I have a relatively complicated form that's used in multiple places on my website (in fact, it's a form from which many other form classes inherit). In the templates, the inherited part of this form is always formatted identically—but that formatting is somehwat involved; each field is rendered and positioned manually in the template.
This means that every template which displays this form has a lot of identical HTML markup that renders the form appropriately.
I would like to create a custom output that can be called, similar to the as_table() methods. I'm aware that one can override the normal_row, error_row, etc. attributes—but the formatting of this form goes beyond that (for example, three of the form's five fields should be printed side-by-side, with a combined title). All of the tutorials/answered-questions I've seen either refer to overriding the above-mentioned attributes, or give instructions on how to manually render forms.
Originally, I was thinking something like this:
Class StrangeForm(form.Forms):
....
def as_table_custom():
html_string = "\
<tr><td>Title 1:</td><td>self.fields['field1']</td><tr>\
<tr><td>Title 2:</td><td>self.fields['field2']</td><tr>\
<tr><td>Titles 3, 4, 5:</td><td>self.fields['field3']\
</td><td>self.fields['field4']</td><td>self.fields['field5']</td></tr>\
"
return html_string
But, after reading through the _html_output() and as_table() methods of Django's forms.py file, it doesn't look like it'll be that easy. If I write this from scratch, have to somehow account for errors, help text, etc. I think.
Is there an easy way to override something such that the form's HTML output can be defined like above? Or do I have to re-write things from scratch. If the latter, how can I account for all of the things I need to account for?
I wouldn't take this approach. You're better off creating the form in an HTML template that you include in the various templates where you have a form you want to display that way.
So create a my_strange_form.html template where you assume a 'form' object is passed in the context with the right number of fields. In that template just create the HTML, using things like {{ field.label_tag }} and {{ field }}. You can loop through the fields with a {% for field in form %} and check the counter of your loop with {{ forloop.counter }}. I foresee a lot of {% if forloop.counter... %} statements to generate the combined row, and it will look ugly, but you'll only have to look at it once :-)
Then in your main templates {% include 'my_strange_form.html' with form=form %}.
Related
I want to achieve something like this within a Django template.
{{ variable.function(parameter) }}
Where variable is a variable passed through a context to a template, in this case, an instance of a model.
I have tried different methods, but no one seems to work.
This is not possible in Django templates: they are crippled on purpose in order to prevent template designers from shooting themselves in the foot. The reasoning is that the only logic in templates should be presentation logic and all business logic should be kept in the view. Some people thinks it is fair enough and some think it is a bit condescending (those dumb template designers are not smart enough to use functions and methods safely).
I can think of 3 choices:
use jinja2 instead.
write a custom template filter.
keep all the logic in the view where Django designers think you are supposed to keep it.
I will not explain how to use Jinja2 because it is already explained in the docs and because the example in the question works verbatim if you switch to it instead of native Django templates. This simply works in Jinja2:
{{ variable.function(parameter) }}
Now the template filter solution: first you must follow a code layout convention. The filter itself would be something like this:
# at your_tag_library.py
#register.filter(name='call_with')
def apply_callable(callable, arg):
return callable(arg)
Then in the template you can do:
{% load your_tag_library %}
{{ variable.function|call_with:parameter }}
Of course the last option is the one from Daniel's answer - precompute the value in the view and just display the result in the template:
context['result'] = variable.function(parameter)
And in your template you just need {{ result }}.
There is no way to do this.
You can create another variable and pass it through the context so you could use it.
Like:
context['result'] = variable.function(parameter)
In your view.
And in your template:
{{ result }}
I have an attribute of objects that can be rendered in html template like this :
{{ mymodels.something }}
In my case, i have forms containing an input field that has name similar with "something", so i want to run something like this in my template:
{% for form in my_form %}
{{ mymodels.form.name }} <!-- is same as mymodels.something -->
{% endfor %}
but it can't be rendered..
How can i do something like that?
Forms are something to gather data on client side - send it over to server side which validates them and does something with them (e.g. writing into models, or maybe passing it back into the context of your next rendering).
When your template is rendered, it also renders your form (building the markup, providing initial values) - when the template engine finished it's job, the HTML code is sent to the browser.
If you want to access form data on rendering time, there will always be the same value: the initial value. Which does not make much sense. As you might just pass the same data to your rendering context and use it from there.
Read the docs for further information on forms, especially the part rendering fields manually might interest you - if your question aims into this direction.
If anyone here is ASP.NET pro, you might know what I mean by user control. I wish to create a similar one in django instead.
So, my problem is that I have several pages in my website, but I need a search bar to appear in every pages. Since I require the views.py to operate this search bar, I cannot do a simple method of
{% include 'something.html' %}
Therefore, can anyone suggest how can I do it?
There are a couple of ways to accomplish what you're wanting to do:
Context Processors
Template Tags
Context Processors can augment the template context with values, regardless of which template is loaded. They are akin to filters in Rails.
Template Tags, like Context Processors, can accomplish anything you can do in Python, but are implemented at the template level.
If you need something to be present on every template, one of the simplest ways to accomplish this is with an inclusion tag, which can also accept values passed to it. An inclusion tag could be implemented at your highest level template, a.k.a your MasterPage, and as long as you don't put it in a block and override it, it would appear on every page that includes that template in its inheritance chain.
If it's just something you want to include on every page, and it doesn't need to do any processing, you should just be able to place the code you want in the top-most template and have subsequent templates inherit that.
I typically have a "base.html" template that all of my templates inherit from. If I need something to be in every page, I put it there. If it's something I want there by default, but want to be able to augment it in subsequent templates, I will place it into a block. That block will let you include or override its default content.
I know this post is kind of old but I just came across it and found a kind-of-solution that works. I call it kind-of-solution because it is a workaround.
I have a few different sites on which I want to display logging information. This display always looks the same (it has the same html) and has the same database table and model class behind it.
My solution/workaround uses the django filters:
in views.py I put the list of log-entries in the context
context = {'list_log': Log.objects.filter(condition = True) }
template = loader.get_template('my_html_file.html')
return HttpResponse(template.render(context, request))
in my_html_file.html I use a custom filter
{{ list_log|get_log_uc|safe }}
in the filters.py I load another html file with this custom filter
#register.filter
def get_log_uc(list_log):
template = loader.get_template('user_control_log.html')
context = { 'list_log' : log }
return template.render(context)
in user_control_log.html I have the user control equivalent html
{% for log in list_log %}
<p>log.something</p>
{% endfor %
Is there a function that returns a list of fields that are expected in template? For example, I have the following template:
hello i am {{ name }}. {% for i in docs %} i have doc {{ i }}
Written in file. And i want to get a dict which contains:
{'name': 'str', 'docs': 'list'}
Is there something like that or i have to write it by myself?
As far as i know, NO....
Your template contains some html and some place holders (and may be something else). What render_to_template doing is, it gets a context dictionary which contain some keys and some data attached to that keys and a template. Then it places the values to those place holders according to their key names, execute some loops or condition checks if your template contains control flows like {% if...%} or {%for....%}
If TEMPLATE_DEBUG is closed in your settings, and if there is a place holder with no matching key in your context dictionary, then it will skip that without raising any error.
Also, if you pass a form object to your template and place your object directly to template as it is (without calling each field separately) [ex: {{form}} or {{form.as_p}} then django will check for fields on the form and palce them as it is shown here. In a such situation, you will only know that form is used. You have to check which fields are used from your Form definition.
If you look through that process, you must know what you need to place your context dictionary. You may write a parser to parse your template but it is far more difficult than just examining the template and find missing data, i guess.
The builtin {% debug %} tag may be helpful for you, however I don't know if I fully understand what you are asking. Basically, if you put the debug tag in your template it will print a lot of useful stuff, including all the variables available in your template.
Perhaps you could take a look at the source code for the debug tag (because they have access to all the variables there), and build a custom tag tag based off of this. Taking a glance at the source, this seems like it would be really simple to do.
I made a simple django form, with a list of choices (in radio buttons):
class MyForm(forms.Form):
choices=forms.ChoiceField( widget=forms.RadioSelect(), choices=[(k,k) for k in ['one','two','three']],label="choose one")
I would like the form to submit automatically when a user selects one of the options. In straightforward HTML I would've done it as
<select name='myselect' onChange="FORM_NAME.submit();">
....
</select>
But I do not know how to integrate this into the form class without writing a template. Specifically, I would need to know FORM_NAME so I can call FORM_NAME.submit() in the above snippet.
Can it be done without using a template?
I think you do not need to know the form name. This should work as well:
<select name='myselect' onChange="this.form.submit();">
A quick solution to integrate this into your form would involve adding a attribute to your widget.
widget=forms.RadioSelect(attrs={'onchange': 'this.form.submit();'})
Now one could argue if this isn't better separated from your form definition (separating definition, style and behaviour), but that should do it.