problem with POST and if statements

[GazK]

I have an image viewing page which resizes an image to a sensible sizebefore
displaying. The user should then be able to choose "25% larger" or smaller
and the resized image display. The problem I am getting with the code below
is that whatever the POST variable value (and I have tested the value
changes correctly), the line marked with *** executes, ie the image gets
smaller. Am I missing some obvious subtlety with IF statements?

Also, when the page reloads, it still displays the previous (ie non-resized)
image, despite the fact that I have confirmed that the actual image in the
directory has changed size. Is it the case that the image has been cached by
the browser? If so, how do I force a reload?

TIA Gaz

if(isset($_POST['submitScale'])) {
if ($_POST['scale'] = "25% smaller") {
resizeImageByPe rcent($thumbLoc ation, "resized", 75);
}
else if ($_POST['scale'] = "25% larger") {
resizeImageByPe rcent($thumbLoc ation, "resized", 125);
}
else if ($_POST['scale'] = "full size") {
resizeImageByPe rcent($original Location, "resized", 100);
}
}

.....blah blah blah some code

<form action="imagevi ew.php3?image_i d=<?echo $row["image_id"]?>"
method="POST">
Make this image&nbsp;<sel ect name="scale">
<option>25% smaller
<option>25% larger
<option>full size
</select>
<input type="submit" name="submitSca le" value="Go!">
</form>

[Zac Hester]

Re: problem with POST and if statements

"GazK" <tosspot@blueyo nder.co.uk> wrote in message
news:mkZRa.3718 2$4c.518@news-binary.blueyond er.co.uk...[color=blue]
> I have an image viewing page which resizes an image to a sensible[/color]
sizebefore[color=blue]
> displaying. The user should then be able to choose "25% larger" or smaller
> and the resized image display. The problem I am getting with the code[/color]
below[color=blue]
> is that whatever the POST variable value (and I have tested the value
> changes correctly), the line marked with *** executes, ie the image gets
> smaller. Am I missing some obvious subtlety with IF statements?
>
> Also, when the page reloads, it still displays the previous (ie[/color]
non-resized)[color=blue]
> image, despite the fact that I have confirmed that the actual image in the
> directory has changed size. Is it the case that the image has been cached[/color]
by[color=blue]
> the browser? If so, how do I force a reload?[/color]

This is how I tell the browser not to cache something:

header('Expires : Mon, 26 Jul 1997 05:00:00 GMT');
header('Last-Modified: '.gmdate('D, d M Y H:i:s').' GMT');
header('Cache-Control: no-cache, must-revalidate');
header('Pragma: no-cache');

I think I got this out of the PHP manual when looking up how to use the
header() function. Oh, if you're serving images off of the file system (and
not through a database or other dynamic means), I've found it works to read
the file in using fread() and send it to the client with the appropriate
"Content-Type" header. I created a bandwidth meter in PHP that used an
image file to test the transfer rate between a client and my server. It
seemed that the easiest way to make sure the image was never cached by the
browser was to use PHP (and the non-caching headers) to send the file
manually. (I'm sure there's an Apache work-around, though.)

By the way, are you changing the "width" and "height" attributes of your
image tag on the front end?

HTH,
Zac

[GazK]

oops corrected post

> I have an image viewing page which resizes an image to a sensible
sizebefore[color=blue]
> displaying. The user should then be able to choose "25% larger" or smaller
> and the resized image display. The problem I am getting with the code[/color]
below[color=blue]
> is that whatever the POST variable value (and I have tested the value
> changes correctly), the line marked with *** executes, ie the image gets
> smaller. Am I missing some obvious subtlety with IF statements?
>
> Also, when the page reloads, it still displays the previous (ie[/color]
non-resized)[color=blue]
> image, despite the fact that I have confirmed that the actual image in the
> directory has changed size. Is it the case that the image has been cached[/color]
by[color=blue]
> the browser? If so, how do I force a reload?
>
> TIA Gaz
>
> if(isset($_POST['submitScale'])) {
> if ($_POST['scale'] = "25% smaller") {
> resizeImageByPe rcent($thumbLoc ation, "resized", 75);***
> }
> else if ($_POST['scale'] = "25% larger") {
> resizeImageByPe rcent($thumbLoc ation, "resized", 125);
> }
> else if ($_POST['scale'] = "full size") {
> resizeImageByPe rcent($original Location, "resized", 100);
> }
> }
>
> ....blah blah blah some code
>
> <form action="imagevi ew.php3?image_i d=<?echo $row["image_id"]?>"
> method="POST">
> Make this image&nbsp;<sel ect name="scale">
> <option>25% smaller
> <option>25% larger
> <option>full size
> </select>
> <input type="submit" name="submitSca le" value="Go!">
> </form>
>
>[/color]

[Zac Hester]

Re: oops corrected post

"GazK" <tosspot@blueyo nder.co.uk> wrote in message
news:nG_Ra.3865 5$4c.5379@news-binary.blueyond er.co.uk...[color=blue][color=green]
> > I have an image viewing page which resizes an image to a sensible[/color]
> sizebefore[color=green]
> > displaying. The user should then be able to choose "25% larger" or[/color][/color]
smaller[color=blue][color=green]
> > and the resized image display. The problem I am getting with the code[/color]
> below[color=green]
> > is that whatever the POST variable value (and I have tested the value
> > changes correctly), the line marked with *** executes, ie the image gets
> > smaller. Am I missing some obvious subtlety with IF statements?
> >
> > Also, when the page reloads, it still displays the previous (ie[/color]
> non-resized)[color=green]
> > image, despite the fact that I have confirmed that the actual image in[/color][/color]
the[color=blue][color=green]
> > directory has changed size. Is it the case that the image has been[/color][/color]
cached[color=blue]
> by[color=green]
> > the browser? If so, how do I force a reload?
> >
> > TIA Gaz
> >
> > if(isset($_POST['submitScale'])) {
> > if ($_POST['scale'] = "25% smaller") {
> > resizeImageByPe rcent($thumbLoc ation, "resized", 75);***
> > }
> > else if ($_POST['scale'] = "25% larger") {
> > resizeImageByPe rcent($thumbLoc ation, "resized", 125);
> > }
> > else if ($_POST['scale'] = "full size") {
> > resizeImageByPe rcent($original Location, "resized", 100);
> > }
> > }[/color][/color]

There's your first problem. Use "==" for comparison, and "=" for
assignment. Assignment returns the value assigned.

-Zac

[Leslie Hoare]

Re: problem with POST and if statements


"Martin Wickman" <wizball@hotbre v.com> wrote in message
news:bf9sou$cfl o8$2@ID-156202.news.uni-berlin.de...
[color=blue]
> Other than that, try a force reload of your browser to make sure you
> dont have any nasty cache problems.[/color]

Kinda offtopic, but I didn't think POST requests were allowed to be cached
anyway.

[Martin Wickman]

Re: problem with POST and if statements

In article <bfa4mt$cpete$1 @ID-194542.news.uni-berlin.de>, Leslie Hoare wrote:[color=blue]
>
> "Martin Wickman" <wizball@hotbre v.com> wrote in message
> news:bf9sou$cfl o8$2@ID-156202.news.uni-berlin.de...
>[color=green]
>> Other than that, try a force reload of your browser to make sure you
>> dont have any nasty cache problems.[/color]
>
> Kinda offtopic, but I didn't think POST requests were allowed to be cached
> anyway.[/color]

Well, try posting something and then reload. See, the browser keeps
the stuff cached. About 'allowed' or not. I dont know, but I would
guess that it's up to each browser to decide whether it should cache
and not.

[GazK]

Re: oops corrected post

doh! thanks, that fixed that part of the problem.

"Zac Hester" <news@planetzac .net> wrote in message
news:3f18875c$3 @news.enetis.ne t...[color=blue]
> "GazK" <tosspot@blueyo nder.co.uk> wrote in message
> news:nG_Ra.3865 5$4c.5379@news-binary.blueyond er.co.uk...[color=green][color=darkred]
> > > I have an image viewing page which resizes an image to a sensible[/color]
> > sizebefore[color=darkred]
> > > displaying. The user should then be able to choose "25% larger" or[/color][/color]
> smaller[color=green][color=darkred]
> > > and the resized image display. The problem I am getting with the code[/color]
> > below[color=darkred]
> > > is that whatever the POST variable value (and I have tested the value
> > > changes correctly), the line marked with *** executes, ie the image[/color][/color][/color]
gets[color=blue][color=green][color=darkred]
> > > smaller. Am I missing some obvious subtlety with IF statements?
> > >
> > > Also, when the page reloads, it still displays the previous (ie[/color]
> > non-resized)[color=darkred]
> > > image, despite the fact that I have confirmed that the actual image in[/color][/color]
> the[color=green][color=darkred]
> > > directory has changed size. Is it the case that the image has been[/color][/color]
> cached[color=green]
> > by[color=darkred]
> > > the browser? If so, how do I force a reload?
> > >
> > > TIA Gaz
> > >
> > > if(isset($_POST['submitScale'])) {
> > > if ($_POST['scale'] = "25% smaller") {
> > > resizeImageByPe rcent($thumbLoc ation, "resized", 75);***
> > > }
> > > else if ($_POST['scale'] = "25% larger") {
> > > resizeImageByPe rcent($thumbLoc ation, "resized", 125);
> > > }
> > > else if ($_POST['scale'] = "full size") {
> > > resizeImageByPe rcent($original Location, "resized", 100);
> > > }
> > > }[/color][/color]
>
> There's your first problem. Use "==" for comparison, and "=" for
> assignment. Assignment returns the value assigned.
>
> -Zac
>
>[/color]