I am building a page with PHP and am making heavy use of templating to split the various parts of each page up into reusable components, each of which has its own stylesheet which is automatically added to the head by script.
However, to save bandwidth and avoid style conflicts in certain situations, I would like to only link those stylesheets which are actually used on a given page. Since the head goes first in the page and the styles go in the head, but there's no way to access something like get_included_files() until the end of the page, I'd (presumably) need a way to reach back into the head and add the link tags later, but I'm not sure how to do that.
The only obvious way I can think of is to necessitate a registry array of all the components which will be used, and then use that to generate the link tags, but that is not really viable because some of the components include other components, so it would be necessary to manually register not just the components included in the top-level file, but all the components included by those components as well.
I figured out a solution. I took each of my components, and basically wrapped them in a class and a public static function of that class, called output(). I can now include() all the components I want to use right at the start, and then just do Component::output() wherever I want it to appear. This way, all the files are included, and visible to get_included_files(), by the time I call output() on the script that generates the head.
Related
I have searched Stack Overflow and found nothing about this. So here it goes
I was wondering if anyone has created server side script (PHP preferred) that can determine what css rules are required for a page to render. Something that would cross reference the HTML with a set group of css files and recreate a lighter version for a specific page.
Since Googles Update and the importance to render blocking scripts/CSS and to lighten the load I think this would be an awesome script.
I am not sure whether the tool you're asking for exists in its "pure form". The closest thing I'm aware of are unused css removal tools like this one. Such tools would accept a css file and a number of html files and remove css rules, that are not used.
Please not that the tool I've linked is designed to be used at build time, not run time. That means you would want to use it to get rid of unused css before/when you deploy your website, not on every request.
I haven't come across such a script but implementing one is not that complicated. My thoughts to implement would be like below:
You could cache the main css declarations in a server-side php array like
$css = array(".tag1"=>array(
"width: 10px;",
"height:10px;"
),
"#tag2"=>array(
"position:relative;",
"float:fixed;"
)
);
Declare a php array of css tags used in the file at the top of the page (like how you do for validation) like $cssused = array(".tag1", "#tag2");
On page load, compare the two arrays (like in_array($cssused, $css) or array_key_exists('#tag2", $css)) and load the css declarations for the tags that match in the main css array inside the <style>...</style> tags.
Whenever you make changes in the file, you have to just add/edit those in the $cssused array.
I am working on revamping an older CMS and I am wondering how I should handle things like multiple css and javascript files that only need to be included on certain pages.
Let's say for example I have the following pages:
services.php -> requires jquery-1.4.2.min.js
index.php -> no javascript required
However, on each of these pages, I am including a file from an includes folder
include 'includes/inc_header.php';
This file contains code like the following:
<!doctype ...>
<html>
<head>
<script type="text/javascript">...
Here is where I run into the problem. I have thought about using an array and looping through and printing each element required. This way each page could simply add the scripts they need to the array. I thought this might get very complicated very fast however.
Can anyone give me a good approach to solving this problem?
Well depending on how much work you wanna do i would reverse the view processing and move to a Front Controller that uses a 2-step view. This way your outer layout with the overall structure (doctype, head, etc.) is rendered last, allowing you to modify the output for this outer layout form within the inner layout.
While this will require potentially intensive restructuring it will give you a lot more flexibility in what you can do. Then again this probably going to be a lot of work so you would have to decide whether it is worth the investment.
You could reverse your logic on your array script idea
Inside your header output files conditionally depending on a flag
eg. (psuedocode)
array core (scripts and css for all pages)
array index (particular index scripts)
array page1 (etc)
then
if page1 merge_array core+page1
loop through and output
So your header has all the permutations but is context aware - maybe through a php variable on each page or by passing a variable to the include or reading some url parameter so only loads those required
I have a medium size legacy php application with almost no javascript integration. I've recently been learning javascript (yes actually learning it) using Douglas Crockfords excellent book and taken YUI as my library of choice. I've tried out a few things and got a few things working but now I want to integrate the various components etc into my application properly, my question is how to go about doing this for ease of maintenance and code reuse.
Currently the application consists of
php pages
smarty templates (html templates with some special template markup) for each section of a page so multiple templates may be used for a single page.
single css file.
I have the following ideas about how to integrate my javascript into the pages.
Write inline javascript in each smarty template with the code required for that section.
Write a seperate .js file to go with each smarty template that is linked in and then a single inline script to run it.
a seperate .js file for each php page which would have all the functionality required for the entire .php page. A small inline function would call whatever functions were required.
Something I havent though of?
Does this make any sense? Does anyone have a good suggestion for this?
Update:
One extra bit of info is that its an internal application, so its not so important to restrict everything to a single file.
Two other options:
A single JS file that contains all the JS for your entire site. Depending on your caching settings, you should be able to get the user to download just one file for the entire site and use a cached version for every other page.
Divide your JS up according to function, rather than page, and include whatever functionality each page requires. E.g. one page may require tabs, form validation and animation, while another may only require tabs.
Or you can have a hybrid of these: one JS file that contains the vast majority of your code and an extra file if needed for particular pages or templates.
None of the approaches mentioned are wrong (though I'd skip the inline JS one as much as possible); which one is best will depend on your precise situation and your personal preferences.
Firstly, most setups allow a master layout template in which you can place a common page opening or, alternatively, each template includes some global header.
That being said, you should do a combination of 1, 2 and 3:
Have a .js that is included in all templates that contains global functionality. Each template may also optionally have it's own .js specific to that page or section of pages. Finally, if there's tiny amounts of code specific to a page (or must be dynamically generated each time), it won't make sense to initiate another http connection for it so have that source be right in the template.
if you don't have a ton of javascript then create an external js file and include it in the header of the webpages and be done with it.
I'm starting to understand the importance of templating in PHP. I'm using PHP itself as a template engine to avoid learning any new language. I'm still not clear on one thing tho, although I have an idea about it. I would like to know what the experts do.
Should I create a full page template, with all tables, forms and everything else (including header and footer), or should I put all of my tables, forms, etc in their own file and then add them to the template as needed.
Here's a small example to clear things up...
Should I
a) create one page with all the tables, forms, and other elements in it and use that as a final product
// Set all the information
$template->title = $username;
$template->user_info = get_user($user_id);
$template->articles = get_articles($user_id);
$template->ads = random_ad($user_info);
// Load the template with everything already in it
$template->load('user_page.tpl')
$template->display();
OR
b) create every table, form, related block element in its own file and then use those to create a final product
// set the title and load the header template
$header['title'] = $username;
$template->load('header.tpl', $header);
// get the user info as an array and load into user profile template
$user_info = get_user($user_id);
$template->load('user_profile.tpl');
// load the new article form
$template->load('new_article_form.tpl');
// get the articles as an array of info and load into user articles template
$articles = get_articles($user_id);
$template->load('user_articles.tpl', $articles);
// get a random ad based on user info
$ads = random_ad($user_info);
$template->load('advertisements.tpl');
// load the footer template and display final page
$template->load('footer.php');
$template->display();
Where every file loaded contains a small portion of what needs to be displayed on the final page.
Because of the Dont Repeat Yourself technique, I would think B, but i would like to know which and why
I would personally say the first approach is best, because it keeps all documents and document fragments semantically complete.
The second approach means that you'll have a <div> in your header.tpl that is closed by a </div> in your footer.tpl (except likely there will be a few tags that applies to). This means if you change your layout, by adding a wrapper div (for example) somewhere, you have to remember to also close it in another file (or, depending on your layout, two or three different files).
It's worse with several different embedded files. Think of how hard it is to debug a site, when one file - that gets included conditionally - has an extra </div>. You get a vague bug report "sometimes the page looks completely messed up, doesn't matter what browser I use" that is very very hard to track down. It's MUCH worse if you're using table-based layouts..
Using the first approach, you can still use the DRY principle. You load the template into a variable. eg:
$userVars['name'] = $currentUser->name;
$templateVars['userinfo'] = $template->load('userinfo.php', $userVars);
...
$template->display('template.tpl', $templateVars);
You can continually nest documents that way. There are many benefits:
Each file is semantically complete HTML - all tags that are opened, are also closed in the same document. It's easy to edit one part of the layout without breaking (possibly unknowningly) anything else.
It's each to cache the output of certain templates, and re-use them
It's easy to apply AJAX to the site. For example, you have a stats.tpl template rendering inside a <div id="stats"> on the first page load. You also have a view that just renders the stats.tpl template by itself, and then use jquery to do $('#stats').load('/ajaxstats.php'), which refreshes that div but without repeating code at all.
Template inheritance for structures common to every template (e.g. layout; header/footer), and template embedding (i.e. including) for reusable bits (e.g. forms).
With approach A and without inheritance, you'd be either including common layout elements (which is IMHO ugly), or duplicating entire layout in every template (which is even worse). And plain approach B would create massive amounts of tiny template bits for everything, which may reduce maintainability.
And for that, I really recommend using real, dedicated templating engine instead of plain PHP. They make life easier (inheritance is one thing; another - variable auto-escaping).
template inheritance would probably make the cleanest code. you can do this now in straight php using PHP Template Inheritance
There is no good or bad solution. There are techniques and guidelines but in time you will learn what approach is better than others.
Just by looking at it i would say that the second approach allows you to be more flexible and breaks down the page into smaller parts. Smaller might some times mean more manageable.
Also the second solution also allows more than 1 persons working on the page since they will only need to work/change parts of the page and not the whole page.
regards,
As gregmac suggested, the first solution is probably preferable. Having said that, I would also suggest to have a look at the various PHP frameworks available, most of which implement templates using various techniques.
Have a look at this list for a start. You may also want to take a look at some stand-alone template engines, such as Smarty, in order to get some ideas or to avoid implementing your own engine.
I have a web application developed using PHP. I want my users to select themes for their pages throughout the application.
Where should I start before using PHP themes?
What should I know about Themes in a PHP application?
Edit:
My question about themes is only about changing the color of the layout, not the images.
Suppose My ADMIN user will have white and Orange, but my staff user will have white and green...
How it can be done in PHP with CodeIgniter?
There are lots of directions you can go with this.
1) "CSS ZEN"
This is where the markup remains unchanged, but you totally change the design just by using CSS and images. Demonstrated very well on http://www.csszengarden.com/
2) MVC Stylee
This is where you create a model that represents the page data and then pass it to a view, which contains some inline echo statements. The idea is that you could send the same model to a totally different view so it could look entirely different, HTML and all. Cake PHP is a good start for this: http://cakephp.org/
Example:
<div class="content">
<? echo $Page->Content ?>
</div>
3) Micro-Markup
With this method, you add your own "special tags" to an HTML page. You then read in your plain HTML page and replace the special tags with the information you want to display. This is good if you want your templates to be recognisable to HTML guys that don't know PHP and might break the PHP code in the MVC app.
Example:
<div class="content">
<#Content#>
</div>
Out of all of these, MVC is a very structured way of achieving what you want - however, I listed the other options as they cater for specific scenarios that might be relevant to you.
I have implemented the concept in all three of these, in situations that were appropriate for each.
Regarding The Edit In The Question
I imagine you'll have "something" that represents your user - so it is as easy as:
(In the event of just wanting to override a few settings...)
<link href="style.css" type="text/css" rel="stylesheet">
<?php if ($User->Type === USER_ADMIN) { ?>
<link href="admin.css" type="text/css" rel="stylesheet">
<?php } ?>
You can adjust this example in the following ways:
Use a switch statement if there will be many user types
If the replacement is total, rather than just a few overrides, you may want to completely swap the stylesheet.
You would usually set up template files that contain the HTML and CSS, and build in the PHP generated values at runtime.
The best approach to this is to have the theme reside in a separate directory, containing no code, just template variables like {mainmenu}, {backbutton}, {content} ... you get my drift. Those are then filled by your PHP script, possibly with the help of a template engine like Smarty (No need to re-invent the wheel here).
There is also the approach of having PHP markup directly in the template file(s) like echo $xyz; while this is a perfectly valid practice I use myself often, I recommend using a template engine over using PHP markup in the code if you want a solid, future-proof templating system because:
First, there is less that a designer can break when working on the HTML.
Second, having PHP markup in the code is a temptation to program PHP logic inside the template (loops, conditions) instead of properly preparing them in the PHP code at the point where the template variables are created. That is terrible for maintenance and the further use of your templates, because you have to replicate that PHP soup into every new template again. After all, you want to have a template engine so others can create new looks for your product, without having to know how to program it.
Third, with the templating engine based approach you have the possibility to add caching where necessary without any additional work. Not possible with the scripting approach. Yes, in a web application you won't be able to cache that much, but with a lot of data, there will be instances where it will help the user experience.
Fourth and least important, it makes your template less easy to export to other applications, and import templates from other applications.
The CSS Zen approach mentioned by Sohnee is great for websites, but is going to be too limited for a web application that uses complex input elements, JS based menus, and the like. It is too often that those elements need to be changed and customized in the markup.
If you have a look at my CodeIgniter Template library it briefly explains how you can set up themes and layouts (the equivalent of header & footer).
If you set up global code such as a Hook or a MY_Controller then you can dynamically set your theme based on the logged in user, the user type, etc.
Eg:
if($user->role == 'admin')
{
$this->template->set_theme('admin_skin');
}
else
{
$this->template->set_theme($user->theme);
}
That is just a VERY basic example of the sort of thing you could use this Template library for.
CMS Solutions
Magento and Wordpress package all theme related files into their own seperate directories. These contain the serverside code, stylesheets, images and javaScript for the theme. The user in effect chooses a directory to use which affects how the page is layed out and styled.
An easier approach
A much easier way to get started would be to accept that the actual content, e.g. HTML of a page would stay the same, but let the user choose from various CSS style sheets.
When choosing a style sheet the system could use JavaScript to load it in dynamically so that the user can preview the look they are choosing.
If you have really good semantic HTML it will be enough to change the CSS files. Unless the design changes are really heavy. Then it would make sense to provide PHP templates that are build with some sort of modules: variables which contain certain HTML structure like navigation or sidebar, etc.
For themes you do not need PHP. Just define your themes in CSS (the best way is one file for each theme) and use a simple JavaScript chooser like at this site: http://www.fotokluburan.cz/switchcss.js.