How to check if uploaded file is binary or ascii?

[veg_all]

I have a script where a user can upload their csv file into a mysql
database. The problem is sometimes a user will upload the raw excel or
access file. How can I perform some simple checks to determine if the
file is binary. I could do some regular expressions to check for
unusual characters, but how would I read the file line by line?

[Chung Leong]

ve*****@yahoo.c om wrote:

I have a script where a user can upload their csv file into a mysql
database. The problem is sometimes a user will upload the raw excel or
access file. How can I perform some simple checks to determine if the
file is binary. I could do some regular expressions to check for
unusual characters, but how would I read the file line by line?

Just look for \x00. Binary files would inevitable have it.

[veg_all]

Chung Leong wrote:

Just look for \x00. Binary files would inevitable have it.

Thanks. Is there a way to do it without reading in the entire file to
memory?

[Marcin Dobrucki]

ve*****@yahoo.c om wrote:

Chung Leong wrote:

>>Just look for \x00. Binary files would inevitable have it.

Thanks. Is there a way to do it without reading in the entire file to
memory?

On linux/unix you can call "file" on the uploaded file.

[Kimmo Laine]

<ve*****@yahoo. comwrote in message
news:11******** *************@b 28g2000cwb.goog legroups.com...

>I have a script where a user can upload their csv file into a mysql
database. The problem is sometimes a user will upload the raw excel or
access file. How can I perform some simple checks to determine if the
file is binary. I could do some regular expressions to check for
unusual characters, but how would I read the file line by line?

how about check the type-value? It should tell the mime-type of the file.
Couldn't you use that to filter out the idiots?
$_FILES['userfile']['type']

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[Colin McKinnon]

Marcin Dobrucki wrote:

ve*****@yahoo.c om wrote:

>Chung Leong wrote:

>>>Just look for \x00. Binary files would inevitable have it.

Thanks. Is there a way to do it without reading in the entire file to
memory?

On linux/unix you can call "file" on the uploaded file.

'file' is very good at guessing file types - but it's still a guess and
possible to circumvent if you're up to mischief.

A better solution is to 'cat -v' the file. Some versions of tr support
regexes too.

C.