[web2py] Re: conditional {{include}} in view

[Gilad Hoshmand]

For those who arrive late, from the docs 
:

{{if some_condition:}}{{include 'this_view.html'}}{{else:}}{{include 
'that_view.html'}}{{pass}}

-- 
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- http://web2py.com/book (Documentation)
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Re: [web2py] Re: conditional {{include}} in view

[Michael Dunga]

wow, just what I wasl ooking for

On Friday, July 8, 2011 at 7:14:48 PM UTC+3, Kernc wrote:
>
> OMG, setting response.view does it for me 110%!
> Confident in the ease of use of web2py, I swear I tried this the very 
> first. Maybe I mistyped it to response.view = 'article.html' or 
> request.view, and then just turned to alternatives. Anyway, now it works! 
> :-D
>
> I also understand your explanation, except one thing: if I have an 
> {{include}} inside a {{block}} as a default value (both these statements 
> are template, non-python statements), and that default is overridden, and 
> since {{block}} somewhat introduces conditioning, the inner {{include}} 
> statement need-not be expanded, so {{block some}}{{include 
> article}}{{end}}, with some block overridden, shouldn't throw error on 
> article variable not set. I think.
>
> Anyway, taking note of your comment regarding not compiled views, I now 
> see I am doing the whole thing wrong, so I'm switching to {{extends}} and 
> {{blocks}} instead (no more need for variable includes). response.view 
> saves the day! :-)
>
> Thank you and KUGW!
>
> On Fri, Jul 8, 2011 at 4:26 PM, Anthony  
> wrote:
>
>> First, if you want to use a particular view, you can always explicitly 
>> assign response.view:
>>  
>> def about():
>> response.view='default/article.html' # This view will be used instead 
>> of 'default/about.html'.
>> # more code
>> return dict(...)
>>  
>> Also, note that the {{include}} statement is not a Python statement -- it 
>> is processed by the template engine before everything is converted to 
>> Python. So, if you have an {{include 'someview.html'}} inside an if 
>> statement, the 'someview.html' template will still be included in the 
>> assembled Python code, though it will only be executed conditionally (based 
>> on the condition of the if statement). Also, because of this, although you 
>> may use variables in your {{include}} statements, as you have, usage of 
>> variables prevents bytecode compiling of the views. The reason is that the 
>> included views have to be determined at compile time, but the value of the 
>> variables is not known until run time.
>>  
>> In the places where you are getting the error about 'article' not being 
>> defined, I assume your controller action is not actually returning a 
>> variable called 'article' to the view. If you need to conditionally test 
>> whether a particular variable is available in a view, you can do {{if 
>> 'article' in response._vars:}} or {{if 'article' in globals():}}.
>>  
>> Anthony
>>  
>>
>> On Friday, July 8, 2011 2:07:16 AM UTC-4, Kernc wrote:
>>
>>> Ok, so this is my setup: 
>>>
>>> I have article() function inside default controller, which obtains 
>>> article title in request.args, puts ('articles/'+str(request.args[0]) 
>>> +'.html') into returned dict(article=...), and serves appropriate 
>>> article's HTML from article.html with 
>>>
>>>  
>>>  
>>> {{include article}} 
>>>  
>>>  
>>>
>>> For example, if I access http://domain/article/with-some-title, it 
>>> renders views/articles/with-some-title.html. 
>>> I like that. :-) 
>>>
>>> But then I have /about URL, which calls about() function inside 
>>> default controller, but which I would like to use the same article 
>>> template from article.html, i.e. to follow DRY. 
>>>
>>> So I have tried to put my content in about.html in a variable 
>>> {{article_content = MARKMIN('About us...')}} and then {{include}} 
>>> modified article.html 
>>>
>>>  
>>> {{if article_content:}}{{=article_content}}{{pass}}{{else}}{{include 
>>> article}}{{pass}} 
>>>  
>>>
>>> (Besides {{if article_content:}} I tried with try-except too. Neither 
>>> worked.) 
>>> When accessing /about, the ticket told me the error was in undefined 
>>> 'article' variable in the include expression. 
>>>
>>> So I tried it another way, by defining block with default content in 
>>> article.html 
>>>
>>> {{block article_content}}{{include article}}{{end}} 
>>>
>>> and extending article.html in about.html 
>>>
>>> {{extend 'article.html'}}{{block article_content}}{{=MARKMIN('About 
>>> us...')}}{{end}} 
>>>
>>> As per documentation, default value inside {{block}} (in my case 
>>> '{{include article}}') should be replaced with specified value (in 
>>> my case {{=MARKMIN(...)}}). But again, the ticket reports the same 
>>> error: 
>>>
>>>   ... 
>>>   File "/home//web2py/gluon/template.py", line 449, in include 
>>> text = self._get_file_text(filename) 
>>>   File "/home//web2py/gluon/template.py", line 430, in 
>>> _get_file_text 
>>> filename = eval(filename, self.context) 
>>>   File "", line 1, in  
>>> NameError: name 'article' is not defined 
>>>
>>> To avoid using {{include}}, the next thing I am about to try is: 
>>>
>>> {{block article_contents}}{{if article:}}{{=open(article).read()}} 
>>> {{pass}}{{end}} 
>>>
>>> but this way I have to maintain os.getcwd() and annote the article 
>>> with proper path to 

[web2py] Re: conditional {{include}} in view

[Anthony]

First, if you want to use a particular view, you can always explicitly 
assign response.view:
 
def about():
response.view='default/article.html' # This view will be used instead of 
'default/about.html'.
# more code
return dict(...)
 
Also, note that the {{include}} statement is not a Python statement -- it is 
processed by the template engine before everything is converted to Python. 
So, if you have an {{include 'someview.html'}} inside an if statement, the 
'someview.html' template will still be included in the assembled Python 
code, though it will only be executed conditionally (based on the condition 
of the if statement). Also, because of this, although you may use variables 
in your {{include}} statements, as you have, usage of variables prevents 
bytecode compiling of the views. The reason is that the included views have 
to be determined at compile time, but the value of the variables is not 
known until run time.
 
In the places where you are getting the error about 'article' not being 
defined, I assume your controller action is not actually returning a 
variable called 'article' to the view. If you need to conditionally test 
whether a particular variable is available in a view, you can do {{if 
'article' in response._vars:}} or {{if 'article' in globals():}}.
 
Anthony
 

On Friday, July 8, 2011 2:07:16 AM UTC-4, Kernc wrote:

 Ok, so this is my setup: 

 I have article() function inside default controller, which obtains 
 article title in request.args, puts ('articles/'+str(request.args[0]) 
 +'.html') into returned dict(article=...), and serves appropriate 
 article's HTML from article.html with 

 !-- various common tags along with body above and /html below... 
 -- 
 article 
 {{include article}}!-- includes the right article/with-some- 
 title.html -- 
 /article 
 !-- ... -- 

 For example, if I access http://domain/article/with-some-title, it 
 renders views/articles/with-some-title.html. 
 I like that. :-) 

 But then I have /about URL, which calls about() function inside 
 default controller, but which I would like to use the same article 
 template from article.html, i.e. to follow DRY. 

 So I have tried to put my content in about.html in a variable 
 {{article_content = MARKMIN('About us...')}} and then {{include}} 
 modified article.html 

 article 
 {{if article_content:}}{{=article_content}}{{pass}}{{else}}{{include 
 article}}{{pass}} 
 /article 

 (Besides {{if article_content:}} I tried with try-except too. Neither 
 worked.) 
 When accessing /about, the ticket told me the error was in undefined 
 'article' variable in the include expression. 

 So I tried it another way, by defining block with default content in 
 article.html 

 {{block article_content}}{{include article}}{{end}} 

 and extending article.html in about.html 

 {{extend 'article.html'}}{{block article_content}}{{=MARKMIN('About 
 us...')}}{{end}} 

 As per documentation, default value inside {{block}} (in my case 
 '{{include article}}') should be replaced with specified value (in 
 my case {{=MARKMIN(...)}}). But again, the ticket reports the same 
 error: 

   ... 
   File /home//web2py/gluon/template.py, line 449, in include 
 text = self._get_file_text(filename) 
   File /home//web2py/gluon/template.py, line 430, in 
 _get_file_text 
 filename = eval(filename, self.context) 
   File string, line 1, in module 
 NameError: name 'article' is not defined 

 To avoid using {{include}}, the next thing I am about to try is: 

 {{block article_contents}}{{if article:}}{{=open(article).read()}} 
 {{pass}}{{end}} 

 but this way I have to maintain os.getcwd() and annote the article 
 with proper path to my views. I don't know how stable this is. 

 Inexperienced as I am, I'm assuming it's possible I'm doing something 
 horribly wrong. What is that? :-) 

 TL;DR: The templating system counter-intuitively gives unconditional 
 priority to {{include}} expressions, which it evaluates first. 

 Oh, and if you can please tell me how I can make the about() function 
 to use the article.html view instead of default about.html view, that 
 would solve my DRY problem as well, I suppose. :-) 

 Thanks!

Re: [web2py] Re: conditional {{include}} in view

[Kernc]

OMG, setting response.view does it for me 110%!
Confident in the ease of use of web2py, I swear I tried this the very first.
Maybe I mistyped it to response.view = 'article.html' or request.view, and
then just turned to alternatives. Anyway, now it works! :-D

I also understand your explanation, except one thing: if I have an
{{include}} inside a {{block}} as a default value (both these statements are
template, non-python statements), and that default is overridden, and since
{{block}} somewhat introduces conditioning, the inner {{include}} statement
need-not be expanded, so {{block some}}{{include article}}{{end}}, with some
block overridden, shouldn't throw error on article variable not set. I
think.

Anyway, taking note of your comment regarding not compiled views, I now see
I am doing the whole thing wrong, so I'm switching to {{extends}} and
{{blocks}} instead (no more need for variable includes). response.view saves
the day! :-)

Thank you and KUGW!

On Fri, Jul 8, 2011 at 4:26 PM, Anthony abasta...@gmail.com wrote:

 First, if you want to use a particular view, you can always explicitly
 assign response.view:

 def about():
 response.view='default/article.html' # This view will be used instead
 of 'default/about.html'.
 # more code
 return dict(...)

 Also, note that the {{include}} statement is not a Python statement -- it
 is processed by the template engine before everything is converted to
 Python. So, if you have an {{include 'someview.html'}} inside an if
 statement, the 'someview.html' template will still be included in the
 assembled Python code, though it will only be executed conditionally (based
 on the condition of the if statement). Also, because of this, although you
 may use variables in your {{include}} statements, as you have, usage of
 variables prevents bytecode compiling of the views. The reason is that the
 included views have to be determined at compile time, but the value of the
 variables is not known until run time.

 In the places where you are getting the error about 'article' not being
 defined, I assume your controller action is not actually returning a
 variable called 'article' to the view. If you need to conditionally test
 whether a particular variable is available in a view, you can do {{if
 'article' in response._vars:}} or {{if 'article' in globals():}}.

 Anthony


 On Friday, July 8, 2011 2:07:16 AM UTC-4, Kernc wrote:

 Ok, so this is my setup:

 I have article() function inside default controller, which obtains
 article title in request.args, puts ('articles/'+str(request.args[**0])
 +'.html') into returned dict(article=...), and serves appropriate
 article's HTML from article.html with

 !-- various common tags along with body above and /html below...
 --
 article
 {{include article}}!-- includes the right article/with-some-
 title.html --
 /article
 !-- ... --

 For example, if I access 
 http://domain/article/with-**some-titlehttp://domain/article/with-some-title,
 it
 renders views/articles/with-some-**title.html.
 I like that. :-)

 But then I have /about URL, which calls about() function inside
 default controller, but which I would like to use the same article
 template from article.html, i.e. to follow DRY.

 So I have tried to put my content in about.html in a variable
 {{article_content = MARKMIN('About us...')}} and then {{include}}
 modified article.html

 article
 {{if article_content:}}{{=article_**content}}{{pass}}{{else}}{{**include
 article}}{{pass}}
 /article

 (Besides {{if article_content:}} I tried with try-except too. Neither
 worked.)
 When accessing /about, the ticket told me the error was in undefined
 'article' variable in the include expression.

 So I tried it another way, by defining block with default content in
 article.html

 {{block article_content}}{{include article}}{{end}}

 and extending article.html in about.html

 {{extend 'article.html'}}{{block article_content}}{{=MARKMIN('**About
 us...')}}{{end}}

 As per documentation, default value inside {{block}} (in my case
 '{{include article}}') should be replaced with specified value (in
 my case {{=MARKMIN(...)}}). But again, the ticket reports the same
 error:

   ...
   File /home//web2py/gluon/**template.py, line 449, in include
 text = self._get_file_text(filename)
   File /home//web2py/gluon/**template.py, line 430, in
 _get_file_text
 filename = eval(filename, self.context)
   File string, line 1, in module
 NameError: name 'article' is not defined

 To avoid using {{include}}, the next thing I am about to try is:

 {{block article_contents}}{{if article:}}{{=open(article).**read()}}
 {{pass}}{{end}}

 but this way I have to maintain os.getcwd() and annote the article
 with proper path to my views. I don't know how stable this is.

 Inexperienced as I am, I'm assuming it's possible I'm doing something
 horribly wrong. What is that? :-)

 TL;DR: The templating system counter-intuitively gives unconditional
 priority to {{include}} 

Re: [web2py] Re: conditional {{include}} in view

[Anthony]

On Friday, July 8, 2011 12:14:48 PM UTC-4, Kernc wrote: 

 I also understand your explanation, except one thing: if I have an 
 {{include}} inside a {{block}} as a default value (both these statements are 
 template, non-python statements), and that default is overridden, and since 
 {{block}} somewhat introduces conditioning, the inner {{include}} statement 
 need-not be expanded, so {{block some}}{{include article}}{{end}}, with some 
 block overridden, shouldn't throw error on article variable not set. I 
 think.

 
Yes, that's a good point -- I'm not sure exactly how blocks work on the back 
end, but apparently it does read that include statement before replacing the 
block content.
 
Anthony