Apache Large File Limit

Using FileUploadFileUpload can be used in a number of different ways, depending upon therequirements of your application. In the simplest case, you will call asingle method to parse the servlet request, and then process the list ofitems as they apply to your application. At the other end of the scale,you might decide to customize FileUpload to take full control of the wayin which individual items are stored; for example, you might decide tostream the content into a database.Here, we will describe the basic principles of FileUpload, and illustratesome of the simpler - and most common - usage patterns. Customization ofFileUpload is described.FileUpload depends on Commons IO, so make sure you have the versionmentioned on the inyour classpath before continuing.

How it worksA file upload request comprises an ordered list of items thatare encoded according to,'Form-based File Upload in HTML'. FileUpload can parse such a requestand provide your application with a list of the individual uploadeditems.

Each such item implements the FileItem interface,regardless of its underlying implementation.This page describes the traditional API of the commons fileuploadlibrary. The traditional API is a convenient approach. However, forultimate performance, you might prefer the faster.Each file item has a number of properties that might be of interest foryour application. For example, every item has a name and a content type,and can provide an InputStream to access its data. On theother hand, you may need to process items differently, depending uponwhether the item is a regular form field - that is, the data came froman ordinary text box or similar HTML field - or an uploaded file. TheFileItem interface provides the methods to make such adetermination, and to access the data in the most appropriate manner.FileUpload creates new file items using a FileItemFactory.This is what gives FileUpload most of its flexibility.

The factory hasultimate control over how each item is created. The factory implementationthat currently ships with FileUpload stores the item's data in memory oron disk, depending on the size of the item (i.e. Bytes of data).

However,this behavior can be customized to suit your application. Servlets and PortletsStarting with version 1.1, FileUpload supports file upload requests inboth servlet and portlet environments. The usage is almost identical inthe two environments, so the remainder of this document refers only tothe servlet environment.If you are building a portlet application, the following are the twodistinctions you should make as you read this document:.Where you see references to the ServletFileUpload class,substitute the PortletFileUpload class.Where you see references to the HttpServletRequest class,substitute the ActionRequest class. The simplest caseThe simplest usage scenario is the following:.Uploaded items should be retained in memory as long as they arereasonably small.Larger items should be written to a temporary file on disk.Very large upload requests should not be permitted.The built-in defaults for the maximum size of an item tobe retained in memory, the maximum permitted size of an uploadrequest, and the location of temporary files are acceptable.Handling a request in this scenario couldn't be much simpler. // Create a factory for disk-based file itemsDiskFileItemFactory factory = new DiskFileItemFactory;// Configure a repository (to ensure a secure temp location is used)ServletContext servletContext = this.getServletConfig.getServletContext;File repository = (File) servletContext.getAttribute('javax.servlet.context.tempdir');factory.setRepository(repository);// Create a new file upload handlerServletFileUpload upload = new ServletFileUpload(factory);// Parse the requestList items = upload.parseRequest(request);That's all that's needed. Really!The result of the parse is a List of file items, each ofwhich implements the FileItem interface. Processing theseitems is discussed below.

Resource cleanupThis section applies only, if you are using the.In other words, it applies, if your uploaded files are written totemporary files before processing them.Such temporary files are deleted automatically, if they are no longerused (more precisely, if the corresponding instance of DiskFileItemis garbage collected. This is done silently by the org.apache.commons.io.FileCleanerTrackerclass, which starts a reaper thread.This reaper thread should be stopped, if it is no longer needed. Ina servlet environment, this is done by using a special servletcontext listener, called.To do so, add a section like the following to your web.xml. Interaction with virus scannersVirus scanners running on the same system as the web container can causesome unexpected behaviours for applications using FileUpload.

This sectiondescribes some of the behaviours that you might encounter, and providessome ideas for how to handle them.The default implementation of FileUpload will cause uploaded items abovea certain size threshold to be written to disk. As soon as such a file isclosed, any virus scanner on the system will wake up and inspect it, andpotentially quarantine the file - that is, move it to a special locationwhere it will not cause problems. This, of course, will be a surprise tothe application developer, since the uploaded file item will no longer beavailable for processing. On the other hand, uploaded items below thatsame threshold will be held in memory, and therefore will not be seen byvirus scanners. This allows for the possibility of a virus being retainedin some form (although if it is ever written to disk, the virus scannerwould locate and inspect it).One commonly used solution is to set aside one directory on the systeminto which all uploaded files will be placed, and to configure the virusscanner to ignore that directory.

Apache Large File Limited

This ensures that files will not beripped out from under the application, but then leaves responsibility forvirus scanning up to the application developer. Scanning the uploadedfiles for viruses can then be performed by an external process, whichmight move clean or cleaned files to an 'approved' location, or byintegrating a virus scanner within the application itself. The details ofconfiguring an external process or integrating virus scanning into anapplication are outside the scope of this document.

Available Languages: When using a large number of Virtual Hosts, Apache may runout of available file descriptors (sometimes called filehandles) if each Virtual Host specifies different logfiles. The total number of file descriptors used by Apache isone for each distinct error log file, one for every other logfile directive, plus 10-20 for internal use. Unix operatingsystems limit the number of file descriptors that may be usedby a process; the limit is typically 64, and may usually beincreased up to a large hard-limit.Although Apache attempts to increase the limit as required,this may not work if:.

Your system does not provide the setrlimitsystem call. The setrlimit(RLIMITNOFILE) call does notfunction on your system (such as Solaris 2.3). The number of file descriptors required exceeds the hardlimit.

Your system imposes other limits on file descriptors,such as a limit on stdio streams only using file descriptorsbelow 256. (Solaris 2)In the event of problems you can:. Reduce the number of log files; don't specify log filesin thesections, but only log to the main log files. (See, below, for moreinformation on doing this.).If you system falls into 1 or 2 (above), then increase thefile descriptor limit before starting Apache, using ascript like. If you want to log multiple virtual hosts to the same log file, youmay want to split up the log files afterwards in order to runstatistical analysis of the various virtual hosts.

This can beaccomplished in the following manner.First, you will need to add the virtual host information to the logentries. This can be done using thedirective, and the%v variable. Add this to the beginningof your log format string: LogFormat '%v%h%l%u%t '%r'%s%b' vhostCustomLog logs/multiplevhostlog vhostThis will create a log file in the common log format, but with thecanonical virtual host (whatever appears in thedirective) prepended toeach line. (See formore about customizing your log files.)When you wish to split your log file into its component parts (onefile per virtual host) you can use the program to accomplishthis.

Apache File Upload Size Limit

You'll find this program in the support directoryof the Apache distribution.Run this program with the command.