CacheKeyGenerator.java
/*
* ====================================================================
* 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 org.apache.hc.client5.http.impl.cache;
import java.net.URI;
import java.net.URISyntaxException;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;
import java.util.Spliterator;
import java.util.Spliterators;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.function.Consumer;
import java.util.stream.StreamSupport;
import org.apache.hc.client5.http.cache.HttpCacheEntry;
import org.apache.hc.core5.annotation.Contract;
import org.apache.hc.core5.annotation.Internal;
import org.apache.hc.core5.annotation.ThreadingBehavior;
import org.apache.hc.core5.function.Resolver;
import org.apache.hc.core5.http.Header;
import org.apache.hc.core5.http.HeaderElement;
import org.apache.hc.core5.http.HttpHeaders;
import org.apache.hc.core5.http.HttpHost;
import org.apache.hc.core5.http.HttpRequest;
import org.apache.hc.core5.http.MessageHeaders;
import org.apache.hc.core5.http.NameValuePair;
import org.apache.hc.core5.http.URIScheme;
import org.apache.hc.core5.http.message.BasicHeaderElementIterator;
import org.apache.hc.core5.http.message.BasicHeaderValueFormatter;
import org.apache.hc.core5.http.message.BasicNameValuePair;
import org.apache.hc.core5.http.message.MessageSupport;
import org.apache.hc.core5.net.PercentCodec;
import org.apache.hc.core5.net.URIAuthority;
import org.apache.hc.core5.net.URIBuilder;
import org.apache.hc.core5.util.Args;
import org.apache.hc.core5.util.CharArrayBuffer;
import org.apache.hc.core5.util.TextUtils;
/**
* @since 4.1
*/
@Contract(threading = ThreadingBehavior.STATELESS)
public class CacheKeyGenerator implements Resolver<URI, String> {
/**
* Default instance of {@link CacheKeyGenerator}.
*/
public static final CacheKeyGenerator INSTANCE = new CacheKeyGenerator();
@Override
public String resolve(final URI uri) {
return generateKey(uri);
}
/**
* Returns text representation of the request URI of the given {@link HttpRequest}.
* This method will use {@link HttpRequest#getPath()}, {@link HttpRequest#getScheme()} and
* {@link HttpRequest#getAuthority()} values when available or attributes of target
* {@link HttpHost } in order to construct an absolute URI.
* <p>
* This method will not attempt to ensure validity of the resultant text representation.
*
* @param target target host
* @param request the {@link HttpRequest}
*
* @return String the request URI
*/
@Internal
public static String getRequestUri(final HttpHost target, final HttpRequest request) {
Args.notNull(target, "Target");
Args.notNull(request, "HTTP request");
final StringBuilder buf = new StringBuilder();
final URIAuthority authority = request.getAuthority();
if (authority != null) {
final String scheme = request.getScheme();
buf.append(scheme != null ? scheme : URIScheme.HTTP.id).append("://");
buf.append(authority.getHostName());
if (authority.getPort() >= 0) {
buf.append(":").append(authority.getPort());
}
} else {
buf.append(target.getSchemeName()).append("://");
buf.append(target.getHostName());
if (target.getPort() >= 0) {
buf.append(":").append(target.getPort());
}
}
final String path = request.getPath();
if (path == null) {
buf.append("/");
} else {
if (buf.length() > 0 && !path.startsWith("/")) {
buf.append("/");
}
buf.append(path);
}
return buf.toString();
}
/**
* Returns normalized representation of the request URI optimized for use as a cache key.
* This method ensures the resultant URI has an explicit port in the authority component,
* and explicit path component and no fragment.
*/
@Internal
public static URI normalize(final URI requestUri) throws URISyntaxException {
Args.notNull(requestUri, "URI");
final URIBuilder builder = new URIBuilder(requestUri);
if (builder.getHost() != null) {
if (builder.getScheme() == null) {
builder.setScheme(URIScheme.HTTP.id);
}
if (builder.getPort() <= -1) {
if (URIScheme.HTTP.same(builder.getScheme())) {
builder.setPort(80);
} else if (URIScheme.HTTPS.same(builder.getScheme())) {
builder.setPort(443);
}
}
}
builder.setFragment(null);
return builder.optimize().build();
}
/**
* Lenient URI parser that normalizes valid {@link URI}s and returns {@code null} for malformed URIs.
*/
@Internal
public static URI normalize(final String requestUri) {
if (requestUri == null) {
return null;
}
try {
return CacheKeyGenerator.normalize(new URI(requestUri));
} catch (final URISyntaxException ex) {
return null;
}
}
/**
* Computes a key for the given request {@link URI} that can be used as
* a unique identifier for cached resources. The URI is expected to
* in an absolute form.
*
* @param requestUri request URI
* @return cache key
*/
public String generateKey(final URI requestUri) {
try {
final URI normalizeRequestUri = normalize(requestUri);
return normalizeRequestUri.toASCIIString();
} catch (final URISyntaxException ex) {
return requestUri.toASCIIString();
}
}
/**
* Computes a root key for the given {@link HttpHost} and {@link HttpRequest}
* that can be used as a unique identifier for cached resources.
*
* @param host The host for this request
* @param request the {@link HttpRequest}
* @return cache key
*/
public String generateKey(final HttpHost host, final HttpRequest request) {
final String s = getRequestUri(host, request);
try {
return generateKey(new URI(s));
} catch (final URISyntaxException ex) {
return s;
}
}
/**
* Returns all variant names contained in {@literal VARY} headers of the given message.
*
* @since 5.4
*/
public static List<String> variantNames(final MessageHeaders message) {
if (message == null) {
return null;
}
final List<String> names = new ArrayList<>();
for (final Iterator<Header> it = message.headerIterator(HttpHeaders.VARY); it.hasNext(); ) {
final Header header = it.next();
MessageSupport.parseTokens(header, names::add);
}
return names;
}
@Internal
public static void normalizeElements(final MessageHeaders message, final String headerName, final Consumer<String> consumer) {
// User-Agent as a special case due to its grammar
if (headerName.equalsIgnoreCase(HttpHeaders.USER_AGENT)) {
final Header header = message.getFirstHeader(headerName);
if (header != null) {
consumer.accept(header.getValue().toLowerCase(Locale.ROOT));
}
} else {
normalizeElements(message.headerIterator(headerName), consumer);
}
}
@Internal
public static void normalizeElements(final Iterator<Header> iterator, final Consumer<String> consumer) {
final Iterator<HeaderElement> it = new BasicHeaderElementIterator(iterator);
StreamSupport.stream(Spliterators.spliteratorUnknownSize(it, Spliterator.NONNULL), false)
.filter(e -> !TextUtils.isBlank(e.getName()))
.map(e -> {
if (e.getValue() == null && e.getParameterCount() == 0) {
return e.getName().toLowerCase(Locale.ROOT);
}
final CharArrayBuffer buf = new CharArrayBuffer(1024);
BasicHeaderValueFormatter.INSTANCE.formatNameValuePair(
buf,
new BasicNameValuePair(
e.getName().toLowerCase(Locale.ROOT),
!TextUtils.isBlank(e.getValue()) ? e.getValue() : null),
false);
if (e.getParameterCount() > 0) {
for (final NameValuePair nvp : e.getParameters()) {
if (!TextUtils.isBlank(nvp.getName())) {
buf.append(';');
BasicHeaderValueFormatter.INSTANCE.formatNameValuePair(
buf,
new BasicNameValuePair(
nvp.getName().toLowerCase(Locale.ROOT),
!TextUtils.isBlank(nvp.getValue()) ? nvp.getValue() : null),
false);
}
}
}
return buf.toString();
})
.sorted()
.distinct()
.forEach(consumer);
}
/**
* Computes a "variant key" for the given request and the given variants.
* @param request originating request
* @param variantNames variant names
* @return variant key
*
* @since 5.4
*/
public String generateVariantKey(final HttpRequest request, final Collection<String> variantNames) {
Args.notNull(variantNames, "Variant names");
final StringBuilder buf = new StringBuilder("{");
final AtomicBoolean firstHeader = new AtomicBoolean();
variantNames.stream()
.map(h -> h.toLowerCase(Locale.ROOT))
.sorted()
.distinct()
.forEach(h -> {
if (!firstHeader.compareAndSet(false, true)) {
buf.append("&");
}
buf.append(PercentCodec.encode(h, StandardCharsets.UTF_8)).append("=");
final AtomicBoolean firstToken = new AtomicBoolean();
normalizeElements(request, h, t -> {
if (!firstToken.compareAndSet(false, true)) {
buf.append(",");
}
buf.append(PercentCodec.encode(t, StandardCharsets.UTF_8));
});
});
buf.append("}");
return buf.toString();
}
/**
* Computes a "variant key" from the headers of the given request if the given
* cache entry can have variants ({@code Vary} header is present).
*
* @param request originating request
* @param entry cache entry
* @return variant key if the given cache entry can have variants, {@code null} otherwise.
*/
public String generateVariantKey(final HttpRequest request, final HttpCacheEntry entry) {
if (entry.containsHeader(HttpHeaders.VARY)) {
final List<String> variantNames = variantNames(entry);
return generateVariantKey(request, variantNames);
}
return null;
}
/**
* Computes a key for the given {@link HttpHost} and {@link HttpRequest}
* that can be used as a unique identifier for cached resources. if the request has a
* {@literal VARY} header the identifier will also include variant key.
*
* @param host The host for this request
* @param request the {@link HttpRequest}
* @param entry the parent entry used to track the variants
* @return cache key
*
* @deprecated Use {@link #generateKey(HttpHost, HttpRequest)} or {@link #generateVariantKey(HttpRequest, Collection)}
*/
@Deprecated
public String generateKey(final HttpHost host, final HttpRequest request, final HttpCacheEntry entry) {
final String rootKey = generateKey(host, request);
final List<String> variantNames = variantNames(entry);
if (variantNames.isEmpty()) {
return rootKey;
}
return generateVariantKey(request, variantNames) + rootKey;
}
}