theEncoding == null) { theHttpRequest.addHeader(Constants.HEADER_ACCEPT, Constants.HEADER_ACCEPT_VALUE_XML_OR_JSON); } else if (theEncoding == EncodingEnum.JSON) { theHttpRequest.addHeader(Constants.HEADER_ACCEPT, Constants.CT_FHIR_JSON); } else if (theEncoding == EncodingEnum.XML) { theHttpRequest.addHeader(Constants.HEADER_ACCEPT, Constants.CT_FHIR_XML); } } private ApacheHttpRequest createHttpRequest(HttpEntity theEntity) { HttpRequestBase request = constructRequestBase(theEntity); ApacheHttpRequest result = new ApacheHttpRequest(myClient, request); addHeaderIfNoneExist(result); return result; } private void addHeaderIfNoneExist(IHttpRequest result) { if (myIfNoneExistParams != null) { StringBuilder b = newHeaderBuilder(myUrl); BaseHttpClientInvocation.appendExtraParamsWithQuestionMark(myIfNoneExistParams, b, b.indexOf("?") == -1); result.addHeader(Constants.HEADER_IF_NONE_EXIST, b.toString()); } if (myIfNoneExistString != null) { StringBuilder b = newHeaderBuilder(myUrl); b.append(b.indexOf("?") == -1 ? '?' : '&'); b.append(myIfNoneExistString.substring(myIfNoneExistString.indexOf('?') + 1)); result.addHeader(Constants.HEADER_IF_NONE_EXIST, b.toString()); } } private StringBuilder newHeaderBuilder(StringBuilder theUrlBase) { StringBuilder b = new StringBuilder(); b.append(theUrlBase); if (theUrlBase.length() > 0 && theUrlBase.charAt(theUrlBase.length() - 1) == '/') { b.deleteCharAt(b.length() - 1); } return b; } private HttpRequestBase constructRequestBase(HttpEntity theEntity) { String url = myUrl.toString(); switch (myRequestType) { case DELETE: return new HttpDelete(url); case OPTIONS: return new HttpOptions(url); case POST: HttpPost httpPost = new HttpPost(url); httpPost.setEntity(theEntity); return httpPost; case PUT: HttpPut httpPut = new HttpPut(url); httpPut.setEntity(theEntity); return httpPut; case GET: default: return new HttpGet(url); } } }