adds simple block templatetag wip

src/wagtail_personalisation/templatetags/wagtail_personalisation_tags.py

@@ -0,0 +1,91 @@
+from django import template
+from django.template import TemplateSyntaxError
+from django.template.base import FilterExpression, kwarg_re
+from django.utils.safestring import mark_safe
+
+from wagtail_personalisation.app_settings import segments_adapter
+from wagtail_personalisation.models import Segment
+
+register = template.Library()
+
+
+def parse_tag(token, parser):
+    """
+    Generic template tag parser.
+
+    Returns a three-tuple: (tag_name, args, kwargs)
+
+    tag_name is a string, the name of the tag.
+
+    args is a list of FilterExpressions, from all the arguments that didn't look like kwargs,
+    in the order they occurred, including any that were mingled amongst kwargs.
+
+    kwargs is a dictionary mapping kwarg names to FilterExpressions, for all the arguments that
+    looked like kwargs, including any that were mingled amongst args.
+
+    (At rendering time, a FilterExpression f can be evaluated by calling f.resolve(context).)
+    """
+    # Split the tag content into words, respecting quoted strings.
+    bits = token.split_contents()
+
+    # Pull out the tag name.
+    tag_name = bits.pop(0)
+
+    # Parse the rest of the args, and build FilterExpressions from them so that
+    # we can evaluate them later.
+    args = []
+    kwargs = {}
+    for bit in bits:
+        # Is this a kwarg or an arg?
+        match = kwarg_re.match(bit)
+        kwarg_format = match and match.group(1)
+        if kwarg_format:
+            key, value = match.groups()
+            kwargs[key] = FilterExpression(value, parser)
+        else:
+            args.append(FilterExpression(bit, parser))
+
+    return (tag_name, args, kwargs)
+
+
+def do_segment(parser, token):
+    """Block that only shows content if user is in chosen segment.
+    """
+    # Parse the tag
+    tag_name, _, kwargs = parse_tag(token, parser)
+
+    # If no segment is provided this block will raise an error
+    if set(kwargs.keys()) != {'name'}:
+        usage = '{% {tag_name} name="segmentname" %} ... {% end{tag_name} %}'.format(tag_name=tag_name)
+        raise TemplateSyntaxError("Usage: %s" % usage)
+
+    nodelist = parser.parse(('endsegment',))
+    parser.delete_first_token()
+
+    return SegmentNode(nodelist, name=kwargs['name'])
+
+
+register.tag('segment', do_segment)
+
+
+class SegmentNode(template.Node):
+    def __init__(self, nodelist, name):
+        self.nodelist = nodelist
+        self.name = name
+
+    def render(self, context):
+        # Check if segment exists
+        name = self.name.resolve(context)
+        segment = Segment.objects.filter(name=name).first()
+        if not segment:
+            return ""
+
+        # Check if user has segment
+        user_segment = segments_adapter.get_segment(segment_id=segment.pk)
+        if not user_segment:
+            return ""
+
+        content = self.nodelist.render(context)
+        content = mark_safe(content)
+
+        return content