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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.HttpCacheEntry;
33 import org.apache.hc.client5.http.cache.Resource;
34 import org.apache.hc.client5.http.cache.ResourceIOException;
35 import org.apache.hc.client5.http.utils.DateUtils;
36 import org.apache.hc.client5.http.validator.ETag;
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.Method;
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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65
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
70 response.setHeaders(entry.getHeaders());
71
72 if (responseShouldContainEntity(request, entry)) {
73 final Resource resource = entry.getResource();
74 final Header h = entry.getFirstHeader(HttpHeaders.CONTENT_TYPE);
75 final ContentType contentType = h != null ? ContentType.parse(h.getValue()) : null;
76 final byte[] content = resource.get();
77 generateContentLength(response, content);
78 response.setBody(content, contentType);
79 }
80
81 final TimeValue age = this.validityStrategy.getCurrentAge(entry, now);
82 if (TimeValue.isPositive(age)) {
83 if (age.compareTo(CacheSupport.MAX_AGE) >= 0) {
84 response.setHeader(HttpHeaders.AGE, Long.toString(CacheSupport.MAX_AGE.toSeconds()));
85 } else {
86 response.setHeader(HttpHeaders.AGE, Long.toString(age.toSeconds()));
87 }
88 }
89
90 return response;
91 }
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97 SimpleHttpResponse generateNotModifiedResponse(final HttpCacheEntry entry) {
98
99 final SimpleHttpResponse response = new SimpleHttpResponse(HttpStatus.SC_NOT_MODIFIED, "Not Modified");
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104 Header dateHeader = entry.getFirstHeader(HttpHeaders.DATE);
105 if (dateHeader == null) {
106 dateHeader = new BasicHeader(HttpHeaders.DATE, DateUtils.formatStandardDate(Instant.now()));
107 }
108 response.addHeader(dateHeader);
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112 final ETag eTag = entry.getETag();
113 if (eTag != null) {
114 response.addHeader(new BasicHeader(HttpHeaders.ETAG, eTag.toString()));
115 }
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117 final Header contentLocationHeader = entry.getFirstHeader(HttpHeaders.CONTENT_LOCATION);
118 if (contentLocationHeader != null) {
119 response.addHeader(contentLocationHeader);
120 }
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125 final Header expiresHeader = entry.getFirstHeader(HttpHeaders.EXPIRES);
126 if (expiresHeader != null) {
127 response.addHeader(expiresHeader);
128 }
129
130 final Header cacheControlHeader = entry.getFirstHeader(HttpHeaders.CACHE_CONTROL);
131 if (cacheControlHeader != null) {
132 response.addHeader(cacheControlHeader);
133 }
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135 final Header varyHeader = entry.getFirstHeader(HttpHeaders.VARY);
136 if (varyHeader != null) {
137 response.addHeader(varyHeader);
138 }
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145
146 if (eTag == null) {
147 final Header lastModifiedHeader = entry.getFirstHeader(HttpHeaders.LAST_MODIFIED);
148 if (lastModifiedHeader != null) {
149 response.addHeader(lastModifiedHeader);
150 }
151 }
152 return response;
153 }
154
155 private void generateContentLength(final HttpResponse response, final byte[] body) {
156 response.removeHeaders(HttpHeaders.TRANSFER_ENCODING);
157 response.setHeader(HttpHeaders.CONTENT_LENGTH, Integer.toString(body.length));
158 }
159
160 private boolean responseShouldContainEntity(final HttpRequest request, final HttpCacheEntry cacheEntry) {
161 return Method.GET.isSame(request.getMethod()) && cacheEntry.getResource() != null;
162 }
163
164 }