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|
from django import template
from django.conf import settings
from django.core.exceptions import ImproperlyConfigured
from haystack.utils import importlib
register = template.Library()
class HighlightNode(template.Node):
def __init__(
self, text_block, query, html_tag=None, css_class=None, max_length=None
):
self.text_block = template.Variable(text_block)
self.query = template.Variable(query)
self.html_tag = html_tag
self.css_class = css_class
self.max_length = max_length
if html_tag is not None:
self.html_tag = template.Variable(html_tag)
if css_class is not None:
self.css_class = template.Variable(css_class)
if max_length is not None:
self.max_length = template.Variable(max_length)
def render(self, context):
text_block = self.text_block.resolve(context)
query = self.query.resolve(context)
kwargs = {}
if self.html_tag is not None:
kwargs["html_tag"] = self.html_tag.resolve(context)
if self.css_class is not None:
kwargs["css_class"] = self.css_class.resolve(context)
if self.max_length is not None:
kwargs["max_length"] = self.max_length.resolve(context)
# Handle a user-defined highlighting function.
if (
hasattr(settings, "HAYSTACK_CUSTOM_HIGHLIGHTER")
and settings.HAYSTACK_CUSTOM_HIGHLIGHTER
):
# Do the import dance.
try:
path_bits = settings.HAYSTACK_CUSTOM_HIGHLIGHTER.split(".")
highlighter_path, highlighter_classname = (
".".join(path_bits[:-1]),
path_bits[-1],
)
highlighter_module = importlib.import_module(highlighter_path)
highlighter_class = getattr(highlighter_module, highlighter_classname)
except (ImportError, AttributeError) as e:
raise ImproperlyConfigured(
"The highlighter '%s' could not be imported: %s"
% (settings.HAYSTACK_CUSTOM_HIGHLIGHTER, e)
)
else:
from haystack.utils.highlighting import Highlighter
highlighter_class = Highlighter
highlighter = highlighter_class(query, **kwargs)
highlighted_text = highlighter.highlight(text_block)
return highlighted_text
@register.tag
def highlight(parser, token):
"""
Takes a block of text and highlights words from a provided query within that
block of text. Optionally accepts arguments to provide the HTML tag to wrap
highlighted word in, a CSS class to use with the tag and a maximum length of
the blurb in characters.
Syntax::
{% highlight <text_block> with <query> [css_class "class_name"] [html_tag "span"] [max_length 200] %}
Example::
# Highlight summary with default behavior.
{% highlight result.summary with request.query %}
# Highlight summary but wrap highlighted words with a div and the
# following CSS class.
{% highlight result.summary with request.query html_tag "div" css_class "highlight_me_please" %}
# Highlight summary but only show 40 characters.
{% highlight result.summary with request.query max_length 40 %}
"""
bits = token.split_contents()
tag_name = bits[0]
if not len(bits) % 2 == 0:
raise template.TemplateSyntaxError(
"'%s' tag requires valid pairings arguments." % tag_name
)
text_block = bits[1]
if len(bits) < 4:
raise template.TemplateSyntaxError(
"'%s' tag requires an object and a query provided by 'with'." % tag_name
)
if bits[2] != "with":
raise template.TemplateSyntaxError(
"'%s' tag's second argument should be 'with'." % tag_name
)
query = bits[3]
arg_bits = iter(bits[4:])
kwargs = {}
for bit in arg_bits:
if bit == "css_class":
kwargs["css_class"] = next(arg_bits)
if bit == "html_tag":
kwargs["html_tag"] = next(arg_bits)
if bit == "max_length":
kwargs["max_length"] = next(arg_bits)
return HighlightNode(text_block, query, **kwargs)
|
