Example usage for org.apache.http.client.cache HeaderConstants LAST_MODIFIED

Introduction

In this page you can find the example usage for org.apache.http.client.cache HeaderConstants LAST_MODIFIED.

Prototype

String LAST_MODIFIED

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Usage

From source file:org.apache.http.impl.client.cache.CachedResponseSuitabilityChecker.java

/**
 * Check entry against If-Modified-Since, if If-Modified-Since is in the future it is invalid as per
 * http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html
 * @param request//from  w w  w  .j a va 2  s. co  m
 * @param entry
 * @param now
 * @return
 */
private boolean lastModifiedValidatorMatches(HttpRequest request, HttpCacheEntry entry, Date now) {
    Header lastModifiedHeader = entry.getFirstHeader(HeaderConstants.LAST_MODIFIED);
    Date lastModified = null;
    try {
        if (lastModifiedHeader != null) {
            lastModified = DateUtils.parseDate(lastModifiedHeader.getValue());
        }
    } catch (DateParseException dpe) {
        // nop
    }

    if (lastModified == null) {
        return false;
    }

    for (Header h : request.getHeaders(HeaderConstants.IF_MODIFIED_SINCE)) {
        try {
            Date ifModifiedSince = DateUtils.parseDate(h.getValue());
            if (ifModifiedSince.after(now) || lastModified.after(ifModifiedSince)) {
                return false;
            }
        } catch (DateParseException dpe) {
            // nop
        }
    }
    return true;
}

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From source file:org.apache.http.impl.client.cache.ConditionalRequestBuilder.java

/**
 * When a {@link HttpCacheEntry} is stale but 'might' be used as a response
 * to an {@link HttpRequest} we will attempt to revalidate the entry with
 * the origin.  Build the origin {@link HttpRequest} here and return it.
 *
 * @param request the original request from the caller
 * @param cacheEntry the entry that needs to be revalidated
 * @return the wrapped request//from  ww w  .j ava  2  s  . co  m
 * @throws ProtocolException when I am unable to build a new origin request.
 */
public HttpRequest buildConditionalRequest(HttpRequest request, HttpCacheEntry cacheEntry)
        throws ProtocolException {
    RequestWrapper wrapperRequest = new RequestWrapper(request);
    wrapperRequest.resetHeaders();
    Header eTag = cacheEntry.getFirstHeader(HeaderConstants.ETAG);
    if (eTag != null) {
        wrapperRequest.setHeader(HeaderConstants.IF_NONE_MATCH, eTag.getValue());
    }
    Header lastModified = cacheEntry.getFirstHeader(HeaderConstants.LAST_MODIFIED);
    if (lastModified != null) {
        wrapperRequest.setHeader(HeaderConstants.IF_MODIFIED_SINCE, lastModified.getValue());
    }
    boolean mustRevalidate = false;
    for (Header h : cacheEntry.getHeaders(HeaderConstants.CACHE_CONTROL)) {
        for (HeaderElement elt : h.getElements()) {
            if (HeaderConstants.CACHE_CONTROL_MUST_REVALIDATE.equalsIgnoreCase(elt.getName())
                    || HeaderConstants.CACHE_CONTROL_PROXY_REVALIDATE.equalsIgnoreCase(elt.getName())) {
                mustRevalidate = true;
                break;
            }
        }
    }
    if (mustRevalidate) {
        wrapperRequest.addHeader("Cache-Control", "max-age=0");
    }
    return wrapperRequest;

}

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