| # runtime.py |
| # Copyright (C) 2006, 2007, 2008, 2009, 2010 Michael Bayer mike_mp@zzzcomputing.com |
| # |
| # This module is part of Mako and is released under |
| # the MIT License: http://www.opensource.org/licenses/mit-license.php |
| |
| """provides runtime services for templates, including Context, |
| Namespace, and various helper functions.""" |
| |
| from mako import exceptions, util |
| import __builtin__, inspect, sys |
| |
| class Context(object): |
| """Provides runtime namespace, output buffer, and various |
| callstacks for templates. |
| |
| See :ref:`runtime_toplevel` for detail on the usage of |
| :class:`.Context`. |
| |
| """ |
| |
| def __init__(self, buffer, **data): |
| self._buffer_stack = [buffer] |
| |
| # original data, minus the builtins |
| self._orig = data |
| |
| # the context data which includes builtins |
| self._data = __builtin__.__dict__.copy() |
| self._data.update(data) |
| self._kwargs = data.copy() |
| self._with_template = None |
| self._outputting_as_unicode = None |
| self.namespaces = {} |
| |
| # "capture" function which proxies to the |
| # generic "capture" function |
| self._data['capture'] = util.partial(capture, self) |
| |
| # "caller" stack used by def calls with content |
| self.caller_stack = self._data['caller'] = CallerStack() |
| |
| @property |
| def lookup(self): |
| """Return the :class:`.TemplateLookup` associated |
| with this :class:`.Context`. |
| |
| """ |
| return self._with_template.lookup |
| |
| @property |
| def kwargs(self): |
| """Return the dictionary of keyword argments associated with this |
| :class:`.Context`. |
| |
| """ |
| return self._kwargs.copy() |
| |
| def push_caller(self, caller): |
| """Pushes a 'caller' callable onto the callstack for |
| this :class:`.Context`.""" |
| |
| |
| self.caller_stack.append(caller) |
| |
| def pop_caller(self): |
| """Pops a 'caller' callable onto the callstack for this |
| :class:`.Context`.""" |
| |
| del self.caller_stack[-1] |
| |
| def keys(self): |
| """Return a list of all names established in this :class:`.Context`.""" |
| |
| return self._data.keys() |
| |
| def __getitem__(self, key): |
| return self._data[key] |
| |
| def _push_writer(self): |
| """push a capturing buffer onto this Context and return |
| the new writer function.""" |
| |
| buf = util.FastEncodingBuffer() |
| self._buffer_stack.append(buf) |
| return buf.write |
| |
| def _pop_buffer_and_writer(self): |
| """pop the most recent capturing buffer from this Context |
| and return the current writer after the pop. |
| |
| """ |
| |
| buf = self._buffer_stack.pop() |
| return buf, self._buffer_stack[-1].write |
| |
| def _push_buffer(self): |
| """push a capturing buffer onto this Context.""" |
| |
| self._push_writer() |
| |
| def _pop_buffer(self): |
| """pop the most recent capturing buffer from this Context.""" |
| |
| return self._buffer_stack.pop() |
| |
| def get(self, key, default=None): |
| """Return a value from this :class:`.Context`.""" |
| |
| return self._data.get(key, default) |
| |
| def write(self, string): |
| """Write a string to this :class:`.Context` object's |
| underlying output buffer.""" |
| |
| self._buffer_stack[-1].write(string) |
| |
| def writer(self): |
| """Return the current writer function""" |
| |
| return self._buffer_stack[-1].write |
| |
| def _copy(self): |
| c = Context.__new__(Context) |
| c._buffer_stack = self._buffer_stack |
| c._data = self._data.copy() |
| c._orig = self._orig |
| c._kwargs = self._kwargs |
| c._with_template = self._with_template |
| c._outputting_as_unicode = self._outputting_as_unicode |
| c.namespaces = self.namespaces |
| c.caller_stack = self.caller_stack |
| return c |
| |
| def locals_(self, d): |
| """create a new :class:`.Context` with a copy of this |
| :class:`Context`'s current state, updated with the given dictionary.""" |
| |
| if len(d) == 0: |
| return self |
| c = self._copy() |
| c._data.update(d) |
| return c |
| |
| def _clean_inheritance_tokens(self): |
| """create a new copy of this :class:`.Context`. with |
| tokens related to inheritance state removed.""" |
| |
| c = self._copy() |
| x = c._data |
| x.pop('self', None) |
| x.pop('parent', None) |
| x.pop('next', None) |
| return c |
| |
| class CallerStack(list): |
| def __init__(self): |
| self.nextcaller = None |
| def __nonzero__(self): |
| return self._get_caller() and True or False |
| def _get_caller(self): |
| return self[-1] |
| def __getattr__(self, key): |
| return getattr(self._get_caller(), key) |
| def _push_frame(self): |
| self.append(self.nextcaller or None) |
| self.nextcaller = None |
| def _pop_frame(self): |
| self.nextcaller = self.pop() |
| |
| |
| class Undefined(object): |
| """Represents an undefined value in a template. |
| |
| All template modules have a constant value |
| ``UNDEFINED`` present which is an instance of this |
| object. |
| |
| """ |
| def __str__(self): |
| raise NameError("Undefined") |
| def __nonzero__(self): |
| return False |
| |
| UNDEFINED = Undefined() |
| |
| class _NSAttr(object): |
| def __init__(self, parent): |
| self.__parent = parent |
| def __getattr__(self, key): |
| ns = self.__parent |
| while ns: |
| if hasattr(ns.module, key): |
| return getattr(ns.module, key) |
| else: |
| ns = ns.inherits |
| raise AttributeError(key) |
| |
| class Namespace(object): |
| """Provides access to collections of rendering methods, which |
| can be local, from other templates, or from imported modules. |
| |
| To access a particular rendering method referenced by a |
| :class:`.Namespace`, use plain attribute access:: |
| |
| ${some_namespace.foo(x, y, z)} |
| |
| :class:`.Namespace` also contains several built-in attributes |
| described here. |
| |
| """ |
| |
| def __init__(self, name, context, module=None, |
| template=None, templateuri=None, |
| callables=None, inherits=None, |
| populate_self=True, calling_uri=None): |
| self.name = name |
| if module is not None: |
| mod = __import__(module) |
| for token in module.split('.')[1:]: |
| mod = getattr(mod, token) |
| self._module = mod |
| else: |
| self._module = None |
| if templateuri is not None: |
| self.template = _lookup_template(context, templateuri, calling_uri) |
| self._templateuri = self.template.module._template_uri |
| else: |
| self.template = template |
| if self.template is not None: |
| self._templateuri = self.template.module._template_uri |
| self.context = context |
| self.inherits = inherits |
| if callables is not None: |
| self.callables = dict([(c.func_name, c) for c in callables]) |
| else: |
| self.callables = None |
| if populate_self and self.template is not None: |
| lclcallable, lclcontext = \ |
| _populate_self_namespace(context, self.template, self_ns=self) |
| |
| template = None |
| """The :class:`.Template` object referenced by this |
| :class:`.Namespace`, if any. |
| |
| """ |
| |
| context = None |
| """The :class:`.Context` object for this namespace. |
| |
| Namespaces are often created with copies of contexts that |
| contain slightly different data, particularly in inheritance |
| scenarios. Using the :class:`.Context` off of a :class:`.Namespace` one |
| can traverse an entire chain of templates that inherit from |
| one-another. |
| |
| """ |
| |
| |
| @property |
| def module(self): |
| """The Python module referenced by this Namespace. |
| |
| If the namespace references a :class:`.Template`, then |
| this module is the equivalent of ``template.module``, |
| i.e. the generated module for the template. |
| |
| """ |
| return self._module or self.template.module |
| |
| @property |
| def filename(self): |
| """The path of the filesystem file used for this |
| Namespace's module or template. |
| |
| If this is a pure module-based |
| Namespace, this evaluates to ``module.__file__``. If a |
| template-based namespace, it evaluates to the original |
| template file location. |
| |
| """ |
| if self._module: |
| return self._module.__file__ |
| else: |
| return self.template.filename |
| |
| @property |
| def uri(self): |
| """The uri for this Namespace's template. |
| |
| I.e. whatever was sent to :meth:`.TemplateLookup.get_template()`. |
| |
| This is the equivalent of :attr:`Template.uri`. |
| |
| """ |
| return self.template.uri |
| |
| @property |
| def attr(self): |
| """Access module level attributes by name. |
| |
| This accessor allows templates to supply "scalar" |
| attributes which are particularly handy in inheritance |
| relationships. See the example in |
| :ref:`inheritance_toplevel`. |
| |
| """ |
| if not hasattr(self, '_attr'): |
| self._attr = _NSAttr(self) |
| return self._attr |
| |
| def get_namespace(self, uri): |
| """Return a :class:`.Namespace` corresponding to the given uri. |
| |
| If the given uri is a relative uri (i.e. it does not |
| contain ia leading slash ``/``), the uri is adjusted to |
| be relative to the uri of the namespace itself. This |
| method is therefore mostly useful off of the built-in |
| ``local`` namespace, described in :ref:`namespace_local` |
| |
| In |
| most cases, a template wouldn't need this function, and |
| should instead use the ``<%namespace>`` tag to load |
| namespaces. However, since all ``<%namespace>`` tags are |
| evaulated before the body of a template ever runs, |
| this method can be used to locate namespaces using |
| expressions that were generated within the body code of |
| the template, or to conditionally use a particular |
| namespace. |
| |
| """ |
| key = (self, uri) |
| if self.context.namespaces.has_key(key): |
| return self.context.namespaces[key] |
| else: |
| ns = Namespace(uri, self.context._copy(), |
| templateuri=uri, |
| calling_uri=self._templateuri) |
| self.context.namespaces[key] = ns |
| return ns |
| |
| def get_template(self, uri): |
| """Return a :class:`.Template` from the given uri. |
| |
| The uri resolution is relative to the uri of this :class:`.Namespace` |
| object's :class:`.Template`. |
| |
| """ |
| return _lookup_template(self.context, uri, self._templateuri) |
| |
| def get_cached(self, key, **kwargs): |
| """Return a value from the :class:`.Cache` referenced by this |
| :class:`.Namespace` object's :class:`.Template`. |
| |
| The advantage to this method versus direct access to the |
| :class:`.Cache` is that the configuration parameters |
| declared in ``<%page>`` take effect here, thereby calling |
| up the same configured backend as that configured |
| by ``<%page>``. |
| |
| """ |
| |
| if self.template: |
| if not self.template.cache_enabled: |
| createfunc = kwargs.get('createfunc', None) |
| if createfunc: |
| return createfunc() |
| else: |
| return None |
| |
| if self.template.cache_dir: |
| kwargs.setdefault('data_dir', self.template.cache_dir) |
| if self.template.cache_type: |
| kwargs.setdefault('type', self.template.cache_type) |
| if self.template.cache_url: |
| kwargs.setdefault('url', self.template.cache_url) |
| return self.cache.get(key, **kwargs) |
| |
| @property |
| def cache(self): |
| """Return the :class:`.Cache` object referenced by this :class:`.Namespace` object's |
| :class:`.Template`. |
| |
| """ |
| return self.template.cache |
| |
| def include_file(self, uri, **kwargs): |
| """Include a file at the given uri""" |
| |
| _include_file(self.context, uri, self._templateuri, **kwargs) |
| |
| def _populate(self, d, l): |
| for ident in l: |
| if ident == '*': |
| for (k, v) in self._get_star(): |
| d[k] = v |
| else: |
| d[ident] = getattr(self, ident) |
| |
| def _get_star(self): |
| if self.callables: |
| for key in self.callables: |
| yield (key, self.callables[key]) |
| if self.template: |
| def get(key): |
| callable_ = self.template._get_def_callable(key) |
| return util.partial(callable_, self.context) |
| for k in self.template.module._exports: |
| yield (k, get(k)) |
| if self._module: |
| def get(key): |
| callable_ = getattr(self._module, key) |
| return util.partial(callable_, self.context) |
| for k in dir(self._module): |
| if k[0] != '_': |
| yield (k, get(k)) |
| |
| def __getattr__(self, key): |
| if self.callables and key in self.callables: |
| return self.callables[key] |
| |
| if self.template and self.template.has_def(key): |
| callable_ = self.template._get_def_callable(key) |
| return util.partial(callable_, self.context) |
| |
| if self._module and hasattr(self._module, key): |
| callable_ = getattr(self._module, key) |
| return util.partial(callable_, self.context) |
| |
| if self.inherits is not None: |
| return getattr(self.inherits, key) |
| raise AttributeError( |
| "Namespace '%s' has no member '%s'" % |
| (self.name, key)) |
| |
| def supports_caller(func): |
| """Apply a caller_stack compatibility decorator to a plain |
| Python function. |
| |
| See the example in :ref:`namespaces_python_modules`. |
| |
| """ |
| |
| def wrap_stackframe(context, *args, **kwargs): |
| context.caller_stack._push_frame() |
| try: |
| return func(context, *args, **kwargs) |
| finally: |
| context.caller_stack._pop_frame() |
| return wrap_stackframe |
| |
| def capture(context, callable_, *args, **kwargs): |
| """Execute the given template def, capturing the output into |
| a buffer. |
| |
| See the example in :ref:`namespaces_python_modules`. |
| |
| """ |
| |
| if not callable(callable_): |
| raise exceptions.RuntimeException( |
| "capture() function expects a callable as " |
| "its argument (i.e. capture(func, *args, **kwargs))" |
| ) |
| context._push_buffer() |
| try: |
| callable_(*args, **kwargs) |
| finally: |
| buf = context._pop_buffer() |
| return buf.getvalue() |
| |
| def _decorate_toplevel(fn): |
| def decorate_render(render_fn): |
| def go(context, *args, **kw): |
| def y(*args, **kw): |
| return render_fn(context, *args, **kw) |
| try: |
| y.__name__ = render_fn.__name__[7:] |
| except TypeError: |
| # < Python 2.4 |
| pass |
| return fn(y)(context, *args, **kw) |
| return go |
| return decorate_render |
| |
| def _decorate_inline(context, fn): |
| def decorate_render(render_fn): |
| dec = fn(render_fn) |
| def go(*args, **kw): |
| return dec(context, *args, **kw) |
| return go |
| return decorate_render |
| |
| def _include_file(context, uri, calling_uri, **kwargs): |
| """locate the template from the given uri and include it in |
| the current output.""" |
| |
| template = _lookup_template(context, uri, calling_uri) |
| (callable_, ctx) = _populate_self_namespace( |
| context._clean_inheritance_tokens(), |
| template) |
| callable_(ctx, **_kwargs_for_include(callable_, context._orig, **kwargs)) |
| |
| def _inherit_from(context, uri, calling_uri): |
| """called by the _inherit method in template modules to set |
| up the inheritance chain at the start of a template's |
| execution.""" |
| |
| if uri is None: |
| return None |
| template = _lookup_template(context, uri, calling_uri) |
| self_ns = context['self'] |
| ih = self_ns |
| while ih.inherits is not None: |
| ih = ih.inherits |
| lclcontext = context.locals_({'next':ih}) |
| ih.inherits = Namespace("self:%s" % template.uri, |
| lclcontext, |
| template = template, |
| populate_self=False) |
| context._data['parent'] = lclcontext._data['local'] = ih.inherits |
| callable_ = getattr(template.module, '_mako_inherit', None) |
| if callable_ is not None: |
| ret = callable_(template, lclcontext) |
| if ret: |
| return ret |
| |
| gen_ns = getattr(template.module, '_mako_generate_namespaces', None) |
| if gen_ns is not None: |
| gen_ns(context) |
| return (template.callable_, lclcontext) |
| |
| def _lookup_template(context, uri, relativeto): |
| lookup = context._with_template.lookup |
| if lookup is None: |
| raise exceptions.TemplateLookupException( |
| "Template '%s' has no TemplateLookup associated" % |
| context._with_template.uri) |
| uri = lookup.adjust_uri(uri, relativeto) |
| try: |
| return lookup.get_template(uri) |
| except exceptions.TopLevelLookupException, e: |
| raise exceptions.TemplateLookupException(str(e)) |
| |
| def _populate_self_namespace(context, template, self_ns=None): |
| if self_ns is None: |
| self_ns = Namespace('self:%s' % template.uri, |
| context, template=template, |
| populate_self=False) |
| context._data['self'] = context._data['local'] = self_ns |
| if hasattr(template.module, '_mako_inherit'): |
| ret = template.module._mako_inherit(template, context) |
| if ret: |
| return ret |
| return (template.callable_, context) |
| |
| def _render(template, callable_, args, data, as_unicode=False): |
| """create a Context and return the string |
| output of the given template and template callable.""" |
| |
| if as_unicode: |
| buf = util.FastEncodingBuffer(unicode=True) |
| elif template.output_encoding: |
| buf = util.FastEncodingBuffer( |
| unicode=as_unicode, |
| encoding=template.output_encoding, |
| errors=template.encoding_errors) |
| else: |
| buf = util.StringIO() |
| context = Context(buf, **data) |
| context._outputting_as_unicode = as_unicode |
| context._with_template = template |
| |
| _render_context(template, callable_, context, *args, |
| **_kwargs_for_callable(callable_, data)) |
| return context._pop_buffer().getvalue() |
| |
| def _kwargs_for_callable(callable_, data): |
| argspec = inspect.getargspec(callable_) |
| # for normal pages, **pageargs is usually present |
| if argspec[2]: |
| return data |
| |
| # for rendering defs from the top level, figure out the args |
| namedargs = argspec[0] + [v for v in argspec[1:3] if v is not None] |
| kwargs = {} |
| for arg in namedargs: |
| if arg != 'context' and arg in data and arg not in kwargs: |
| kwargs[arg] = data[arg] |
| return kwargs |
| |
| def _kwargs_for_include(callable_, data, **kwargs): |
| argspec = inspect.getargspec(callable_) |
| namedargs = argspec[0] + [v for v in argspec[1:3] if v is not None] |
| for arg in namedargs: |
| if arg != 'context' and arg in data and arg not in kwargs: |
| kwargs[arg] = data[arg] |
| return kwargs |
| |
| def _render_context(tmpl, callable_, context, *args, **kwargs): |
| import mako.template as template |
| # create polymorphic 'self' namespace for this |
| # template with possibly updated context |
| if not isinstance(tmpl, template.DefTemplate): |
| # if main render method, call from the base of the inheritance stack |
| (inherit, lclcontext) = _populate_self_namespace(context, tmpl) |
| _exec_template(inherit, lclcontext, args=args, kwargs=kwargs) |
| else: |
| # otherwise, call the actual rendering method specified |
| (inherit, lclcontext) = _populate_self_namespace(context, tmpl.parent) |
| _exec_template(callable_, context, args=args, kwargs=kwargs) |
| |
| def _exec_template(callable_, context, args=None, kwargs=None): |
| """execute a rendering callable given the callable, a |
| Context, and optional explicit arguments |
| |
| the contextual Template will be located if it exists, and |
| the error handling options specified on that Template will |
| be interpreted here. |
| """ |
| template = context._with_template |
| if template is not None and \ |
| (template.format_exceptions or template.error_handler): |
| error = None |
| try: |
| callable_(context, *args, **kwargs) |
| except Exception, e: |
| _render_error(template, context, e) |
| except: |
| e = sys.exc_info()[0] |
| _render_error(template, context, e) |
| else: |
| callable_(context, *args, **kwargs) |
| |
| def _render_error(template, context, error): |
| if template.error_handler: |
| result = template.error_handler(context, error) |
| if not result: |
| raise error |
| else: |
| error_template = exceptions.html_error_template() |
| if context._outputting_as_unicode: |
| context._buffer_stack[:] = [util.FastEncodingBuffer(unicode=True)] |
| else: |
| context._buffer_stack[:] = [util.FastEncodingBuffer( |
| error_template.output_encoding, |
| error_template.encoding_errors)] |
| |
| context._with_template = error_template |
| error_template.render_context(context, error=error) |
