Java tutorial
/* * Copyright 2002-2010 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 * * 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. */ package jails.http; import java.net.URI; import java.nio.charset.Charset; import java.text.ParseException; import java.text.SimpleDateFormat; import java.util.ArrayList; import java.util.Collection; import java.util.Collections; import java.util.Date; import java.util.EnumSet; import java.util.Iterator; import java.util.LinkedHashMap; import java.util.LinkedList; import java.util.List; import java.util.Locale; import java.util.Map; import java.util.Set; import java.util.TimeZone; import org.springframework.util.Assert; import org.springframework.util.LinkedCaseInsensitiveMap; import org.springframework.util.MultiValueMap; import org.springframework.util.StringUtils; /** * Represents HTTP request and response headers, mapping string header names to list of string values. * * <p>In addition to the normal methods defined by {@link Map}, this class offers the following convenience methods: * <ul> * <li>{@link #getFirst(String)} returns the first value associated with a given header name</li> * <li>{@link #add(String, String)} adds a header value to the list of values for a header name</li> * <li>{@link #set(String, String)} sets the header value to a single string value</li> * </ul> * * <p>Inspired by {@link com.sun.net.httpserver.Headers}. * * @author Arjen Poutsma * @since 3.0 */ public class HttpHeaders implements MultiValueMap<String, String> { private static final String ACCEPT = "Accept"; private static final String ACCEPT_CHARSET = "Accept-Charset"; private static final String ALLOW = "Allow"; private static final String CACHE_CONTROL = "Cache-Control"; private static final String CONTENT_DISPOSITION = "Content-Disposition"; private static final String CONTENT_LENGTH = "Content-Length"; private static final String CONTENT_TYPE = "Content-Type"; private static final String DATE = "Date"; private static final String ETAG = "ETag"; private static final String EXPIRES = "Expires"; private static final String IF_MODIFIED_SINCE = "If-Modified-Since"; private static final String IF_NONE_MATCH = "If-None-Match"; private static final String LAST_MODIFIED = "Last-Modified"; private static final String LOCATION = "Location"; private static final String PRAGMA = "Pragma"; private static final String[] DATE_FORMATS = new String[] { "EEE, dd MMM yyyy HH:mm:ss zzz", "EEE, dd-MMM-yy HH:mm:ss zzz", "EEE MMM dd HH:mm:ss yyyy" }; private static TimeZone GMT = TimeZone.getTimeZone("GMT"); private final Map<String, List<String>> headers; /** * Private constructor that can create read-only {@code HttpHeader} instances. */ private HttpHeaders(Map<String, List<String>> headers, boolean readOnly) { Assert.notNull(headers, "'headers' must not be null"); if (readOnly) { Map<String, List<String>> map = new LinkedCaseInsensitiveMap<List<String>>(headers.size(), Locale.ENGLISH); for (Entry<String, List<String>> entry : headers.entrySet()) { List<String> values = Collections.unmodifiableList(entry.getValue()); map.put(entry.getKey(), values); } this.headers = Collections.unmodifiableMap(map); } else { this.headers = headers; } } /** * Constructs a new, empty instance of the {@code HttpHeaders} object. */ public HttpHeaders() { this(new LinkedCaseInsensitiveMap<List<String>>(8, Locale.ENGLISH), false); } /** * Returns {@code HttpHeaders} object that can only be read, not written to. */ public static HttpHeaders readOnlyHttpHeaders(HttpHeaders headers) { return new HttpHeaders(headers, true); } /** * Set the list of acceptable {@linkplain MediaType media types}, as specified by the {@code Accept} header. * @param acceptableMediaTypes the acceptable media types */ public void setAccept(List<MediaType> acceptableMediaTypes) { set(ACCEPT, MediaType.toString(acceptableMediaTypes)); } /** * Return the list of acceptable {@linkplain MediaType media types}, as specified by the {@code Accept} header. * <p>Returns an empty list when the acceptable media types are unspecified. * @return the acceptable media types */ public List<MediaType> getAccept() { String value = getFirst(ACCEPT); return (value != null ? MediaType.parseMediaTypes(value) : Collections.<MediaType>emptyList()); } /** * Set the list of acceptable {@linkplain Charset charsets}, as specified by the {@code Accept-Charset} header. * @param acceptableCharsets the acceptable charsets */ public void setAcceptCharset(List<Charset> acceptableCharsets) { StringBuilder builder = new StringBuilder(); for (Iterator<Charset> iterator = acceptableCharsets.iterator(); iterator.hasNext();) { Charset charset = iterator.next(); builder.append(charset.name().toLowerCase(Locale.ENGLISH)); if (iterator.hasNext()) { builder.append(", "); } } set(ACCEPT_CHARSET, builder.toString()); } /** * Return the list of acceptable {@linkplain Charset charsets}, as specified by the {@code Accept-Charset} * header. * @return the acceptable charsets */ public List<Charset> getAcceptCharset() { List<Charset> result = new ArrayList<Charset>(); String value = getFirst(ACCEPT_CHARSET); if (value != null) { String[] tokens = value.split(",\\s*"); for (String token : tokens) { int paramIdx = token.indexOf(';'); if (paramIdx == -1) { result.add(Charset.forName(token)); } else { result.add(Charset.forName(token.substring(0, paramIdx))); } } } return result; } /** * Set the set of allowed {@link HttpMethod HTTP methods}, as specified by the {@code Allow} header. * @param allowedMethods the allowed methods */ public void setAllow(Set<HttpMethod> allowedMethods) { set(ALLOW, StringUtils.collectionToCommaDelimitedString(allowedMethods)); } /** * Return the set of allowed {@link HttpMethod HTTP methods}, as specified by the {@code Allow} header. * <p>Returns an empty set when the allowed methods are unspecified. * @return the allowed methods */ public Set<HttpMethod> getAllow() { String value = getFirst(ALLOW); if (value != null) { List<HttpMethod> allowedMethod = new ArrayList<HttpMethod>(5); String[] tokens = value.split(",\\s*"); for (String token : tokens) { allowedMethod.add(HttpMethod.valueOf(token)); } return EnumSet.copyOf(allowedMethod); } else { return EnumSet.noneOf(HttpMethod.class); } } /** * Sets the (new) value of the {@code Cache-Control} header. * @param cacheControl the value of the header */ public void setCacheControl(String cacheControl) { set(CACHE_CONTROL, cacheControl); } /** * Returns the value of the {@code Cache-Control} header. * @return the value of the header */ public String getCacheControl() { return getFirst(CACHE_CONTROL); } /** * Sets the (new) value of the {@code Content-Disposition} header for {@code form-data}. * @param name the control name * @param filename the filename, may be {@code null} */ public void setContentDispositionFormData(String name, String filename) { Assert.notNull(name, "'name' must not be null"); StringBuilder builder = new StringBuilder("form-data; name=\""); builder.append(name).append('\"'); if (filename != null) { builder.append("; filename=\""); builder.append(filename).append('\"'); } set(CONTENT_DISPOSITION, builder.toString()); } /** * Set the length of the body in bytes, as specified by the {@code Content-Length} header. * @param contentLength the content length */ public void setContentLength(long contentLength) { set(CONTENT_LENGTH, Long.toString(contentLength)); } /** * Return the length of the body in bytes, as specified by the {@code Content-Length} header. * <p>Returns -1 when the content-length is unknown. * @return the content length */ public long getContentLength() { String value = getFirst(CONTENT_LENGTH); return (value != null ? Long.parseLong(value) : -1); } /** * Set the {@linkplain MediaType media type} of the body, as specified by the {@code Content-Type} header. * @param mediaType the media type */ public void setContentType(MediaType mediaType) { Assert.isTrue(!mediaType.isWildcardType(), "'Content-Type' cannot contain wildcard type '*'"); Assert.isTrue(!mediaType.isWildcardSubtype(), "'Content-Type' cannot contain wildcard subtype '*'"); set(CONTENT_TYPE, mediaType.toString()); } /** * Return the {@linkplain MediaType media type} of the body, as specified by the {@code Content-Type} header. * <p>Returns {@code null} when the content-type is unknown. * @return the content type */ public MediaType getContentType() { String value = getFirst(CONTENT_TYPE); return (value != null ? MediaType.parseMediaType(value) : null); } /** * Sets the date and time at which the message was created, as specified by the {@code Date} header. * <p>The date should be specified as the number of milliseconds since January 1, 1970 GMT. * @param date the date */ public void setDate(long date) { setDate(DATE, date); } /** * Returns the date and time at which the message was created, as specified by the {@code Date} header. * <p>The date is returned as the number of milliseconds since January 1, 1970 GMT. Returns -1 when the date is unknown. * @return the creation date/time * @throws IllegalArgumentException if the value can't be converted to a date */ public long getDate() { return getFirstDate(DATE); } /** * Sets the (new) entity tag of the body, as specified by the {@code ETag} header. * @param eTag the new entity tag */ public void setETag(String eTag) { set(ETAG, quote(eTag)); } /** * Returns the entity tag of the body, as specified by the {@code ETag} header. * @return the entity tag */ public String getETag() { return unquote(getFirst(ETAG)); } /** * Sets the date and time at which the message is no longer valid, as specified by the {@code Expires} header. * <p>The date should be specified as the number of milliseconds since January 1, 1970 GMT. * @param expires the new expires header value */ public void setExpires(long expires) { setDate(EXPIRES, expires); } /** * Returns the date and time at which the message is no longer valid, as specified by the {@code Expires} header. * <p>The date is returned as the number of milliseconds since January 1, 1970 GMT. Returns -1 when the date is unknown. * @return the expires value */ public long getExpires() { return getFirstDate(EXPIRES); } /** * Sets the (new) value of the {@code If-Modified-Since} header. * <p>The date should be specified as the number of milliseconds since January 1, 1970 GMT. * @param ifModifiedSince the new value of the header */ public void setIfModifiedSince(long ifModifiedSince) { setDate(IF_MODIFIED_SINCE, ifModifiedSince); } /** * Returns the value of the {@code IfModifiedSince} header. * <p>The date is returned as the number of milliseconds since January 1, 1970 GMT. Returns -1 when the date is unknown. * @return the header value */ public long getIfNotModifiedSince() { return getFirstDate(IF_MODIFIED_SINCE); } /** * Sets the (new) value of the {@code If-None-Match} header. * @param ifNoneMatch the new value of the header */ public void setIfNoneMatch(String ifNoneMatch) { set(IF_NONE_MATCH, quote(ifNoneMatch)); } /** * Sets the (new) values of the {@code If-None-Match} header. * @param ifNoneMatchList the new value of the header */ public void setIfNoneMatch(List<String> ifNoneMatchList) { StringBuilder builder = new StringBuilder(); for (Iterator<String> iterator = ifNoneMatchList.iterator(); iterator.hasNext();) { String ifNoneMatch = iterator.next(); builder.append(quote(ifNoneMatch)); if (iterator.hasNext()) { builder.append(", "); } } set(IF_NONE_MATCH, builder.toString()); } /** * Returns the value of the {@code If-None-Match} header. * @return the header value */ public List<String> getIfNoneMatch() { List<String> result = new ArrayList<String>(); String value = getFirst(IF_NONE_MATCH); if (value != null) { String[] tokens = value.split(",\\s*"); for (String token : tokens) { result.add(unquote(token)); } } return result; } /** * Sets the time the resource was last changed, as specified by the {@code Last-Modified} header. * <p>The date should be specified as the number of milliseconds since January 1, 1970 GMT. * @param lastModified the last modified date */ public void setLastModified(long lastModified) { setDate(LAST_MODIFIED, lastModified); } /** * Returns the time the resource was last changed, as specified by the {@code Last-Modified} header. * <p>The date is returned as the number of milliseconds since January 1, 1970 GMT. Returns -1 when the date is unknown. * @return the last modified date */ public long getLastModified() { return getFirstDate(LAST_MODIFIED); } /** * Set the (new) location of a resource, as specified by the {@code Location} header. * @param location the location */ public void setLocation(URI location) { set(LOCATION, location.toASCIIString()); } /** * Return the (new) location of a resource, as specified by the {@code Location} header. * <p>Returns {@code null} when the location is unknown. * @return the location */ public URI getLocation() { String value = getFirst(LOCATION); return (value != null ? URI.create(value) : null); } /** * Sets the (new) value of the {@code Pragma} header. * @param pragma the value of the header */ public void setPragma(String pragma) { set(PRAGMA, pragma); } /** * Returns the value of the {@code Pragma} header. * @return the value of the header */ public String getPragma() { return getFirst(PRAGMA); } // Utility methods private String quote(String s) { Assert.notNull(s); if (!s.startsWith("\"")) { s = "\"" + s; } if (!s.endsWith("\"")) { s = s + "\""; } return s; } private String unquote(String s) { if (s == null) { return null; } if (s.startsWith("\"")) { s = s.substring(1); } if (s.endsWith("\"")) { s = s.substring(0, s.length() - 1); } return s; } private long getFirstDate(String headerName) { String headerValue = getFirst(headerName); if (headerValue == null) { return -1; } for (String dateFormat : DATE_FORMATS) { SimpleDateFormat simpleDateFormat = new SimpleDateFormat(dateFormat, Locale.US); simpleDateFormat.setTimeZone(GMT); try { return simpleDateFormat.parse(headerValue).getTime(); } catch (ParseException e) { // ignore } } throw new IllegalArgumentException( "Cannot parse date value \"" + headerValue + "\" for \"" + headerName + "\" header"); } private void setDate(String headerName, long date) { SimpleDateFormat dateFormat = new SimpleDateFormat(DATE_FORMATS[0], Locale.US); dateFormat.setTimeZone(GMT); set(headerName, dateFormat.format(new Date(date))); } // 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} */ public String getFirst(String headerName) { List<String> headerValues = headers.get(headerName); return headerValues != null ? headerValues.get(0) : null; } /** * 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) */ public void add(String headerName, String headerValue) { List<String> headerValues = headers.get(headerName); if (headerValues == null) { headerValues = new LinkedList<String>(); this.headers.put(headerName, headerValues); } headerValues.add(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) */ public void set(String headerName, String headerValue) { List<String> headerValues = new LinkedList<String>(); headerValues.add(headerValue); headers.put(headerName, headerValues); } public void setAll(Map<String, String> values) { for (Entry<String, String> entry : values.entrySet()) { set(entry.getKey(), entry.getValue()); } } public Map<String, String> toSingleValueMap() { LinkedHashMap<String, String> singleValueMap = new LinkedHashMap<String, String>(this.headers.size()); for (Entry<String, List<String>> entry : headers.entrySet()) { singleValueMap.put(entry.getKey(), entry.getValue().get(0)); } return singleValueMap; } // Map implementation public int size() { return this.headers.size(); } public boolean isEmpty() { return this.headers.isEmpty(); } public boolean containsKey(Object key) { return this.headers.containsKey(key); } public boolean containsValue(Object value) { return this.headers.containsValue(value); } public List<String> get(Object key) { return this.headers.get(key); } public List<String> put(String key, List<String> value) { return this.headers.put(key, value); } public List<String> remove(Object key) { return this.headers.remove(key); } public void putAll(Map<? extends String, ? extends List<String>> m) { this.headers.putAll(m); } public void clear() { this.headers.clear(); } public Set<String> keySet() { return this.headers.keySet(); } public Collection<List<String>> values() { return this.headers.values(); } public Set<Entry<String, List<String>>> entrySet() { return this.headers.entrySet(); } @Override public boolean equals(Object other) { if (this == other) { return true; } if (!(other instanceof HttpHeaders)) { return false; } HttpHeaders otherHeaders = (HttpHeaders) other; return this.headers.equals(otherHeaders.headers); } @Override public int hashCode() { return this.headers.hashCode(); } @Override public String toString() { return this.headers.toString(); } }