Basic beginner question - setting defaults in init.php

[SamC]

Hi,

New to PW and more a designer than a developer, currently learning Javascript with basic knowledge of PHP (on the never-ending todo list) and beginner level experience in other languages, C++, Python, Java. I have used Umbraco, Drupal 7 (mainly), Wordpress, Craft CMS (my favourite for past year or so) before this and CMS is something I love playing around with! I am looking for something I can get more permanently involved with and I had a good look over the code for the 'Default Site Profile (Intermediate Edition)' PW site.

As far as my PHP knowledge goes, I can decipher renderNav(), but I'm struggling with renderNavTree().

One thing I don't get initially is this in '_init.php':

$title = $page->get('headline|title'); // headline if available, otherwise title
$content = $page->body;
$sidebar = $page->sidebar;

I understand that these variables are for usage elsewhere as defaults. However, why does the $title variable need '$page->get' when the other ones just need '$page->body' and '$page->sidebar'?

In '/setup/fields' I can see that 'title' and 'body' are both fields so not sure why these are different. Any advice is most appreciated.

Thanks.

Edited July 23, 2016 by SamC
More descriptive title

[DaveP]

Hi SamC and welcome.

20 minutes ago, SamC said:

$page->get('headline|title');

is used to get either headline or title, depending whether both or only title are populated. If headline has a value it is returned, or else title.

In PW, $page->field returns one value, which may be null.

$page->get('selector') returns one value from multiple possible values (like 'headline|title' above).

$page->find('selector') will return zero or more values in an array.

Typical cases where headline and title may be different would be a short entry in navigation (eg Home) and a longer heading for the page (eg Welcome to Our Site).

[SamC]

Hi DaveP,

Thanks, that was most useful. So would you do stuff like:

if ($page->field) {
	echo 'field value here'; //or whatever
}

What I'm asking is if a page field can either (1) not exist, (2) exist and be empty or (3) exist and contain data, to get the value or print nothing to screen (without errors), will points (1) and (2) both return NULL? Or do you first have to check a field actually exists? Thanks.

[szabesz]

@SamC Welcome to the Forum!

This might answer your question:

https://processwire.com/api/types/nullpage/

more to read on the topic:

https://processwire.com/api/ref/wire-data/

https://processwire.com/api/what/

 

[Robin S]

1 hour ago, SamC said:

What I'm asking is if a page field can either (1) not exist, (2) exist and be empty or (3) exist and contain data, to get the value or print nothing to screen (without errors), will points (1) and (2) both return NULL? Or do you first have to check a field actually exists?

 Ryan has some good advice about field checks in this blog post.

[SamC]

Excellent, thanks a lot people. This is exactly what I'm looking for. The thorough looking documentation will certainly keep me busy for awhile

[horst]

4 hours ago, SamC said:

The thorough looking documentation will certainly keep me busy for awhile

But don't forget to play with code too.

... and welcome to the forums, @SamC

[SamC]

29 minutes ago, horst said:

But don't forget to play with code too.

... and welcome to the forums, @SamC

Yeah for sure! Been creating a simple blog page with a couple of new templates (blog-index.php and blog-entry.php). Wanted to show submitted by date and name (other than my username). Thanks to this forum (how to add fields to system templates) and a youtube video (general templating and curly braces usage within a string, handy!), managed to cobble together:

//blog-entry.php
$publish_date = date('d-M-y', $page->created);
//custom field displayname in user template
$created_by = $page->createdUser->displayname;

$content = "Published on: {$publish_date} by {$created_by}";
//show above post entry body field
$content .= $page->body;

Seems quite straightforward so far (famous last words), feels like Craft, but without Twig. I've got a fair bit of free time at the moment which doesn't happen all that often so a great opportunity to learn

Thanks for making me feel so welcome everyone.

[szabesz]

@SamC If you need a template engine, there are maintained modules to build upon:

Smarty, Twig, Jade and more:

http://modules.processwire.com/modules/template-engine-factory/

Latte only:

http://modules.processwire.com/modules/template-latte-replace/

Recommended tutorial to jump start: Basic ProcessWire website workflow

http://blog.mauriziobonani.com/tags/#processwire

[SamC]

1 hour ago, szabesz said:

@SamC If you need a template engine, there are maintained modules to build upon:

Smarty, Twig, Jade and more:

http://modules.processwire.com/modules/template-engine-factory/

Latte only:

http://modules.processwire.com/modules/template-latte-replace/

Recommended tutorial to jump start: Basic ProcessWire website workflow

http://blog.mauriziobonani.com/tags/#processwire

That's some awesome info, thanks! Will probably try and get Twig up and running at some point, I find PHP mashed in with HTML all over the place quite difficult to comprehend sometimes.