com.threewks.thundr.bind.http.MultipartHttpBinder.java Source code

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Here is the source code for com.threewks.thundr.bind.http.MultipartHttpBinder.java

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/*
 * This file is a component of thundr, a software library from 3wks.
 * Read more: http://3wks.github.io/thundr/
 * Copyright (C) 2014 3wks, <thundr@3wks.com.au>
 *
 * 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.threewks.thundr.bind.http;

import java.io.InputStream;
import java.util.Arrays;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.fileupload.FileItemIterator;
import org.apache.commons.fileupload.FileItemStream;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

import com.threewks.thundr.bind.BindException;
import com.threewks.thundr.bind.Binder;
import com.threewks.thundr.bind.parameter.ParameterBinderRegistry;
import com.threewks.thundr.http.ContentType;
import com.threewks.thundr.http.MultipartFile;
import com.threewks.thundr.introspection.ParameterDescription;
import com.threewks.thundr.util.Streams;

public class MultipartHttpBinder implements Binder {

    private List<ContentType> supportedContentTypes = Arrays.asList(ContentType.MultipartFormData);
    private ServletFileUpload upload = new ServletFileUpload();
    private ParameterBinderRegistry parameterBinderRegistry;

    public MultipartHttpBinder(ParameterBinderRegistry parameterBinderRegistry) {
        super();
        this.parameterBinderRegistry = parameterBinderRegistry;
    }

    @Override
    public void bindAll(Map<ParameterDescription, Object> bindings, HttpServletRequest req,
            HttpServletResponse resp, Map<String, String> pathVariables) {
        if (ContentType.matchesAny(req.getContentType(), supportedContentTypes) && shouldTryToBind(bindings)) {
            Map<String, List<String>> formFields = new HashMap<String, List<String>>();
            Map<String, MultipartFile> fileFields = new HashMap<String, MultipartFile>();
            extractParameters(req, formFields, fileFields);
            Map<String, String[]> parameterMap = ParameterBinderRegistry.convertListMapToArrayMap(formFields);
            parameterBinderRegistry.bind(bindings, parameterMap, fileFields);
        }
    }

    /**
     * If all parameters have been bound, we don't need to try to bind. This means we won't consume the stream leaving it in tact to be read in controllers.
     * 
     * @param bindings
     * @return
     */
    boolean shouldTryToBind(Map<ParameterDescription, Object> bindings) {
        return bindings.values().contains(null);
    }

    void extractParameters(HttpServletRequest req, Map<String, List<String>> formFields,
            Map<String, MultipartFile> fileFields) {
        try {
            FileItemIterator itemIterator = upload.getItemIterator(req);
            while (itemIterator.hasNext()) {
                FileItemStream item = itemIterator.next();
                InputStream stream = item.openStream();

                String fieldName = item.getFieldName();
                if (item.isFormField()) {
                    List<String> existing = formFields.get(fieldName);
                    if (existing == null) {
                        existing = new LinkedList<String>();
                        formFields.put(fieldName, existing);
                    }
                    existing.add(Streams.readString(stream));
                } else {
                    MultipartFile file = new MultipartFile(item.getName(), Streams.readBytes(stream),
                            item.getContentType());
                    fileFields.put(fieldName, file);
                }
                stream.close();
            }
        } catch (Exception e) {
            throw new BindException(e, "Failed to bind multipart form data: %s", e.getMessage());
        }
    }
}