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27 package org.apache.hc.client5.http.impl.cache;
28
29 import java.time.Instant;
30
31 import org.apache.hc.client5.http.async.methods.SimpleHttpResponse;
32 import org.apache.hc.client5.http.cache.HeaderConstants;
33 import org.apache.hc.client5.http.cache.HttpCacheEntry;
34 import org.apache.hc.client5.http.cache.Resource;
35 import org.apache.hc.client5.http.cache.ResourceIOException;
36 import org.apache.hc.client5.http.utils.DateUtils;
37 import org.apache.hc.core5.http.ContentType;
38 import org.apache.hc.core5.http.Header;
39 import org.apache.hc.core5.http.HttpHeaders;
40 import org.apache.hc.core5.http.HttpRequest;
41 import org.apache.hc.core5.http.HttpResponse;
42 import org.apache.hc.core5.http.HttpStatus;
43 import org.apache.hc.core5.http.HttpVersion;
44 import org.apache.hc.core5.http.message.BasicHeader;
45 import org.apache.hc.core5.util.TimeValue;
46
47
48
49
50 class CachedHttpResponseGenerator {
51
52 private final CacheValidityPolicy validityStrategy;
53
54 CachedHttpResponseGenerator(final CacheValidityPolicy validityStrategy) {
55 super();
56 this.validityStrategy = validityStrategy;
57 }
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66 SimpleHttpResponse generateResponse(final HttpRequest request, final HttpCacheEntry entry) throws ResourceIOException {
67 final Instant now =Instant.now();
68 final SimpleHttpResponse response = new SimpleHttpResponse(entry.getStatus());
69 response.setVersion(HttpVersion.DEFAULT);
70
71 response.setHeaders(entry.getHeaders());
72
73 if (responseShouldContainEntity(request, entry)) {
74 final Resource resource = entry.getResource();
75 final Header h = entry.getFirstHeader(HttpHeaders.CONTENT_TYPE);
76 final ContentType contentType = h != null ? ContentType.parse(h.getValue()) : null;
77 final byte[] content = resource.get();
78 addMissingContentLengthHeader(response, content);
79 response.setBody(content, contentType);
80 }
81
82 final TimeValue age = this.validityStrategy.getCurrentAge(entry, now);
83 if (TimeValue.isPositive(age)) {
84 if (age.compareTo(CacheValidityPolicy.MAX_AGE) >= 0) {
85 response.setHeader(HeaderConstants.AGE, "" + CacheValidityPolicy.MAX_AGE.toSeconds());
86 } else {
87 response.setHeader(HeaderConstants.AGE, "" + age.toSeconds());
88 }
89 }
90
91 return response;
92 }
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97
98 SimpleHttpResponse generateNotModifiedResponse(final HttpCacheEntry entry) {
99
100 final SimpleHttpResponse response = new SimpleHttpResponse(HttpStatus.SC_NOT_MODIFIED, "Not Modified");
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106 Header dateHeader = entry.getFirstHeader(HttpHeaders.DATE);
107 if (dateHeader == null) {
108 dateHeader = new BasicHeader(HttpHeaders.DATE, DateUtils.formatStandardDate(Instant.now()));
109 }
110 response.addHeader(dateHeader);
111
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114 final Header etagHeader = entry.getFirstHeader(HeaderConstants.ETAG);
115 if (etagHeader != null) {
116 response.addHeader(etagHeader);
117 }
118
119 final Header contentLocationHeader = entry.getFirstHeader(HttpHeaders.CONTENT_LOCATION);
120 if (contentLocationHeader != null) {
121 response.addHeader(contentLocationHeader);
122 }
123
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127 final Header expiresHeader = entry.getFirstHeader(HeaderConstants.EXPIRES);
128 if (expiresHeader != null) {
129 response.addHeader(expiresHeader);
130 }
131
132 final Header cacheControlHeader = entry.getFirstHeader(HeaderConstants.CACHE_CONTROL);
133 if (cacheControlHeader != null) {
134 response.addHeader(cacheControlHeader);
135 }
136
137 final Header varyHeader = entry.getFirstHeader(HeaderConstants.VARY);
138 if (varyHeader != null) {
139 response.addHeader(varyHeader);
140 }
141
142 return response;
143 }
144
145 private void addMissingContentLengthHeader(final HttpResponse response, final byte[] body) {
146 if (transferEncodingIsPresent(response)) {
147 return;
148 }
149
150
151 response.setHeader(HttpHeaders.CONTENT_LENGTH, Integer.toString(body.length));
152 }
153
154 private boolean transferEncodingIsPresent(final HttpResponse response) {
155 final Header hdr = response.getFirstHeader(HttpHeaders.TRANSFER_ENCODING);
156 return hdr != null;
157 }
158
159 private boolean responseShouldContainEntity(final HttpRequest request, final HttpCacheEntry cacheEntry) {
160 return request.getMethod().equals(HeaderConstants.GET_METHOD) && cacheEntry.getResource() != null;
161 }
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170 public SimpleHttpResponse getErrorForRequest(final RequestProtocolError errorCheck) {
171 switch (errorCheck) {
172 case BODY_BUT_NO_LENGTH_ERROR:
173 return SimpleHttpResponse.create(HttpStatus.SC_LENGTH_REQUIRED);
174
175 case WEAK_ETAG_AND_RANGE_ERROR:
176 return SimpleHttpResponse.create(HttpStatus.SC_BAD_REQUEST,
177 "Weak eTag not compatible with byte range", ContentType.DEFAULT_TEXT);
178
179 case WEAK_ETAG_ON_PUTDELETE_METHOD_ERROR:
180 return SimpleHttpResponse.create(HttpStatus.SC_BAD_REQUEST,
181 "Weak eTag not compatible with PUT or DELETE requests");
182
183 case NO_CACHE_DIRECTIVE_WITH_FIELD_NAME:
184 return SimpleHttpResponse.create(HttpStatus.SC_BAD_REQUEST,
185 "No-Cache directive MUST NOT include a field name");
186
187 default:
188 throw new IllegalStateException(
189 "The request was compliant, therefore no error can be generated for it.");
190
191 }
192 }
193
194 }