A few general optimization questions...please point me in the right direction :)

Dolemite50

Hello,

I'm curious on a few things here in regards to optimizing and consolidating code. Any advice would be much appreciated and I thank you kindly.

I have a dynamic menu which uses images as links for each item. 5 items are static and about 7 are conditional (e.g. "only display this menu item if $member_website_url != ""). For each dynamic menu item that is true, it prints another row, inserts the proper image, and sets it's url.

Instead of redundantly describing the menu item layout for each conditional like this:
if($website){
echo"<tr><td colspan=\"3\"><a href=\"$website\" class=\"nav\"><img src=\"imgs/website_menu_pic.gif\" width=\"280\" height=\"27\" border=\"0\" /></a></td></tr>";
..I describe it once in a function which allows variables for the image and link like so:

 
function echo_rollover($link, $roll_img){
echo"<tr><td colspan=\"3\"><a href=\"$link\" class=\"nav\"><img src=\"imgs/band/$roll_img\" width=\"280\" height=\"27\" border=\"0\" /></a></td></tr>";
}
//then..
if($website){
echo_rollover($website, "website.gif"); 
}

Okay,..so my questions are:

//////////////////REDUCING CODE WITH FUNCTIONS////////////////
1. If the server is already in the "echoing menu-item mode"; should I print the static menu items in the same way? I'm liking the reduced code but is that just un-necessary strain on the server?

Along the same lines; what if I have a page with 8 identical tables, but only the center content changes. Should I declare the table code in a function and reduce filesize?

///////////////////SEPERATING CODE AND CONTENT////////////////

I've read that it is good practice to keep your php and html seperated as much as possible. On the above menu example; instead of running the if statements in the menu section of the html; should I be doing it at the top with the rest of my php? If so, how would I append the results of conditionals to a variable so I only need to echo $menu_output where needed? I'm not sure how I would do it while using that function.
Some pages on my site have includes that require queries. I put the query code on each individual include because they would only need to be run if that file was loaded. I put them all at the top of the include files, but in the long run I don't think that I'm properly seperating content because the code would run in the middle of the main page somewhere. Is that a big deal? Is it better to do a check at the top of the main page to see which section it's on, and then run the queries for that section's include along with the rest of the page's queries? One drawback I see there is that I would have to code a lot of queries and inflate the main page's filesize when only 10% of it would be used at any time.

///////////////////////////GENERAL PHP////////////////////////////////////
1. I typically set variables for mysql query results and url variables at the top of the page like this:
$name=$row['name'];
..and call them later in the page like this "The name is <? echo $name ?>". Is it better to bypass the $name variable and just use "The name is <? echo $row['name']; ?>" or "The number is <? echo $_GET['number']" ?> ?

Lastly; my site has personal pages for members with several different sections such as Images, Bio,...etc,.. These pages use includes for the header, footer, and the left and right columns. Only the center section is updated when browsing between each member's pages and I would like to reduce mysql queries. Can anybody recommend a good method for this? I've considered just using hidden fields on each page and checking for variables there before querying but there has to be a better way.

Ok all, sorry for the bombardment but I've had these questions in the back of my mind for a long time. If anybody could shed some advice on any of them I'd really appreciate it.

Thanks

Norman_Graham

Hi Dolemite

Where to start with all this ...

Functions which do something useful are good. Those which don't are a waste of time. That's about the only rule.
Separating code and content is good. How you code each individual PHP file is up to you. If someone else can read the code and understand what's going on (separation of PHP and HTML; comments!), then that's good news. Where you put the variable statements and such like is irrelevant. I put them at the top of the page. My only tip is: if you use the variable more than once, then for goodness sake declare it at the top of the page.
If you want to really create well-designed code, use PHP5 and OOP and read some articles about three-tier web-design or similar. Backend (data) - logic (code) - content (html).
The load on the server is determined by the amount of processing. If you have a humungous PHP file with thousands of lines of code, it doesn't matter a b0[[0Ckz. If only 10% of the code is actually processing, then that is the load on the server - no more.
If you have a standard page in which the "bit in the middle" is altered depending on what the user asks for, then you only need one PHP file. The link to the page should include URL variables and be picked up using $_GET[] on the actual page, e.g. www.mysite.info/mypage.php?content=somestuff. You basically hava template in which you exchange the "bit in the middle" each time.

Does that answer any of your questions?

Norm

Dolemite50

Hey there,

Thanks for the brain stormin', Norman.

That was a great help, I appreciate you taking the time. I'm left with just a few trailers here, and no biggee if you can't get back to this.

Well I've officialy gone function crazy. I don't know where I should be drawing the line here, but I'm cutting down on a ton of code. I made one for the redundant Flash object info. Would you consider a snippet of that size worth breaking down to a function? I use a lot of Flash and the code for it is Bulky Bulkerton.
Here's what it looks like:

function flash_movie($w, $h, $file, $fvars){
echo"<object classid=\"clsid:D27CDB6E-AE6D-11cf-96B8-444553540000\" codebase=\"http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=7,0,19,0\" width=\"$w\" height=\"$h\">
<param name=FlashVars value=\"$fvars\">
<param name=\"movie\" value=\"$file\" />
<param name=\"quality\" value=\"high\" />
<embed src=\"$file\" FlashVars=\"$fvars\" quality=\"high\" pluginspage=\"http://www.macromedia.com/go/getflashplayer\" type=\"application/x-shockwave-flash\" width=\"$w\" height=\"$h\"></embed>
</object>";
}

Is that overkill? I guess I'm just not sure of the balance between overworking the server and keeping code light. I'd better go take a cold shower before I code something like
function print_the_word_the($t);

You emphasized putting the var at the top of the page if used more than once. Can you please explain why? Here's what I don't get; why is it necessary to declare variables a second time when $row['variable'] stores the same thing? On one query I pull about 30 items from a few tables at once so I end up with 30 lines of $this=$row['this'] and $that=$row['that'] at the top of the page. Scattered throughout the body are places I use them like "This is called <?php echo $this ?>". Sooo,..what's wrong with letting the script hear it straight from the horse's mouth? Wouldn't "This is called <?php echo $row['this'] ?>". do the same thing and cut out 30 lines of middlemen? I'm definitely not doubting you, I'm just thick-skulled sometimes. Weedpacket needed a sledgehammer to finally convince me how important it is to normalize.
Thanks for the tip, I'll definitely check it out.
Roger that. Out of curiousity; the other 90% doesn't account for filesize at all? So if I have a 10k file and add a 100k conditional which is false; would it still be a 10k download for the client?
I currently have the site setup as you mentioned. The middle content is an include based on "section". e.g. /band.php?section=music would tell the middle area to include music.php. The problem is that in order to change sections I need to reload band.php, which runs all of the queries for the header and L/R columns again. I would love for the main page and the other includes to just sit back and have a smoke while the middle area changes independantly. I'm thinking that I should at least use hidden fields so that it won't need to touch the database more than once while browsing between a profile's sections.

Well thanks again Norm! Mighty kind of you to help a brother out.

Norman_Graham

Hi Dolemite and happy New Year

Are you liable to use your Flash params function more than once this decade? If yes, then it's worth having.
I like to see what I'm dealing with at the top of the page. I like giving variable memorable names. In order to keep the URL short, I might make the variable something like "ab" or "z1" or something. That's incomprehensible in the code though, so I'll declare it: $pageNumber = $GET[ab]
The other reason for declaring variables is that I use PHP with register globals switched off, as it should be. I don't want to have to use $GET or $_POST five times in a row to extract one variable. That would be messy, not to say stupid.
You're welcome.
The user isn't downloading anything except the HTML which appears in the browser. If you need 5000 lines of code to produce the line "Hi, and welcome to my website", then the user will only download a handful of bytes. It might take a while for the 5000 lines of code to process, but the load on the internet connection is still almost zero. Remember: PHP is server-side. It is not the same as a client application such as JavaScript.
If you want to do that, use frames. I hate frames, not least because you can't bookmark the page and you can't link to it and most times you can't print out the bit you want either. However, use them if you like. Don't bother your head worrying about re-loading headers and footers, however. The load on the server and the internet connection is negligible, unless you've got images in your headers and footers. [edit: but in any case, the browser will cache the image, at least for the duration of the session]

All da best

Norm

Weedpacket

It's a Good Thing to separate the code that displays data from the code that fetches or processes data (that's that tiered design Norman Graham mentioned). For your example function, there is actually very little code in it at all for the server! If you were keen on reducing it to its minimum:

function flash_movie($w, $h, $file, $fvars){
?>
<object classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000"
	codebase="http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=7,0,19,0"
	width="<?php echo $w?>" height="<?php echo $h?>">
<param name=FlashVars value="<?php echo $fvars?>">
<param name="movie" value="<?php echo $file?>" />
<param name="quality" value="high" />
<embed src="<?php echo $file?>" FlashVars="<?php echo $fvars?>"
	quality="high" pluginspage="http://www.macromedia.com/go/getflashplayer"
	type="application/x-shockwave-flash"
	width="<?php echo $w?>" height="<?php echo $h?>"></embed>
</object>
<?php
}

then only the bits that matter to PHP are actually parsed by PHP.

I've been told that this article has a kind of legendary status.

You don't need to use frames for that; but if you want to use one of the alternatives, then Javascript would be necessary to handle the communication with the server, to request the new contents.

If you want to reduce the workload on your server connection by minimising the filesize sent out to the client, then I found a good way of doing that is a smart use of CSS layout. In one recent experience of mine, I had 150kB of HTML table tag soup. Redoing the page using CSS left me with two files totalling less than 20kB that still looked the same - and I didn't need the spacer.gif no more neither! An added bonus that even on its own is big enough to be worth the exercise was that, with a much simplified HTML (Like, <ul class="navbar"><li>navbar item 1</li><li>navbar item 2</li></ul> instead of <tr> and <td> and <img src="spacer.gif"> all over) it was a lot more straightforward to generate dynamically: I could have one function to generate any list on the page no matter how it looked. Effectively:

output_ul($list_items, $class="")
{
    echo empty($class) ? '<ul>' : '<ul class="'.$class.'">';
    foreach($list_items as $list_item) echo '<li>'.$list_item.'</li>';
    echo '</ul>';
}

And that would work for navbars, breadcrumbs, headlines, bullet points and so on.

Plus the CSS file would be downloaded and the client would cache it so it wouldn't need to be downloaded again. Let the client do the hard work of laying out the page. After all, the client will no doubt be running on a computer that's more powerful than the avionics of a Columbia-class Space Shuttle; it should be up to the task of working out how wide to make the margins around a paragraph!

(Third time I did an intranet site, pretty much the entire page was built on the client side out of Javascript; when it came to putting a tree listing on the page, all the code for building the HTML was in a Javascript library the client had already downloaded, and all I needed to output was (in the <head>) a Javascript array that said what the tree contained, and then '<script type="text/javascript">render_tree(directory_listing);</script>' at the appropriate spot in the body.