Why django finds errors inside comment blocks in template? - python

Sometime Django finds an error in a template. I Would like to comment out the row to debug but django keeps to find the error even in the comment.
For example this link give me an error because url 'prova' don't exist.
<!--Prova<br/>-->
another example: here {{ field }} give an error (and I don't know why but this is another problem)
<!--{% for field in form.visible_fields %}
{{ field.errors }}
{{ field.label }}
{{ field }}
{{ field.help_text }}
<br />
{% endfor %}-->
Maybe there's another way to comment?
Thank you

Django still parses the code; it doesn't care about HTML comments. If you want to ensure that it does not get rendered at all, you should use the Django comment tags, {% comment %}...{% endcomment %}.
For a single line, you can wrap things in {# ... #}.
See the docs.

Related

Is it possible to flash tags with flask? [duplicate]

I'm building an admin for Flask and SQLAlchemy, and I want to pass the HTML for the different inputs to my view using render_template. The templating framework seems to escape the HTML automatically, so all <"'> characters are converted to HTML entities. How can I disable that so that the HTML renders correctly?
To turn off autoescaping when rendering a value, use the |safe filter.
{{ something|safe }}
Only do this on data you trust, since rendering untrusted data without escaping is a cross-site scripting vulnerability.
MarkupSafe provides Jinja's autoescaping behavior. You can import Markup and use it to declare a value HTML safe from the code:
from markupsafe import Markup
value = Markup('<strong>The HTML String</strong>')
Pass that to the templates and you don't have to use the |safe filter on it.
From the Jinja docs section HTML Escaping:
When automatic escaping is enabled everything is escaped by default
except for values explicitly marked as safe. Those can either be
marked by the application or in the template by using the |safe
filter.
Example:
<div class="info">
{{data.email_content|safe}}
</div>
When you have a lot of variables that don't need escaping, you can use an autoescape override block:
{% autoescape false %}
{{ something }}
{{ something_else }}
<b>{{ something_important }}</b>
{% endautoescape %}
For handling line-breaks specifically, I tried a number of options before finally settling for this:
{% set list1 = data.split('\n') %}
{% for item in list1 %}
{{ item }}
{% if not loop.last %}
<br/>
{% endif %}
{% endfor %}
The nice thing about this approach is that it's compatible with the auto-escaping, leaving everything nice and safe. It can also be combined with filters, like urlize.
Of course it's similar to Helge's answer, but doesn't need a macro (relying instead on Jinja's built-in split function) and also doesn't add an unnecesssary <br/> after the last item.
Some people seem to turn autoescape off which carries security risks to manipulate the string display.
If you only want to insert some linebreaks into a string and convert the linebreaks into <br />, then you could take a jinja macro like:
{% macro linebreaks_for_string( the_string ) -%}
{% if the_string %}
{% for line in the_string.split('\n') %}
<br />
{{ line }}
{% endfor %}
{% else %}
{{ the_string }}
{% endif %}
{%- endmacro %}
and in your template just call this with
{{ linebreaks_for_string( my_string_in_a_variable ) }}
Use the safe filter in your template, and then sanitize the HTML with the bleach library in your view. Using bleach, you can whitelist the HTML tags that you need to use.
This is the safest, as far as I know. I tried both the safe filter and the Markup class, and both ways allowed me to execute unwanted JavaScript. Not very safe!

How to manage quotes sent to HTML page from Flask? [duplicate]

I'm building an admin for Flask and SQLAlchemy, and I want to pass the HTML for the different inputs to my view using render_template. The templating framework seems to escape the HTML automatically, so all <"'> characters are converted to HTML entities. How can I disable that so that the HTML renders correctly?
To turn off autoescaping when rendering a value, use the |safe filter.
{{ something|safe }}
Only do this on data you trust, since rendering untrusted data without escaping is a cross-site scripting vulnerability.
MarkupSafe provides Jinja's autoescaping behavior. You can import Markup and use it to declare a value HTML safe from the code:
from markupsafe import Markup
value = Markup('<strong>The HTML String</strong>')
Pass that to the templates and you don't have to use the |safe filter on it.
From the Jinja docs section HTML Escaping:
When automatic escaping is enabled everything is escaped by default
except for values explicitly marked as safe. Those can either be
marked by the application or in the template by using the |safe
filter.
Example:
<div class="info">
{{data.email_content|safe}}
</div>
When you have a lot of variables that don't need escaping, you can use an autoescape override block:
{% autoescape false %}
{{ something }}
{{ something_else }}
<b>{{ something_important }}</b>
{% endautoescape %}
For handling line-breaks specifically, I tried a number of options before finally settling for this:
{% set list1 = data.split('\n') %}
{% for item in list1 %}
{{ item }}
{% if not loop.last %}
<br/>
{% endif %}
{% endfor %}
The nice thing about this approach is that it's compatible with the auto-escaping, leaving everything nice and safe. It can also be combined with filters, like urlize.
Of course it's similar to Helge's answer, but doesn't need a macro (relying instead on Jinja's built-in split function) and also doesn't add an unnecesssary <br/> after the last item.
Some people seem to turn autoescape off which carries security risks to manipulate the string display.
If you only want to insert some linebreaks into a string and convert the linebreaks into <br />, then you could take a jinja macro like:
{% macro linebreaks_for_string( the_string ) -%}
{% if the_string %}
{% for line in the_string.split('\n') %}
<br />
{{ line }}
{% endfor %}
{% else %}
{{ the_string }}
{% endif %}
{%- endmacro %}
and in your template just call this with
{{ linebreaks_for_string( my_string_in_a_variable ) }}
Use the safe filter in your template, and then sanitize the HTML with the bleach library in your view. Using bleach, you can whitelist the HTML tags that you need to use.
This is the safest, as far as I know. I tried both the safe filter and the Markup class, and both ways allowed me to execute unwanted JavaScript. Not very safe!

Django: How to associate a comment to its corresponding OP in the HTML template?

I have designed a simplistic posting and comment system where each postcomment object is associated with its corresponding newpost object using foreign key. My problem is that the comments in the template aren’t showing under their corresponding newpost object. For example, if there are a total of 3 newposts and 3 comments under each post for a total of 9 comments, the template displays all 9 comments under each 3 posts (for a total of 27 comments). I need help figuring out how to correctly associate each comment with its corresponding post and not just loop through my ‘allcomments’ field under each post. Thanks for any help and hints.
postset = pagename.newpost_set.all().order_by('-postdate') #i use this to get a queryset of all posts on the selected page and order them so newest posts show up at the top
allposts = newpost.objects.filter(newposttag=‘userpage’) #i use this to get a queryset of all posts on the corresponding user’s page for the next line, this might seem redundant after the above, but it works because the postset is what I end up using in the template.
allcomments = postcomment.objects.filter(commenttag=allposts) #i use this to get a queryset of all the comments from each post in the ‘allposts’ queryset
Here is my template for displaying the above information that I have acquired
{% for postset in postset %}
<br>{{ postset.postcontent }} {{postset.postdate }} - {{ postset.postlikes }} likes Comment</br>
{% for allcomments in allcomments %}
<br> {{ allcomments.comment }} {{allcomments.postcommentdate }} - {{ allcomments.commentlikes}}
{% endfor %}
{% endfor %}
How about updating your template as follows:
{% for post in postset %}
<br>{{ post.postcontent }} {{post.postdate }} - {{ post.postlikes }} likes Comment</br>
{% for comment in post.postcomment_set.all %}
<br> {{ comment.comment }} {{comment.postcommentdate }} - {{ comment.commentlikes}} </br>
{% endfor %}
{% endfor %}
This way, you iterate over your posts and for each post, you retrieve the comments related to that post through the post.postcomment_set.all expression.
Please let me know if that helps you.
ps: I don't think that you need those three queries in your view though.

How does the {{ form }} tag work in Django-registration app

I downloaded and installed django-registration app. I also downloaded a template that has this strange piece of code
{{ form }}
that magically creates 4 labels and 4 textboxes for the user to enter his registration information. How does it work?
{% extends "registration/registration_base.html" %}
{% block title %}Register for an account{% endblock %}
{% block content %}
<table>
<form method='post' action=''>{% csrf_token %}
{{ form }}
<tr><td></td><td><input type="submit" value="Send activation email" /></td>
</form>
</table>
{% endblock %}
It is part of django forms. See the documentation for more info.
https://docs.djangoproject.com/en/1.3/topics/forms/
If you are really interested check out the source code.
https://code.djangoproject.com/browser/django/trunk/django/forms
A django form (but other objects, too) has a unicode method, which is invoked, when a string representation of the object is requested. As you can see in the code, it just passes the call on to as_table - which in turn uses a generic helper function: _html_output. This basically loops over all the fields and constructs the HTML which then is returned and displayed on the page.

Passing HTML to template using Flask/Jinja2

I'm building an admin for Flask and SQLAlchemy, and I want to pass the HTML for the different inputs to my view using render_template. The templating framework seems to escape the HTML automatically, so all <"'> characters are converted to HTML entities. How can I disable that so that the HTML renders correctly?
To turn off autoescaping when rendering a value, use the |safe filter.
{{ something|safe }}
Only do this on data you trust, since rendering untrusted data without escaping is a cross-site scripting vulnerability.
MarkupSafe provides Jinja's autoescaping behavior. You can import Markup and use it to declare a value HTML safe from the code:
from markupsafe import Markup
value = Markup('<strong>The HTML String</strong>')
Pass that to the templates and you don't have to use the |safe filter on it.
From the Jinja docs section HTML Escaping:
When automatic escaping is enabled everything is escaped by default
except for values explicitly marked as safe. Those can either be
marked by the application or in the template by using the |safe
filter.
Example:
<div class="info">
{{data.email_content|safe}}
</div>
When you have a lot of variables that don't need escaping, you can use an autoescape override block:
{% autoescape false %}
{{ something }}
{{ something_else }}
<b>{{ something_important }}</b>
{% endautoescape %}
For handling line-breaks specifically, I tried a number of options before finally settling for this:
{% set list1 = data.split('\n') %}
{% for item in list1 %}
{{ item }}
{% if not loop.last %}
<br/>
{% endif %}
{% endfor %}
The nice thing about this approach is that it's compatible with the auto-escaping, leaving everything nice and safe. It can also be combined with filters, like urlize.
Of course it's similar to Helge's answer, but doesn't need a macro (relying instead on Jinja's built-in split function) and also doesn't add an unnecesssary <br/> after the last item.
Some people seem to turn autoescape off which carries security risks to manipulate the string display.
If you only want to insert some linebreaks into a string and convert the linebreaks into <br />, then you could take a jinja macro like:
{% macro linebreaks_for_string( the_string ) -%}
{% if the_string %}
{% for line in the_string.split('\n') %}
<br />
{{ line }}
{% endfor %}
{% else %}
{{ the_string }}
{% endif %}
{%- endmacro %}
and in your template just call this with
{{ linebreaks_for_string( my_string_in_a_variable ) }}
Use the safe filter in your template, and then sanitize the HTML with the bleach library in your view. Using bleach, you can whitelist the HTML tags that you need to use.
This is the safest, as far as I know. I tried both the safe filter and the Markup class, and both ways allowed me to execute unwanted JavaScript. Not very safe!

Categories

Resources