/*
 * $Header: /home/cvs/jakarta-commons/httpclient/src/java/org/apache/commons/httpclient/methods/MultipartPostMethod.java,v 1.26 2004/06/13 20:22:19 olegk Exp $
 * $Revision: 1.26 $
 * $Date: 2004/06/13 20:22:19 $
 *
 * ====================================================================
 *
 *  Copyright 2002-2004 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.methods;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;

import org.apache.commons.httpclient.HttpConnection;
import org.apache.commons.httpclient.HttpException;
import org.apache.commons.httpclient.HttpState;
import org.apache.commons.httpclient.methods.multipart.FilePart;
import org.apache.commons.httpclient.methods.multipart.Part;
import org.apache.commons.httpclient.methods.multipart.StringPart;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * Implements the HTTP multipart POST method.
 * <p>
 * The HTTP multipart POST method is defined in section 3.3 of
 * <a href="http://www.ietf.org/rfc/rfc1867.txt">RFC1867</a>:
 * <blockquote>
 * The media-type multipart/form-data follows the rules of all multipart
 * MIME data streams as outlined in RFC 1521. The multipart/form-data contains 
 * a series of parts. Each part is expected to contain a content-disposition 
 * header where the value is "form-data" and a name attribute specifies 
 * the field name within the form, e.g., 'content-disposition: form-data; 
 * name="xxxxx"', where xxxxx is the field name corresponding to that field.
 * Field names originally in non-ASCII character sets may be encoded using 
 * the method outlined in RFC 1522.
 * </blockquote>
 * </p>
 * <p>
 *
 * @author <a href="mailto:mattalbright@yahoo.com">Matthew Albright</a>
 * @author <a href="mailto:jsdever@apache.org">Jeff Dever</a>
 * @author <a href="mailto:adrian@ephox.com">Adrian Sutton</a>
 * @author <a href="mailto:mdiggory@latte.harvard.edu">Mark Diggory</a>
 * @author <a href="mailto:mbowler@GargoyleSoftware.com">Mike Bowler</a>
 * @author <a href="mailto:oleg@ural.ru">Oleg Kalnichevski</a>
 *
 * @since 2.0
 */
public class MultipartPostMethod extends ExpectContinueMethod {

    /** The Content-Type for multipart/form-data. */
    public static final String MULTIPART_FORM_CONTENT_TYPE = 
        "multipart/form-data";

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

    /** The parameters for this method */
    private final List parameters = new ArrayList();

    /**
     * No-arg constructor.
     */
    public MultipartPostMethod() {
        super();
    }

    /**
     * Constructor specifying a URI.
     *
     * @param uri either an absolute or relative URI
     */
    public MultipartPostMethod(String uri) {
        super(uri);
    }

    /**
     * Returns <tt>true</tt> 
     * 
     * @return <tt>true</tt>
     * 
     * @since 2.0beta1
     */
    protected boolean hasRequestContent() {
        return true;
    }

    /**
     * Returns <tt>"POST"</tt>.
     * @return <tt>"POST"</tt>
     */
    public String getName() {
        return "POST";
    }

    /**
     * Adds a text field part
     * 
     * @param parameterName The name of the parameter.
     * @param parameterValue The value of the parameter.
     */
    public void addParameter(String parameterName, String parameterValue) {
        LOG.trace("enter addParameter(String parameterName, String parameterValue)");
        Part param = new StringPart(parameterName, parameterValue);
        parameters.add(param);
    }

    /**
     * Adds a binary file part
     * 
     * @param parameterName The name of the parameter
     * @param parameterFile The name of the file.
     * @throws FileNotFoundException If the file cannot be found.
     */
    public void addParameter(String parameterName, File parameterFile) 
    throws FileNotFoundException {
        LOG.trace("enter MultipartPostMethod.addParameter(String parameterName, "
            + "File parameterFile)");
        Part param = new FilePart(parameterName, parameterFile);
        parameters.add(param);
    }

    /**
     * Adds a binary file part with the given file name
     * 
     * @param parameterName The name of the parameter
     * @param fileName The file name
     * @param parameterFile The file
     * @throws FileNotFoundException If the file cannot be found.
     */
    public void addParameter(String parameterName, String fileName, File parameterFile) 
    throws FileNotFoundException {
        LOG.trace("enter MultipartPostMethod.addParameter(String parameterName, "
            + "String fileName, File parameterFile)");
        Part param = new FilePart(parameterName, fileName, parameterFile);
        parameters.add(param);
    }
        
    /**
     * Adds a part.
     * 
     * @param part The part to add.
     */
    public void addPart (final Part part) {
        LOG.trace("enter addPart(Part part)");
        parameters.add(part);
    }

    /**
     * Returns all parts.
     * 
     * @return an array of containing all parts
     */
    public Part[] getParts() {
        return (Part[]) parameters.toArray(new Part[parameters.size()]);
    }

    /**
     * Adds a <tt>Content-Length</tt> request header, as long as no 
     * <tt>Content-Length</tt> request header already exists.
     *
     * @param state current state of http requests
     * @param conn the connection to use for I/O
     *
     * @throws IOException if an I/O (transport) error occurs. Some transport exceptions
     *                     can be recovered from.
     * @throws HttpException  if a protocol exception occurs. Usually protocol exceptions 
     *                    cannot be recovered from.
     * 
     * @since 3.0
     */
    protected void addContentLengthRequestHeader(HttpState state,
                                                 HttpConnection conn)
    throws IOException, HttpException {
        LOG.trace("enter EntityEnclosingMethod.addContentLengthRequestHeader("
                  + "HttpState, HttpConnection)");

        if (getRequestHeader("Content-Length") == null) { 
            long len = getRequestContentLength();
            addRequestHeader("Content-Length", String.valueOf(len));
        }
        removeRequestHeader("Transfer-Encoding");
    }

    /**
     * Adds a <tt>Content-Type</tt> request header.
     *
     * @param state current state of http requests
     * @param conn the connection to use for I/O
     *
     * @throws IOException if an I/O (transport) error occurs. Some transport exceptions
     *                     can be recovered from.
     * @throws HttpException  if a protocol exception occurs. Usually protocol exceptions 
     *                    cannot be recovered from.
     * 
     * @since 3.0
     */
    protected void addContentTypeRequestHeader(HttpState state,
                                                 HttpConnection conn)
    throws IOException, HttpException {
        LOG.trace("enter EntityEnclosingMethod.addContentTypeRequestHeader("
                  + "HttpState, HttpConnection)");

        if (!parameters.isEmpty()) {
            StringBuffer buffer = new StringBuffer(MULTIPART_FORM_CONTENT_TYPE);
            if (Part.getBoundary() != null) {
                buffer.append("; boundary=");
                buffer.append(Part.getBoundary());
            }
            setRequestHeader("Content-Type", buffer.toString());
        }
    }

    /**
     * Populates the request headers map to with additional 
     * {@link org.apache.commons.httpclient.Header headers} to be submitted to 
     * the given {@link HttpConnection}.
     *
     * <p>
     * This implementation adds tt>Content-Length</tt> and <tt>Content-Type</tt>
     * headers, when appropriate.
     * </p>
     *
     * <p>
     * Subclasses may want to override this method to to add additional
     * headers, and may choose to invoke this implementation (via
     * <tt>super</tt>) to add the "standard" headers.
     * </p>
     *
     * @param state the {@link HttpState state} information associated with this method
     * @param conn the {@link HttpConnection connection} used to execute
     *        this HTTP method
     *
     * @throws IOException if an I/O (transport) error occurs. Some transport exceptions
     *                     can be recovered from.
     * @throws HttpException  if a protocol exception occurs. Usually protocol exceptions 
     *                    cannot be recovered from.
     *
     * @see #writeRequestHeaders
     */
    protected void addRequestHeaders(HttpState state, HttpConnection conn) 
    throws IOException, HttpException {
        LOG.trace("enter MultipartPostMethod.addRequestHeaders(HttpState state, "
            + "HttpConnection conn)");
        super.addRequestHeaders(state, conn);
        addContentLengthRequestHeader(state, conn);
        addContentTypeRequestHeader(state, conn);
    }

    /**
     * Writes the request body to the given {@link HttpConnection connection}.
     *
     * @param state the {@link HttpState state} information associated with this method
     * @param conn the {@link HttpConnection connection} used to execute
     *        this HTTP method
     *
     * @return <tt>true</tt>
     *
     * @throws IOException if an I/O (transport) error occurs. Some transport exceptions
     *                     can be recovered from.
     * @throws HttpException  if a protocol exception occurs. Usually protocol exceptions 
     *                    cannot be recovered from.
     */
    protected boolean writeRequestBody(HttpState state, HttpConnection conn) 
    throws IOException, HttpException {
        LOG.trace("enter MultipartPostMethod.writeRequestBody(HttpState state, "
            + "HttpConnection conn)");
        OutputStream out = conn.getRequestOutputStream();
        Part.sendParts(out, getParts());
        return true;
    }

    /**
     * <p>Return the length of the request body.</p>
     *
     * <p>Once this method has been invoked, the request parameters cannot be
     * altered until the method is {@link #recycle recycled}.</p>
     * 
     * @return The request content length.
     */
    protected long getRequestContentLength() throws IOException {
        LOG.trace("enter MultipartPostMethod.getRequestContentLength()");
        return Part.getLengthOfParts(getParts());
    }


    /**
     * Recycles the HTTP method so that it can be used again.
     * Note that all of the instance variables will be reset
     * once this method has been called. This method will also
     * release the connection being used by this HTTP method.
     * 
     * @see #releaseConnection()
     * 
     * @deprecated no longer supported and will be removed in the future
     *             version of HttpClient
     */
    public void recycle() {
        LOG.trace("enter MultipartPostMethod.recycle()");
        super.recycle();
        parameters.clear();
    }
}