from django import template, VERSION
from django.template.base import FilterExpression
from django.template.loader import get_template
from django.conf import settings
from ..exceptions import SiteMessageConfigurationError
register = template.Library()
_CONTEXT_FLATTEN = VERSION >= (1, 11)
@register.tag
def sitemessage_prefs_table(parser, token):
tokens = token.split_contents()
use_template = detect_clause(parser, 'template', tokens)
prefs_obj = detect_clause(parser, 'from', tokens)
tokens_num = len(tokens)
if tokens_num in (1, 3):
return sitemessage_prefs_tableNode(prefs_obj, use_template)
else:
raise template.TemplateSyntaxError(
'`sitemessage_prefs_table` tag expects the following notation: '
'{% sitemessage_prefs_table from user_prefs template "sitemessage/my_pref_table.html" %}.')
class sitemessage_prefs_tableNode(template.Node):
def __init__(self, prefs_obj, use_template):
self.use_template = use_template
self.prefs_obj = prefs_obj
def render(self, context):
resolve = lambda arg: arg.resolve(context) if isinstance(arg, FilterExpression) else arg
prefs_obj = resolve(self.prefs_obj)
if not isinstance(prefs_obj, tuple):
if settings.DEBUG:
raise SiteMessageConfigurationError(
'`sitemessage_prefs_table` template tag expects a tuple generated '
'by `get_user_preferences_for_ui` but `%s` is given.' % type(prefs_obj))
return '' # Silent fall.
context.push()
context['sitemessage_user_prefs'] = prefs_obj
contents = get_template(
resolve(self.use_template or 'sitemessage/user_prefs_table.html')
).render(context.flatten() if _CONTEXT_FLATTEN else context)
context.pop()
return contents
def detect_clause(parser, clause_name, tokens):
"""Helper function detects a certain clause in tag tokens list.
Returns its value.
"""
if clause_name in tokens:
t_index = tokens.index(clause_name)
clause_value = parser.compile_filter(tokens[t_index + 1])
del tokens[t_index:t_index + 2]
else:
clause_value = None
return clause_value
