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/*
* 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.
*/
package jakarta.servlet.http;
import java.io.IOException;
import java.util.Collection;
import java.util.Map;
import java.util.function.Supplier;
import jakarta.servlet.ServletResponse;
/**
* Extends the {@link ServletResponse} interface to provide HTTP-specific functionality in sending a response. For
* example, it has methods to access HTTP headers and cookies.
*
* The servlet container creates an HttpServletResponse
object and passes it as an argument to the
* servlet's service methods (doGet
, doPost
, etc).
*
* @see jakarta.servlet.ServletResponse
*/
public interface HttpServletResponse extends ServletResponse {
/**
* Adds the specified cookie to the response. This method can be called multiple times to set more than one cookie.
*
* @param cookie the Cookie to return to the client
*/
void addCookie(Cookie cookie);
/**
* Returns a boolean indicating whether the named response header has already been set.
*
* @param name the header name
*
* @return true
if the named response header has already been set; false
otherwise
*/
boolean containsHeader(String name);
/**
* Encodes the specified URL by including the session ID in it, or, if encoding is not needed, returns the URL
* unchanged. The implementation of this method includes the logic to determine whether the session ID needs to be
* encoded in the URL. For example, if the browser supports cookies, or session tracking is turned off, URL encoding
* is unnecessary.
*
* For robust session tracking, all URLs emitted by a servlet should be run through this method. Otherwise, URL
* rewriting cannot be used with browsers which do not support cookies.
*
* @param url the url to be encoded.
*
* @return the encoded URL if encoding is needed; the unchanged URL otherwise.
*/
String encodeURL(String url);
/**
* Encodes the specified URL for use in the sendRedirect
method or, if encoding is not needed, returns
* the URL unchanged. The implementation of this method includes the logic to determine whether the session ID needs
* to be encoded in the URL. Because the rules for making this determination can differ from those used to decide
* whether to encode a normal link, this method is separated from the encodeURL
method.
*
* All URLs sent to the HttpServletResponse.sendRedirect
method should be run through this method.
* Otherwise, URL rewriting cannot be used with browsers which do not support cookies.
*
* @param url the url to be encoded.
*
* @return the encoded URL if encoding is needed; the unchanged URL otherwise.
*
* @see #sendRedirect
*/
String encodeRedirectURL(String url);
/**
* Sends an error response to the client using the specified status code and clears the output buffer. The server
* defaults to creating the response to look like an HTML-formatted server error page containing the specified
* message, setting the content type to "text/html", leaving cookies and other headers unmodified. If an error-page
* declaration has been made for the web application corresponding to the status code passed in, it will be served
* back in preference to the suggested msg parameter.
*
* If the response has already been committed, this method throws an IllegalStateException. After using this method,
* the response should be considered to be committed and should not be written to.
*
* @param sc the error status code
* @param msg the descriptive message
*
* @exception IOException If an input or output exception occurs
* @exception IllegalStateException If the response was committed
*/
void sendError(int sc, String msg) throws IOException;
/**
* Sends an error response to the client using the specified status code and clears the buffer. This is equivalent
* to calling {@link #sendError(int, String)} with the same status code and null
for the message.
*
* @param sc the error status code
*
* @exception IOException If an input or output exception occurs
* @exception IllegalStateException If the response was committed before this method call
*/
void sendError(int sc) throws IOException;
/**
* Sends a redirect response to the client using the specified redirect location URL with the status code
* {@link #SC_FOUND} 302 (Found), clears the response buffer and commits the response. The response buffer will be
* replaced with a short hypertext note as per RFC 9110.
*
* This method has no effect if called from an include.
*
* @param location the redirect location URL (may be absolute or relative)
*
* @exception IOException If an input or output exception occurs
* @exception IllegalArgumentException If a relative URL is given and cannot be converted into an absolute URL
* @exception IllegalStateException If the response was already committed when this method was called
*
* @see #sendRedirect(String, int, boolean)
*/
default void sendRedirect(String location) throws IOException {
sendRedirect(location, SC_FOUND, true);
}
/**
* Sends a redirect response to the client using the specified redirect location URL with the status code
* {@link #SC_FOUND} 302 (Found), optionally clears the response buffer and commits the response. If the response
* buffer is cleared, it will be replaced with a short hypertext note as per RFC 9110.
*
* This method has no effect if called from an include.
*
* @param location the redirect location URL (may be absolute or relative)
* @param clearBuffer if {@code true}, clear the buffer and replace it with the data set by this method otherwise
* retain the existing buffer
*
* @exception IOException If an input or output exception occurs
* @exception IllegalArgumentException If a relative URL is given and cannot be converted into an absolute URL
* @exception IllegalStateException If the response was already committed when this method was called
*
* @see #sendRedirect(String, int, boolean)
*
* @since Servlet 6.1
*/
default void sendRedirect(String location, boolean clearBuffer) throws IOException {
sendRedirect(location, SC_FOUND, clearBuffer);
}
/**
* Sends a redirect response to the client using the specified redirect location URL and status code, clears the
* response buffer and commits the response. The response buffer will be replaced with a short hypertext note as per
* RFC 9110.
*
* This method has no effect if called from an include.
*
* @param location the redirect location URL (may be absolute or relative)
* @param sc the status code to use for the redirect
*
* @exception IOException If an input or output exception occurs
* @exception IllegalArgumentException If a relative URL is given and cannot be converted into an absolute URL
* @exception IllegalStateException If the response was already committed when this method was called
*
* @see #sendRedirect(String, int, boolean)
*
* @since Servlet 6.1
*/
default void sendRedirect(String location, int sc) throws IOException {
sendRedirect(location, sc, true);
}
/**
* Sends a redirect response to the client using the specified redirect location URL and status code, optionally
* clears the response buffer and commits the response. If the response buffer is cleared, it will be replaced with
* a short hypertext note as per RFC 9110.
*
* This method has no effect if called from an include.
*
* This method accepts both relative and absolute URLs. Absolute URLs passed to this method are used as provided as
* the redirect location URL. Relative URLs are converted to absolute URLs unless a container specific
* feature/option is provided that controls whether relative URLs passed to this method are converted to absolute
* URLs or used as provided for the redirect location URL. If converting a relative URL to an absolute URL then:
*
* - If the location is relative without a leading '/' the container interprets it as relative to the current
* request URI.
* - If the location is relative with a leading '/' the container interprets it as relative to the servlet
* container root.
* - If the location is relative with two leading '/' the container interprets it as a network-path reference (see
* RFC 3986: Uniform Resource Identifier (URI): Generic Syntax,
* section 4.2 "Relative Reference").
*
*
* If the response has already been committed, this method throws an IllegalStateException. After using this method,
* the response should be considered to be committed and should not be written to.
*
* @param location the redirect location URL (may be absolute or relative)
* @param sc the status code to use for the redirect
* @param clearBuffer if {@code true}, clear the buffer and replace it with the data set by this method otherwise
* retain the existing buffer
*
* @exception IOException If an input or output exception occurs
* @exception IllegalArgumentException If a relative URL is given and cannot be converted into an absolute URL
* @exception IllegalStateException If the response was already committed when this method was called
*
* @since Servlet 6.1
*/
void sendRedirect(String location, int sc, boolean clearBuffer) throws IOException;
/**
* Sets a response header with the given name and date-value. The date is specified in terms of milliseconds since
* the epoch. If the header had already been set, the new value overwrites the previous one. The
* containsHeader
method can be used to test for the presence of a header before setting its value.
*
* @param name the name of the header to set
* @param date the assigned date value
*
* @see #containsHeader
* @see #addDateHeader
*/
void setDateHeader(String name, long date);
/**
* Adds a response header with the given name and date-value. The date is specified in terms of milliseconds since
* the epoch. This method allows response headers to have multiple values.
*
* @param name the name of the header to set
* @param date the additional date value
*
* @see #setDateHeader
*/
void addDateHeader(String name, long date);
/**
* Sets a response header with the given name and value. If the header had already been set, the new value
* overwrites the previous one. The containsHeader
method can be used to test for the presence of a
* header before setting its value.
*
* @param name the name of the header
* @param value the header value If it contains octet string, it should be encoded according to RFC 2047
* (http://www.ietf.org/rfc/rfc2047.txt)
*
* @see #containsHeader
* @see #addHeader
*/
void setHeader(String name, String value);
/**
* Adds a response header with the given name and value. This method allows response headers to have multiple
* values.
*
* @param name the name of the header
* @param value the additional header value If it contains octet string, it should be encoded according to RFC 2047
* (http://www.ietf.org/rfc/rfc2047.txt)
*
* @see #setHeader
*/
void addHeader(String name, String value);
/**
* Sets a response header with the given name and integer value. If the header had already been set, the new value
* overwrites the previous one. The containsHeader
method can be used to test for the presence of a
* header before setting its value.
*
* @param name the name of the header
* @param value the assigned integer value
*
* @see #containsHeader
* @see #addIntHeader
*/
void setIntHeader(String name, int value);
/**
* Adds a response header with the given name and integer value. This method allows response headers to have
* multiple values.
*
* @param name the name of the header
* @param value the assigned integer value
*
* @see #setIntHeader
*/
void addIntHeader(String name, int value);
/**
* Sets the status code for this response. This method is used to set the return status code when there is no error
* (for example, for the status codes SC_OK or SC_MOVED_TEMPORARILY). If there is an error, and the caller wishes to
* invoke an error-page defined in the web application, the sendError
method should be used instead.
*
* The container clears the buffer and sets the Location header, preserving cookies and other headers.
*
* @param sc the status code
*
* @see #sendError
*/
void setStatus(int sc);
/**
* Get the HTTP status code for this Response.
*
* @return The HTTP status code for this Response
*
* @since Servlet 3.0
*/
int getStatus();
/**
* Return the value for the specified header, or null
if this header has not been set. If more than one
* value was added for this name, only the first is returned; use {@link #getHeaders(String)} to retrieve all of
* them.
*
* @param name Header name to look up
*
* @return The first value for the specified header. This is the raw value so if multiple values are specified in
* the first header then they will be returned as a single header value .
*
* @since Servlet 3.0
*/
String getHeader(String name);
/**
* Return a Collection of all the header values associated with the specified header name.
*
* @param name Header name to look up
*
* @return The values for the specified header. These are the raw values so if multiple values are specified in a
* single header that will be returned as a single header value.
*
* @since Servlet 3.0
*/
Collection getHeaders(String name);
/**
* Get the header names set for this HTTP response.
*
* @return The header names set for this HTTP response.
*
* @since Servlet 3.0
*/
Collection getHeaderNames();
/**
* Configure the supplier of the trailer headers. The supplier will be called in the scope of the thread that
* completes the response.
* Trailers that don't meet the requirements of RFC 7230, section 4.1.2 will be ignored.
* The default implementation is a NO-OP.
*
* @param supplier The supplier for the trailer headers
*
* @throws IllegalStateException if this method is called when the underlying protocol does not support trailer
* headers or if using HTTP/1.1 and the response has already been committed
*
* @since Servlet 4.0
*/
default void setTrailerFields(Supplier