PHP implementation file security Download _php Foundation

You're going to laugh at me. "Downloading files" is worth saying so easily? Of course it's not as simple as imagination. For example, if you want the customer to fill out a form, you can download a file, your first idea must be "Redirect" method, first check whether the form has been completed and complete, and then the URL to the file, so that customers can download, but if you want to do a "online shopping" E-commerce site , consider security issues, you do not want users to directly copy the URL to download the file, I suggest you use PHP directly read the actual file and then download the method to do. The procedure is as follows:

$file _name = "Info_check.exe";
$file _dir = "/public/www/download/";
if (!file_exists ($file _dir. $file _name)) {//check whether the file exists
echo "File not found";
Exit
} else {
$file = fopen ($file _dir. $file _name, "R"); Open File
Input File Label
Header ("Content-type:application/octet-stream");
Header ("Accept-ranges:bytes");
Header ("Accept-length:". FileSize ($file _dir. $file _name));
Header ("content-disposition:attachment; Filename= ". $file _name);
Output file contents
Echo fread ($file, FileSize ($file _dir. $file _name));
Fclose ($file);
Exit;}

If the file path is "http" or "FTP" URL, the source code will change a little bit, the program is as follows:

$file _name = "Info_check.exe";
$file _dir = "http://www.easycn.net/";
$file = @ fopen ($file _dir. $file _name, "R");
if (! $file) {
echo "File not found";
} else {
Header ("Content-type:application/octet-stream");
Header ("content-disposition:attachment; Filename= ". $file _name);
while (!feof ($file)) {
Echo fread ($file, 50000);
}
Fclose ($file);
}

This allows you to output the file directly with PHP.