/*
* Copyright 2004 The Apache Software Foundation
*
* 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 javax.servlet.http;

import javax.servlet.ServletRequest;
import java.util.Enumeration;

/**
 *
 * Extends the {@link javax.servlet.ServletRequest} interface
 * to provide request information for HTTP servlets. 
 *
 * <p>The servlet container creates an <code>HttpServletRequest</code> 
 * object and passes it as an argument to the servlet's service
 * methods (<code>doGet</code>, <code>doPost</code>, etc).
 *
 *
 * @author 	Various
 * @version	$Version$
 *
 *
 */

public interface HttpServletRequest extends ServletRequest {

    /**
    * String identifier for Basic authentication. Value "BASIC"
    */
    public static final String BASIC_AUTH = "BASIC";
    /**
    * String identifier for Form authentication. Value "FORM"
    */
    public static final String FORM_AUTH = "FORM";
    /**
    * String identifier for Client Certificate authentication. Value "CLIENT_CERT"
    */
    public static final String CLIENT_CERT_AUTH = "CLIENT_CERT";
    /**
    * String identifier for Digest authentication. Value "DIGEST"
    */
    public static final String DIGEST_AUTH = "DIGEST";

    /**
     * Returns the name of the authentication scheme used to protect
     * the servlet. All servlet containers support basic, form and client 
     * certificate authentication, and may additionally support digest 
     * authentication.
     * If the servlet is not authenticated <code>null</code> is returned. 
     *
     * <p>Same as the value of the CGI variable AUTH_TYPE.
     *
     *
     * @return		one of the static members BASIC_AUTH, 
     *			FORM_AUTH, CLIENT_CERT_AUTH, DIGEST_AUTH
     *			(suitable for == comparison) or
     *			the container-specific string indicating
     *			the authentication scheme, or
     *			<code>null</code> if the request was 
     *			not authenticated.     
     *
     */
   
    public String getAuthType();
    
   
    /**
     *
     * Returns an array containing all of the <code>Cookie</code>
     * objects the client sent with this request.
     * This method returns <code>null</code> if no cookies were sent.
     *
     * @return		an array of all the <code>Cookies</code>
     *			included with this request, or <code>null</code>
     *			if the request has no cookies
     *
     *
     */

    public Cookie[] getCookies();
    
    
    /**
     *
     * Returns the value of the specified request header
     * as a <code>long</code> value that represents a 
     * <code>Date</code> object. Use this method with
     * headers that contain dates, such as
     * <code>If-Modified-Since</code>. 
     *
     * <p>The date is returned as
     * the number of milliseconds since January 1, 1970 GMT.
     * The header name is case insensitive.
     *
     * <p>If the request did not have a header of the
     * specified name, this method returns -1. If the header
     * can't be converted to a date, the method throws
     * an <code>IllegalArgumentException</code>.
     *
     * @param name		a <code>String</code> specifying the
     *				name of the header
     *
     * @return			a <code>long</code> value
     *				representing the date specified
     *				in the header expressed as
     *				the number of milliseconds
     *				since January 1, 1970 GMT,
     *				or -1 if the named header
     *				was not included with the
     *				request
     *
     * @exception	IllegalArgumentException	If the header value
     *							can't be converted
     *							to a date
     *
     */

    public long getDateHeader(String name);
    
    
    /**
     *
     * Returns the value of the specified request header
     * as a <code>String</code>. If the request did not include a header
     * of the specified name, this method returns <code>null</code>.
     * If there are multiple headers with the same name, this method
     * returns the first head in the request.
     * The header name is case insensitive. You can use
     * this method with any request header.
     *
     * @param name		a <code>String</code> specifying the
     *				header name
     *
     * @return			a <code>String</code> containing the
     *				value of the requested
     *				header, or <code>null</code>
     *				if the request does not
     *				have a header of that name
     *
     */			

    public String getHeader(String name); 


    /**
     *
     * Returns all the values of the specified request header
     * as an <code>Enumeration</code> of <code>String</code> objects.
     *
     * <p>Some headers, such as <code>Accept-Language</code> can be sent
     * by clients as several headers each with a different value rather than
     * sending the header as a comma separated list.
     *
     * <p>If the request did not include any headers
     * of the specified name, this method returns an empty
     * <code>Enumeration</code>.
     * The header name is case insensitive. You can use
     * this method with any request header.
     *
     * @param name		a <code>String</code> specifying the
     *				header name
     *
     * @return			an <code>Enumeration</code> containing
     *                  	the values of the requested header. If
     *                  	the request does not have any headers of
     *                  	that name return an empty
     *                  	enumeration. If 
     *                  	the container does not allow access to
     *                  	header information, return null
     *
     */			

    public Enumeration getHeaders(String name); 
    
    
    /**
     *
     * Returns an enumeration of all the header names
     * this request contains. If the request has no
     * headers, this method returns an empty enumeration.
     *
     * <p>Some servlet containers do not allow
     * servlets to access headers using this method, in
     * which case this method returns <code>null</code>
     *
     * @return			an enumeration of all the
     *				header names sent with this
     *				request; if the request has
     *				no headers, an empty enumeration;
     *				if the servlet container does not
     *				allow servlets to use this method,
     *				<code>null</code>
     *				
     *
     */

    public Enumeration getHeaderNames();
    
    
    /**
     *
     * Returns the value of the specified request header
     * as an <code>int</code>. If the request does not have a header
     * of the specified name, this method returns -1. If the
     * header cannot be converted to an integer, this method
     * throws a <code>NumberFormatException</code>.
     *
     * <p>The header name is case insensitive.
     *
     * @param name		a <code>String</code> specifying the name
     *				of a request header
     *
     * @return			an integer expressing the value 
     * 				of the request header or -1
     *				if the request doesn't have a
     *				header of this name
     *
     * @exception	NumberFormatException		If the header value
     *							can't be converted
     *							to an <code>int</code>
     */

    public int getIntHeader(String name);
    
    
    /**
     *
     * Returns the name of the HTTP method with which this 
     * request was made, for example, GET, POST, or PUT.
     * Same as the value of the CGI variable REQUEST_METHOD.
     *
     * @return			a <code>String</code> 
     *				specifying the name
     *				of the method with which
     *				this request was made
     *
     */
 
    public String getMethod();
    
    
    /**
     *
     * Returns any extra path information associated with
     * the URL the client sent when it made this request.
     * The extra path information follows the servlet path
     * but precedes the query string and will start with
     * a "/" character.
     *
     * <p>This method returns <code>null</code> if there
     * was no extra path information.
     *
     * <p>Same as the value of the CGI variable PATH_INFO.
     *
     *
     * @return		a <code>String</code>, decoded by the
     *			web container, specifying 
     *			extra path information that comes
     *			after the servlet path but before
     *			the query string in the request URL;
     *			or <code>null</code> if the URL does not have
     *			any extra path information
     *
     */
     
    public String getPathInfo();
    

    /**
     *
     * Returns any extra path information after the servlet name
     * but before the query string, and translates it to a real
     * path. Same as the value of the CGI variable PATH_TRANSLATED.
     *
     * <p>If the URL does not have any extra path information,
     * this method returns <code>null</code> or the servlet container
     * cannot translate the virtual path to a real path for any reason
     * (such as when the web application is executed from an archive).
     *
     * The web container does not decode this string.
     *
     *
     * @return		a <code>String</code> specifying the
     *			real path, or <code>null</code> if
     *			the URL does not have any extra path
     *			information
     *
     *
     */

    public String getPathTranslated();
    

    /**
     *
     * Returns the portion of the request URI that indicates the context
     * of the request.  The context path always comes first in a request
     * URI.  The path starts with a "/" character but does not end with a "/"
     * character.  For servlets in the default (root) context, this method
     * returns "". The container does not decode this string.
     *
     *
     * @return		a <code>String</code> specifying the
     *			portion of the request URI that indicates the context
     *			of the request
     *
     *
     */

    public String getContextPath();
    
    
    /**
     *
     * Returns the query string that is contained in the request
     * URL after the path. This method returns <code>null</code>
     * if the URL does not have a query string. Same as the value
     * of the CGI variable QUERY_STRING. 
     *
     * @return		a <code>String</code> containing the query
     *			string or <code>null</code> if the URL 
     *			contains no query string. The value is not
     *			decoded by the container.
     *
     */

    public String getQueryString();
    
    
    /**
     *
     * Returns the login of the user making this request, if the
     * user has been authenticated, or <code>null</code> if the user 
     * has not been authenticated.
     * Whether the user name is sent with each subsequent request
     * depends on the browser and type of authentication. Same as the 
     * value of the CGI variable REMOTE_USER.
     *
     * @return		a <code>String</code> specifying the login
     *			of the user making this request, or <code>null</code>
     *			if the user login is not known
     *
     */

    public String getRemoteUser();
    
    
    /**
     *
     * Returns a boolean indicating whether the authenticated user is included
     * in the specified logical "role".  Roles and role membership can be
     * defined using deployment descriptors.  If the user has not been
     * authenticated, the method returns <code>false</code>.
     *
     * @param role		a <code>String</code> specifying the name
     *				of the role
     *
     * @return		a <code>boolean</code> indicating whether
     *			the user making this request belongs to a given role;
     *			<code>false</code> if the user has not been 
     *			authenticated
     *
     */

    public boolean isUserInRole(String role);
    
    
    /**
     *
     * Returns a <code>java.security.Principal</code> object containing
     * the name of the current authenticated user. If the user has not been
     * authenticated, the method returns <code>null</code>.
     *
     * @return		a <code>java.security.Principal</code> containing
     *			the name of the user making this request;
     *			<code>null</code> if the user has not been 
     *			authenticated
     *
     */

    public java.security.Principal getUserPrincipal();
    
    
    /**
     *
     * Returns the session ID specified by the client. This may
     * not be the same as the ID of the current valid session
     * for this request.
     * If the client did not specify a session ID, this method returns
     * <code>null</code>.
     *
     *
     * @return		a <code>String</code> specifying the session
     *			ID, or <code>null</code> if the request did
     *			not specify a session ID
     *
     * @see		#isRequestedSessionIdValid
     *
     */

    public String getRequestedSessionId();
    
    
    /**
     *
     * Returns the part of this request's URL from the protocol
     * name up to the query string in the first line of the HTTP request.
     * The web container does not decode this String.
     * For example:
     *
     * 

     * <table summary="Examples of Returned Values">
     * <tr align=left><th>First line of HTTP request      </th>
     * <th>     Returned Value</th>
     * <tr><td>POST /some/path.html HTTP/1.1<td><td>/some/path.html
     * <tr><td>GET http://foo.bar/a.html HTTP/1.0
     * <td><td>/a.html
     * <tr><td>HEAD /xyz?a=b HTTP/1.1<td><td>/xyz
     * </table>
     *
     * <p>To reconstruct an URL with a scheme and host, use
     * {@link HttpUtils#getRequestURL}.
     *
     * @return		a <code>String</code> containing
     *			the part of the URL from the 
     *			protocol name up to the query string
     *
     * @see		HttpUtils#getRequestURL
     *
     */

    public String getRequestURI();
    
    /**
     *
     * Reconstructs the URL the client used to make the request.
     * The returned URL contains a protocol, server name, port
     * number, and server path, but it does not include query
     * string parameters.
     *
     * <p>Because this method returns a <code>StringBuffer</code>,
     * not a string, you can modify the URL easily, for example,
     * to append query parameters.
     *
     * <p>This method is useful for creating redirect messages
     * and for reporting errors.
     *
     * @return		a <code>StringBuffer</code> object containing
     *			the reconstructed URL
     *
     */
    public StringBuffer getRequestURL();
    

    /**
     *
     * Returns the part of this request's URL that calls
     * the servlet. This path starts with a "/" character
     * and includes either the servlet name or a path to
     * the servlet, but does not include any extra path
     * information or a query string. Same as the value of
     * the CGI variable SCRIPT_NAME.
     *
     * <p>This method will return an empty string ("") if the
     * servlet used to process this request was matched using
     * the "/*" pattern.
     *
     * @return		a <code>String</code> containing
     *			the name or path of the servlet being
     *			called, as specified in the request URL,
     *			decoded, or an empty string if the servlet
     *			used to process the request is matched
     *			using the "/*" pattern.
     *
     */

    public String getServletPath();
    
    
    /**
     *
     * Returns the current <code>HttpSession</code>
     * associated with this request or, if there is no
     * current session and <code>create</code> is true, returns 
     * a new session.
     *
     * <p>If <code>create</code> is <code>false</code>
     * and the request has no valid <code>HttpSession</code>,
     * this method returns <code>null</code>.
     *
     * <p>To make sure the session is properly maintained,
     * you must call this method before 
     * the response is committed. If the container is using cookies
     * to maintain session integrity and is asked to create a new session
     * when the response is committed, an IllegalStateException is thrown.
     *
     *
     *
     *
     * @param create	<code>true</code> to create
     *			a new session for this request if necessary; 
     *			<code>false</code> to return <code>null</code>
     *			if there's no current session
     *			
     *
     * @return 		the <code>HttpSession</code> associated 
     *			with this request or <code>null</code> if
     * 			<code>create</code> is <code>false</code>
     *			and the request has no valid session
     *
     * @see	#getSession()
     *
     *
     */

    public HttpSession getSession(boolean create);
    
    
    /**
     *
     * Returns the current session associated with this request,
     * or if the request does not have a session, creates one.
     * 
     * @return		the <code>HttpSession</code> associated
     *			with this request
     *
     * @see	#getSession(boolean)
     *
     */

    public HttpSession getSession();
    
    
    /**
     *
     * Checks whether the requested session ID is still valid.
     *
     * @return			<code>true</code> if this
     *				request has an id for a valid session
     *				in the current session context;
     *				<code>false</code> otherwise
     *
     * @see			#getRequestedSessionId
     * @see			#getSession
     * @see			HttpSessionContext
     *
     */

    public boolean isRequestedSessionIdValid();
    
    
    /**
     *
     * Checks whether the requested session ID came in as a cookie.
     *
     * @return			<code>true</code> if the session ID
     *				came in as a
     *				cookie; otherwise, <code>false</code>
     *
     *
     * @see			#getSession
     *
     */ 

    public boolean isRequestedSessionIdFromCookie();
    
    
    /**
     *
     * Checks whether the requested session ID came in as part of the 
     * request URL.
     *
     * @return			<code>true</code> if the session ID
     *				came in as part of a URL; otherwise,
     *				<code>false</code>
     *
     *
     * @see			#getSession
     *
     */
    
    public boolean isRequestedSessionIdFromURL();
    
    
    /**
     *
     * @deprecated		As of Version 2.1 of the Java Servlet
     *				API, use {@link #isRequestedSessionIdFromURL}
     *				instead.
     *
     */

    public boolean isRequestedSessionIdFromUrl();


}