Android example source code file (MultipartEntity.java)

This example Android source code file (MultipartEntity.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

abstracthttpentity, bytearrayinputstream, bytearrayoutputstream, content, httpparams, illegalargumentexception, illegalstateexception, io, ioexception, log, multipartentity, override, random, string, stringbuffer, util

The MultipartEntity.java Android example source code

/*
 * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//httpclient/src/java/org/apache/commons/httpclient/methods/multipart/MultipartRequestEntity.java,v 1.1 2004/10/06 03:39:59 mbecke Exp $
 * $Revision: 502647 $
 * $Date: 2007-02-02 17:22:54 +0100 (Fri, 02 Feb 2007) $
 *
 * ====================================================================
 *
 *  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.
 * ====================================================================
 *
 * 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 com.android.internal.http.multipart;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Random;

import org.apache.http.Header;
import org.apache.http.entity.AbstractHttpEntity;
import org.apache.http.message.BasicHeader;
import org.apache.http.params.HttpParams;
import org.apache.http.protocol.HTTP;
import org.apache.http.util.EncodingUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * Implements a request entity suitable for an 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:
 * <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>This entity is designed to be used in conjunction with the 
 * {@link org.apache.http.HttpRequest} to provide
 * multipart posts.  Example usage:</p>
 * <pre>
 *  File f = new File("/path/fileToUpload.txt");
 *  HttpRequest request = new HttpRequest("http://host/some_path");
 *  Part[] parts = {
 *      new StringPart("param_name", "value"),
 *      new FilePart(f.getName(), f)
 *  };
 *  filePost.setEntity(
 *      new MultipartRequestEntity(parts, filePost.getParams())
 *      );
 *  HttpClient client = new HttpClient();
 *  int status = client.executeMethod(filePost);
 * </pre>
 * 
 * @since 3.0
 */
public class MultipartEntity extends AbstractHttpEntity {

    private static final Log log = LogFactory.getLog(MultipartEntity.class);
    
    /** The Content-Type for multipart/form-data. */
    private static final String MULTIPART_FORM_CONTENT_TYPE = "multipart/form-data";
    
    /**
     * Sets the value to use as the multipart boundary.
     * <p>
     * This parameter expects a value if type {@link String}.
     * </p>
     */
    public static final String MULTIPART_BOUNDARY = "http.method.multipart.boundary";
    
    /**
     * The pool of ASCII chars to be used for generating a multipart boundary.
     */
    private static byte[] MULTIPART_CHARS = EncodingUtils.getAsciiBytes(
        "-_1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ");
    
    /**
     * Generates a random multipart boundary string.
    */
    private static byte[] generateMultipartBoundary() {
        Random rand = new Random();
        byte[] bytes = new byte[rand.nextInt(11) + 30]; // a random size from 30 to 40
        for (int i = 0; i < bytes.length; i++) {
            bytes[i] = MULTIPART_CHARS[rand.nextInt(MULTIPART_CHARS.length)];
        }
        return bytes;
    }
    
    /** The MIME parts as set by the constructor */
    protected Part[] parts;
    
    private byte[] multipartBoundary;
    
    private HttpParams params;
    
    private boolean contentConsumed = false;
    
    /**
     * Creates a new multipart entity containing the given parts.
     * @param parts The parts to include.
     * @param params The params of the HttpMethod using this entity.
     */
    public MultipartEntity(Part[] parts, HttpParams params) {      
      if (parts == null) {
          throw new IllegalArgumentException("parts cannot be null");
      }
      if (params == null) {
          throw new IllegalArgumentException("params cannot be null");
      }
      this.parts = parts;
      this.params = params;
    }
    
    public MultipartEntity(Part[] parts) {
      setContentType(MULTIPART_FORM_CONTENT_TYPE);
      if (parts == null) {
          throw new IllegalArgumentException("parts cannot be null");
      }
      this.parts = parts;
      this.params = null;
    }
    
    /**
     * Returns the MIME boundary string that is used to demarcate boundaries of
     * this part. The first call to this method will implicitly create a new
     * boundary string. To create a boundary string first the 
     * HttpMethodParams.MULTIPART_BOUNDARY parameter is considered. Otherwise 
     * a random one is generated.
     * 
     * @return The boundary string of this entity in ASCII encoding.
     */
    protected byte[] getMultipartBoundary() {
        if (multipartBoundary == null) {
            String temp = null;
            if (params != null) {
              temp = (String) params.getParameter(MULTIPART_BOUNDARY);
            }
            if (temp != null) {
                multipartBoundary = EncodingUtils.getAsciiBytes(temp);
            } else {
                multipartBoundary = generateMultipartBoundary();
            }
        }
        return multipartBoundary;
    }

    /**
     * Returns <code>true if all parts are repeatable, false otherwise.
     */
    public boolean isRepeatable() {
        for (int i = 0; i < parts.length; i++) {
            if (!parts[i].isRepeatable()) {
                return false;
            }
        }
        return true;
    }

    /* (non-Javadoc)
     */
    public void writeTo(OutputStream out) throws IOException {
        Part.sendParts(out, parts, getMultipartBoundary());
    }
    /* (non-Javadoc)
     * @see org.apache.commons.http.AbstractHttpEntity.#getContentType()
     */
    @Override
    public Header getContentType() {
      StringBuffer buffer = new StringBuffer(MULTIPART_FORM_CONTENT_TYPE);
      buffer.append("; boundary=");
      buffer.append(EncodingUtils.getAsciiString(getMultipartBoundary()));
      return new BasicHeader(HTTP.CONTENT_TYPE, buffer.toString());

    }

    /* (non-Javadoc)
     */
    public long getContentLength() {
        try {
            return Part.getLengthOfParts(parts, getMultipartBoundary());            
        } catch (Exception e) {
            log.error("An exception occurred while getting the length of the parts", e);
            return 0;
        }
    }    
 
    public InputStream getContent() throws IOException, IllegalStateException {
          if(!isRepeatable() && this.contentConsumed ) {
              throw new IllegalStateException("Content has been consumed");
          }
          this.contentConsumed = true;
          
          ByteArrayOutputStream baos = new ByteArrayOutputStream();
          Part.sendParts(baos, this.parts, this.multipartBoundary);
          ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
          return bais;
    }
  
    public boolean isStreaming() {
        return false;
    }
}