Java tutorial
/* * ==================================================================== * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you 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. * ==================================================================== * * This software consists of voluntary contributions made by many * individuals on behalf of the Apache Software Foundation. For more * information on the Apache Software Foundation, please see * <http://www.apache.org/>. * */ package com.apigee.sdk.apm.http.impl.client.cache; import java.util.ArrayList; import java.util.Date; import java.util.List; import org.apache.http.Header; import org.apache.http.HeaderElement; import org.apache.http.HttpEntityEnclosingRequest; import org.apache.http.HttpRequest; import org.apache.http.HttpResponse; import org.apache.http.HttpStatus; import org.apache.http.HttpVersion; import org.apache.http.ProtocolVersion; import org.apache.http.client.ClientProtocolException; import org.apache.http.impl.client.RequestWrapper; import org.apache.http.impl.cookie.DateParseException; import org.apache.http.impl.cookie.DateUtils; import org.apache.http.message.BasicHeader; import org.apache.http.protocol.HTTP; import com.apigee.sdk.apm.http.annotation.Immutable; import com.apigee.sdk.apm.http.client.cache.HeaderConstants; /** * @since 4.1 */ @Immutable class ResponseProtocolCompliance { /** * When we get a response from a down stream server (Origin Server) we * attempt to see if it is HTTP 1.1 Compliant and if not, attempt to make it * so. * * @param request * The {@link HttpRequest} that generated an origin hit and * response * @param response * The {@link HttpResponse} from the origin server * @throws ClientProtocolException * when we are unable to 'convert' the response to a compliant * one */ public void ensureProtocolCompliance(HttpRequest request, HttpResponse response) throws ClientProtocolException { if (backendResponseMustNotHaveBody(request, response)) { response.setEntity(null); } authenticationRequiredDidNotHaveAProxyAuthenticationHeader(request, response); notAllowedResponseDidNotHaveAnAllowHeader(request, response); unauthorizedResponseDidNotHaveAWWWAuthenticateHeader(request, response); requestDidNotExpect100ContinueButResponseIsOne(request, response); transferEncodingIsNotReturnedTo1_0Client(request, response); ensurePartialContentIsNotSentToAClientThatDidNotRequestIt(request, response); ensure200ForOPTIONSRequestWithNoBodyHasContentLengthZero(request, response); ensure206ContainsDateHeader(response); identityIsNotUsedInContentEncoding(response); warningsWithNonMatchingWarnDatesAreRemoved(response); } private void warningsWithNonMatchingWarnDatesAreRemoved(HttpResponse response) { Date responseDate = null; try { responseDate = DateUtils.parseDate(response.getFirstHeader("Date").getValue()); } catch (DateParseException e) { } if (responseDate == null) return; Header[] warningHeaders = response.getHeaders("Warning"); if (warningHeaders == null || warningHeaders.length == 0) return; List<Header> newWarningHeaders = new ArrayList<Header>(); boolean modified = false; for (Header h : warningHeaders) { for (WarningValue wv : WarningValue.getWarningValues(h)) { Date warnDate = wv.getWarnDate(); if (warnDate == null || warnDate.equals(responseDate)) { newWarningHeaders.add(new BasicHeader("Warning", wv.toString())); } else { modified = true; } } } if (modified) { response.removeHeaders("Warning"); for (Header h : newWarningHeaders) { response.addHeader(h); } } } private void identityIsNotUsedInContentEncoding(HttpResponse response) { Header[] hdrs = response.getHeaders("Content-Encoding"); if (hdrs == null || hdrs.length == 0) return; List<Header> newHeaders = new ArrayList<Header>(); boolean modified = false; for (Header h : hdrs) { StringBuilder buf = new StringBuilder(); boolean first = true; for (HeaderElement elt : h.getElements()) { if ("identity".equalsIgnoreCase(elt.getName())) { modified = true; } else { if (!first) buf.append(","); buf.append(elt.toString()); first = false; } } String newHeaderValue = buf.toString(); if (!"".equals(newHeaderValue)) { newHeaders.add(new BasicHeader("Content-Encoding", newHeaderValue)); } } if (!modified) return; response.removeHeaders("Content-Encoding"); for (Header h : newHeaders) { response.addHeader(h); } } private void authenticationRequiredDidNotHaveAProxyAuthenticationHeader(HttpRequest request, HttpResponse response) throws ClientProtocolException { if (response.getStatusLine().getStatusCode() != HttpStatus.SC_PROXY_AUTHENTICATION_REQUIRED) return; if (response.getFirstHeader(HeaderConstants.PROXY_AUTHENTICATE) == null) throw new ClientProtocolException("407 Response did not contain a Proxy-Authentication header"); } private void notAllowedResponseDidNotHaveAnAllowHeader(HttpRequest request, HttpResponse response) throws ClientProtocolException { if (response.getStatusLine().getStatusCode() != HttpStatus.SC_METHOD_NOT_ALLOWED) return; if (response.getFirstHeader(HeaderConstants.ALLOW) == null) throw new ClientProtocolException("405 Response did not contain an Allow header."); } private void unauthorizedResponseDidNotHaveAWWWAuthenticateHeader(HttpRequest request, HttpResponse response) throws ClientProtocolException { if (response.getStatusLine().getStatusCode() != HttpStatus.SC_UNAUTHORIZED) return; if (response.getFirstHeader(HeaderConstants.WWW_AUTHENTICATE) == null) { throw new ClientProtocolException( "401 Response did not contain required WWW-Authenticate challenge header"); } } private void ensure206ContainsDateHeader(HttpResponse response) { if (response.getFirstHeader(HTTP.DATE_HEADER) == null) { response.addHeader(HTTP.DATE_HEADER, DateUtils.formatDate(new Date())); } } private void ensurePartialContentIsNotSentToAClientThatDidNotRequestIt(HttpRequest request, HttpResponse response) throws ClientProtocolException { if (request.getFirstHeader(HeaderConstants.RANGE) != null) return; if (response.getFirstHeader(HeaderConstants.CONTENT_RANGE) != null) { throw new ClientProtocolException( "Content-Range was returned for a request that did not ask for a Content-Range."); } } private void ensure200ForOPTIONSRequestWithNoBodyHasContentLengthZero(HttpRequest request, HttpResponse response) { if (!request.getRequestLine().getMethod().equalsIgnoreCase(HeaderConstants.OPTIONS_METHOD)) { return; } if (response.getStatusLine().getStatusCode() != HttpStatus.SC_OK) { return; } if (response.getFirstHeader(HTTP.CONTENT_LEN) == null) { response.addHeader(HTTP.CONTENT_LEN, "0"); } } private boolean backendResponseMustNotHaveBody(HttpRequest request, HttpResponse backendResponse) { return HeaderConstants.HEAD_METHOD.equals(request.getRequestLine().getMethod()) || backendResponse.getStatusLine().getStatusCode() == HttpStatus.SC_NO_CONTENT || backendResponse.getStatusLine().getStatusCode() == HttpStatus.SC_RESET_CONTENT || backendResponse.getStatusLine().getStatusCode() == HttpStatus.SC_NOT_MODIFIED; } private void requestDidNotExpect100ContinueButResponseIsOne(HttpRequest request, HttpResponse response) throws ClientProtocolException { if (response.getStatusLine().getStatusCode() != HttpStatus.SC_CONTINUE) { return; } if (!requestWasWrapped(request)) { return; } ProtocolVersion originalProtocol = getOriginalRequestProtocol((RequestWrapper) request); if (originalProtocol.compareToVersion(HttpVersion.HTTP_1_1) >= 0) { return; } if (originalRequestDidNotExpectContinue((RequestWrapper) request)) { throw new ClientProtocolException("The incoming request did not contain a " + "100-continue header, but the response was a Status 100, continue."); } } private void transferEncodingIsNotReturnedTo1_0Client(HttpRequest request, HttpResponse response) { if (!requestWasWrapped(request)) { return; } ProtocolVersion originalProtocol = getOriginalRequestProtocol((RequestWrapper) request); if (originalProtocol.compareToVersion(HttpVersion.HTTP_1_1) >= 0) { return; } removeResponseTransferEncoding(response); } private void removeResponseTransferEncoding(HttpResponse response) { response.removeHeaders("TE"); response.removeHeaders(HTTP.TRANSFER_ENCODING); } private boolean originalRequestDidNotExpectContinue(RequestWrapper request) { try { HttpEntityEnclosingRequest original = (HttpEntityEnclosingRequest) request.getOriginal(); return !original.expectContinue(); } catch (ClassCastException ex) { return false; } } private ProtocolVersion getOriginalRequestProtocol(RequestWrapper request) { return request.getOriginal().getProtocolVersion(); } private boolean requestWasWrapped(HttpRequest request) { return request instanceof RequestWrapper; } }