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1 package cachingfilter;
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2
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3 import java.io.IOException;
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4 import java.text.DateFormat;
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5 import java.text.SimpleDateFormat;
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6 import java.util.Enumeration;
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7 import java.util.TimeZone;
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8 import java.util.Date;
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9 import java.util.Locale;
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10 import java.util.Map;
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11 import java.util.HashMap;
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12 import javax.servlet.http.HttpServletRequest;
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13 import javax.servlet.http.HttpServletRequestWrapper;
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14 import org.slf4j.Logger;
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15 import org.slf4j.LoggerFactory;
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16 import org.eclipse.jetty.server.AbstractHttpConnection;
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17
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18
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19 final class CachingRequestWrapper extends HttpServletRequestWrapper {
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20 private static final Logger logger = LoggerFactory.getLogger(CachingRequestWrapper.class);
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21
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22 static final String IF_MODIFIED_SINCE = "If-Modified-Since".toLowerCase();
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23 static final String IF_NONE_MATCH = "If-None-Match".toLowerCase();
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24 static final String ACCEPT_ENCODING = "Accept-Encoding".toLowerCase();
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25
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26 final Map<String,Object> headerMap = new HashMap<String,Object>();
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27
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28 CachingRequestWrapper(HttpServletRequest request) throws IOException {
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29 super(request);
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30 checkRequest(request);
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31 }
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32
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33 private static void checkRequest(HttpServletRequest request) throws IOException {
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34 AbstractHttpConnection c = ((org.eclipse.jetty.server.Request) request).getConnection();
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35 if (c.getRequestFields().containsKey("Host")) {
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36 for (Enumeration<String> e2 = c.getRequestFields().getValues("Host"); e2.hasMoreElements();) {
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37 if (e2.nextElement().trim().endsWith(":")) {
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38 throw new IOException("Bad 'Host' request header (ends with colon)");
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39 }
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40 }
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41 }
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42 }
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43
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44 public String getHeader(String name) {
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45 /*
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46 String v = getHeader2(name);
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47 logger.trace("getHeader "+name+" = "+v);
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48 return v;
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49 }
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50 public String getHeader2(String name) {
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51 */
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52 String key = name.toLowerCase();
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53 if( headerMap.containsKey(key) ) {
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54 Object val = headerMap.get(key);
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55 if( val instanceof Long ) {
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56 long date = (Long)val;
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57 if( date == -1 )
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58 return null;
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59 return formatDate(date);
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60 }
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61 return (String)val;
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62 }
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63 return super.getHeader(name);
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64 }
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65
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66 public long getDateHeader(String name) {
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67 /*
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68 long v = getDateHeader2(name);
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69 logger.trace("getDateHeader "+name+" = "+v);
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70 return v;
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71 }
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72 public long getDateHeader2(String name) {
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73 */
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74 String key = name.toLowerCase();
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75 if( headerMap.containsKey(key) )
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76 return (Long)headerMap.get(key);
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77 return super.getDateHeader(name);
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78 }
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79
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80 boolean isCacheable() {
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81 boolean isCacheable = false;
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82 Long val = (Long)headerMap.get(IF_MODIFIED_SINCE);
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83 if( val!=null ) {
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84 try {
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85 long cachedLastModified = val;
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86 if( cachedLastModified != -1 ) {
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87 long ifModifiedSince = super.getDateHeader(IF_MODIFIED_SINCE);
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88 //logger.trace("cachedLastModified = "+cachedLastModified+" ifModifiedSince = "+ifModifiedSince);
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89 if( cachedLastModified > ifModifiedSince )
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90 return false;
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91 isCacheable = true;
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92 }
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93 } catch(IllegalArgumentException e) {
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94 logger.warn("bad date, user-agent="+getHeader("user-agent"),e);
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95 }
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96 }
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97 String etag = (String)headerMap.get(IF_NONE_MATCH);
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98 if( etag != null ) {
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99 String ifNoneMatch = super.getHeader(IF_NONE_MATCH);
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100 if( !etag.equals(ifNoneMatch) )
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101 return false;
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102 isCacheable = true;
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103 }
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104 return isCacheable;
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105 }
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106
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107
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108 private static ThreadLocal<DateFormat> dateFormat = new ThreadLocal<DateFormat>() {
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109 protected synchronized DateFormat initialValue() {
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110 DateFormat httpDateFormat = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss z", Locale.US);
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111 httpDateFormat.setTimeZone(TimeZone.getTimeZone("GMT"));
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112 return httpDateFormat;
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113 }
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114 };
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115
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116 private String formatDate(long date) {
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117 return dateFormat.get().format(new Date(date));
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118 }
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119 }
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