FormBodyPart.java

/*
 * Copyright (c) 2013. wyouflf (wyouflf@gmail.com)
 *
 * 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 com.lidroid.xutils.http.client.multipart;

import com.lidroid.xutils.http.client.multipart.content.ContentBody;

/**
 * FormBodyPart class represents a content body that can be used as a part of multipart encoded
 * entities. This class automatically populates the header with standard fields based on
 * the content description of the enclosed body.
 *
 * @since 4.0
 */
public class FormBodyPart {

    private final String name;
    private final MinimalFieldHeader header;

    private final ContentBody body;

    public FormBodyPart(final String name, final ContentBody body) {
        super();
        if (name == null) {
            throw new IllegalArgumentException("Name may not be null");
        }
        if (body == null) {
            throw new IllegalArgumentException("Body may not be null");
        }
        this.name = name;
        this.body = body;
        this.header = new MinimalFieldHeader();

        generateContentDisposition(body);
        generateContentType(body);
        generateTransferEncoding(body);
    }

    public FormBodyPart(final String name, final ContentBody body, final String contentDisposition) {
        super();
        if (name == null) {
            throw new IllegalArgumentException("Name may not be null");
        }
        if (body == null) {
            throw new IllegalArgumentException("Body may not be null");
        }
        this.name = name;
        this.body = body;
        this.header = new MinimalFieldHeader();

        if (contentDisposition != null) {
            addField(MIME.CONTENT_DISPOSITION, contentDisposition);
        } else {
            generateContentDisposition(body);
        }
        generateContentType(body);
        generateTransferEncoding(body);
    }

    public String getName() {
        return this.name;
    }

    public ContentBody getBody() {
        return this.body;
    }

    public MinimalFieldHeader getHeader() {
        return this.header;
    }

    public void addField(final String name, final String value) {
        if (name == null) {
            throw new IllegalArgumentException("Field name may not be null");
        }
        this.header.addField(new MinimalField(name, value));
    }

    protected void generateContentDisposition(final ContentBody body) {
        StringBuilder buffer = new StringBuilder();
        buffer.append("form-data; name=\"");
        buffer.append(getName());
        buffer.append("\"");
        if (body.getFilename() != null) {
            buffer.append("; filename=\"");
            buffer.append(body.getFilename());
            buffer.append("\"");
        }
        addField(MIME.CONTENT_DISPOSITION, buffer.toString());
    }

    protected void generateContentType(final ContentBody body) {
        StringBuilder buffer = new StringBuilder();
        buffer.append(body.getMimeType()); // MimeType cannot be null
        if (body.getCharset() != null) { // charset may legitimately be null
            buffer.append("; charset=");
            buffer.append(body.getCharset());
        }
        addField(MIME.CONTENT_TYPE, buffer.toString());
    }

    protected void generateTransferEncoding(final ContentBody body) {
        addField(MIME.CONTENT_TRANSFER_ENC, body.getTransferEncoding()); // TE cannot be null
    }

}