Cannot upload .csv using text/plain

[John]

I am using Excel to save a spreadsheet in .csv format. This creates a
text file with extension .csv
But when I try to upload the file to the server by checking for its
MIME type using $_FILE['userfile']['type'] I get my own error message
that the file is not text file. If I change the extension to .txt I am
able to upload the file.
This is not reliable as it is only relying on extensions rather than
contents of the file. Is there a reliable way of checking for file
formats. I would like to upload jpeg, gif and text files reliably.

Thank you
John

[Shawn Wilson]

John wrote:

I am using Excel to save a spreadsheet in .csv format. This creates a
text file with extension .csv
But when I try to upload the file to the server by checking for its
MIME type using $_FILE['userfile']['type'] I get my own error message
that the file is not text file. If I change the extension to .txt I am
able to upload the file.
This is not reliable as it is only relying on extensions rather than
contents of the file. Is there a reliable way of checking for file
formats. I would like to upload jpeg, gif and text files reliably.

For gif and jpeg, you can use getimagesize() (the 3rd or 4th array element, I
think). Not sure how you'd go about validating a CSV though.

Regards,
Shawn
--
Shawn Wilson
sh***@glassgiant.com
http://www.glassgiant.com

[John Dunlop]

John wrote:

I am using Excel to save a spreadsheet in .csv format. This creates a
text file with extension .csv
But when I try to upload the file to the server by checking for its
MIME type using $_FILE['userfile']['type']
I trust you meant $_FILES.
I get my own error message that the file is not text file.
The value of $_FILES['userfile']['type'] is whatever the file's media
type was deemed to be at the client-side, if such deeming took place
at all; as the Content-Type header is optional in multipart types
(and data sets of "file upload forms" ought to be sent using
multipart/form-data), a file's media type may be absent from the
request -- you couldn't, then, figure out the file's media type from
$_FILES. Morever, if a browser tries but is unable to determine an
appropriate media type, it should fall back on the oft-misused
application/octet-stream type (RFC2388, sec. 3), i.e., labelled the
entity body "arbitrary binary data" (RFC2046, sec. 4.5.1).

Internet Explorer 6.0, for example, sends a Content-Type value of
application/octet-stream with CSV files, which is fine; Opera 7.10
sends text/comma-separated-values, which is curious since that media
type isn't registered. There is, in fact, no registered media type
for CSV files. Many transactions are conducted with text/x-csv or
other private subtypes.

I wonder how a TSV (Tab Separated Values, media type text/tab-
separated-values) file would bear up.
If I change the extension to .txt I am able to upload the file. This
is not reliable as it is only relying on extensions rather than
contents of the file.
There is no normative source limiting the determining of files' media
types from filename extensions. Manifold heuristics may be employed.
Is there a reliable way of checking for file formats.
Not "bullet proof",

http://www.php.net/manual/en/ref.mime-magic.php
http://www.php.net/manual/en/functio...ntent-type.php
I would like to upload jpeg, gif and text files reliably.

Shawn's already proposed getimagesize for JPEGs and GIFs.

http://www.php.net/manual/en/function.getimagesize.php

--
Jock