I want to display an error from a field in my Flask-WTF form with JavaScript. Printing out form.errors['password'] gives ['This field is required'], but I don't want [' '] in the output. How do I display the error in the right format?
Each field can have multiple errors, so they are always contained in a list, even if there is only one error. There is nothing special about Jinja or Flask-WTF here, you just need to pay attention to the data you're working with.
{{ form.password.errors[0] }}
{{ form.errors['password'][0] }}
Related
If I was to use the following in my Jinja template:
{% set data['enabled'] = True %}
I receive the error TemplateSyntaxError: expected token '=', got '['. Setting one word variables is fine, but as the error states, setting dictionary values through Jinja brings an error.
Is there a workaround for this issue? Thanks.
Jinja2 tries to limit assignments in its code to remove the logic from the view (check out an MVC explanation).
If you still want to do an assignment you will have to use update with a do block. For this you have to enable Expression Statements. After that you can try something like this:
{% do data.update({'enabled':'True'}) %}
I have installed jinja highlight in a small flask app. The highlighting works great when used directly in templates, but when I call it from the database and try to apply it on an entry, it does not render - it gives me the raw output from the db.
The code from the example:
{% highlight 'python' %}
from fridge import Beer
glass = Beer(lt=500)
glass.drink()
{% endhighlight %}
works in the template, but when I try to write and save an entry with the same content, the output is exactly the same, no formatting. I have tried {{ entry }}, {{entry|safe }} and the result is the same.
What am I doing wrong? While this is a particular jinja2 extension, I suppose the problem is more general.
I've noticed that my template is rendering my model.CharField and model.TextField without any excess whitespace.
For example, if I enter data such as...
This is a test
to see what happens.
The rendered object field will appear as...
This is a test to see what happens.
Is this an intentional feature of Django or have I missed some filter or parameter somewhere?
I've checked the field itself with some debug code (print object.field) and it does contains the extra whitespace, so the problem is in the rendering side.
How can I allow the user to enter paragraphs of data in TextFields? How can I preserve the whitespace that the user may have entered?
As you can see even in StackOverflow your spaces do not display, this is from the source of your question:
This is a test
to see what happens.
Will save in the database as:
This is a test\n\n\nto see what happens.
You have to problems when rendering as html:
Extra spaces between words are stripped on display by the browser, unless it is between <pre></pre> tags
Linebreaks will be rendered as plain text linebreaks, which do not display in the browser unless between <pre></pre> tags.
For spaces, you can use such a template filter to replace them with their html entity equivalent: .
To convert database linebreaks in HTML linebreaks, use linebreaksbr built-in filters. For example, if {{ foo }} is: test\nbar, then {{ foo|linebreaksbr }} will render: test<br />bar
Create a "templatetags" folder in some of your apps with an __init__.py file in it.
Save the snippet for example in someapp/templatetags/replace_tag.py
Load the template filter in the template as such {% load replace_tag %}
Combine replace and linebreaksbr as such: {{ foo|linebreaksbr|replace:" "," " }}
You can also make your own template filter that will process the text into the HTML you need. In any case, refer to the custom template filter documentation for complete information.
In a django template, is it possible to have two (or more) dots after a variable? For example, say I have a list of objects that I first want to use a list-index lookup for and then once I have the object, I want to call its method for getting the absolute url, should that work?
For example:
{% for entry in myList %}
{{ entry.0.get_absolute_url }}
{% endfor %}
So the 0 is asking for the first item in the list which is an object, then I want to get the absolute url. It doesn't work when I try it but it doesn't return an error either. Is there a better way to accomplish what I'm trying to do?
To clarify it, what's strange is that:
This works:
{{ singleObject.get_absolute_url }}
In that case if I just try {{ singleObject }}, I get the unicode value of that object so something like: John Smith
This doesn't work:
{% for object in objectList %}
{{ object.get_absolute_url }}
{% endfor %}
But in this case, if I put in {{ object }}, I no longer get the unicode value. I get: [<Name: John Smith>] (name being the name of the model)
Basically, the method works when it's outside of a loop. Could there be any reason for that?
more than one dot absolutely works.
based on your comment, there is no entry.0 because entry IS the first item in the list cause you are already looping through `myList'
just use entry.get_absolute_url instead
but if you only want to print out the url for the first entry, forgo the for loop and just use myList.0.get_absolute_url
UPDATE:
there's a tip from 'the pragmatic programmer' that says:
``select’’ Isn’t Broken
It is rare to find a bug in the OS or the
compiler, or even a third-party product or library. The bug is most
likely in the application.
i think you assumed that django templates were behaving weird, when the truth is you were not building your list correctly. don't be afraid to show some of your actual code, by abstracting the problem for us, you removed the part that included the problem
I got it. I had brackets around each item in my list like so:
objectList = [['John Smith'], ['Jim Jones'], ['Bill White']]
Silly me! Thanks so much for your all your input
What you are doing is perfectly acceptable in Django templates. There is no better way to accomplish what you're trying to do.
I'm using google appengine (python, of course :) ) and I'd like to do a string.replace on a string from the template file.
{% for item in items %}
<p>{{ item.code.replace( '_', ' ' ) }}</p>
{% endfor %}
But that isn't working. So we cannot execute anything other than basic checks in the app engine templates. Is that Correct ?
Another related problem is I'm trying to shorten a string and make it available to the template.
Each furniture object has a name and a longer description field. In this view I'm rendering, I want only the first 50 characters of the description field.
So I tried something like
items = db.GqlQuery( 'select * from furniture' )
# edit: if you change the above line to
# items = db.GqlQuery( 'select * from furniture' ).fetch( 1000 )
# the .fetch() command makes the addition of dynamic properties work!
for item in items :
item.shortdescr = item.description[ 0:50 ]
# pass data off to template for rendering
self.response.out.write(
template.render( 'furnitureAll.html', { 'items' : items } )
)
Template goes
{% for item in items %}
<p>{{ item.name }}</p>
<p>{{ item.shortdescr }}</p>
<!-- items.shortdescr does not exist here,
probably because I did not .put() it previously. -->
{% endfor %}
Since that didn't work, I tried changing the Gql Query to shorten the string instead. But I'm quickly realizing Gql isn't like SQL. I'm trying to write queries like
select name,LEFT( description, 50 ) from furniture
With little success
I have little experience with Google AppEngine, but my understanding is that it is very closely related to Django. Your templates do not actually contain Python code, even if some of the structures you use in them look like it.
Both of your questions should be solved using template filters. If it was Django, I would use something like this for your second question:
{{ item.description|truncatewords:10 }}
For your first question (string replace), there may be no built-in filter you can use for that. You will need to write your own. Something like this;
from google.appengine.ext.webapp.template import create_template_register
register = create_template_register()
#register.filter
def replace_underscores(strng):
return strng.replace('_', ' ')
Then, in your template, you can do this:
{{ item.code|replace_underscores }}
Apart from the argument-less .fetch() call in your code, which I believe can't possibly work (you ALWAYS have to pass fetch an argument -- the max number of entities you're willing to fetch!), I can't reproduce your problem -- assigning a new attribute (including one obtained by processing existing ones) to each item just works fine in my tests.
Can you please reproduce your observed problem in as tiny as compass as possible and edit your question to include all relevant files pls? Seems to be the only way we could help you with your weird observed bug!
BTW, select name,LEFT( description, 50 ) or whatever OF COURSE won't work in GQL -- GQL, very very explicitly, ONLY supports select * to get whole entities, or select __key__ to get just the entities' keys -- that's all; NO selectivity of columns in the select, much less any OPERATIONS on them!-)