JFLZdMlzABA/V7sIVOFXqyI/AAAAAAAABX0/qDu2YGSVSGQyGwjKthmATDObIwI19b5rQCLcB/s1600/codeigniter-download-file-from-url-server-example.png' alt='Generate File To Download Php' title='Generate File To Download Php' />The right way to handle file downloads in PHPIve seen many download scripts written in PHP, from simple one liners to dedicated classes. Yet, at least half of them share common errors in many cases programmers simply copy the code from something that works, without even attempting to understand what it really does. What follows is not a complete working download script, but rather a set of issues you should be aware about and that will allow you to write better code. Never accept paths as input. Its very tempting to write something likebut before you do, think about it anyone could request any file on the server, even if its outside the public html area. Guessing is not too difficult and in a few tries, an attacker could obtain configuration or password files. You might think youre being extra clever by doing something likemypathmysecretpath. GETfile mypath mysecretpath. File-Manager4.jpg' alt='Generate File To Download Php' title='Generate File To Download Php' />GETfile but an attacker can use relative paths to evade that. What you must do always is sanitize the input. Accept only file names, like this pathpartspathinfoGETfile filenamepathpartsbasename filepathmysecretpath. GETfile. And work only with the file name and add the path to it youserlf. Naruto Shippuden Dragon Blade Chronicles Wii Pal Download more. Even better would be to accept only numeric IDs and get the file path and name from a database or even a text file or key value array if its something that doesnt change often. Anything is better than blindly accept requests. If you need to restrict access to a file, you should generate encrypted, one time IDs, so you can be sure a generated path can be used only once. Use headers correctly. This is a very widespread problem and unfortunately even the PHP manual is plagued with errors. Developers usually say this works for me and they copy stuff they dont fully understand. First of all, I notice the use of headers like Content Description and Content Transfer Encoding. Generate File To Download Php' title='Generate File To Download Php' />Working PHP code for File upload and download. Description of parameters client and server side affecting upload and download word of files. Script storing. A list of the most important PHP class script and libraries for generating PDF files, PDF manipulation and HTML to PDF conversion. Download 7. 3. 0. Installers Offline installer is recommended for slow and unreliable connections Notes Windows Offline Installer Online Installer. Generate File To Download Php' title='Generate File To Download Php' />DownloadHelper the easy way to Web videos. Download tons of videos from most of YouTube like sites. Parameters. string. The header string. There are two specialcase header calls. The first is a header that starts with the string HTTP case is not. There is no such thing in HTTP. Dont believe me Have a look at RFC2. HTTP, unlike MIME, does not use Content Transfer Encoding, and does use Transfer Encoding and Content Encoding. You may add those headers if you want, but they do absolutely nothing. Sadly, this wrong example is present even in the PHP manual. Second, regarding the MIME type, I often see things like Content Type applicationforce download. Generate File To Download Php' title='Generate File To Download Php' />Theres no such thing and Content Type applicationoctet stream RFC1. If youre thinking about Internet Explorer, its even better to specify it clearly rather than force it to sniff the content. See MIME Type Detection in Internet Explorer for details. Even worse, I see these kinds of statements headerContent Type applicationforce download headerContent Type applicationoctet stream headerContent Type applicationdownload headerContent Type applicationforce download. Content Type applicationoctet stream. Content Type applicationdownload The author must have been really frustrated and added three Content Type headers. The only problem is, as specified in the header manual entry, The optional replace parameter indicates whether the header should replace a previous similar header, or add a second header of the same type. By default it will replace. So unless you specify headerContent Type some value, FALSE, the new Content Type header will replace the old one. Forcing download and Internet Explorer bugs. What would it be like to not having to worry about old versions of Internet Explorer A better world, thats for sure. To force a file to download, the correct way is headerContent Disposition attachment filenamefilename headerContent Disposition attachment filenamefilename Note the quotes in the filename are required in case the file may contain spaces. The code above will fail in IE6 unless the following are added headerPragma public headerCache Control must revalidate, post check0, pre check0 headerPragma public. Cache Control must revalidate, post check0, pre check0 Now, the use of Cache Control is wrong in this case, especially to both values set to zero, according to Microsoft, but it works in IE6 and IE7 and later ignores it so no harm done. If you still get strange results when downloading especially in IE, make sure that the PHP output compression is disabled, as well as any server compression sometimes the server inadvertently applies compression on the output produced by the PHP script. Handling large file sizesreadfile is a simple way to ouput files files. Historically it had some performance issues and while the documentation claims there are no memory problems, real life scenarios beg to differ  output buffering and other subtle things. Regardless, if you need byte ranges support, you still have to output the old fashioned way. The simplest way to handle this is to output the file in chunks settimelimit0 filefopenfilepath,rb whileIf youre on Apache, theres a very cool module called modxsendfile that makes the download simpler and faster. You just output a header and the module takes care of the rest. Of course, you must be able to install it and it also makes the code less portable so you probably wont want to use this for redistributable code. Disable Gzip output compression output buffering. This is the source of many seemingly obscure errors. If you have output buffering, the file will not be sent to the user in chunks but only at the end of the script. Secondly, youre most likely to be outputting a binary file that does not need compression anyway. Thirdly, some older browserserver combinations might become confused that youre requesting a text file PHP but youre sending compressed data with a different content type. To avoid this, assuming youre using Apache, create a. This will disable compression in that folder. Resumable downloads. For large files, its useful to allow downloads to be resumed. Doing so is more involved, but its really worth doing, especially if you serve large files or videoaudio. Im not going to write a complete example, but to point you in the right direction. First, you need to signal the browser that you support ranges headerAccept Ranges bytes headerAccept Ranges bytes Again, Ive seen examples in which the actual byte range is given e. At the start of your script, after checking the file if it exists, etc., you have to check if a range is requested ifissetSERVERHTTPRANGErangeSERVERHTTPRANGE if issetSERVERHTTPRANGE. SERVERHTTPRANGE Ranges can be expressed like bytes 9. Be aware that multiple ranges can be specified e. So, now that you have the range, you have to make sure thats expressed in bytes, that it does not contain multiple ranges and that the range itself is valid end is greater that the start, start is not negative, and end is not larger than the file itself. Note that bytes is not a valid request. If the range is not valid, you must outputheaderHTTP1. Requested Range Not Satisfiable headerHTTP1. Requested Range Not Satisfiable yet again, many scripts get this wrong by sending 4. Do not try to guess or fix the ranges as it may result in corrupted downloads, which are more dangerous than failed ones. Then, you must send a bunch of headers headerHTTP1. Playhouse Disney Stanley Games Online.