# Virtual pages

**URL:** <https://www.ruby-forum.com/t/virtual-pages/112143>\
**Category:** Radiant CMS\
**Created:** [August 15, 2007, 9:34pm UTC](https://www.ruby-forum.com/t/virtual-pages/112143 "2007-08-15T21:34:32Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![phudson1442](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/c68b51/32.png) [@phudson1442](https://www.ruby-forum.com/u/phudson1442)\
**Post date:** [August 15, 2007, 9:34pm UTC](https://www.ruby-forum.com/t/virtual-pages/112143/1 "2007-08-15T21:34:32Z")

</div>

I generated an extension and created a simple page called  
“simple\_page.rb” :

class SimplePage \< Page  
def virtual?  
true  
end

def cache?  
false  
end

def render  
lazy\_initialize\_parser\_and\_context  
if layout  
parse\_object(layout)  
else  
render\_page\_part(:body)  
end  
end  
end

And in the \_extension.rb file I added SimplePage to  
the activate method:

def activate  
# admin.tabs.add “Mc Coy”, “/admin/mc\_coy”, :after =\>  
“Layouts”, :visibility =\> [:all]  
SimplePage  
end

When I set they page type on a page to “Simple” and try to access the  
page, I get a 404.

Examining the log and injecting logger statements it seems that the  
find\_by\_url method on the page is unable to locate the slug of the  
virtual page:  
SELECT \* FROM pages WHERE (pages.parent\_id = 1) AND (pages.“slug” =  
‘simple’) LIMIT 1  
Returns a row when executed from a postgresql console session but  
fails to return a row when executing inside of Radiant.

I can also make the page a env dump page, for example, and don’t get  
a 404 error. When I turn the page back into a “Simple” page, I go  
back to 404-ville.

Any thoughts? Am I not understanding how the virtual page dealy  
works? Any input would be much appreciated.

---

<div class="post-metadata">

**Author:** ![phudson1442](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/c68b51/32.png) [@phudson1442](https://www.ruby-forum.com/u/phudson1442)\
**Post date:** [August 15, 2007, 9:38pm UTC](https://www.ruby-forum.com/t/virtual-pages/112143/2 "2007-08-15T21:38:32Z")

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i was playing with virtual pages yesterday and couldn’t quite figure  
out their usage either. i had a very similar situation, but time was  
critical so i setup a page type that looked for post parameters and  
in the URL.

im interested in any responses involving Virtual pages.

---

<div class="post-metadata">

**Author:** ![phudson1442](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/c68b51/32.png) [@phudson1442](https://www.ruby-forum.com/u/phudson1442)\
**Post date:** [August 15, 2007, 11:34pm UTC](https://www.ruby-forum.com/t/virtual-pages/112143/3 "2007-08-15T23:34:56Z")

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Mucho thanks-os.

For any other interested parties:  
This is a simple non-caching page, but it is not virtual (where you  
could do interesting stuff inside the render method):

class SimplePage \< Page

def cache?  
false  
end

def render  
lazy\_initialize\_parser\_and\_context  
if layout  
parse\_object(layout)  
else  
render\_page\_part(:body)  
end  
end  
end

This is the smallest example of a non-caching virtual page, where you  
can do interesting stuff inside the find\_by\_url and I’m assuming  
render (please let me know if I’m wrong about that.)

class BonzePage \< Page  
def virtual?  
true  
end

def cache?  
false  
end

tag “complain” do | tag |  
"Jim, I’m a doctor, not a " + @request.parameters[:url].to\_s  
end

def find\_by\_url(url, live = true, clean = false)  
url = clean\_url(url) if clean  
return self  
end

end

---

<div class="post-metadata">

**Author:** ![phudson1442](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/c68b51/32.png) [@phudson1442](https://www.ruby-forum.com/u/phudson1442)\
**Post date:** [August 15, 2007, 10:07pm UTC](https://www.ruby-forum.com/t/virtual-pages/112143/4 "2007-08-15T22:07:35Z")

</div>

Paul H. wrote:

> When I set they page type on a page to “Simple” and try to access the  
> page, I get a 404.
> 
> Examining the log and injecting logger statements it seems that the  
> find\_by\_url method on the page is unable to locate the slug of the  
> virtual page:  
> SELECT \* FROM pages WHERE (pages.parent\_id = 1) AND (pages.“slug” =  
> ‘simple’) LIMIT 1  
> Returns a row when executed from a postgresql console session but  
> fails to return a row when executing inside of Radiant.

That’s because of this code:

[http://dev.radiantcms.org/radiant/browser/trunk/radiant/app/models/page.rb#L128](http://dev.radiantcms.org/radiant/browser/trunk/radiant/app/models/page.rb#L128)

By default, the find\_by\_url method is setup to not find virtual pages.  
Most of the time, in order to use a virtual page you need anotheranother  
page type that overrides the find\_by\_url method. This is exactly what  
the archive page does:

[http://dev.radiantcms.org/radiant/browser/trunk/radiant/app/models/archive\_page.rb#L18](http://dev.radiantcms.org/radiant/browser/trunk/radiant/app/models/archive_page.rb#L18)

with the archive index pages:

[http://dev.radiantcms.org/radiant/browser/trunk/radiant/app/models/archive\_day\_index\_page.rb#L14](http://dev.radiantcms.org/radiant/browser/trunk/radiant/app/models/archive_day_index_page.rb#L14)  
[http://dev.radiantcms.org/radiant/browser/trunk/radiant/lib/archive\_index\_tags\_and\_methods.rb#L43](http://dev.radiantcms.org/radiant/browser/trunk/radiant/lib/archive_index_tags_and_methods.rb#L43)

> I can also make the page a env dump page, for example, and don’t get  
> a 404 error. When I turn the page back into a “Simple” page, I go  
> back to 404-ville.

Right. That’s because the env dump page is not a virtual page. Virtual  
pages don’t show up in standard queries.

What exactly is a virtual page? That’s a hard question. The simple  
answer is it is a page does not have its own URL. The File Not Found  
page is an excellent example. You wouldn’t want the File Not Found page  
to show up in search results or a list of a page’s children. Because of  
this it is marked “virtual”. Queries for displaying pages should, for  
the most part, exclude virtual pages.

–  
John L.  
[http://wiseheartdesign.com](http://wiseheartdesign.com)