| # -*- coding: utf-8 -*- |
| """ |
| jinja2.environment |
| ~~~~~~~~~~~~~~~~~~ |
| |
| Provides a class that holds runtime and parsing time options. |
| |
| :copyright: 2007 by Armin Ronacher. |
| :license: BSD, see LICENSE for more details. |
| """ |
| import sys |
| from jinja2.lexer import Lexer |
| from jinja2.parser import Parser |
| from jinja2.optimizer import optimize |
| from jinja2.compiler import generate |
| from jinja2.runtime import Undefined, TemplateContext |
| from jinja2.debug import translate_exception |
| from jinja2.utils import import_string, LRUCache, Markup |
| from jinja2.defaults import DEFAULT_FILTERS, DEFAULT_TESTS, DEFAULT_NAMESPACE |
| |
| |
| # for direct template usage we have up to ten living environments |
| _spontaneous_environments = LRUCache(10) |
| |
| |
| def get_spontaneous_environment(*args): |
| """Return a new spontaneus environment. A spontaneus environment is an |
| unnamed and unaccessable (in theory) environment that is used for |
| template generated from a string and not from the file system. |
| """ |
| try: |
| env = _spontaneous_environments.get(args) |
| except TypeError: |
| return Environment(*args) |
| if env is not None: |
| return env |
| _spontaneous_environments[args] = env = Environment(*args) |
| return env |
| |
| |
| def template_from_code(environment, code, globals, uptodate=None, |
| template_class=None): |
| """Generate a new template object from code. It's used in the |
| template constructor and the loader `load` implementation. |
| """ |
| t = object.__new__(template_class or environment.template_class) |
| namespace = { |
| 'environment': environment, |
| '__jinja_template__': t |
| } |
| exec code in namespace |
| t.environment = environment |
| t.name = namespace['name'] |
| t.filename = code.co_filename |
| t.root_render_func = namespace['root'] |
| t.blocks = namespace['blocks'] |
| t.globals = globals |
| |
| # debug and loader helpers |
| t._debug_info = namespace['debug_info'] |
| t._uptodate = uptodate |
| |
| return t |
| |
| |
| class Environment(object): |
| """The Jinja environment. |
| |
| The core component of Jinja is the `Environment`. It contains |
| important shared variables like configuration, filters, tests, |
| globals and others. |
| """ |
| |
| #: if this environment is sandboxed. Modifying this variable won't make |
| #: the environment sandboxed though. For a real sandboxed environment |
| #: have a look at jinja2.sandbox |
| sandboxed = False |
| |
| def __init__(self, |
| block_start_string='{%', |
| block_end_string='%}', |
| variable_start_string='{{', |
| variable_end_string='}}', |
| comment_start_string='{#', |
| comment_end_string='#}', |
| line_statement_prefix=None, |
| trim_blocks=False, |
| extensions=(), |
| optimized=True, |
| undefined=Undefined, |
| finalize=unicode, |
| loader=None): |
| # !!Important notice!! |
| # The constructor accepts quite a few arguments that should be |
| # passed by keyword rather than position. However it's important to |
| # not change the order of arguments because it's used at least |
| # internally in those cases: |
| # - spontaneus environments (i18n extension and Template) |
| # - unittests |
| # If parameter changes are required only add parameters at the end |
| # and don't change the arguments (or the defaults!) of the arguments |
| # up to (but excluding) loader. |
| """Here the possible initialization parameters: |
| |
| ========================= ============================================ |
| `block_start_string` the string marking the begin of a block. |
| this defaults to ``'{%'``. |
| `block_end_string` the string marking the end of a block. |
| defaults to ``'%}'``. |
| `variable_start_string` the string marking the begin of a print |
| statement. defaults to ``'{{'``. |
| `comment_start_string` the string marking the begin of a |
| comment. defaults to ``'{#'``. |
| `comment_end_string` the string marking the end of a comment. |
| defaults to ``'#}'``. |
| `line_statement_prefix` If given and a string, this will be used as |
| prefix for line based statements. See the |
| documentation for more details. |
| `trim_blocks` If this is set to ``True`` the first newline |
| after a block is removed (block, not |
| variable tag!). Defaults to ``False``. |
| `extensions` List of Jinja extensions to use. |
| `optimized` should the optimizer be enabled? Default is |
| ``True``. |
| `undefined` a subclass of `Undefined` that is used to |
| represent undefined variables. |
| `finalize` A callable that finalizes the variable. Per |
| default this is `unicode`, other useful |
| builtin finalizers are `escape`. |
| `loader` the loader which should be used. |
| ========================= ============================================ |
| """ |
| |
| # santity checks |
| assert issubclass(undefined, Undefined), 'undefined must be ' \ |
| 'a subclass of undefined because filters depend on it.' |
| assert block_start_string != variable_start_string != \ |
| comment_start_string, 'block, variable and comment ' \ |
| 'start strings must be different' |
| |
| # lexer / parser information |
| self.block_start_string = block_start_string |
| self.block_end_string = block_end_string |
| self.variable_start_string = variable_start_string |
| self.variable_end_string = variable_end_string |
| self.comment_start_string = comment_start_string |
| self.comment_end_string = comment_end_string |
| self.line_statement_prefix = line_statement_prefix |
| self.trim_blocks = trim_blocks |
| |
| # runtime information |
| self.undefined = undefined |
| self.optimized = optimized |
| self.finalize = finalize |
| |
| # defaults |
| self.filters = DEFAULT_FILTERS.copy() |
| self.tests = DEFAULT_TESTS.copy() |
| self.globals = DEFAULT_NAMESPACE.copy() |
| |
| # set the loader provided |
| self.loader = loader |
| |
| # create lexer |
| self.lexer = Lexer(self) |
| |
| # load extensions |
| self.extensions = [] |
| for extension in extensions: |
| if isinstance(extension, basestring): |
| extension = import_string(extension) |
| self.extensions.append(extension(self)) |
| |
| def subscribe(self, obj, argument): |
| """Get an item or attribute of an object.""" |
| try: |
| return getattr(obj, str(argument)) |
| except (AttributeError, UnicodeError): |
| try: |
| return obj[argument] |
| except (TypeError, LookupError): |
| return self.undefined(obj=obj, name=argument) |
| |
| def parse(self, source, name=None): |
| """Parse the sourcecode and return the abstract syntax tree. This tree |
| of nodes is used by the compiler to convert the template into |
| executable source- or bytecode. |
| """ |
| return Parser(self, source, name).parse() |
| |
| def lex(self, source, name=None): |
| """Lex the given sourcecode and return a generator that yields tokens. |
| The stream returned is not usable for Jinja but can be used if |
| Jinja templates should be processed by other tools (for example |
| syntax highlighting etc) |
| |
| The tuples are returned in the form ``(lineno, token, value)``. |
| """ |
| return self.lexer.tokeniter(source, name) |
| |
| def compile(self, source, name=None, filename=None, globals=None, |
| raw=False): |
| """Compile a node or source. The name is the load name of the |
| template after it was joined using `join_path` if necessary, |
| filename is the estimated filename of the template on the file |
| system. If the template came from a database or memory this |
| can be omitted. |
| """ |
| if isinstance(source, basestring): |
| source = self.parse(source, name) |
| if self.optimized: |
| node = optimize(source, self, globals or {}) |
| source = generate(node, self, name, filename) |
| if raw: |
| return source |
| if filename is None: |
| filename = '<template>' |
| elif isinstance(filename, unicode): |
| filename = filename.encode('utf-8') |
| return compile(source, filename, 'exec') |
| |
| def join_path(self, template, parent): |
| """Join a template with the parent. By default all the lookups are |
| relative to the loader root, but if the paths should be relative this |
| function can be used to calculate the real filename.""" |
| return template |
| |
| def get_template(self, name, parent=None, globals=None): |
| """Load a template.""" |
| if self.loader is None: |
| raise TypeError('no loader for this environment specified') |
| if parent is not None: |
| name = self.join_path(name, parent) |
| globals = self.make_globals(globals) |
| return self.loader.load(self, name, globals) |
| |
| def from_string(self, source, globals=None, template_class=None): |
| """Load a template from a string.""" |
| globals = self.make_globals(globals) |
| return template_from_code(self, self.compile(source, globals=globals), |
| globals, template_class) |
| |
| def make_globals(self, d): |
| """Return a dict for the globals.""" |
| if d is None: |
| return self.globals |
| return dict(self.globals, **d) |
| |
| |
| class Template(object): |
| """The central template object. This class represents a compiled template |
| and is used to evaluate it. |
| |
| Normally the template object is generated from an `Environment` but it |
| also has a constructor that makes it possible to create a template |
| instance directly using the constructor. It takes the same arguments as |
| the environment constructor but it's not possible to specify a loader. |
| |
| Every template object has a few methods and members that are guaranteed |
| to exist. However it's important that a template object should be |
| considered immutable. Modifications on the object are not supported. |
| |
| Template objects created from the constructor rather than an environment |
| do have an `environment` attribute that points to a temporary environment |
| that is probably shared with other templates created with the constructor |
| and compatible settings. |
| |
| >>> template = Template('Hello {{ name }}!') |
| >>> template.render(name='John Doe') |
| u'Hello John Doe!' |
| |
| >>> stream = template.stream(name='John Doe') |
| >>> stream.next() |
| u'Hello John Doe!' |
| >>> stream.next() |
| Traceback (most recent call last): |
| ... |
| StopIteration |
| """ |
| |
| def __new__(cls, source, |
| block_start_string='{%', |
| block_end_string='%}', |
| variable_start_string='{{', |
| variable_end_string='}}', |
| comment_start_string='{#', |
| comment_end_string='#}', |
| line_statement_prefix=None, |
| trim_blocks=False, |
| extensions=(), |
| optimized=True, |
| undefined=Undefined, |
| finalize=unicode): |
| env = get_spontaneous_environment( |
| block_start_string, block_end_string, variable_start_string, |
| variable_end_string, comment_start_string, comment_end_string, |
| line_statement_prefix, trim_blocks, tuple(extensions), optimized, |
| undefined, finalize) |
| return env.from_string(source, template_class=cls) |
| |
| def render(self, *args, **kwargs): |
| """Render the template into a string.""" |
| try: |
| return u''.join(self.generate(*args, **kwargs)) |
| except: |
| # hide the `generate` frame |
| exc_type, exc_value, tb = sys.exc_info() |
| raise exc_type, exc_value, tb.tb_next |
| |
| def stream(self, *args, **kwargs): |
| """Return a `TemplateStream` that generates the template.""" |
| try: |
| return TemplateStream(self.generate(*args, **kwargs)) |
| except: |
| # hide the `generate` frame |
| exc_type, exc_value, tb = sys.exc_info() |
| raise exc_type, exc_value, tb.tb_next |
| |
| def generate(self, *args, **kwargs): |
| """Return a generator that generates the template.""" |
| # assemble the context |
| context = dict(*args, **kwargs) |
| |
| # if the environment is using the optimizer locals may never |
| # override globals as optimizations might have happened |
| # depending on values of certain globals. This assertion goes |
| # away if the python interpreter is started with -O |
| if __debug__ and self.environment.optimized: |
| overrides = set(context) & set(self.globals) |
| if overrides: |
| plural = len(overrides) != 1 and 's' or '' |
| raise AssertionError('the per template variable%s %s ' |
| 'override%s global variable%s. ' |
| 'With an enabled optimizer this ' |
| 'will lead to unexpected results.' % |
| (plural, ', '.join(overrides), plural or ' a', plural)) |
| |
| try: |
| for event in self.root_render_func(self.new_context(context)): |
| yield event |
| except: |
| exc_type, exc_value, tb = translate_exception(sys.exc_info()) |
| raise exc_type, exc_value, tb |
| |
| def new_context(self, vars): |
| """Create a new template context for this template.""" |
| return TemplateContext(self.environment, dict(self.globals, **vars), |
| self.name, self.blocks) |
| |
| def include(self, context=None): |
| """Include this template. When passed a template context or dict |
| the template is evaluated in that context and an `IncludedTemplate` |
| object is returned. This object then exposes all the exported |
| variables as attributes and renders the contents of the template |
| when converted to unicode. |
| """ |
| if context is None: |
| context = self.new_context({}) |
| elif isinstance(context, TemplateContext): |
| context = self.new_context(context.get_root()) |
| else: |
| context = self.new_context(context) |
| return IncludedTemplate(self, context) |
| |
| def get_corresponding_lineno(self, lineno): |
| """Return the source line number of a line number in the |
| generated bytecode as they are not in sync. |
| """ |
| for template_line, code_line in reversed(self.debug_info): |
| if code_line <= lineno: |
| return template_line |
| return 1 |
| |
| @property |
| def is_up_to_date(self): |
| """If this variable is `False` there is a newer version available.""" |
| if self._uptodate is None: |
| return True |
| return self._uptodate() |
| |
| @property |
| def debug_info(self): |
| """The debug info mapping.""" |
| return [tuple(map(int, x.split('='))) for x in |
| self._debug_info.split('&')] |
| |
| def __repr__(self): |
| return '<%s %r>' % ( |
| self.__class__.__name__, |
| self.name or '<from string>' |
| ) |
| |
| |
| class IncludedTemplate(object): |
| """Represents an included template.""" |
| |
| def __init__(self, template, context): |
| body = Markup(u''.join(template.root_render_func(context))) |
| self.__dict__.update(context.get_exported()) |
| self._name = template.name |
| self._rendered_body = body |
| |
| __html__ = lambda x: x._rendered_body |
| __unicode__ = lambda x: unicode(x._rendered_body) |
| |
| def __str__(self): |
| return unicode(self._rendered_body).encode('utf-8') |
| |
| def __repr__(self): |
| return '<%s %r>' % ( |
| self.__class__.__name__, |
| self._name |
| ) |
| |
| |
| class TemplateStream(object): |
| """This class wraps a generator returned from `Template.generate` so that |
| it's possible to buffer multiple elements so that it's possible to return |
| them from a WSGI application which flushes after each iteration. |
| """ |
| |
| def __init__(self, gen): |
| self._gen = gen |
| self._next = gen.next |
| self.buffered = False |
| |
| def disable_buffering(self): |
| """Disable the output buffering.""" |
| self._next = self._gen.next |
| self.buffered = False |
| |
| def enable_buffering(self, size=5): |
| """Enable buffering. Buffer `size` items before yielding them.""" |
| if size <= 1: |
| raise ValueError('buffer size too small') |
| |
| def generator(): |
| buf = [] |
| c_size = 0 |
| push = buf.append |
| next = self._gen.next |
| |
| while 1: |
| try: |
| while c_size < size: |
| push(next()) |
| c_size += 1 |
| except StopIteration: |
| if not c_size: |
| raise |
| yield u''.join(buf) |
| del buf[:] |
| c_size = 0 |
| |
| self.buffered = True |
| self._next = generator().next |
| |
| def __iter__(self): |
| return self |
| |
| def next(self): |
| return self._next() |
| |
| |
| # hook in default template class. if anyone reads this comment: ignore that |
| # it's possible to use custom templates ;-) |
| Environment.template_class = Template |
