On 01/20/2012 12:18 PM, Dee Ayy wrote:
Obviously I don't want a Flash/Gears solution.

FYI: Your #6 should be:
The server uploads...

Actually, from the perspective that he described it, his phrasing would be correct. The server is actually receiving from the client the data. This data is being downloaded from the client by the server.

Even though I do not want a Flash/Gears solution, I would be happy
with your #8 stating:
I won't fail silently, I'll report the problem to the user.

This all depends on your programming that report process. ie: check the file size and spit out an error instead of continuing.

Do you know the correct settings on any applicable LAMP/AJAX stack to
get the error you claim is available in your step #8 and where to look
for this error?  Is $_FILES['attachment'] supposed to be set and
hopefully something is in $_FILES['attachment']['error']?
I decided to post here instead of trying various permutations.

LAMP/AJAX has nothing to do with this issue.

He said "The server invokes your PHP script". Therefor it is up to you to generating that error. You need to examine the filesize your self and stop things at this point if you want this error to be created.

MySQL max_allowed_packet was mentioned because even if you correct #8,
MySQL can choke on what Apache allowed through, and I included the DB

Write your PHP script correctly and mysql will never be in the picture.

I never claimed I want to know the file size before upload, just that
some solutions may do this.

On Fri, Jan 20, 2012 at 11:50 AM, Maciek Sokolewicz
<maciek.sokolew...@gmail.com>  wrote:
Your problem here is the fact that you do not seem to grasp what is
hapenning when a file is being uploaded, hence your question. So let me
1. A user goes to your page by entering it into the browser.
2. The page is downloaded to the client, and the connection is closed.
3. The user chooses to upload a file via an HTML control (ie. an HTML input
element of type="file".
4. The user submits the form
5. The browser makes a connection to the server containing a header saying
"the following data is a file".
6. The server downloads all of the data from the user
7. The server parses the data, finds the header stating that the content is
a file
8. The server invokes your PHP script, which decides "whoa! wait a minute,
that file is too large" and shows an error.
9. The server removes the file from memory / temporary storage
10. The server sends back the error to the client, and closes the

The point I am trying to make here is the fact that the server does not know
the size of the file, until it has fully downloaded it, since it is not
given in any way. Good browsers let the server know what size to *expect*,
but even then, you can't rely on it.

All checking of how large a file is has to happen client-side. Due to
security reasons, languages such as javascript are not allowed to view any
details about files on your disk, and thus can't be used to determine the
filesize before sending anything to the server.

The reason flash and gears can do this, is because these are designed
differently and actually form a separate program inside your browser, which
is not limited in its activity, as javascript (and vbscript in IE) are.

So... you can use Flash and Gears to prevent upload of a too large file to
your server. But not plain HTML and/or javascript. Since the server does not
check the size until AFTER it has fully downloaded the file, there is no
setting in Apache, PHP, MySQL (which has absolutely nothing to do with
uploading at all), etc. Which are all server-side and ran after the upload
has finished.

In other words: use the Flash/Gears solution, or just decide you don't mind
if a large file is uploaded. In the last case you can always reject the file

- Tul

On 20-01-2012 18:15, Dee Ayy wrote:

Please advise the proper settings (Apache/PHP/HTML/MySQL/Anything else
I missed) to allow a specific byte size upload and to deny 1 byte over
with error reporting in LAMP/AJAX.  I've heard of Flash and Gears
solutions, but these require additional installs for the user -- just
to know the file size before an upload.

The server is Apache 2.
PHP is 5.1.6
HTML has
<!DOCTYPE html>
<input type="hidden" name="MAX_FILE_SIZE" value="1030000" />
<input type="file" name="attachment" />

PHP ini :
file_uploads    On      On
upload_max_filesize     2M      2M
post_max_size   8M      8M

I believe MySQL max_allowed_packet 1,048,576 was affecting the MySQL
INSERT, so I changed MAX_FILE_SIZE to 1030000 above.

Now I am seeing cases where
if(isset($_FILES['attachment'])&&    $_FILES['attachment']['size']>    0){

evaluates to FALSE

How can I know that a file upload was attempted yet failed or will fail?

My last test case had the web page still claiming it was busy, yet I
noticed that the above condition must have evaluated to FALSE, failing
silently due to missing error reporting on my part (or the system's

I am willing to make 2 requests:
1) just to find out if the attempted upload will fail and inform the user.
2) for the actual upload if it should succeed.


Jim Lucas


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