Solution for PHP ultra-large file download and resumable download

This article provides a detailed analysis of PHP large file downloads and resumable download solutions. For more information, see The php memory overflow problem recently exported, the reason is that the temporary files read during the download process are too large to accommodate the PHP memory. if you want to change the PHP memory limit as soon as possible, this is only a slow solution, therefore, another method is to read and download files in multiple parts.
The source code is as follows:

The code is as follows:

$ SourceFile = "1.tmp"; // temporary file name to be downloaded
$ OutFile = "..xls"; // download the file name saved to the client
$ File_extension = strtolower (substr (strrchr ($ sourceFile, "."), 1); // get the file extension
// Echo $ sourceFile;
If (! Ereg ("[tmp | txt | rar | pdf | doc]", $ file_extension) exit ("illegal resource download ");
// Check whether the file exists
If (! Is_file ($ sourceFile )){
Die ("404 File not found!");
}
$ Len = filesize ($ sourceFile); // get the file size
$ Filename = basename ($ sourceFile); // get the file name
$ OutFile_extension = strtolower (substr (strrchr ($ outFile, "."), 1); // get the file extension
// Specify the output browser format based on the extension
Switch ($ outFile_extension ){
Case "exe ":
$ Ctype = "application/octet-stream ";
Break;
Case "zip ":
$ Ctype = "application/zip ";
Break;
Case "mp3 ":
$ Ctype = "audio/mpeg ";
Break;
Case "mpg ":
$ Ctype = "video/mpeg ";
Break;
Case "avi ":
$ Ctype = "video/x-msvideo ";
Break;
Default:
$ Ctype = "application/force-download ";
}
// Begin writing headers
Header ("Cache-Control :");
Header ("Cache-Control: public ");
// Set the output browser format
Header ("Content-Type: $ ctype ");
Header ("Content-Disposition: attachment; filename =". $ outFile );
Header ("Accept-Ranges: bytes ");
$ Size = filesize ($ sourceFile );
// If $ _ SERVER ['http _ range'] parameter exists
If (isset ($ _ SERVER ['http _ range']) {
/* The Range header can request one or more sub-ranges of an object.
For example,
Indicates the first 500 bytes: bytes = 0-499
Indicates the second 500 bytes: bytes = 500-999
Indicates the last 500 bytes: bytes =-500
Indicates the range after 500 bytes: bytes = 500-
First and Last bytes: bytes = 0-0,-1
Specify the following ranges: bytes = 500-600,601-999.
However, the server can ignore this request header. if the unconditional GET contains the Range request header, the response will be returned with the status code 206 (PartialContent) instead of 200 (OK ).
*/
// The value of connecting to $ _ SERVER ['http _ range'] again after the breakpoint is bytes = 4390912-
List ($ a, $ range) = explode ("=", $ _ SERVER ['http _ range']);
// If yes, download missing part
Str_replace ($ range, "-", $ range); // What is this sentence ....
$ Size2 = $ size-1; // total file bytes
$ New_length = $ size2-$ range; // Obtain the length of the next download.
Header ("HTTP/1.1 206 Partial Content ");
Header ("Content-Length: $ new_length"); // The total Length of input
Header ("Content-Range: bytes $ range $ size2/$ size"); // Content-Range: bytes 4908618-4988927/4988928 95%
} Else {
// The first connection
$ Size2 = $ size-1;
Header ("Content-Range: bytes 0-$ size2/$ size"); // Content-Range: bytes 0-4988927/4988928
Header ("Content-Length:". $ size); // total output Length
}
// Open the file
$ Fp = fopen ("$ sourceFile", "rb ");
// Set the pointer position
Fseek ($ fp, $ range );
// Unreal output
While (! Feof ($ fp )){
// Set the maximum file execution time
Set_time_limit (0 );
Print (fread ($ fp, 1024*8); // output file
Flush (); // OUTPUT BUFFER
Ob_flush ();
}
Fclose ($ fp );
Exit ();