PHP in Templates: Pain or Pleasure

Probing ExpressionEngine’s Parse Order EECI2010, June 2nd, San Francisco, USA
PHP in templates: Pain or Pleasure?

Hi! I’m Low! Lodewijk Schutte @low

ExpressionEngine Templates - CSS, JavaScript, RSS Page, Static, XML and
Web Page - Not just for presentation, but contain logic - Are parsed by EE’s Template Parser in a certain order

EE’s Parse 1.Snippets, global-, segment- and embed variables 2.PHP on
Input 3.Segment-, embed- & global simple conditionals 4.Preload replace variables 5.Module and plugin tags 6.PHP on Output 7.Advanced conditionals 8.Embedded templates 9.Other variables

{exp:channel:entries channel="news" status="open{if segment_2 == 'all'}|featured{/if}" dynamic="no"}
<!-‐-‐ News items -‐-‐> {/exp:channel:entries} Will work:

{exp:channel:entries channel="news" status="open{if member_group == '5'}|featured{/if}" dynamic="no"}
<!-‐-‐ News items -‐-‐> {/exp:channel:entries} Won’t work:

#5: exp-tag processing - Tags at root level are parsed,
rinse, repeat - Plugin tags look inside for other tags and parse those ﬁrst, recursively - This order can be reversed with parse="inward" on any plugin tag

Low Variables Parse at stage #1, #5 or #9. You
choose!

Low Variables example Name Type Early parsing {show_warning} Checkbox Yes
{warning_message} Text input No {warning_level} Radio group No

Low Variables example

Low Variables example {if show_warning == 'y'} <div class="warning level-‐{warning_level}">
<h2>Warning!</h2> {exp:textile} {exp:low_variables:parse var="warning_message"} {/exp:textile} </div> {/if}

Low Variables example <div class="warning level-‐{warning_level}"> <h2>Warning!</h2> {exp:textile}
{exp:low_variables:parse var="warning_message"} {/exp:textile} </div>

Low Variables example <div class="warning level-‐{warning_level}"> <h2>Warning!</h2> {exp:textile}
Look behind you, a {warning_level}-‐headed monkey! {/exp:textile} </div>

Low Variables example <div class="warning level-‐{warning_level}"> <h2>Warning!</h2> <p>
Look behind you, a {warning_level}-‐headed monkey! </p> </div>

Low Variables example <div class="warning level-‐three"> <h2>Warning!</h2> <p>
Look behind you, a three-‐headed monkey! </p> </div>

Low Variables For EE 1.6.8+ and EE 2.0.2+ Get it
now at loweblog.com or devot-ee.com

embed embed segment variables exp-tags advanced conditional s user deﬁned
global variables

Input Output {exp} $php <html> {exp} $php <html>

Why (not) use PHP? Pros Cons Increase performance Possible security
issues Extend EE without add-ons Speciﬁc customization More control and ﬂexibility

Some best practices - Save templates as ﬁles, use editor
- Logic ﬁrst, parse variables later - Use alternative syntax - Never assume

- Idea: better advanced conditionals - Problem: EE still parses
code in {if ...} {if:else} {/if} conditionals, which impacts performance - Solution: use PHP on input to handle conditionals, thus only generating EE code that should be parsed Example #1

- Idea: fully hackable URL - Problem: superﬂuous segment, the
template name - Solution: use PHP in index to select the right embed Example #2

- Idea: show channel entries with title beginning with X
- Problem: {exp:channel:entries} tag cannot do this out of the box - Solution: use PHP on input to get entry_ids and feed those to the {exp:channel:entries} tag Example #3

- Idea: track where 404s are coming from - Problem:
cannot do this out of the box or without third party software - Solution: hijack Referrer module and use PHP in the 404 template to add records to the database Example #4

- Idea: show banners in between blog posts (post, banner,
post, post, banner, post, post, banner...) - Problem: cannot do this elegantly out of the box - Solution: use PHP on output to store banners in array and display them at the right position Example #5

- Idea: customized RSS feed - Problem: cumbersome if not
impossible out of the box - Solution part 1: use PHP on input to catch form and generate a custom URL - Solution part 2: use PHP on input to read segments and set parameters in RSS feed Example #6

Questions?

http://www.flickr.com/photos/thebees/3412843560/ http://www.flickr.com/photos/arne-list/2934797540/ http://www.flickr.com/photos/abennett96/3625684918/ http://www.flickr.com/photos/goopymart/291244864/ Look for slides at slideshare.net/lodewijkschutte

PHP in Templates: Pain or Pleasure

PHP in Templates: Pain or Pleasure

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