PHP large file download, resumable download

Recently, the company encountered a php memory overflow problem when exporting order information. The reason is that the temporary file generated during download is too large to accommodate the PHP memory, when I thought of changing the PHP memory limit, it was just a slow task. so I thought of another way to read and download files in multiple parts. Recently, the company encountered a php memory overflow problem when exporting order information. The reason is that the temporary file generated during download is too large to accommodate the PHP memory, when I thought of changing the PHP memory limit, it was just a slow task. so I thought of another way to read and download files in multiple parts.

The source 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 ();