What do you think about unify templates feature?

J. Pablo Martín Cobos

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Jan 17, 2019, 9:02:35 AM1/17/19

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Hi,

From one year ago, I am using an own command for Django templates that unify them. With an example it is easy to see. If I am to render for example a template call news.html like it:

1. news.html

{% extends "base.html" %}

{% block title %}

{% include "inc.news.title.html" %}

{% endblock %}

{% block content %}

{% for news_item in news %}

<h2>{{ news_item.title }}</h2>

<p>{{ news_item.subtitle }}</p>

{% endfor %}

{% endblock %}

2. base.html

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

<head>

<title>{% block title %}{% endblock %}</title>

</head>

<body>

{% block content %}{% endblock %}

</body>

</html>

3. inc.news.title.html

News

With this command I preproces every template of a settings variable and I get something like this:

news.unify.html

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

<head>

</head>

<body>

{% for news_item in news %}

                <h2>{{ news_item.title }}</h2>

                <p>{{ news_item.subtitle }}</p>

            {% endfor %}

</body>

</html>

So I have a two improves:

It is more fast. And in a real project a view can render easyly 50 templates
I use news.html to develop and news.unify.html to production. So I don't lose legilibility.

What do you think about "unify templates feature"? Do you know if exists a similar public project in github/gitlab/bitbucket etc?

Best,

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Pablo Martín Cobos

Computer engineer

Python/Django developer

652 53 37 36

goi...@gmail.com

J. Pablo Martín Cobos

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Jan 18, 2019, 9:32:05 AM1/18/19

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I answer between lines

El jue., 17 ene. 2019 a las 18:42, Maciek Olko (<macie...@gmail.com>) escribió:

Did you try to measure the difference in time of rendering standard and your way?

Yes. I have several examples:

App	Template	Num templates rendered before unify	Num templates rendered after unify	Time render template before unify (ms)	Time render template after unify (ms)	Improve
Django admin	admin/index.html	3	1	75 - 110	71 - 79	22%
Django admin	admin/change_list.html	26	Command error	180-300	Command error
Django admin	admin/change_form.html	16	Command error	350-400	Command error
Django constance	admin/constance/change_list.html	7	1	350-400	150-250	75%
Django su	su/login.html	5	3	15- 20	10 - 12	54%

My command currently does not work with several complex templates like admin/change_list.html or admin/change_form.html But we can improve it, currently it works with almost all.

If there is a nice improve with views that render few templates... imagine with views with a lot of templates.

I have measure these times with django-debug-toolbar-template-timings

With this email only I want to know if you see it can be a important feature to add to Django framework... or it is a silly thing.

Best,

Regards,
Maciej

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J. Pablo Martín Cobos

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Jan 18, 2019, 9:40:57 AM1/18/19

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I answer between lines

El vie., 18 ene. 2019 a las 5:03, shiva kumar (<kannamshi...@gmail.com>) escribió:

Could you please explain about it. I hadn't understood ur idea.

Currently: with you render a view, this render a template. But usually, this template extends of another and include others. So Django has to get these templates to create an HTML. This process get time.
My proposal: Preprocess templates for some (or all) them. Creating a template without extends or includes. So, in my previous email you can see, Django render less templates, so Django win time.

We can get a backend a little faster with very little effort.

Best!

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Juan Pablo Martín Cobos

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J. Pablo Martín Cobos

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Jan 18, 2019, 3:33:34 PM1/18/19

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Hi another time,

I am tring to reply every people in this email:

Josh

I was not using django.template.loaders.cached.Loader, but the result are very similar i.e:

App

Template

Num templates rendered before unify

Num templates rendered after unify

AVG Time render template before unify (ms)

AVG Time render template after unify (ms)

Django admin

admin/index.html

3

1

80

70

Django constance

admin/constance/change_list.html

7

1

330

180

Django su

su/login.html

5

3

10

5

Pavlos:

Yes, I wrote this email to contribute another time. Actually I am already Django contributor[1][2]
I didn't share my code, because it is not a nice code. For me it is a teoric question. I don't want anybody have a bad opinion of this proposal for the implementation. But I am sharing [3] it without problems, but please I know this solution is incomplete for many reason.
About your question: "I am not sure I understood anything so far. Are you just pre-rendering {% include %} tags, so the template engine doesn't have to do that in runtime?" Yes :-)
About it: "I think what you did is addressed more neatly with the django.template.loaders.cached.Loader, as Josh Smeaton mentioned." and "Experimenting like this, even if you end up rediscovering something that exists" It is something different than django cache loader, of course I know django cache loader, I fixed a problem with django cached loader [4] five years ago :-). With django cache loader, we get django get a template quickly. But If your view finally render 3 templates, django cached loader will have to get 3 templates (from cache). With my proposal your view render only 1 template (This is not 100% true, 1 + templates about templatetags except extends and include)

Jani:

Currently you only need move the new template result to the old path of the template. But it is only because I want. If you change this line [5] for this other you don't need any change:

destination_name = template.origin.name

8 years ago I requested a feature related with templates, now I have a new request :-) 8 years ago I tried resolved my proposal, now I only want propose something :-D

I think in this change for Django :-)

REF's

1. https://github.com/django/django/pulls?q=is%3Apr+author%3Agoinnn+is%3Aclosed

2. https://code.djangoproject.com/query?status=assigned&status=closed&status=new&reporter=~pmartin&col=id&col=summary&col=status&col=owner&col=type&col=component&col=version&desc=1&order=id

3. https://gist.github.com/goinnn/8a42314fccdd13bcf4df256a277ec1f6 (tested in Django 1.8 - 1.11)

4. https://github.com/django/django/pull/1936/commits/e669bca5c8fe6d13ea745d338203cd9e7470ae6b

5. https://gist.github.com/goinnn/8a42314fccdd13bcf4df256a277ec1f6#file-unify_templates-py-L58

6. https://code.djangoproject.com/ticket/15053

Best,

El vie., 18 ene. 2019 a las 14:11, Jani Tiainen (<red...@gmail.com>) escribió:

Hi.

Does this require changes to django internals or can it work as an external package?

Also you should release it as a package so people can start using it, also preferably releasing it with BSD license like Django itself is. Otherwise there are very little chances that your solution would make to django it self.

Improvements to rendering are always welcome, but they must come without too much maintenance burden.

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- Well planned is half done, and a half done has been sufficient before...

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Juan Pablo Martín Cobos

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J. Pablo Martín Cobos

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Jan 18, 2019, 5:24:13 PM1/18/19

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Sorry, I reply beetween lines

[6]

Jani Tiainen

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Jan 18, 2019, 8:26:14 PM1/18/19

to 'Anoosha Masood Keen' via Django developers (Contributions to Django itself), django...@googlegroups.com

Hi,

Lets try this again.

Your system could be nice if it really helps rendering speed.

But does it require changes in Django core itself, or is it completely standalone package that doesn't require changing Django itself to operate? If it requires changes in Django itself, it would be useful to describe what changes are needed and why.

Note that you can even no build custom rendering engines since Django supports those now (with default implementations for Django Templating Language and Jinja2) your system actually might fall in this category.

Even code is bad you really need to start get some momentum for your system. Otherwise it's really hard to provide any feedback for example there might be some edgecases you might not have thought of.

To view this discussion on the web visit https://groups.google.com/d/msgid/django-developers/CALNyWLGJ5ZqHT%2B11YC6sHmRskR7s2u%3DAYmhpKfhd5_eautM-SA%40mail.gmail.com.

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J. Pablo Martín Cobos

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Jan 18, 2019, 10:18:41 PM1/18/19

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I reply beetween lines,

El vie., 18 ene. 2019 a las 21:25, Jani Tiainen (<red...@gmail.com>) escribió:

Hi,

Lets try this again.

Your system could be nice if it really helps rendering speed.

Yes we get several miliseconds per request.

But does it require changes in Django core itself, or is it completely standalone package that doesn't require changing Django itself to operate? If it requires changes in Django itself, it would be useful to describe what changes are needed and why.

You don't need any change in Django. This command generates a new template. I paste another time my first example:

1. news.html

{% extends "base.html" %}

{% block title %}

{% include "inc.news.title.html" %}

{% endblock %}

{% block content %}

{% for news_item in news %}

<h2>{{ news_item.title }}</h2>

<p>{{ news_item.subtitle }}</p>

{% endfor %}

{% endblock %}

2. base.html

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

<head>

<title>{% block title %}{% endblock %}</title>

</head>

<body>

{% block content %}{% endblock %}

</body>

</html>

3. inc.news.title.html

News

With this command I preprocess every template of a settings variable and I get something like this:

news.unify.html (or if you want the command can overwrite news.html)

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

<head>

</head>

<body>

{% for news_item in news %}

                <h2>{{ news_item.title }}</h2>

                <p>{{ news_item.subtitle }}</p>

            {% endfor %}

</body>

</html>

It is only a preprocess to get time for each request.

Note that you can even no build custom rendering engines since Django supports those now (with default implementations for Django Templating Language and Jinja2) your system actually might fall in this category.

No, It is not a new render engine. It would be a pre render engine. It is a new feature.

Even code is bad you really need to start get some momentum for your system. Otherwise it's really hard to provide any feedback for example there might be some edgecases you might not have thought of.

I want to know if this is a nice feature for Django community, then I will create a ticket... and if nobody resolve it I will propose a change, but I know ifor experience it is very hard collaborate with code in Django, and more difficult with a new feature.

To understand it, the best is to use the command with a simple template such as admin/index.html.

Best,

To view this discussion on the web visit https://groups.google.com/d/msgid/django-developers/CAHn91odTc%2B6mO3F5-hv_A5kBqT9Sk_3NtLKboxSyun_tQCDpVA%40mail.gmail.com.

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Jani Tiainen

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Jan 19, 2019, 6:08:37 AM1/19/19

to 'Anoosha Masood Keen' via Django developers (Contributions to Django itself), django...@googlegroups.com

Hi,

You said that this doesn't require any change in Django at all.

So this doesn't need to be in Django at all, it can survive as its own and that way it should be.

So make your enhancement as reusable app and release it to public. Get people to use it. Fix the bugs that appears. Write a good documentation. Give the support.

To view this discussion on the web visit https://groups.google.com/d/msgid/django-developers/CALNyWLGRhOCZ-1LU_5fRWJV_oB7DGBQAvSRU68cCp4r1mMdH5Q%40mail.gmail.com.

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