uk.co.weft.maybeupload
Class MaybeUploadServlet

java.lang.Object
  javax.servlet.GenericServlet
      javax.servlet.http.HttpServlet
          uk.co.weft.maybeupload.MaybeUploadServlet

All Implemented Interfaces:

java.io.Serializable, javax.servlet.Servlet, javax.servlet.ServletConfig

Direct Known Subclasses:

Servlet, SnoopServlet

public abstract class MaybeUploadServlet

extends javax.servlet.http.HttpServlet

A superclass for Servlets which may need to handle file upload. Sun's Servlet class does not transparently handle multipart/form-data requests and, indeed, makes it extremely difficult for application-layer classes to handle them. This class is written as a wrapper round Sun's Servlet class which makes multipart/form-data handling transparent.

This class (and consequently all servlets which are subclasses of this class) know about the following configuration parameters:

allow_overwrite

Boolean: whether or not to allow uploaded files to overwrite previously uploaded files with the same name. Default is we don't.

max_upload

Integer: maximum size in bytes of file to upload. Optional. Default is 524288.

save_uploaded

Boolean: whether or not to save uploaded files directly to disk. Optional. Default is we do. If we don't, the uploaded file will be returned as a java.io.ByteArrayInputStream by a call to MaybeUploadRequestWrapper.get()

silently_rename

Boolean: whether or not to rename files whose names collide with existing files in the upload directory. Default is we do. Note that if both allow_overwrite and silently_rename are false and a name collision occurs, we will throw an UploadException.

upload_dir_path

String: A path to a directory in the server-side local file-system in which uploaded files can be saved. Optional. Defaults to the value of javax.servlet.context.tempdir. Note that as of 1.10pre8 the path will first be treated as local to the web-app in which the servlet resides. If no directory is found within the web-app document root, it will then be treated as global to the file system. If no writable directory is found on this second attempt it will fail.

upload_dir_url

String: the path to my upload directory (work directory) within the document root of the web server, if it is within the document root of the web server, else null. For example, if uploadDirPath was "/home/httpd/htdocs/upload", and the document root of the Web server was /home/httpd/htdocs, then it would make sense to have uploadDirURL set to "/upload/"A Optional. No Default.

All parameters may be supplied either as context-params or as init-params; if both are supplied the servlet-specific init-param will override the context-param.

NOTE: This code relies heavily on the Tomcat reference implementation and is thus in part Copyright (c) 1999 The Apache Software Foundation. All rights reserved.

"This product includes software developed by the Apache Software Foundation (http://www.apache.org/)."

Version:

$Revision: 1.1.4.2 $ This revision: $Author: simon $

Author:

Simon Brooke (simon[at]jasmine.org.uk)

See Also:

Serialized Form

Field Summary

protected boolean	allowOverwrite whether to allow uploaded files to be overwritten when new files are uploaded; default is we don't
protected int	maxUpload the maximum upload size: by default, half a megabyte.
protected boolean	saveUploadedFilesToDisk whether or not to save uploads directly to disk; default is we do
protected boolean	silentlyRename whether or not to rename uploaded files to prevent name collisions; default is we do
protected java.io.File	uploadDir the actual upload directory as a file object
protected java.lang.String	uploadDirPath file system local path to where I unpack files I have uploaded
protected java.lang.String	uploadDirURL the path to my upload directory (work directory) within the document root of the web server, if it is within the document root of the web server, else null.

Constructor Summary

MaybeUploadServlet()

Method Summary

protected void	doDelete(MaybeUploadRequestWrapper req, javax.servlet.http.HttpServletResponse resp) Simple wrapper round HttpServlet.doDelete( ), so that you can depend on having a MaybeUploadRequestWrapper in your code.
protected void	doGet(MaybeUploadRequestWrapper req, javax.servlet.http.HttpServletResponse resp) Simple wrapper round HttpServlet.doGet( ), so that you can depend on having a MaybeUploadRequestWrapper in your code.
protected void	doHead(MaybeUploadRequestWrapper req, javax.servlet.http.HttpServletResponse resp) doHead is a bit more tricky.
protected void	doOptions(MaybeUploadRequestWrapper req, javax.servlet.http.HttpServletResponse resp) Simple wrapper round HttpServlet.doOptions( ), so that you can depend on having a MaybeUploadRequestWrapper in your code.
protected void	doPost(MaybeUploadRequestWrapper req, javax.servlet.http.HttpServletResponse resp) Simple wrapper round HttpServlet.doPost( ), so that you can depend on having a MaybeUploadRequestWrapper in your code.
protected void	doPut(MaybeUploadRequestWrapper req, javax.servlet.http.HttpServletResponse resp) Simple wrapper round HttpServlet.doPut( ), so that you can depend on having a MaybeUploadRequestWrapper in your code.
protected void	doTrace(MaybeUploadRequestWrapper req, javax.servlet.http.HttpServletResponse resp) Simple wrapper round HttpServlet.doTrace( ), so that you can depend on having a MaybeUploadRequestWrapper in your code.
java.io.File	getUploadDir()
java.lang.String	getUploadURL()
void	init(javax.servlet.ServletConfig config) initialise my variables from my configuration
void	service(javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse resp) Service a request.

Methods inherited from class javax.servlet.http.HttpServlet

doDelete, doGet, doHead, doOptions, doPost, doPut, doTrace, getLastModified, service

Methods inherited from class javax.servlet.GenericServlet

destroy, getInitParameter, getInitParameterNames, getServletConfig, getServletContext, getServletInfo, getServletName, init, log, log

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

uploadDir

protected java.io.File uploadDir

the actual upload directory as a file object

uploadDirPath

protected java.lang.String uploadDirPath

file system local path to where I unpack files I have uploaded

uploadDirURL

protected java.lang.String uploadDirURL

the path to my upload directory (work directory) within the document root of the web server, if it is within the document root of the web server, else null. For example, if uploadDirPath was "/home/httpd/htdocs/upload", and the document root of the Web server was /home/httpd/htdocs, then it would make sense to have uploadDirURL set to "/upload/"

allowOverwrite

protected boolean allowOverwrite

whether to allow uploaded files to be overwritten when new files are uploaded; default is we don't

saveUploadedFilesToDisk

protected boolean saveUploadedFilesToDisk

whether or not to save uploads directly to disk; default is we do

silentlyRename

protected boolean silentlyRename

whether or not to rename uploaded files to prevent name collisions; default is we do

maxUpload

protected int maxUpload

the maximum upload size: by default, half a megabyte.

Constructor Detail

MaybeUploadServlet

public MaybeUploadServlet()

Method Detail

getUploadDir

public java.io.File getUploadDir()

Returns:

my upload directory. Note that the upload directory cannot be set dynamically at run-time for security reasons

getUploadURL

public java.lang.String getUploadURL()

Returns:

as a String, the base URL for my upload directory if any. If returned, may be an absolute URL or a URL fragment relative to the document root of the HTTP server hosting the Servlet engine. In null, means that you cannot access the upload directory via HTTP

init

public void init(javax.servlet.ServletConfig config)
          throws javax.servlet.ServletException

initialise my variables from my configuration

Parameters:

config - my configuration

Throws:

javax.servlet.ServletException - doesn't; thing which specialise me may

javax.servlet.UnavailableException - if can't write to upload directory

service

public void service(javax.servlet.http.HttpServletRequest req,
                    javax.servlet.http.HttpServletResponse resp)
             throws javax.servlet.ServletException,
                    java.io.IOException

Service a request. This method heavily dependent on the reference implementation.

Parameters:

req - the request to be serviced

resp - the response being constructed to this request

Throws:

javax.servlet.ServletException

java.io.IOException

doDelete

protected void doDelete(MaybeUploadRequestWrapper req,
                        javax.servlet.http.HttpServletResponse resp)
                 throws javax.servlet.ServletException,
                        java.io.IOException

Simple wrapper round HttpServlet.doDelete( ), so that you can depend on having a MaybeUploadRequestWrapper in your code.

Parameters:

req - a request wrapper which know how to handle upload

resp - a standard servlet response

Throws:

javax.servlet.ServletException

java.io.IOException

doGet

protected void doGet(MaybeUploadRequestWrapper req,
                     javax.servlet.http.HttpServletResponse resp)
              throws javax.servlet.ServletException,
                     java.io.IOException

Simple wrapper round HttpServlet.doGet( ), so that you can depend on having a MaybeUploadRequestWrapper in your code.

Parameters:

req - a request wrapper which know how to handle upload

resp - a standard servlet response

Throws:

javax.servlet.ServletException

java.io.IOException

doHead

protected void doHead(MaybeUploadRequestWrapper req,
                      javax.servlet.http.HttpServletResponse resp)
               throws javax.servlet.ServletException,
                      java.io.IOException

doHead is a bit more tricky. not really handled in this version, although I'll happily integrate code from anyone else who is sufficiently confident to write an implementation. Could just copy the HttpServlet version, but...

Parameters:

req - a request wrapper which know how to handle upload

resp - a standard servlet response

Throws:

javax.servlet.ServletException

java.io.IOException

doOptions

protected void doOptions(MaybeUploadRequestWrapper req,
                         javax.servlet.http.HttpServletResponse resp)
                  throws javax.servlet.ServletException,
                         java.io.IOException

Simple wrapper round HttpServlet.doOptions( ), so that you can depend on having a MaybeUploadRequestWrapper in your code.

Parameters:

req - a request wrapper which know how to handle upload

resp - a standard servlet response

Throws:

javax.servlet.ServletException

java.io.IOException

doPost

protected void doPost(MaybeUploadRequestWrapper req,
                      javax.servlet.http.HttpServletResponse resp)
               throws javax.servlet.ServletException,
                      java.io.IOException

Simple wrapper round HttpServlet.doPost( ), so that you can depend on having a MaybeUploadRequestWrapper in your code.

Parameters:

req - a request wrapper which know how to handle upload

resp - a standard servlet response

Throws:

javax.servlet.ServletException

java.io.IOException

doPut

protected void doPut(MaybeUploadRequestWrapper req,
                     javax.servlet.http.HttpServletResponse resp)
              throws javax.servlet.ServletException,
                     java.io.IOException

Simple wrapper round HttpServlet.doPut( ), so that you can depend on having a MaybeUploadRequestWrapper in your code.

Parameters:

req - a request wrapper which know how to handle upload

resp - a standard servlet response

Throws:

javax.servlet.ServletException

java.io.IOException

doTrace

protected void doTrace(MaybeUploadRequestWrapper req,
                       javax.servlet.http.HttpServletResponse resp)
                throws javax.servlet.ServletException,
                       java.io.IOException

Simple wrapper round HttpServlet.doTrace( ), so that you can depend on having a MaybeUploadRequestWrapper in your code.

Parameters:

req - a request wrapper which know how to handle upload

resp - a standard servlet response

Throws:

javax.servlet.ServletException

java.io.IOException