From bccb8897e6ab0fe8d2e5b9bcb725ac28b1c8e566 Mon Sep 17 00:00:00 2001
From: Malcolm Tredinnick <malcolm.tredinnick@gmail.com>
Date: Sun, 17 Jun 2007 07:11:37 +0000
Subject: [PATCH] Fixed #4565 -- Changed template rendering to use iterators,
rather than creating large strings, as much as possible. This is all
backwards compatible. Thanks, Brian Harring.
git-svn-id: http://code.djangoproject.com/svn/django/trunk@5482 bcc190cf-cafb-0310-a4f2-bffc1f526a37
---
.../admin/templatetags/admin_modify.py | 13 +-
.../admin/templatetags/adminapplist.py | 4 +-
django/contrib/admin/templatetags/log.py | 4 +-
.../contrib/comments/templatetags/comments.py | 18 +--
django/core/servers/basehttp.py | 9 +-
django/http/__init__.py | 18 +--
django/oldforms/__init__.py | 4 +
django/shortcuts/__init__.py | 2 +-
django/template/__init__.py | 84 ++++++++-----
django/template/defaulttags.py | 112 ++++++++++--------
django/template/loader.py | 33 ++++--
django/template/loader_tags.py | 25 ++--
django/test/utils.py | 20 +++-
django/views/debug.py | 6 +-
django/views/defaults.py | 4 +-
django/views/generic/create_update.py | 6 +-
django/views/generic/date_based.py | 12 +-
django/views/generic/list_detail.py | 4 +-
django/views/generic/simple.py | 2 +-
django/views/static.py | 2 +-
docs/templates_python.txt | 63 ++++++++--
21 files changed, 284 insertions(+), 161 deletions(-)
diff --git a/django/contrib/admin/templatetags/admin_modify.py b/django/contrib/admin/templatetags/admin_modify.py
index f9cad005d5..b8836caa5a 100644
--- a/django/contrib/admin/templatetags/admin_modify.py
+++ b/django/contrib/admin/templatetags/admin_modify.py
@@ -94,15 +94,15 @@ class FieldWidgetNode(template.Node):
return cls.nodelists[klass]
get_nodelist = classmethod(get_nodelist)
- def render(self, context):
+ def iter_render(self, context):
bound_field = template.resolve_variable(self.bound_field_var, context)
context.push()
context['bound_field'] = bound_field
- output = self.get_nodelist(bound_field.field.__class__).render(context)
+ for chunk in self.get_nodelist(bound_field.field.__class__).iter_render(context):
+ yield chunk
context.pop()
- return output
class FieldWrapper(object):
def __init__(self, field ):
@@ -157,7 +157,7 @@ class EditInlineNode(template.Node):
def __init__(self, rel_var):
self.rel_var = rel_var
- def render(self, context):
+ def iter_render(self, context):
relation = template.resolve_variable(self.rel_var, context)
context.push()
if relation.field.rel.edit_inline == models.TABULAR:
@@ -169,10 +169,9 @@ class EditInlineNode(template.Node):
original = context.get('original', None)
bound_related_object = relation.bind(context['form'], original, bound_related_object_class)
context['bound_related_object'] = bound_related_object
- t = loader.get_template(bound_related_object.template_name())
- output = t.render(context)
+ for chunk in loader.get_template(bound_related_object.template_name()).iter_render(context):
+ yield chunk
context.pop()
- return output
def output_all(form_fields):
return ''.join([str(f) for f in form_fields])
diff --git a/django/contrib/admin/templatetags/adminapplist.py b/django/contrib/admin/templatetags/adminapplist.py
index 10e09ca0b6..53455d6c74 100644
--- a/django/contrib/admin/templatetags/adminapplist.py
+++ b/django/contrib/admin/templatetags/adminapplist.py
@@ -7,7 +7,7 @@ class AdminApplistNode(template.Node):
def __init__(self, varname):
self.varname = varname
- def render(self, context):
+ def iter_render(self, context):
from django.db import models
from django.utils.text import capfirst
app_list = []
@@ -54,7 +54,7 @@ class AdminApplistNode(template.Node):
'models': model_list,
})
context[self.varname] = app_list
- return ''
+ return ()
def get_admin_app_list(parser, token):
"""
diff --git a/django/contrib/admin/templatetags/log.py b/django/contrib/admin/templatetags/log.py
index 8d52d2e944..96db2373b4 100644
--- a/django/contrib/admin/templatetags/log.py
+++ b/django/contrib/admin/templatetags/log.py
@@ -10,14 +10,14 @@ class AdminLogNode(template.Node):
def __repr__(self):
return "<GetAdminLog Node>"
- def render(self, context):
+ def iter_render(self, context):
if self.user is None:
context[self.varname] = LogEntry.objects.all().select_related()[:self.limit]
else:
if not self.user.isdigit():
self.user = context[self.user].id
context[self.varname] = LogEntry.objects.filter(user__id__exact=self.user).select_related()[:self.limit]
- return ''
+ return ()
class DoGetAdminLog:
"""
diff --git a/django/contrib/comments/templatetags/comments.py b/django/contrib/comments/templatetags/comments.py
index 5c02c16f95..a43b11f452 100644
--- a/django/contrib/comments/templatetags/comments.py
+++ b/django/contrib/comments/templatetags/comments.py
@@ -24,7 +24,7 @@ class CommentFormNode(template.Node):
self.photo_options, self.rating_options = photo_options, rating_options
self.is_public = is_public
- def render(self, context):
+ def iter_render(self, context):
from django.conf import settings
from django.utils.text import normalize_newlines
import base64
@@ -33,7 +33,7 @@ class CommentFormNode(template.Node):
try:
self.obj_id = template.resolve_variable(self.obj_id_lookup_var, context)
except template.VariableDoesNotExist:
- return ''
+ return
# Validate that this object ID is valid for this content-type.
# We only have to do this validation if obj_id_lookup_var is provided,
# because do_comment_form() validates hard-coded object IDs.
@@ -67,9 +67,9 @@ class CommentFormNode(template.Node):
context['hash'] = Comment.objects.get_security_hash(context['options'], context['photo_options'], context['rating_options'], context['target'])
context['logout_url'] = settings.LOGOUT_URL
default_form = loader.get_template(COMMENT_FORM)
- output = default_form.render(context)
+ for chunk in default_form.iter_render(context):
+ yield chunk
context.pop()
- return output
class CommentCountNode(template.Node):
def __init__(self, package, module, context_var_name, obj_id, var_name, free):
@@ -77,7 +77,7 @@ class CommentCountNode(template.Node):
self.context_var_name, self.obj_id = context_var_name, obj_id
self.var_name, self.free = var_name, free
- def render(self, context):
+ def iter_render(self, context):
from django.conf import settings
manager = self.free and FreeComment.objects or Comment.objects
if self.context_var_name is not None:
@@ -86,7 +86,7 @@ class CommentCountNode(template.Node):
content_type__app_label__exact=self.package,
content_type__model__exact=self.module, site__id__exact=settings.SITE_ID).count()
context[self.var_name] = comment_count
- return ''
+ return ()
class CommentListNode(template.Node):
def __init__(self, package, module, context_var_name, obj_id, var_name, free, ordering, extra_kwargs=None):
@@ -96,14 +96,14 @@ class CommentListNode(template.Node):
self.ordering = ordering
self.extra_kwargs = extra_kwargs or {}
- def render(self, context):
+ def iter_render(self, context):
from django.conf import settings
get_list_function = self.free and FreeComment.objects.filter or Comment.objects.get_list_with_karma
if self.context_var_name is not None:
try:
self.obj_id = template.resolve_variable(self.context_var_name, context)
except template.VariableDoesNotExist:
- return ''
+ return ()
kwargs = {
'object_id__exact': self.obj_id,
'content_type__app_label__exact': self.package,
@@ -127,7 +127,7 @@ class CommentListNode(template.Node):
comment_list = [c for c in comment_list if not c.is_hidden or (user_id == c.user_id)]
context[self.var_name] = comment_list
- return ''
+ return ()
class DoCommentForm:
"""
diff --git a/django/core/servers/basehttp.py b/django/core/servers/basehttp.py
index 80a0bf6a91..9e603b42d4 100644
--- a/django/core/servers/basehttp.py
+++ b/django/core/servers/basehttp.py
@@ -309,7 +309,7 @@ class ServerHandler(object):
"""
if not self.result_is_file() and not self.sendfile():
for data in self.result:
- self.write(data)
+ self.write(data, False)
self.finish_content()
self.close()
@@ -377,7 +377,7 @@ class ServerHandler(object):
else:
self._write('Status: %s\r\n' % self.status)
- def write(self, data):
+ def write(self, data, flush=True):
"""'write()' callable as specified by PEP 333"""
assert type(data) is StringType,"write() argument must be string"
@@ -394,7 +394,8 @@ class ServerHandler(object):
# XXX check Content-Length and truncate if too many bytes written?
self._write(data)
- self._flush()
+ if flush:
+ self._flush()
def sendfile(self):
"""Platform-specific file transmission
@@ -421,8 +422,6 @@ class ServerHandler(object):
if not self.headers_sent:
self.headers['Content-Length'] = "0"
self.send_headers()
- else:
- pass # XXX check if content-length was too short?
def close(self):
try:
diff --git a/django/http/__init__.py b/django/http/__init__.py
index ca3b5eab24..a8c8afe433 100644
--- a/django/http/__init__.py
+++ b/django/http/__init__.py
@@ -222,6 +222,12 @@ class HttpResponse(object):
content = ''.join(self._container)
if isinstance(content, unicode):
content = content.encode(self._charset)
+
+ # If self._container was an iterator, we have just exhausted it, so we
+ # need to save the results for anything else that needs access
+ if not self._is_string:
+ self._container = [content]
+ self._is_string = True
return content
def _set_content(self, value):
@@ -231,14 +237,10 @@ class HttpResponse(object):
content = property(_get_content, _set_content)
def __iter__(self):
- self._iterator = self._container.__iter__()
- return self
-
- def next(self):
- chunk = self._iterator.next()
- if isinstance(chunk, unicode):
- chunk = chunk.encode(self._charset)
- return chunk
+ for chunk in self._container:
+ if isinstance(chunk, unicode):
+ chunk = chunk.encode(self._charset)
+ yield chunk
def close(self):
if hasattr(self._container, 'close'):
diff --git a/django/oldforms/__init__.py b/django/oldforms/__init__.py
index 5814eef7ff..ea1f425ad3 100644
--- a/django/oldforms/__init__.py
+++ b/django/oldforms/__init__.py
@@ -309,6 +309,10 @@ class FormField(object):
return data
html2python = staticmethod(html2python)
+ def iter_render(self, data):
+ # this even needed?
+ return (self.render(data),)
+
def render(self, data):
raise NotImplementedError
diff --git a/django/shortcuts/__init__.py b/django/shortcuts/__init__.py
index 81381d08c1..3a0f6a0091 100644
--- a/django/shortcuts/__init__.py
+++ b/django/shortcuts/__init__.py
@@ -7,7 +7,7 @@ from django.http import HttpResponse, Http404
from django.db.models.manager import Manager
def render_to_response(*args, **kwargs):
- return HttpResponse(loader.render_to_string(*args, **kwargs))
+ return HttpResponse(loader.render_to_iter(*args, **kwargs))
load_and_render = render_to_response # For backwards compatibility.
def get_object_or_404(klass, *args, **kwargs):
diff --git a/django/template/__init__.py b/django/template/__init__.py
index 4f2ddfc8b3..0d1256c4dc 100644
--- a/django/template/__init__.py
+++ b/django/template/__init__.py
@@ -55,6 +55,7 @@ times with multiple contexts)
'\n<html>\n\n</html>\n'
"""
import re
+import types
from inspect import getargspec
from django.conf import settings
from django.template.context import Context, RequestContext, ContextPopException
@@ -167,9 +168,12 @@ class Template(object):
for subnode in node:
yield subnode
- def render(self, context):
+ def iter_render(self, context):
"Display stage -- can be called many times"
- return self.nodelist.render(context)
+ return self.nodelist.iter_render(context)
+
+ def render(self, context):
+ return ''.join(self.iter_render(context))
def compile_string(template_string, origin):
"Compiles template_string into NodeList ready for rendering"
@@ -698,10 +702,26 @@ def resolve_variable(path, context):
del bits[0]
return current
+class NodeBase(type):
+ def __new__(cls, name, bases, attrs):
+ """
+ Ensures that either a 'render' or 'render_iter' method is defined on
+ any Node sub-class. This avoids potential infinite loops at runtime.
+ """
+ if not (isinstance(attrs.get('render'), types.FunctionType) or
+ isinstance(attrs.get('iter_render'), types.FunctionType)):
+ raise TypeError('Unable to create Node subclass without either "render" or "iter_render" method.')
+ return type.__new__(cls, name, bases, attrs)
+
class Node(object):
+ __metaclass__ = NodeBase
+
+ def iter_render(self, context):
+ return (self.render(context),)
+
def render(self, context):
"Return the node rendered as a string"
- pass
+ return ''.join(self.iter_render(context))
def __iter__(self):
yield self
@@ -717,13 +737,12 @@ class Node(object):
class NodeList(list):
def render(self, context):
- bits = []
+ return ''.join(self.iter_render(context))
+
+ def iter_render(self, context):
for node in self:
- if isinstance(node, Node):
- bits.append(self.render_node(node, context))
- else:
- bits.append(node)
- return ''.join(bits)
+ for chunk in node.iter_render(context):
+ yield chunk
def get_nodes_by_type(self, nodetype):
"Return a list of all nodes of the given type"
@@ -732,24 +751,26 @@ class NodeList(list):
nodes.extend(node.get_nodes_by_type(nodetype))
return nodes
- def render_node(self, node, context):
- return(node.render(context))
class DebugNodeList(NodeList):
- def render_node(self, node, context):
- try:
- result = node.render(context)
- except TemplateSyntaxError, e:
- if not hasattr(e, 'source'):
- e.source = node.source
- raise
- except Exception, e:
- from sys import exc_info
- wrapped = TemplateSyntaxError('Caught an exception while rendering: %s' % e)
- wrapped.source = node.source
- wrapped.exc_info = exc_info()
- raise wrapped
- return result
+ def iter_render(self, context):
+ for node in self:
+ if not isinstance(node, Node):
+ yield node
+ continue
+ try:
+ for chunk in node.iter_render(context):
+ yield chunk
+ except TemplateSyntaxError, e:
+ if not hasattr(e, 'source'):
+ e.source = node.source
+ raise
+ except Exception, e:
+ from sys import exc_info
+ wrapped = TemplateSyntaxError('Caught an exception while rendering: %s' % e)
+ wrapped.source = node.source
+ wrapped.exc_info = exc_info()
+ raise wrapped
class TextNode(Node):
def __init__(self, s):
@@ -758,6 +779,9 @@ class TextNode(Node):
def __repr__(self):
return "<Text Node: '%s'>" % self.s[:25]
+ def iter_render(self, context):
+ return (self.s,)
+
def render(self, context):
return self.s
@@ -781,6 +805,9 @@ class VariableNode(Node):
else:
return output
+ def iter_render(self, context):
+ return (self.render(context),)
+
def render(self, context):
output = self.filter_expression.resolve(context)
return self.encode_output(output)
@@ -869,6 +896,9 @@ class Library(object):
def __init__(self, vars_to_resolve):
self.vars_to_resolve = vars_to_resolve
+ #def iter_render(self, context):
+ # return (self.render(context),)
+
def render(self, context):
resolved_vars = [resolve_variable(var, context) for var in self.vars_to_resolve]
return func(*resolved_vars)
@@ -891,7 +921,7 @@ class Library(object):
def __init__(self, vars_to_resolve):
self.vars_to_resolve = vars_to_resolve
- def render(self, context):
+ def iter_render(self, context):
resolved_vars = [resolve_variable(var, context) for var in self.vars_to_resolve]
if takes_context:
args = [context] + resolved_vars
@@ -907,7 +937,7 @@ class Library(object):
else:
t = get_template(file_name)
self.nodelist = t.nodelist
- return self.nodelist.render(context_class(dict))
+ return self.nodelist.iter_render(context_class(dict))
compile_func = curry(generic_tag_compiler, params, defaults, getattr(func, "_decorated_function", func).__name__, InclusionNode)
compile_func.__doc__ = func.__doc__
diff --git a/django/template/defaulttags.py b/django/template/defaulttags.py
index 6a6665a445..45005fa988 100644
--- a/django/template/defaulttags.py
+++ b/django/template/defaulttags.py
@@ -14,12 +14,11 @@ if not hasattr(__builtins__, 'reversed'):
for index in xrange(len(data)-1, -1, -1):
yield data[index]
-
register = Library()
class CommentNode(Node):
- def render(self, context):
- return ''
+ def iter_render(self, context):
+ return ()
class CycleNode(Node):
def __init__(self, cyclevars, variable_name=None):
@@ -28,6 +27,9 @@ class CycleNode(Node):
self.counter = -1
self.variable_name = variable_name
+ def iter_render(self, context):
+ return (self.render(context),)
+
def render(self, context):
self.counter += 1
value = self.cyclevars[self.counter % self.cyclevars_len]
@@ -36,29 +38,32 @@ class CycleNode(Node):
return value
class DebugNode(Node):
- def render(self, context):
+ def iter_render(self, context):
from pprint import pformat
- output = [pformat(val) for val in context]
- output.append('\n\n')
- output.append(pformat(sys.modules))
- return ''.join(output)
+ for val in context:
+ yield pformat(val)
+ yield "\n\n"
+ yield pformat(sys.modules)
class FilterNode(Node):
def __init__(self, filter_expr, nodelist):
self.filter_expr, self.nodelist = filter_expr, nodelist
- def render(self, context):
+ def iter_render(self, context):
output = self.nodelist.render(context)
# apply filters
context.update({'var': output})
filtered = self.filter_expr.resolve(context)
context.pop()
- return filtered
+ return (filtered,)
class FirstOfNode(Node):
def __init__(self, vars):
self.vars = vars
+ def iter_render(self, context):
+ return (self.render(context),)
+
def render(self, context):
for var in self.vars:
try:
@@ -94,8 +99,7 @@ class ForNode(Node):
nodes.extend(self.nodelist_loop.get_nodes_by_type(nodetype))
return nodes
- def render(self, context):
- nodelist = NodeList()
+ def iter_render(self, context):
if 'forloop' in context:
parentloop = context['forloop']
else:
@@ -103,12 +107,12 @@ class ForNode(Node):
context.push()
try:
values = self.sequence.resolve(context, True)
+ if values is None:
+ values = ()
+ elif not hasattr(values, '__len__'):
+ values = list(values)
except VariableDoesNotExist:
- values = []
- if values is None:
- values = []
- if not hasattr(values, '__len__'):
- values = list(values)
+ values = ()
len_values = len(values)
if self.reversed:
values = reversed(values)
@@ -127,12 +131,17 @@ class ForNode(Node):
'parentloop': parentloop,
}
if unpack:
- # If there are multiple loop variables, unpack the item into them.
+ # If there are multiple loop variables, unpack the item into
+ # them.
context.update(dict(zip(self.loopvars, item)))
else:
context[self.loopvars[0]] = item
+
+ # We inline this to avoid the overhead since ForNode is pretty
+ # common.
for node in self.nodelist_loop:
- nodelist.append(node.render(context))
+ for chunk in node.iter_render(context):
+ yield chunk
if unpack:
# The loop variables were pushed on to the context so pop them
# off again. This is necessary because the tag lets the length
@@ -141,7 +150,6 @@ class ForNode(Node):
# context.
context.pop()
context.pop()
- return nodelist.render(context)
class IfChangedNode(Node):
def __init__(self, nodelist, *varlist):
@@ -149,7 +157,7 @@ class IfChangedNode(Node):
self._last_seen = None
self._varlist = varlist
- def render(self, context):
+ def iter_render(self, context):
if 'forloop' in context and context['forloop']['first']:
self._last_seen = None
try:
@@ -167,11 +175,9 @@ class IfChangedNode(Node):
self._last_seen = compare_to
context.push()
context['ifchanged'] = {'firstloop': firstloop}
- content = self.nodelist.render(context)
+ for chunk in self.nodelist.iter_render(context):
+ yield chunk
context.pop()
- return content
- else:
- return ''
class IfEqualNode(Node):
def __init__(self, var1, var2, nodelist_true, nodelist_false, negate):
@@ -182,7 +188,7 @@ class IfEqualNode(Node):
def __repr__(self):
return "<IfEqualNode>"
- def render(self, context):
+ def iter_render(self, context):
try:
val1 = resolve_variable(self.var1, context)
except VariableDoesNotExist:
@@ -192,8 +198,8 @@ class IfEqualNode(Node):
except VariableDoesNotExist:
val2 = None
if (self.negate and val1 != val2) or (not self.negate and val1 == val2):
- return self.nodelist_true.render(context)
- return self.nodelist_false.render(context)
+ return self.nodelist_true.iter_render(context)
+ return self.nodelist_false.iter_render(context)
class IfNode(Node):
def __init__(self, bool_exprs, nodelist_true, nodelist_false, link_type):
@@ -218,7 +224,7 @@ class IfNode(Node):
nodes.extend(self.nodelist_false.get_nodes_by_type(nodetype))
return nodes
- def render(self, context):
+ def iter_render(self, context):
if self.link_type == IfNode.LinkTypes.or_:
for ifnot, bool_expr in self.bool_exprs:
try:
@@ -226,8 +232,8 @@ class IfNode(Node):
except VariableDoesNotExist:
value = None
if (value and not ifnot) or (ifnot and not value):
- return self.nodelist_true.render(context)
- return self.nodelist_false.render(context)
+ return self.nodelist_true.iter_render(context)
+ return self.nodelist_false.iter_render(context)
else:
for ifnot, bool_expr in self.bool_exprs:
try:
@@ -235,8 +241,8 @@ class IfNode(Node):
except VariableDoesNotExist:
value = None
if not ((value and not ifnot) or (ifnot and not value)):
- return self.nodelist_false.render(context)
- return self.nodelist_true.render(context)
+ return self.nodelist_false.iter_render(context)
+ return self.nodelist_true.iter_render(context)
class LinkTypes:
and_ = 0,
@@ -247,11 +253,11 @@ class RegroupNode(Node):
self.target, self.expression = target, expression
self.var_name = var_name
- def render(self, context):
+ def iter_render(self, context):
obj_list = self.target.resolve(context, True)
if obj_list == None: # target_var wasn't found in context; fail silently
context[self.var_name] = []
- return ''
+ return ()
output = [] # list of dictionaries in the format {'grouper': 'key', 'list': [list of contents]}
for obj in obj_list:
grouper = self.expression.resolve(obj, True)
@@ -261,7 +267,7 @@ class RegroupNode(Node):
else:
output.append({'grouper': grouper, 'list': [obj]})
context[self.var_name] = output
- return ''
+ return ()
def include_is_allowed(filepath):
for root in settings.ALLOWED_INCLUDE_ROOTS:
@@ -273,10 +279,10 @@ class SsiNode(Node):
def __init__(self, filepath, parsed):
self.filepath, self.parsed = filepath, parsed
- def render(self, context):
+ def iter_render(self, context):
if not include_is_allowed(self.filepath):
if settings.DEBUG:
- return "[Didn't have permission to include file]"
+ return ("[Didn't have permission to include file]",)
else:
return '' # Fail silently for invalid includes.
try:
@@ -287,23 +293,25 @@ class SsiNode(Node):
output = ''
if self.parsed:
try:
- t = Template(output, name=self.filepath)
- return t.render(context)
+ return Template(output, name=self.filepath).iter_render(context)
except TemplateSyntaxError, e:
if settings.DEBUG:
return "[Included template had syntax error: %s]" % e
else:
return '' # Fail silently for invalid included templates.
- return output
+ return (output,)
class LoadNode(Node):
- def render(self, context):
- return ''
+ def iter_render(self, context):
+ return ()
class NowNode(Node):
def __init__(self, format_string):
self.format_string = format_string
+ def iter_render(self, context):
+ return (self.render(context),)
+
def render(self, context):
from datetime import datetime
from django.utils.dateformat import DateFormat
@@ -332,6 +340,9 @@ class TemplateTagNode(Node):
def __init__(self, tagtype):
self.tagtype = tagtype
+ def iter_render(self, context):
+ return (self.render(context),)
+
def render(self, context):
return self.mapping.get(self.tagtype, '')
@@ -341,18 +352,18 @@ class URLNode(Node):
self.args = args
self.kwargs = kwargs
- def render(self, context):
+ def iter_render(self, context):
from django.core.urlresolvers import reverse, NoReverseMatch
args = [arg.resolve(context) for arg in self.args]
kwargs = dict([(k, v.resolve(context)) for k, v in self.kwargs.items()])
try:
- return reverse(self.view_name, args=args, kwargs=kwargs)
+ return (reverse(self.view_name, args=args, kwargs=kwargs),)
except NoReverseMatch:
try:
project_name = settings.SETTINGS_MODULE.split('.')[0]
return reverse(project_name + '.' + self.view_name, args=args, kwargs=kwargs)
except NoReverseMatch:
- return ''
+ return ()
class WidthRatioNode(Node):
def __init__(self, val_expr, max_expr, max_width):
@@ -360,6 +371,9 @@ class WidthRatioNode(Node):
self.max_expr = max_expr
self.max_width = max_width
+ def iter_render(self, context):
+ return (self.render(context),)
+
def render(self, context):
try:
value = self.val_expr.resolve(context)
@@ -383,13 +397,13 @@ class WithNode(Node):
def __repr__(self):
return "<WithNode>"
- def render(self, context):
+ def iter_render(self, context):
val = self.var.resolve(context)
context.push()
context[self.name] = val
- output = self.nodelist.render(context)
+ for chunk in self.nodelist.iter_render(context):
+ yield chunk
context.pop()
- return output
#@register.tag
def comment(parser, token):
diff --git a/django/template/loader.py b/django/template/loader.py
index 03e6f8d49d..45cf5a9d7c 100644
--- a/django/template/loader.py
+++ b/django/template/loader.py
@@ -87,14 +87,12 @@ def get_template_from_string(source, origin=None, name=None):
"""
return Template(source, origin, name)
-def render_to_string(template_name, dictionary=None, context_instance=None):
+def _render_setup(template_name, dictionary=None, context_instance=None):
"""
- Loads the given template_name and renders it with the given dictionary as
- context. The template_name may be a string to load a single template using
- get_template, or it may be a tuple to use select_template to find one of
- the templates in the list. Returns a string.
+ Common setup code for render_to_string and render_to_iter.
"""
- dictionary = dictionary or {}
+ if dictionary is None:
+ dictionary = {}
if isinstance(template_name, (list, tuple)):
t = select_template(template_name)
else:
@@ -103,7 +101,28 @@ def render_to_string(template_name, dictionary=None, context_instance=None):
context_instance.update(dictionary)
else:
context_instance = Context(dictionary)
- return t.render(context_instance)
+ return t, context_instance
+
+def render_to_string(template_name, dictionary=None, context_instance=None):
+ """
+ Loads the given template_name and renders it with the given dictionary as
+ context. The template_name may be a string to load a single template using
+ get_template, or it may be a tuple to use select_template to find one of
+ the templates in the list. Returns a string.
+ """
+ t, c = _render_setup(template_name, dictionary=dictionary, context_instance=context_instance)
+ return t.render(c)
+
+def render_to_iter(template_name, dictionary=None, context_instance=None):
+ """
+ Loads the given template_name and renders it with the given dictionary as
+ context. The template_name may be a string to load a single template using
+ get_template, or it may be a tuple to use select_template to find one of
+ the templates in the list. Returns a string.
+ """
+ t, c = _render_setup(template_name, dictionary=dictionary, context_instance=context_instance)
+ return t.iter_render(c)
+
def select_template(template_name_list):
"Given a list of template names, returns the first that can be loaded."
diff --git a/django/template/loader_tags.py b/django/template/loader_tags.py
index 4439e0b010..d12d0b55ad 100644
--- a/django/template/loader_tags.py
+++ b/django/template/loader_tags.py
@@ -15,14 +15,14 @@ class BlockNode(Node):
def __repr__(self):
return "<Block Node: %s. Contents: %r>" % (self.name, self.nodelist)
- def render(self, context):
+ def iter_render(self, context):
context.push()
# Save context in case of block.super().
self.context = context
context['block'] = self
- result = self.nodelist.render(context)
+ for chunk in self.nodelist.iter_render(context):
+ yield chunk
context.pop()
- return result
def super(self):
if self.parent:
@@ -59,7 +59,7 @@ class ExtendsNode(Node):
else:
return get_template_from_string(source, origin, parent)
- def render(self, context):
+ def iter_render(self, context):
compiled_parent = self.get_parent(context)
parent_is_child = isinstance(compiled_parent.nodelist[0], ExtendsNode)
parent_blocks = dict([(n.name, n) for n in compiled_parent.nodelist.get_nodes_by_type(BlockNode)])
@@ -79,7 +79,7 @@ class ExtendsNode(Node):
parent_block.parent = block_node.parent
parent_block.add_parent(parent_block.nodelist)
parent_block.nodelist = block_node.nodelist
- return compiled_parent.render(context)
+ return compiled_parent.iter_render(context)
class ConstantIncludeNode(Node):
def __init__(self, template_path):
@@ -91,27 +91,26 @@ class ConstantIncludeNode(Node):
raise
self.template = None
- def render(self, context):
+ def iter_render(self, context):
if self.template:
- return self.template.render(context)
- else:
- return ''
+ return self.template.iter_render(context)
+ return ()
class IncludeNode(Node):
def __init__(self, template_name):
self.template_name = template_name
- def render(self, context):
+ def iter_render(self, context):
try:
template_name = resolve_variable(self.template_name, context)
t = get_template(template_name)
- return t.render(context)
+ return t.iter_render(context)
except TemplateSyntaxError, e:
if settings.TEMPLATE_DEBUG:
raise
- return ''
+ return ()
except:
- return '' # Fail silently for invalid included templates.
+ return () # Fail silently for invalid included templates.
def do_block(parser, token):
"""
diff --git a/django/test/utils.py b/django/test/utils.py
index f5122fa96d..303a223183 100644
--- a/django/test/utils.py
+++ b/django/test/utils.py
@@ -11,12 +11,21 @@ from django.template import Template
TEST_DATABASE_PREFIX = 'test_'
def instrumented_test_render(self, context):
- """An instrumented Template render method, providing a signal
- that can be intercepted by the test system Client
-
+ """
+ An instrumented Template render method, providing a signal that can be
+ intercepted by the test system Client.
"""
dispatcher.send(signal=signals.template_rendered, sender=self, template=self, context=context)
return self.nodelist.render(context)
+
+def instrumented_test_iter_render(self, context):
+ """
+ An instrumented Template iter_render method, providing a signal that can be
+ intercepted by the test system Client.
+ """
+ for chunk in self.nodelist.iter_render(context):
+ yield chunk
+ dispatcher.send(signal=signals.template_rendered, sender=self, template=self, context=context)
class TestSMTPConnection(object):
"""A substitute SMTP connection for use during test sessions.
@@ -44,7 +53,9 @@ def setup_test_environment():
"""
Template.original_render = Template.render
+ Template.original_iter_render = Template.iter_render
Template.render = instrumented_test_render
+ Template.iter_render = instrumented_test_render
mail.original_SMTPConnection = mail.SMTPConnection
mail.SMTPConnection = TestSMTPConnection
@@ -59,7 +70,8 @@ def teardown_test_environment():
"""
Template.render = Template.original_render
- del Template.original_render
+ Template.iter_render = Template.original_iter_render
+ del Template.original_render, Template.original_iter_render
mail.SMTPConnection = mail.original_SMTPConnection
del mail.original_SMTPConnection
diff --git a/django/views/debug.py b/django/views/debug.py
index a534f17b33..75b1a26af9 100644
--- a/django/views/debug.py
+++ b/django/views/debug.py
@@ -137,7 +137,7 @@ def technical_500_response(request, exc_type, exc_value, tb):
'template_does_not_exist': template_does_not_exist,
'loader_debug_info': loader_debug_info,
})
- return HttpResponseServerError(t.render(c), mimetype='text/html')
+ return HttpResponseServerError(t.iter_render(c), mimetype='text/html')
def technical_404_response(request, exception):
"Create a technical 404 error response. The exception should be the Http404."
@@ -160,7 +160,7 @@ def technical_404_response(request, exception):
'request_protocol': request.is_secure() and "https" or "http",
'settings': get_safe_settings(),
})
- return HttpResponseNotFound(t.render(c), mimetype='text/html')
+ return HttpResponseNotFound(t.iter_render(c), mimetype='text/html')
def empty_urlconf(request):
"Create an empty URLconf 404 error response."
@@ -168,7 +168,7 @@ def empty_urlconf(request):
c = Context({
'project_name': settings.SETTINGS_MODULE.split('.')[0]
})
- return HttpResponseNotFound(t.render(c), mimetype='text/html')
+ return HttpResponseNotFound(t.iter_render(c), mimetype='text/html')
def _get_lines_from_file(filename, lineno, context_lines, loader=None, module_name=None):
"""
diff --git a/django/views/defaults.py b/django/views/defaults.py
index 701aebabd6..aea54c963f 100644
--- a/django/views/defaults.py
+++ b/django/views/defaults.py
@@ -76,7 +76,7 @@ def page_not_found(request, template_name='404.html'):
The path of the requested URL (e.g., '/app/pages/bad_page/')
"""
t = loader.get_template(template_name) # You need to create a 404.html template.
- return http.HttpResponseNotFound(t.render(RequestContext(request, {'request_path': request.path})))
+ return http.HttpResponseNotFound(t.iter_render(RequestContext(request, {'request_path': request.path})))
def server_error(request, template_name='500.html'):
"""
@@ -86,4 +86,4 @@ def server_error(request, template_name='500.html'):
Context: None
"""
t = loader.get_template(template_name) # You need to create a 500.html template.
- return http.HttpResponseServerError(t.render(Context({})))
+ return http.HttpResponseServerError(t.iter_render(Context({})))
diff --git a/django/views/generic/create_update.py b/django/views/generic/create_update.py
index 28987f7544..d1b8e34037 100644
--- a/django/views/generic/create_update.py
+++ b/django/views/generic/create_update.py
@@ -68,7 +68,7 @@ def create_object(request, model, template_name=None,
c[key] = value()
else:
c[key] = value
- return HttpResponse(t.render(c))
+ return HttpResponse(t.iter_render(c))
def update_object(request, model, object_id=None, slug=None,
slug_field=None, template_name=None, template_loader=loader,
@@ -141,7 +141,7 @@ def update_object(request, model, object_id=None, slug=None,
c[key] = value()
else:
c[key] = value
- response = HttpResponse(t.render(c))
+ response = HttpResponse(t.iter_render(c))
populate_xheaders(request, response, model, getattr(object, object._meta.pk.attname))
return response
@@ -195,6 +195,6 @@ def delete_object(request, model, post_delete_redirect,
c[key] = value()
else:
c[key] = value
- response = HttpResponse(t.render(c))
+ response = HttpResponse(t.iter_render(c))
populate_xheaders(request, response, model, getattr(object, object._meta.pk.attname))
return response
diff --git a/django/views/generic/date_based.py b/django/views/generic/date_based.py
index d13c0293be..d4941388dd 100644
--- a/django/views/generic/date_based.py
+++ b/django/views/generic/date_based.py
@@ -44,7 +44,7 @@ def archive_index(request, queryset, date_field, num_latest=15,
c[key] = value()
else:
c[key] = value
- return HttpResponse(t.render(c), mimetype=mimetype)
+ return HttpResponse(t.iter_render(c), mimetype=mimetype)
def archive_year(request, year, queryset, date_field, template_name=None,
template_loader=loader, extra_context=None, allow_empty=False,
@@ -92,7 +92,7 @@ def archive_year(request, year, queryset, date_field, template_name=None,
c[key] = value()
else:
c[key] = value
- return HttpResponse(t.render(c), mimetype=mimetype)
+ return HttpResponse(t.iter_render(c), mimetype=mimetype)
def archive_month(request, year, month, queryset, date_field,
month_format='%b', template_name=None, template_loader=loader,
@@ -158,7 +158,7 @@ def archive_month(request, year, month, queryset, date_field,
c[key] = value()
else:
c[key] = value
- return HttpResponse(t.render(c), mimetype=mimetype)
+ return HttpResponse(t.iter_render(c), mimetype=mimetype)
def archive_week(request, year, week, queryset, date_field,
template_name=None, template_loader=loader,
@@ -206,7 +206,7 @@ def archive_week(request, year, week, queryset, date_field,
c[key] = value()
else:
c[key] = value
- return HttpResponse(t.render(c), mimetype=mimetype)
+ return HttpResponse(t.iter_render(c), mimetype=mimetype)
def archive_day(request, year, month, day, queryset, date_field,
month_format='%b', day_format='%d', template_name=None,
@@ -270,7 +270,7 @@ def archive_day(request, year, month, day, queryset, date_field,
c[key] = value()
else:
c[key] = value
- return HttpResponse(t.render(c), mimetype=mimetype)
+ return HttpResponse(t.iter_render(c), mimetype=mimetype)
def archive_today(request, **kwargs):
"""
@@ -339,6 +339,6 @@ def object_detail(request, year, month, day, queryset, date_field,
c[key] = value()
else:
c[key] = value
- response = HttpResponse(t.render(c), mimetype=mimetype)
+ response = HttpResponse(t.iter_render(c), mimetype=mimetype)
populate_xheaders(request, response, model, getattr(obj, obj._meta.pk.name))
return response
diff --git a/django/views/generic/list_detail.py b/django/views/generic/list_detail.py
index 16d55202da..b2a68d61f1 100644
--- a/django/views/generic/list_detail.py
+++ b/django/views/generic/list_detail.py
@@ -84,7 +84,7 @@ def object_list(request, queryset, paginate_by=None, page=None,
model = queryset.model
template_name = "%s/%s_list.html" % (model._meta.app_label, model._meta.object_name.lower())
t = template_loader.get_template(template_name)
- return HttpResponse(t.render(c), mimetype=mimetype)
+ return HttpResponse(t.iter_render(c), mimetype=mimetype)
def object_detail(request, queryset, object_id=None, slug=None,
slug_field=None, template_name=None, template_name_field=None,
@@ -126,6 +126,6 @@ def object_detail(request, queryset, object_id=None, slug=None,
c[key] = value()
else:
c[key] = value
- response = HttpResponse(t.render(c), mimetype=mimetype)
+ response = HttpResponse(t.iter_render(c), mimetype=mimetype)
populate_xheaders(request, response, model, getattr(obj, obj._meta.pk.name))
return response
diff --git a/django/views/generic/simple.py b/django/views/generic/simple.py
index 69a494931e..f4afb07aa0 100644
--- a/django/views/generic/simple.py
+++ b/django/views/generic/simple.py
@@ -15,7 +15,7 @@ def direct_to_template(request, template, extra_context={}, mimetype=None, **kwa
dictionary[key] = value
c = RequestContext(request, dictionary)
t = loader.get_template(template)
- return HttpResponse(t.render(c), mimetype=mimetype)
+ return HttpResponse(t.iter_render(c), mimetype=mimetype)
def redirect_to(request, url, **kwargs):
"""
diff --git a/django/views/static.py b/django/views/static.py
index 3ec4ca14a1..1e99c8c50a 100644
--- a/django/views/static.py
+++ b/django/views/static.py
@@ -92,7 +92,7 @@ def directory_index(path, fullpath):
'directory' : path + '/',
'file_list' : files,
})
- return HttpResponse(t.render(c))
+ return HttpResponse(t.iter_render(c))
def was_modified_since(header=None, mtime=0, size=0):
"""
diff --git a/docs/templates_python.txt b/docs/templates_python.txt
index f3e2f2c64b..c967df1a49 100644
--- a/docs/templates_python.txt
+++ b/docs/templates_python.txt
@@ -219,13 +219,13 @@ be replaced with the name of the invalid variable.
While ``TEMPLATE_STRING_IF_INVALID`` can be a useful debugging tool,
it is a bad idea to turn it on as a 'development default'.
-
+
Many templates, including those in the Admin site, rely upon the
silence of the template system when a non-existent variable is
encountered. If you assign a value other than ``''`` to
``TEMPLATE_STRING_IF_INVALID``, you will experience rendering
problems with these templates and sites.
-
+
Generally, ``TEMPLATE_STRING_IF_INVALID`` should only be enabled
in order to debug a specific template problem, then cleared
once debugging is complete.
@@ -693,14 +693,15 @@ how the compilation works and how the rendering works.
When Django compiles a template, it splits the raw template text into
''nodes''. Each node is an instance of ``django.template.Node`` and has
-a ``render()`` method. A compiled template is, simply, a list of ``Node``
-objects. When you call ``render()`` on a compiled template object, the template
-calls ``render()`` on each ``Node`` in its node list, with the given context.
-The results are all concatenated together to form the output of the template.
+either a ``render()`` or ``iter_render()`` method. A compiled template is,
+simply, a list of ``Node`` objects. When you call ``render()`` on a compiled
+template object, the template calls ``render()`` on each ``Node`` in its node
+list, with the given context. The results are all concatenated together to
+form the output of the template.
Thus, to define a custom template tag, you specify how the raw template tag is
converted into a ``Node`` (the compilation function), and what the node's
-``render()`` method does.
+``render()`` or ``iter_render()`` method does.
Writing the compilation function
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -770,7 +771,8 @@ Writing the renderer
~~~~~~~~~~~~~~~~~~~~
The second step in writing custom tags is to define a ``Node`` subclass that
-has a ``render()`` method.
+has a ``render()`` method (we will discuss the ``iter_render()`` alternative
+in `Improving rendering speed`_, below).
Continuing the above example, we need to define ``CurrentTimeNode``::
@@ -874,7 +876,7 @@ current context, available in the ``render`` method::
def __init__(self, date_to_be_formatted, format_string):
self.date_to_be_formatted = date_to_be_formatted
self.format_string = format_string
-
+
def render(self, context):
try:
actual_date = resolve_variable(self.date_to_be_formatted, context)
@@ -1175,6 +1177,48 @@ For more examples of complex rendering, see the source code for ``{% if %}``,
.. _configuration:
+Improving rendering speed
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+For most practical purposes, the ``render()`` method on a ``Node`` will be
+sufficient and the simplest way to implement a new tag. However, if your
+template tag is expected to produce large strings via ``render()``, you can
+speed up the rendering process (and reduce memory usage) using iterative
+rendering via the ``iter_render()`` method.
+
+The ``iter_render()`` method should either be an iterator that yields string
+chunks, one at a time, or a method that returns a sequence of string chunks.
+The template renderer will join the successive chunks together when creating
+the final output. The improvement over the ``render()`` method here is that
+you do not need to create one large string containing all the output of the
+``Node``, instead you can produce the output in smaller chunks.
+
+By way of example, here's a trivial ``Node`` subclass that simply returns the
+contents of a file it is given::
+
+ class FileNode(Node):
+ def __init__(self, filename):
+ self.filename = filename
+
+ def iter_render(self):
+ for line in file(self.filename):
+ yield line
+
+For very large files, the full file contents will never be read entirely into
+memory when this tag is used, which is a useful optimisation.
+
+If you define an ``iter_render()`` method on your ``Node`` subclass, you do
+not need to define a ``render()`` method. The reverse is true as well: the
+default ``Node.iter_render()`` method will call your ``render()`` method if
+necessary. A useful side-effect of this is that you can develop a new tag
+using ``render()`` and producing all the output at once, which is easy to
+debug. Then you can rewrite the method as an iterator, rename it to
+``iter_render()`` and everything will still work.
+
+It is compulsory, however, to define *either* ``render()`` or ``iter_render()``
+in your subclass. If you omit them both, a ``TypeError`` will be raised when
+the code is imported.
+
Configuring the template system in standalone mode
==================================================
@@ -1206,3 +1250,4 @@ is of obvious interest.
.. _settings file: ../settings/#using-settings-without-the-django-settings-module-environment-variable
.. _settings documentation: ../settings/
+