/*
 * $Header: /home/cvs/jakarta-commons/httpclient/src/java/org/apache/commons/httpclient/params/HttpMethodParams.java,v 1.15 2004/09/17 08:00:51 oglueck Exp $
 * $Revision: 1.15 $
 * $Date: 2004/09/17 08:00:51 $
 *
 * ====================================================================
 *
 *  Copyright 1999-2004 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.
 * ====================================================================
 *
 * 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.commons.httpclient.params;

import org.apache.commons.httpclient.HttpMethodRetryHandler;
import org.apache.commons.httpclient.HttpVersion;
import org.apache.commons.httpclient.cookie.CookiePolicy;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * This class represents a collection of HTTP protocol parameters applicable to 
 * {@link org.apache.commons.httpclient.HttpMethod HTTP methods}. Protocol 
 * parameters may be linked together to form a hierarchy. If a particular 
 * parameter value has not been explicitly defined in the collection itself, 
 * its value will be drawn from the parent collection of parameters.
 * 
 * @author <a href="mailto:oleg@ural.ru">Oleg Kalnichevski</a>
 * @author Christian Kohlschuetter
 * 
 * @version $Revision: 1.15 $
 * 
 * @since 3.0
 */
public class HttpMethodParams extends DefaultHttpParams {

    /** Log object for this class. */
    private static final Log LOG = LogFactory.getLog(HttpMethodParams.class);

    /**
     * Defines the content of the <tt>User-Agent</tt> header used by  
     * {@link org.apache.commons.httpclient.HttpMethod HTTP methods}.
     * <p>
     * This parameter expects a value of type {@link String}.
     * </p>
     */
    public static final String USER_AGENT = "http.useragent"; 

    /**
     * Defines the {@link HttpVersion HTTP protocol version} used by  
     * {@link org.apache.commons.httpclient.HttpMethod HTTP methods} per
     * default.
     * <p>
     * This parameter expects a value of type {@link HttpVersion}.
     * </p>
     */
    public static final String PROTOCOL_VERSION = "http.protocol.version"; 

    /**
     * Defines whether {@link org.apache.commons.httpclient.HttpMethod HTTP methods} should
     * reject ambiguous {@link org.apache.commons.httpclient.StatusLine HTTP status line}.
     * <p>
     * This parameter expects a value of type {@link Boolean}.
     * </p>
     */
    public static final String UNAMBIGUOUS_STATUS_LINE = "http.protocol.unambiguous-statusline"; 

    /**
     * Defines whether {@link org.apache.commons.httpclient.Cookie cookies} should be put on 
     * a single {@link org.apache.commons.httpclient.Header response header}.
     * <p>
     * This parameter expects a value of type {@link Boolean}.
     * </p>
     */
    public static final String SINGLE_COOKIE_HEADER = "http.protocol.single-cookie-header"; 

    /**
     * Defines whether responses with an invalid <tt>Transfer-Encoding</tt> header should be 
     * rejected.
     * <p>
     * This parameter expects a value of type {@link Boolean}.
     * </p>
     */
    public static final String STRICT_TRANSFER_ENCODING = "http.protocol.strict-transfer-encoding"; 

    /**
     * Defines whether the content body sent in response to 
     * {@link org.apache.commons.httpclient.methods.HeadMethod} should be rejected.
     * <p>
     * This parameter expects a value of type {@link Boolean}.
     * </p>
     */
    public static final String REJECT_HEAD_BODY = "http.protocol.reject-head-body"; 

    /**
     * Sets period of time in milliseconds to wait for a content body sent in response to 
     * {@link org.apache.commons.httpclient.methods.HeadMethod HEAD method} from a 
     * non-compliant server. If the parameter is not set or set to <tt>-1</tt> non-compliant 
     * response body check is disabled.
     * <p>
     * This parameter expects a value of type {@link Integer}.
     * </p>
     */
    public static final String HEAD_BODY_CHECK_TIMEOUT = "http.protocol.head-body-timeout"; 

    /**
     * <p>
     * Activates 'Expect: 100-Continue' handshake for the 
     * {@link org.apache.commons.httpclient.methods.ExpectContinueMethod 
     * entity enclosing methods}. The purpose of the 'Expect: 100-Continue'
     * handshake to allow a client that is sending a request message with 
     * a request body to determine if the origin server is willing to 
     * accept the request (based on the request headers) before the client
     * sends the request body.
     * </p>
     * 
     * <p>
     * The use of the 'Expect: 100-continue' handshake can result in 
     * noticable peformance improvement for entity enclosing requests
     * (such as POST and PUT) that require the target server's 
     * authentication.
     * </p>
     * 
     * <p>
     * 'Expect: 100-continue' handshake should be used with 
     * caution, as it may cause problems with HTTP servers and 
     * proxies that do not support HTTP/1.1 protocol.
     * </p>
     * 
     * This parameter expects a value of type {@link Boolean}.
     */
    public static final String USE_EXPECT_CONTINUE = "http.protocol.expect-continue"; 

    /**
     * Defines the charset to be used when encoding 
     * {@link org.apache.commons.httpclient.Credentials}. If not defined then the 
     * {@link #HTTP_ELEMENT_CHARSET} should be used.
     * <p>
     * This parameter expects a value of type {@link String}.
     * </p>
     */
    public static final String CREDENTIAL_CHARSET = "http.protocol.credential-charset"; 
    
    /**
     * Defines the charset to be used for encoding HTTP protocol elements.
     * <p>
     * This parameter expects a value of type {@link String}.
     * </p>
     */
    public static final String HTTP_ELEMENT_CHARSET = "http.protocol.element-charset"; 
    
    /**
     * Defines the charset to be used for encoding content body.
     * <p>
     * This parameter expects a value of type {@link String}.
     * </p>
     */
    public static final String HTTP_CONTENT_CHARSET = "http.protocol.content-charset"; 
    
    /**
     * Defines {@link CookiePolicy cookie policy} to be used for cookie management.
     * <p>
     * This parameter expects a value of type {@link String}.
     * </p>
     */
    public static final String COOKIE_POLICY = "http.protocol.cookie-policy";
    
    /**
     * Defines HttpClient's behavior when a response provides more bytes than
     * expected (specified with Content-Length, for example).
     * <p>
     * Such surplus data makes the HTTP connection unreliable for keep-alive
     * requests, as malicious response data (faked headers etc.) can lead to undesired
     * results on the next request using that connection.
     * </p>
     * <p>
     * If this parameter is set to <code>true</code>, any detection of extra
     * input data will generate a warning in the log.
     * </p>
     * <p>
     * This parameter expects a value of type {@link Boolean}.
     * </p>
     */
    public static final String WARN_EXTRA_INPUT = "http.protocol.warn-extra-input";
    
    /**
     * Defines the maximum number of ignorable lines before we expect
     * a HTTP response's status code.
     * <p>
     * With HTTP/1.1 persistent connections, the problem arises that
     * broken scripts could return a wrong Content-Length
     * (there are more bytes sent than specified).<br />
     * Unfortunately, in some cases, this is not possible after the bad response,
     * but only before the next one. <br />
     * So, HttpClient must be able to skip those surplus lines this way.
     * </p>
     * <p>
     * Set this to 0 to disallow any garbage/empty lines before the status line.<br />
     * To specify no limit, use {@link java.lang.Integer#MAX_VALUE} (default in lenient mode).
     * </p>
     *  
     * This parameter expects a value of type {@link Integer}.
     */
    public static final String STATUS_LINE_GARBAGE_LIMIT = "http.protocol.status-line-garbage-limit";

    /**
     * Sets the socket timeout (<tt>SO_TIMEOUT</tt>) in milliseconds to be used when executing the method. 
     * A timeout value of zero is interpreted as an infinite timeout.
     * <p>
     * This parameter expects a value of type {@link Integer}.
     * </p>
     * @see java.net.SocketOptions#SO_TIMEOUT
     */
    public static final String SO_TIMEOUT = "http.socket.timeout"; 

    /**
     * The key used to look up the date patterns used for parsing. The String patterns are stored
     * in a {@link java.util.Collection} and must be compatible with 
     * {@link java.text.SimpleDateFormat}.
     * <p>
     * This parameter expects a value of type {@link java.util.Collection}.
     * </p>
     */
    public static final String DATE_PATTERNS = "http.dateparser.patterns";

    /**
     * Sets the method retry handler parameter.
     * <p>
     * This parameter expects a value of type {@link HttpMethodRetryHandler}.
     * </p>
     */ 
    public static final String RETRY_HANDLER = "http.method.retry-handler";
    
    /**
     * Sets the maximum buffered response size (in bytes) that triggers no warning. Buffered
     * responses exceeding this size will trigger a warning in the log.
     * <p>
     * This parameter expects a value if type {@link Integer}.
     * </p>
     */
    public static final String BUFFER_WARN_TRIGGER_LIMIT = "http.method.response.buffer.warnlimit";
    
    /**
     * Creates a new collection of parameters with the collection returned
     * by {@link #getDefaultParams()} as a parent. The collection will defer
     * to its parent for a default value if a particular parameter is not 
     * explicitly set in the collection itself.
     * 
     * @see #getDefaultParams()
     */
    public HttpMethodParams() {
        super(getDefaultParams());
    }

    /**
     * Creates a new collection of parameters with the given parent. 
     * The collection will defer to its parent for a default value 
     * if a particular parameter is not explicitly set in the collection
     * itself.
     * 
     * @param defaults the parent collection to defer to, if a parameter
     * is not explictly set in the collection itself.
     *
     * @see #getDefaultParams()
     */
    public HttpMethodParams(HttpParams defaults) {
        super(defaults);
    }

    /**
     * Returns the charset to be used for writing HTTP headers.
     * @return The charset
     */
    public String getHttpElementCharset() {
        String charset = (String) getParameter(HTTP_ELEMENT_CHARSET);
        if (charset == null) {
            LOG.warn("HTTP element charset not configured, using US-ASCII");
            charset = "US-ASCII";
        }
        return charset;
    }
    
    /**
     * Sets the charset to be used for writing HTTP headers.
     * @param charset The charset
     */
    public void setHttpElementCharset(String charset) {
        setParameter(HTTP_ELEMENT_CHARSET, charset);
    }

    /**
     * Returns the default charset to be used for writing content body, 
     * when no charset explicitly specified.
     * @return The charset
     */
    public String getContentCharset() {
        String charset = (String) getParameter(HTTP_CONTENT_CHARSET);
        if (charset == null) {
            LOG.warn("Default content charset not configured, using ISO-8859-1");
            charset = "ISO-8859-1";
        }
        return charset;
    }
    
    /**
     * Sets the default charset to be used for writing content body,
     * when no charset explicitly specified.
     * @param charset The charset
     */
    public void setContentCharset(String charset) {
        setParameter(HTTP_CONTENT_CHARSET, charset);
    }

    /**
     * Returns the charset to be used for {@link org.apache.commons.httpclient.Credentials}. If
     * not configured the {@link #HTTP_ELEMENT_CHARSET HTTP element charset} is used.
     * @return The charset
     */
    public String getCredentialCharset() {
        String charset = (String) getParameter(CREDENTIAL_CHARSET);
        if (charset == null) {
            LOG.debug("Credential charset not configured, using HTTP element charset");
            charset = getHttpElementCharset();
        }
        return charset;
    }
    
    /**
     * Sets the charset to be used for writing HTTP headers.
     * @param charset The charset
     */
    public void setCredentialCharset(String charset) {
        setParameter(CREDENTIAL_CHARSET, charset);
    }
    
    /**
     * Returns {@link HttpVersion HTTP protocol version} to be used by the 
     * {@link org.apache.commons.httpclient.HttpMethod HTTP methods} that 
     * this collection of parameters applies to. 
     *
     * @return {@link HttpVersion HTTP protocol version}
     */
    public HttpVersion getVersion() { 
        Object param = getParameter(PROTOCOL_VERSION);
        if (param == null) {
            return HttpVersion.HTTP_1_1;
        }
        return (HttpVersion)param;
    }
    
    /**
     * Assigns the {@link HttpVersion HTTP protocol version} to be used by the 
     * {@link org.apache.commons.httpclient.HttpMethod HTTP methods} that 
     * this collection of parameters applies to. 
     *
     * @param version the {@link HttpVersion HTTP protocol version}
     */
    public void setVersion(HttpVersion version) {
        setParameter(PROTOCOL_VERSION, version);
    }


    /**
     * Returns {@link CookiePolicy cookie policy} to be used by the 
     * {@link org.apache.commons.httpclient.HttpMethod HTTP methods} 
     * this collection of parameters applies to. 
     *
     * @return {@link CookiePolicy cookie policy}
     */
    public String getCookiePolicy() { 
        Object param = getParameter(COOKIE_POLICY);
        if (param == null) {
            return CookiePolicy.DEFAULT;
        }
        return (String)param;
    }
    
    /**
     * Assigns the {@link CookiePolicy cookie policy} to be used by the 
     * {@link org.apache.commons.httpclient.HttpMethod HTTP methods} 
     * this collection of parameters applies to. 
     *
     * @param policy the {@link CookiePolicy cookie policy}
     */
    public void setCookiePolicy(String policy) {
        setParameter(COOKIE_POLICY, policy);
    }

    /**
     * Returns the default socket timeout (<tt>SO_TIMEOUT</tt>) in milliseconds which is the 
     * timeout for waiting for data. A timeout value of zero is interpreted as an infinite 
     * timeout.  
     *
     * @return timeout in milliseconds
     */
    public int getSoTimeout() {
        return getIntParameter(SO_TIMEOUT, 0);
    }

    /**
     * Sets the default socket timeout (<tt>SO_TIMEOUT</tt>) in milliseconds which is the 
     * timeout for waiting for data. A timeout value of zero is interpreted as an infinite 
     * timeout.  
     *
     * @param timeout Timeout in milliseconds
     */
    public void setSoTimeout(int timeout) {
        setIntParameter(SO_TIMEOUT, timeout);
    }

    private static final String[] PROTOCOL_STRICTNESS_PARAMETERS = {
        UNAMBIGUOUS_STATUS_LINE,
        SINGLE_COOKIE_HEADER,
        STRICT_TRANSFER_ENCODING,
        REJECT_HEAD_BODY,
        WARN_EXTRA_INPUT
    };
    
    /**
     * Makes the {@link org.apache.commons.httpclient.HttpMethod HTTP methods} 
     * strictly follow the HTTP protocol specification (RFC 2616 and other relevant RFCs).
     * It must be noted that popular HTTP agents have different degree of HTTP protocol 
     * compliance and some HTTP serves are programmed to expect the behaviour that does not 
     * strictly adhere to the HTTP specification.  
     */
    public void makeStrict() {
        setParameters(PROTOCOL_STRICTNESS_PARAMETERS, new Boolean(true));
        setIntParameter(STATUS_LINE_GARBAGE_LIMIT, 0);
    }

    /**
     * Makes the {@link org.apache.commons.httpclient.HttpMethod HTTP methods}
     * attempt to mimic the exact behaviour of commonly used HTTP agents, 
     * which many HTTP servers expect, even though such behaviour may violate   
     * the HTTP protocol specification (RFC 2616 and other relevant RFCs).
     */
    public void makeLenient() {
        setParameters(PROTOCOL_STRICTNESS_PARAMETERS, new Boolean(false));
        setIntParameter(STATUS_LINE_GARBAGE_LIMIT, Integer.MAX_VALUE);
    }

}