For more information, see the HTTP response header when downloading files.

For more information, see the HTTP response header when downloading files. When I learned how to use PHP to download files, the textbook said that three http message headers should be provided:

Header ("Content-type: application/octet-stream"); // The high-speed browser transmits the file stream header ("Accept-Length: 2048 "); // file size header ("Content-Disposition: attachment; filename=abc.txt"); // specify the file name

The message headers "Content-type" and "Content-Disposition" are not quite understandable, so I have made two examples:

A. php:

   
  
B. php:
  
    
  
My problem is:
1. there is one missing message header on both pages. Why can all files be downloaded successfully?
2. although the size of the specified file is 2048 bytes, the actual output is only "123". Why can the file be downloaded normally?
Is the "Accept-Length" message header configurable?
  
I have just learned about http. please answer the questions I have asked. do not introduce a deeper concept because I cannot understand it ..
Thank you! :)
  
 
 
Reply to discussion (solution)
It is not Accept-Length, it is Content-Length
I don't know who misled everyone into using Accept-Length. The RFC standard does not contain this Header.
 
  
It is not Accept-Length, it is Content-Length
I don't know who misled everyone into using Accept-Length. The RFC standard does not contain this Header.
  
  
Thank you for your prompt!
Can you help me solve my questions?
 
1. there is one missing message header on both pages. Why can all files be downloaded successfully?
  
Because you have not set the Content-Length, the output at the end of the default connection is the downloaded Content.
  
2. although the size of the specified file is 2048 bytes, the actual output is only "123". Why can the file be downloaded normally? Is the "Accept-Length" message header configurable?
  
Accept-Length indicates the maximum acceptable string Length. So it can be set.
 
  
1. there is one missing message header on both pages. Why can all files be downloaded successfully?
   
Because you have not set the Content-Length, the output at the end of the default connection is the downloaded Content.
   
2. although the size of the specified file is 2048 bytes, the actual output is only "123". Why can the file be downloaded normally? Is the "Accept-Length" message header configurable?
   
Accept-Length indicates the maximum acceptable string Length. So it can be set.
  
  
Thank you, buddy!
 
Good, learning.