Can PHP read the meta files? - php

Question

I built a parsial uploading in PHP and Client-Side Javascript.
The Flow
Convert the file to base64 so I get the base64 string
Slice the base64 string into some pieces
Post every piece and the position to upload handler
The upload handler make the post data as a single file in one same folder
If the iteration stop, the JS tell the upload handler to build the code
Then the upload handler make all files as a single file then decode the base64 to a new file
The problem
When the build finished, I can't read the result file as same as the $_FILES in file uploading. So I can't get:
Original size
Original extension
I wonder can PHP read the information about the file?
I expect some function like this (not the actual function)
$file = read_the_file('/path/to/file');
$metas = read_meta_file($file);
and then you can get what type of file and some others data.
Note
Currently, the file that I work with is a video file.

Answer 1

You can get the information about the file with the help of php function named pathinfo
How to use pathinfo:
print_r(pathinfo("/path_of_file/123.txt"));
It will return .....
Array ( [dirname] => /path_of_file [basename] => 123.txt [extension] => txt )
2. You can get the size of the file with the help of php function named filesize
How to use filesize:
echo filesize("123.txt");
It will return the size of file in bytes.
I hope, This will help you.
Good Luck.

Answer 2

You can use pathinfo php function
For file size you can use filesize function
To get extension from base_64 then you can use finfo_buffer function
echo finfo_buffer(finfo_open(), $base64, FILEINFO_MIME_TYPE);

Answer 3

But you would need to store somewhere that extension - in video files for example in ID3 tags (and use the lib https://github.com/JamesHeinrich/getID3/ to extract it). That is most likely NOT what you want to do as you would need to edit the file on the frontend.
Another option is to use mime_content_type(after you file has finished uploading) - for a "mp4" file, even without extension, it will give you "video/mp4", for mkv "video/x-matroska". Etc. based on the mime-type you can build the extension again - for example:
$exts = [
"video/x-matroska" => "mkv",
"video/mp4" => "mp4"
];
and then:
$extension = $exts[mime_content_type("..path..to..file")];
(of course first with checking if the entry exists there).
Extension itself is NOT stored in any metadata so you cannot simply extract it.
While having the mime-type you can also use any popular libs - like:
https://github.com/ralouphie/mimey
to convert mime-type to extension.
To get the file size it is best to simply use the filesize function.
Another option would be to simply send the original file name with the last post (the one which tells the backend that the file has finished): probably the most reliable one.