Develop Reference

BUG: When passing django.messages variable through HTML tag

messages.info(request, 'Attendance Ready To Be Taken!')
Over here i use django messages to send a string to the user
{% for message in messages %}
{% if message == 'Attendance Ready To Be Taken!' %}
<div class="alert success">
  <span class="closebtn">×</span>  
    <strong>SUCCESS!</strong> {{message}}
 </div>
{% else %}
<div class="alert">
  <span class="closebtn">×</span>  
    <strong>WARNING!</strong> {{message}}
</div>
{% endif %}
{% endfor %}
However, although the string is clearly the same..it doesn’t output SUCCESS message.
It can display the message indeed..but I want to filter if it’s a success message to be green..and error message to be red..just for user interface to warn users
.alert {
    padding: 20px;
    background-color: #f44336;
    color: white;
    opacity: 1;
    transition: opacity 0.6s;
    margin-bottom: 15px;
}
.alert.success {background-color: #04AA6D;}
Above is the CSS code for the two messages' styles for your reference.
The message “Attendance ready to be taken” should be showing green..but it’s red color in the webpage.
So I guess it didn’t fulfill the conditional 'if' statement. That’s why it goes to 'else', and becomes red color.
But I'm not sure why it doesn’t. Because the message displayed is the same thing as the string i compared it with..
Does anyone know what's causing this weird bug?

You have sent the info message, so its tag is info.
The best to apply CSS classes dynamically is to make use of Message tags.
Then define the tags of messages in the view as:
messages.info(request, 'Attendance Ready To Be Taken!', extra_tags='success')
Then this success tag will also become class in the element dynamically.
Use in the template as:
{% if messages %}
{% for message in messages %}
<div class="alert {% if message.tags %} {{message.tags}} {% endif %}">
<span class="closebtn">×</span>
<strong>SUCCESS!</strong> {{message}}
</div>
{% endfor %}
{% endif %}
To send error message which has error tag by default:
messages.error(request, 'Attendance Not completed !', extra_tags='red')
Then the red tag will also become class.
The template can be same just need to add this css:
.red {
background-color: red;
}
This way it works dynamically.
Another possible solution:
You can use MESSAGE_LEVEL, they allow us to group by type so that they can be filtered or displayed differently in views and templates. Level is an integer describing the type of the message.
Level Value
DEBUG 10
INFO 20
SUCCESS 25
WARNING 30
ERROR 40
Then with your current code simply check the message in template using {% if message.level == 20 %}, so:
{% for message in messages %}
{% if message.level == 20 %}
<div class="alert success">
<span class="closebtn">×</span>
<strong>SUCCESS!</strong> {{message}}
</div>
{% else %}
<div class="alert">
<span class="closebtn">×</span>
<strong>WARNING!</strong> {{message}}
</div>
{% endif %}
{% endfor %}

Flask: include template as several blocks

I am building a Flask application where I have widgets to include in several pages.
For example, a widget is dedicated to display a rotating gif when an Ajax request is made: html, js and css code defines this widget. Here is a simplified version:
includes/spinner.html
<style>
#loading {
position: absolute;
top: 50vh;
left: 50vw;
}
</style>
<img id="loading" src="{{url_for('static', filename='img/loader.gif')}}"/>
<script>
$(document).ajaxStart(function () {
activateSpinning();
}).ajaxStop(function () {
deactivateSpinning();
});
</script>
I'd like to figure out the best way to embed this code in the pages without requiring to create three different files to include.
Something like using the same include statement with a context variable?
includes/spinner.html
{% if context == "headers" %}...{% endif %}
{% if context == "body" %}...{% endif %}
{% if context == "js" %}...{% endif %}
layout.html
{% set context = "headers" %}
{% include "includes/spinner.html" %}
Or perhaps rendering multiple templates for a page:
includes/spinner.html
{% extends "layout/layout.html" %}
{% block headers %}...{% endblock %}
{% block body %}...{% endblock %}
{% block js %}...{% endblock %}
app/routes.py
#app.route("/", methods=["GET", "POST"])
def index():
...
render_template(["pages/index.html", "includes/spinner.html"], title="Import image")
Both solutions work but I'm not sure of the right way to do it and I can't really find a guide on best practices related to this use case. Do you have any ideas about this?

Statik: Implement navigation from data/views

I have a website build via Statik (a static web site generator, build with python).
Now I'd like to build a navigation out from my existing data or views, via a property like e.g. show_in_navigation = Boolean.
I thought about writing a custom template tag to get a list of all instances with show_in_navigation = True - but I don't know where to start or what would be the best approach in the first place;-)
My goal is a Twitter Bootstrap navbar-nav component filled with my show_in_navigation entries (with a bonus for highlighting the current page).
Any hints or tips?
My current implementation defines a navigation_bar variable in the main configuration:
# config.yml
context:
static:
navigation_bar: [['home', 'Home'], ['about', 'About'], ['contact', 'Contact']]
# templates/includes/navigation.html
<ul>
{% for pk, title in navigation_bar %}
<li {% if pk == active_page %} class="active"{% endif %}>
{{ title }}
</li>
{% endfor %}
</ul>
# templates/about.html
{% extends "base.html" %}
{% set active_page = "about" %}
... but that seems to be very verbose and not dry (e.g. repeating site titles, setting the active page)...

webapp2, Jinja2: how to cut large html file into multiple html files

When I blog, I like to separate each blog-post into its own .html file (is that ok?)
This prevents the file getting too big, and makes it easy to go back and edit a previously written blog post if need be.
Occasionally the blog post will contain css/js/ajax/template variables.
But on my website, I like all the blog posts on one page (so I can scroll through them all, instead of going to a separate page for each post)
Here is an html file that contains two blog posts:
{% extends "base.html" %}
{% block blog_posts %}
<!-- links/targest for the side menu to jump to a post -->
<li>Post2 - April 2012</li>
<li>Post1 - Feb 2012</li>
{% endblock %}
{% block content %}
<div id="post1">
spam1 blah blah
</div>
<div id="post2">
spam2
</div>
{% endblock %}
and in base.html I have something like:
<div id="content-container">
<div id="section-navigation">
<ul>
{% block blog_posts %}
{% endblock %}
</ul>
</div>
<div id="content">
{% block content %}{% endblock %}
</div>
</div>
What is the best way for me to split these blog posts out into separate files using webapp2 and jinja2?
e.g. blog1.html might look like:
{% block blog_posts %}
<!-- links/targest for the side menu to jump to a post -->
<li>Post1 - Feb 2012</li>
{% endblock %}
{% block content %}
<div id="post1">
spam1 blah blah
</div>
{% endblock %}
(And I would want the links and the blogposts to be displayed in the right order on the website)
I could think of a way of doing it where post2 extends post1.html, post3 extends post2.html etc, but I would prefer to fan out more
"Henry and Kafura introduced Software Structure Metrics Based on Information Flow in 1981[2] which measures complexity as a function of fan in and fan out."
Thanks

#robert king, your design has data embedded directly in the template. Templates should only contain the blueprint to a view, and they should be rendered with new data generated from your main code every time. I simulate this process here (Edited to illustrate the use of a loop to extract post titles, and the display of a single post.):
import jinja2
# NOTE: in this template there is no data relating to specific posts.
# There are only references to data structures passed in from your main code
page_template = jinja2.Template('''
<!-- this is a navigation block that should probably be in base.html -->
{% block blog_posts %}
<!-- links/targets for the side menu to jump to a post -->
{% for post in posts %}
<li><a href="{{ post.url }}">{{ post.title }}
- {{ post.date }}</a></li>
{% endfor %}
{% endblock %}
<!-- this is a content block that should probably be in page.html -->
{% block content %}
<div id="post">
<h1>{{ current.title }}</h1>
<h2>{{ current.date }}</h2>
<p>{{ current.content }}</p>
</div>
{% endblock %}
''')
# NOTE your main code would create a data structure such as this
# list of dictionaries ready to pass in to your template
list_of_posts = [
{ 'url' : '#post1',
'title' : 'My first post',
'date' : 'Feb 2012',
'content' : 'My first post is about Hello World.'},
{ 'url' : '#post2',
'title' : 'My second post',
'date' : 'Apr 2012',
'content' : 'My second post is about Foo Bar.'}
]
# Pass in a full list of posts and a variable containing the last
# post in the list, assumed to be the most recent.
print page_template.render(posts = list_of_posts,
current = list_of_posts[-1])
Hope this helps.
EDIT See also my answer to a question on "Site fragments - composite views"

I just found another option in the jinja2 tutorial. I think it makes more sense for my handler to pass my template a list of filenames of blog posts, and then to include the blog posts.
include - returns the rendered contents of that file into the current namespace:
{% include 'header.html' %}
<div ...
{% include 'footer.html' %}
Included templates have access to the variables of the active context by default. For more details about context behavior of imports and includes see Import Context Behavior.
From Jinja 2.2 onwards you can mark an include with ignore missing in which case Jinja will ignore the statement if the template to be ignored does not exist. When combined with with or without context it has to be placed before the context visibility statement. Here some valid examples:
{% include "sidebar.html" ignore missing %}
{% include "sidebar.html" ignore missing with context %}
{% include "sidebar.html" ignore missing without context %}
New in version 2.2.
You can also provide a list of templates that are checked for existence before inclusion. The first template that exists will be included. If ignore missing is given, it will fall back to rendering nothing if none of the templates exist, otherwise it will raise an exception. Example:
{% include ['page_detailed.html', 'page.html'] %}
{% include ['special_sidebar.html', 'sidebar.html'] ignore missing %}

When I read the raw html file (file.read()) and passed the data to my template, it escaped all the html.
instead of {{data}} i had to use {{data|safe}} which allowed raw html.
something like:
class HomeHandler(BaseHandler):
def get(self):
file_names = sorted(os.listdir('blog_posts'))
html = [open('blog_posts/%s' % fn).read() for fn in file_names]
templates = {'html': enumerate(html)}
self.render_template('home.html', **templates)
{% block content %}
{% for num,data in html %}
<div id="post{{num}}">
{{data|safe}}
</div>
<br />
<img src="http://www.sadmuffin.net/screamcute/graphics/graphics-page-divider/page-divider-007.gif" border=0>
<br />
{% endfor %}
{% endblock %}
(make sure the directory isn't a static directory)

Highlighting link of currently opened category tab in css

I am trying to highlight a link of a currently opened category tab, here is what i have already done:
globs.py
def globs(request):
cats = Category.objects.all()
return {'cats': cats}
views.py
def news_by_category(request, slug):
c = Category.objects.get(slug=slug)
news = News.objects.filter(category=c, status='p').order_by('-id')
#news = c.news_set.all().order_by('-id')
return object_list(
request,
news,
paginate_by = 5,
extra_context = {'c':c},
template_name = 'news_by_category.html')
base.html #bodyclass
<body class="{% block bodyclass %}{% endblock %}">
news_by_category.html
{% block bodyclass %}{{c|cut:" "}}{% endblock %}
base.html
<li><h4>Categories:</h4></li>
{% for i in cats %}
<li class="{{i.name|safe|cut:" "}}_li">
{{ i.name }}
</li> {% endfor %}
What i need to do now is to create style for every category, in category list, I could achieve this easily by styling inside a html file, but I'm not sure wether that would be proper (Would it?). I came up with some css styling,
{% for i in cats %}
body.{{ i|safe|cut:" "}} li.{{i|safe|cut:" "}}_li {
color: red;
}
but as I can't use django template tags inside my .css file, this wont work.
My questions:
1) How could i make this css file work for me. Any chance for a little step by step?
2) If I failed step1, how improper would it be to style those few li elements inside html file?
EDIT: /trying another way
I tried using:
base.html
{% for i in cats %}
<li class="{% ifequal 'request.get_full_path' '/k/{{ i.slug }}/' %}active{% endifequal %}">
{{ i.name }}
</li> {% endfor %}
.css
.active {{color:red;}
When i compared {{ request.get_full_path }} and /k/{{i.slug}}/ both returned same thing... but if its inside ifequal it doesnt seem to work.

You can create a simple class named "active" or something along those lines and add it to the current tab. Then, in your CSS you apply the active styles to that class. So you just append the active class and it'll automatically take the active style.

If you have a url:
{% url app:home i.slug as home %}
<li {% ifequal request.get_full_path home %}class="active"{% endifequal %}>