Allow passing arguments to the Jinja2 template prepare method.

2 files changed, 50 insertions, 9 deletions

diff --git a/bottle.py b/bottle.py
index 8d03532..b6f322b 100755
--- a/bottle.py
+++ b/bottle.py
@@ -1272,13 +1272,17 @@ class BaseTemplate(object):
     """ Base class and minimal API for template adapters """
     extentions = ['tpl','html','thtml','stpl']
 
-    def __init__(self, source=None, name=None, lookup=[], encoding='utf8'):
+    def __init__(self, source=None, name=None, lookup=[], encoding='utf8',
+                 filters=None, tests=None):
         """ Create a new template.
         If the source parameter (str or buffer) is missing, the name argument
         is used to guess a template filename. Subclasses can assume that
         either self.source or self.filename is set. Both are strings.
         The lookup-argument works similar to sys.path for templates.
         The encoding parameter is used to decode byte strings or files.
+        The parameters filters and tests are both jinja2 specific. The both
+        contains dicts of the form {'name': function, ...} in order to pass them
+        to jinja2.environment.filters or jinja2.environment..tests.
         """
         self.name = name
         self.source = source.read() if hasattr(source, 'read') else source
@@ -1291,7 +1295,7 @@ class BaseTemplate(object):
                 raise TemplateError('Template %s not found.' % repr(name))
         if not self.source and not self.filename:
             raise TemplateError('No template specified.')
-        self.prepare()
+        self.prepare(filters=filters, tests=tests)
 
     @classmethod
     def search(cls, name, lookup=[]):
@@ -1324,7 +1328,7 @@ class MakoTemplate(BaseTemplate):
     default_filters=None
     global_variables={}
 
-    def prepare(self):
+    def prepare(self, **kwargs):
         from mako.template import Template
         from mako.lookup import TemplateLookup
         #TODO: This is a hack... http://github.com/defnull/bottle/issues#issue/8
@@ -1345,7 +1349,7 @@ class MakoTemplate(BaseTemplate):
 
 
 class CheetahTemplate(BaseTemplate):
-    def prepare(self):
+    def prepare(self, **kwargs):
         from Cheetah.Template import Template
         self.context = threading.local()
         self.context.vars = {}
@@ -1364,10 +1368,21 @@ class CheetahTemplate(BaseTemplate):
 class Jinja2Template(BaseTemplate):
     env = None # hopefully, a Jinja environment is actually thread-safe
     prefix = "#"
-    def prepare(self):
+    def prepare(self, filters=None, tests=None):
+        """
+        Both parameters are passed through the template function.
+        :param filters: dict with custom filters {"name": function}
+        :param tests: dict with custom tests {"name": function}
+        """
         if not self.env:
             from jinja2 import Environment, FunctionLoader
-            self.env = Environment(line_statement_prefix=self.prefix, loader=FunctionLoader(self.loader))
+            self.env = Environment(line_statement_prefix=self.prefix,
+                        loader=FunctionLoader(self.loader)
+                       )
+            if filters:
+                self.env.filters.update(filters)
+            if tests:
+                self.env.tests.update(tests)
         if self.source:
             self.tpl = self.env.from_string(self.source)
         else:
@@ -1387,7 +1402,7 @@ class SimpleTemplate(BaseTemplate):
     blocks = ('if','elif','else','except','finally','for','while','with','def','class')
     dedent_blocks = ('elif', 'else', 'except', 'finally')
 
-    def prepare(self):
+    def prepare(self, **kwargs):
         if self.source:
             self.code = self.translate(self.source)
             self.co = compile(self.code, '<string>', 'exec')
@@ -1518,9 +1533,15 @@ def template(tpl, template_adapter=SimpleTemplate, **args):
     lookup = args.get('template_lookup', TEMPLATE_PATH)
     if tpl not in TEMPLATES or DEBUG:
         if "\n" in tpl or "{" in tpl or "%" in tpl or '$' in tpl:
-            TEMPLATES[tpl] = template_adapter(source=tpl, lookup=lookup)
+            TEMPLATES[tpl] = template_adapter(source=tpl, lookup=lookup,
+                                filters=args.get('filters'),
+                                tests=args.get('tests')
+                             )
         else:
-            TEMPLATES[tpl] = template_adapter(name=tpl, lookup=lookup)
+            TEMPLATES[tpl] = template_adapter(name=tpl, lookup=lookup,
+                                filters=args.get('filters'),
+                                tests=args.get('tests')
+                             )
     if not TEMPLATES[tpl]:
         abort(500, 'Template (%s) not found' % tpl)
     args['abort'] = abort
diff --git a/test/test_jinja2.py b/test/test_jinja2.py
index 985316a..9cdacad 100644
--- a/test/test_jinja2.py
+++ b/test/test_jinja2.py
@@ -1,6 +1,8 @@
+# -*- coding: utf-8 -*-
 import unittest
 from bottle import Jinja2Template
 
+
 class TestJinja2Template(unittest.TestCase):
 
     def test_string(self):
@@ -31,6 +33,24 @@ class TestJinja2Template(unittest.TestCase):
         t = Jinja2Template(name='jinja2_inherit', lookup=['./views/']).render()
         self.assertEqual('begin abc end', ''.join(t))
 
+    def test_custom_filters(self):
+        """Templates: jinja2 custom filters """
+        from bottle import jinja2_template as template
+        filters = {"star": lambda var: u"".join((u'*', var, u'*'))}
+        res = template("start {{var|star}} end", var="var", filters=filters)
+        self.assertEqual("start *var* end", res)
+
+    def test_custom_tests(self):
+        """Templates: jinja2 custom tests """
+        from bottle import jinja2_template as template
+        TEMPL = u"""{% if var is even %}gerade{% else %}ungerade{% endif %}"""
+        tests={"even": lambda x: False if x % 2 else True}
+        res = template(TEMPL, var=2, tests=tests)
+        self.assertEqual("gerade", res)
+        res = template(TEMPL, var=1, tests=tests)
+        self.assertEqual("ungerade", res)
+
+
 try:
   import jinja2
 except ImportError: