/*
* Copyright 2002-2007 the original author or authors.
*
* 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 org.springframework.web.multipart;
import javax.servlet.http.HttpServletRequest;
/**
* A strategy interface for multipart file upload resolution in accordance
* with <a href="http://www.ietf.org/rfc/rfc1867.txt">RFC 1867</a>.
* Implementations are typically usable both within an application context
* and standalone.
*
* <p>There is only one concrete implementation included in Spring,
* as of Spring 2.5:
* <ul>
* <li>{@link org.springframework.web.multipart.commons.CommonsMultipartResolver} for Jakarta Commons FileUpload
* </ul>
*
* <p>There is no default resolver implementation used for Spring
* {@link org.springframework.web.servlet.DispatcherServlet DispatcherServlets},
* as an application might choose to parse its multipart requests itself. To define
* an implementation, create a bean with the id "multipartResolver" in a
* {@link org.springframework.web.servlet.DispatcherServlet DispatcherServlet's}
* application context. Such a resolver gets applied to all requests handled
* by that {@link org.springframework.web.servlet.DispatcherServlet}.
*
* <p>If a {@link org.springframework.web.servlet.DispatcherServlet} detects
* a multipart request, it will resolve it via the configured
* {@link org.springframework.web.multipart.MultipartResolver} and pass on a
* wrapped {@link javax.servlet.http.HttpServletRequest}.
* Controllers can then cast their given request to the
* {@link org.springframework.web.multipart.MultipartHttpServletRequest}
* interface, which permits access to any
* {@link org.springframework.web.multipart.MultipartFile MultipartFiles}.
* Note that this cast is only supported in case of an actual multipart request.
*
* <pre class="code">
* public ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response) {
* MultipartHttpServletRequest multipartRequest = (MultipartHttpServletRequest) request;
* MultipartFile multipartFile = multipartRequest.getFile("image");
* ...
* }</pre>
*
* Instead of direct access, command or form controllers can register a
* {@link org.springframework.web.multipart.support.ByteArrayMultipartFileEditor}
* or {@link org.springframework.web.multipart.support.StringMultipartFileEditor}
* with their data binder, to automatically apply multipart content to command
* bean properties.
*
* <p>As an alternative to using a
* {@link org.springframework.web.multipart.MultipartResolver} with a
* {@link org.springframework.web.servlet.DispatcherServlet},
* a {@link org.springframework.web.multipart.support.MultipartFilter} can be
* registered in <code>web.xml</code>. It will delegate to a corresponding
* {@link org.springframework.web.multipart.MultipartResolver} bean in the root
* application context. This is mainly intended for applications that do not
* use Spring's own web MVC framework.
*
* <p>Note: There is hardly ever a need to access the
* {@link org.springframework.web.multipart.MultipartResolver} itself
* from application code. It will simply do its work behind the scenes,
* making
* {@link org.springframework.web.multipart.MultipartHttpServletRequest MultipartHttpServletRequests}
* available to controllers.
*
* @author Juergen Hoeller
* @author Trevor D. Cook
* @since 29.09.2003
* @see MultipartHttpServletRequest
* @see MultipartFile
* @see org.springframework.web.multipart.commons.CommonsMultipartResolver
* @see org.springframework.web.multipart.support.ByteArrayMultipartFileEditor
* @see org.springframework.web.multipart.support.StringMultipartFileEditor
* @see org.springframework.web.servlet.DispatcherServlet
*/
public interface MultipartResolver {
/**
* Determine if the given request contains multipart content.
* <p>Will typically check for content type "multipart/form-data", but the actually
* accepted requests might depend on the capabilities of the resolver implementation.
* @param request the servlet request to be evaluated
* @return whether the request contains multipart content
*/
boolean isMultipart(HttpServletRequest request);
/**
* Parse the given HTTP request into multipart files and parameters,
* and wrap the request inside a
* {@link org.springframework.web.multipart.MultipartHttpServletRequest} object
* that provides access to file descriptors and makes contained
* parameters accessible via the standard ServletRequest methods.
* @param request the servlet request to wrap (must be of a multipart content type)
* @return the wrapped servlet request
* @throws MultipartException if the servlet request is not multipart, or if
* implementation-specific problems are encountered (such as exceeding file size limits)
* @see MultipartHttpServletRequest#getFile
* @see MultipartHttpServletRequest#getFileNames
* @see MultipartHttpServletRequest#getFileMap
* @see javax.servlet.http.HttpServletRequest#getParameter
* @see javax.servlet.http.HttpServletRequest#getParameterNames
* @see javax.servlet.http.HttpServletRequest#getParameterMap
*/
MultipartHttpServletRequest resolveMultipart(HttpServletRequest request) throws MultipartException;
/**
* Cleanup any resources used for the multipart handling,
* like a storage for the uploaded files.
* @param request the request to cleanup resources for
*/
void cleanupMultipart(MultipartHttpServletRequest request);
}