Java tutorial
/* * Copyright 2002-2017 the original author or authors. * * Licensed 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 * * https://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. */ package org.springframework.web.socket; import java.util.ArrayList; import java.util.Collection; import java.util.Collections; import java.util.List; import java.util.Map; import java.util.Set; import org.springframework.http.HttpHeaders; import org.springframework.lang.Nullable; import org.springframework.util.CollectionUtils; /** * An {@link org.springframework.http.HttpHeaders} variant that adds support for * the HTTP headers defined by the WebSocket specification RFC 6455. * * @author Rossen Stoyanchev * @since 4.0 */ public class WebSocketHttpHeaders extends HttpHeaders { public static final String SEC_WEBSOCKET_ACCEPT = "Sec-WebSocket-Accept"; public static final String SEC_WEBSOCKET_EXTENSIONS = "Sec-WebSocket-Extensions"; public static final String SEC_WEBSOCKET_KEY = "Sec-WebSocket-Key"; public static final String SEC_WEBSOCKET_PROTOCOL = "Sec-WebSocket-Protocol"; public static final String SEC_WEBSOCKET_VERSION = "Sec-WebSocket-Version"; private static final long serialVersionUID = -6644521016187828916L; private final HttpHeaders headers; /** * Create a new instance. */ public WebSocketHttpHeaders() { this(new HttpHeaders(), false); } /** * Create an instance that wraps the given pre-existing HttpHeaders and also * propagate all changes to it. * @param headers the HTTP headers to wrap */ public WebSocketHttpHeaders(HttpHeaders headers) { this(headers, false); } /** * Private constructor that can create read-only {@code WebSocketHttpHeader} instances. */ private WebSocketHttpHeaders(HttpHeaders headers, boolean readOnly) { this.headers = readOnly ? HttpHeaders.readOnlyHttpHeaders(headers) : headers; } /** * Returns {@code WebSocketHttpHeaders} object that can only be read, not written to. */ public static WebSocketHttpHeaders readOnlyWebSocketHttpHeaders(WebSocketHttpHeaders headers) { return new WebSocketHttpHeaders(headers, true); } /** * Sets the (new) value of the {@code Sec-WebSocket-Accept} header. * @param secWebSocketAccept the value of the header */ public void setSecWebSocketAccept(@Nullable String secWebSocketAccept) { set(SEC_WEBSOCKET_ACCEPT, secWebSocketAccept); } /** * Returns the value of the {@code Sec-WebSocket-Accept} header. * @return the value of the header */ @Nullable public String getSecWebSocketAccept() { return getFirst(SEC_WEBSOCKET_ACCEPT); } /** * Returns the value of the {@code Sec-WebSocket-Extensions} header. * @return the value of the header */ public List<WebSocketExtension> getSecWebSocketExtensions() { List<String> values = get(SEC_WEBSOCKET_EXTENSIONS); if (CollectionUtils.isEmpty(values)) { return Collections.emptyList(); } else { List<WebSocketExtension> result = new ArrayList<>(values.size()); for (String value : values) { result.addAll(WebSocketExtension.parseExtensions(value)); } return result; } } /** * Sets the (new) value(s) of the {@code Sec-WebSocket-Extensions} header. * @param extensions the values for the header */ public void setSecWebSocketExtensions(List<WebSocketExtension> extensions) { List<String> result = new ArrayList<>(extensions.size()); for (WebSocketExtension extension : extensions) { result.add(extension.toString()); } set(SEC_WEBSOCKET_EXTENSIONS, toCommaDelimitedString(result)); } /** * Sets the (new) value of the {@code Sec-WebSocket-Key} header. * @param secWebSocketKey the value of the header */ public void setSecWebSocketKey(@Nullable String secWebSocketKey) { set(SEC_WEBSOCKET_KEY, secWebSocketKey); } /** * Returns the value of the {@code Sec-WebSocket-Key} header. * @return the value of the header */ @Nullable public String getSecWebSocketKey() { return getFirst(SEC_WEBSOCKET_KEY); } /** * Sets the (new) value of the {@code Sec-WebSocket-Protocol} header. * @param secWebSocketProtocol the value of the header */ public void setSecWebSocketProtocol(String secWebSocketProtocol) { set(SEC_WEBSOCKET_PROTOCOL, secWebSocketProtocol); } /** * Sets the (new) value of the {@code Sec-WebSocket-Protocol} header. * @param secWebSocketProtocols the value of the header */ public void setSecWebSocketProtocol(List<String> secWebSocketProtocols) { set(SEC_WEBSOCKET_PROTOCOL, toCommaDelimitedString(secWebSocketProtocols)); } /** * Returns the value of the {@code Sec-WebSocket-Key} header. * @return the value of the header */ public List<String> getSecWebSocketProtocol() { List<String> values = get(SEC_WEBSOCKET_PROTOCOL); if (CollectionUtils.isEmpty(values)) { return Collections.emptyList(); } else if (values.size() == 1) { return getValuesAsList(SEC_WEBSOCKET_PROTOCOL); } else { return values; } } /** * Sets the (new) value of the {@code Sec-WebSocket-Version} header. * @param secWebSocketVersion the value of the header */ public void setSecWebSocketVersion(@Nullable String secWebSocketVersion) { set(SEC_WEBSOCKET_VERSION, secWebSocketVersion); } /** * Returns the value of the {@code Sec-WebSocket-Version} header. * @return the value of the header */ @Nullable public String getSecWebSocketVersion() { return getFirst(SEC_WEBSOCKET_VERSION); } // Single string methods /** * Return the first header value for the given header name, if any. * @param headerName the header name * @return the first header value; or {@code null} */ @Override @Nullable public String getFirst(String headerName) { return this.headers.getFirst(headerName); } /** * Add the given, single header value under the given name. * @param headerName the header name * @param headerValue the header value * @throws UnsupportedOperationException if adding headers is not supported * @see #put(String, List) * @see #set(String, String) */ @Override public void add(String headerName, @Nullable String headerValue) { this.headers.add(headerName, headerValue); } /** * Set the given, single header value under the given name. * @param headerName the header name * @param headerValue the header value * @throws UnsupportedOperationException if adding headers is not supported * @see #put(String, List) * @see #add(String, String) */ @Override public void set(String headerName, @Nullable String headerValue) { this.headers.set(headerName, headerValue); } @Override public void setAll(Map<String, String> values) { this.headers.setAll(values); } @Override public Map<String, String> toSingleValueMap() { return this.headers.toSingleValueMap(); } // Map implementation @Override public int size() { return this.headers.size(); } @Override public boolean isEmpty() { return this.headers.isEmpty(); } @Override public boolean containsKey(Object key) { return this.headers.containsKey(key); } @Override public boolean containsValue(Object value) { return this.headers.containsValue(value); } @Override public List<String> get(Object key) { return this.headers.get(key); } @Override public List<String> put(String key, List<String> value) { return this.headers.put(key, value); } @Override public List<String> remove(Object key) { return this.headers.remove(key); } @Override public void putAll(Map<? extends String, ? extends List<String>> m) { this.headers.putAll(m); } @Override public void clear() { this.headers.clear(); } @Override public Set<String> keySet() { return this.headers.keySet(); } @Override public Collection<List<String>> values() { return this.headers.values(); } @Override public Set<Entry<String, List<String>>> entrySet() { return this.headers.entrySet(); } @Override public boolean equals(@Nullable Object other) { if (this == other) { return true; } if (!(other instanceof WebSocketHttpHeaders)) { return false; } WebSocketHttpHeaders otherHeaders = (WebSocketHttpHeaders) other; return this.headers.equals(otherHeaders.headers); } @Override public int hashCode() { return this.headers.hashCode(); } @Override public String toString() { return this.headers.toString(); } }