Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.8/site-packages/tornado/template.py: 21%

4# Licensed under the Apache License, Version 2.0 (the "License"); you may

5# not use this file except in compliance with the License. You may obtain

6# a copy of the License at

8# http://www.apache.org/licenses/LICENSE-2.0

10# Unless required by applicable law or agreed to in writing, software

11# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT

12# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the

13# License for the specific language governing permissions and limitations

14# under the License.

16"""A simple template system that compiles templates to Python code.

18Basic usage looks like::

20 t = template.Template("<html>{{ myvalue }}</html>")

21 print(t.generate(myvalue="XXX"))

23`Loader` is a class that loads templates from a root directory and caches

24the compiled templates::

26 loader = template.Loader("/home/btaylor")

27 print(loader.load("test.html").generate(myvalue="XXX"))

29We compile all templates to raw Python. Error-reporting is currently... uh,

30interesting. Syntax for the templates::

32 ### base.html

33 <html>

34 <head>

35 <title>{% block title %}Default title{% end %}</title>

36 </head>

37 <body>

38 <ul>

39 {% for student in students %}

40 {% block student %}

41 <li>{{ escape(student.name) }}</li>

42 {% end %}

43 {% end %}

44 </ul>

45 </body>

46 </html>

48 ### bold.html

49 {% extends "base.html" %}

51 {% block title %}A bolder title{% end %}

53 {% block student %}

54 <li><span style="bold">{{ escape(student.name) }}</span></li>

55 {% end %}

57Unlike most other template systems, we do not put any restrictions on the

58expressions you can include in your statements. ``if`` and ``for`` blocks get

59translated exactly into Python, so you can do complex expressions like::

61 {% for student in [p for p in people if p.student and p.age > 23] %}

62 <li>{{ escape(student.name) }}</li>

63 {% end %}

65Translating directly to Python means you can apply functions to expressions

66easily, like the ``escape()`` function in the examples above. You can pass

67functions in to your template just like any other variable

68(In a `.RequestHandler`, override `.RequestHandler.get_template_namespace`)::

70 ### Python code

71 def add(x, y):

72 return x + y

73 template.execute(add=add)

75 ### The template

76 {{ add(1, 2) }}

78We provide the functions `escape() <.xhtml_escape>`, `.url_escape()`,

79`.json_encode()`, and `.squeeze()` to all templates by default.

81Typical applications do not create `Template` or `Loader` instances by

82hand, but instead use the `~.RequestHandler.render` and

83`~.RequestHandler.render_string` methods of

84`tornado.web.RequestHandler`, which load templates automatically based

85on the ``template_path`` `.Application` setting.

87Variable names beginning with ``_tt_`` are reserved by the template

88system and should not be used by application code.

90Syntax Reference

91----------------

93Template expressions are surrounded by double curly braces: ``{{ ... }}``.

94The contents may be any python expression, which will be escaped according

95to the current autoescape setting and inserted into the output. Other

96template directives use ``{% %}``.

98To comment out a section so that it is omitted from the output, surround it

99with ``{# ... #}``.

100

101

102To include a literal ``{{``, ``{%``, or ``{#`` in the output, escape them as

103``{{!``, ``{%!``, and ``{#!``, respectively.

104

105

106``{% apply *function* %}...{% end %}``

107 Applies a function to the output of all template code between ``apply``

108 and ``end``::

109

110 {% apply linkify %}{{name}} said: {{message}}{% end %}

111

112 Note that as an implementation detail apply blocks are implemented

113 as nested functions and thus may interact strangely with variables

114 set via ``{% set %}``, or the use of ``{% break %}`` or ``{% continue %}``

115 within loops.

116

117``{% autoescape *function* %}``

118 Sets the autoescape mode for the current file. This does not affect

119 other files, even those referenced by ``{% include %}``. Note that

120 autoescaping can also be configured globally, at the `.Application`

121 or `Loader`.::

122

123 {% autoescape xhtml_escape %}

124 {% autoescape None %}

125

126``{% block *name* %}...{% end %}``

127 Indicates a named, replaceable block for use with ``{% extends %}``.

128 Blocks in the parent template will be replaced with the contents of

129 the same-named block in a child template.::

130

131

132 <title>{% block title %}Default title{% end %}</title>

133

134

135 {% extends "base.html" %}

136 {% block title %}My page title{% end %}

137

138``{% comment ... %}``

139 A comment which will be removed from the template output. Note that

140 there is no ``{% end %}`` tag; the comment goes from the word ``comment``

141 to the closing ``%}`` tag.

142

143``{% extends *filename* %}``

144 Inherit from another template. Templates that use ``extends`` should

145 contain one or more ``block`` tags to replace content from the parent

146 template. Anything in the child template not contained in a ``block``

147 tag will be ignored. For an example, see the ``{% block %}`` tag.

148

149``{% for *var* in *expr* %}...{% end %}``

150 Same as the python ``for`` statement. ``{% break %}`` and

151 ``{% continue %}`` may be used inside the loop.

152

153``{% from *x* import *y* %}``

154 Same as the python ``import`` statement.

155

156``{% if *condition* %}...{% elif *condition* %}...{% else %}...{% end %}``

157 Conditional statement - outputs the first section whose condition is

158 true. (The ``elif`` and ``else`` sections are optional)

159

160``{% import *module* %}``

161 Same as the python ``import`` statement.

162

163``{% include *filename* %}``

164 Includes another template file. The included file can see all the local

165 variables as if it were copied directly to the point of the ``include``

166 directive (the ``{% autoescape %}`` directive is an exception).

167 Alternately, ``{% module Template(filename, **kwargs) %}`` may be used

168 to include another template with an isolated namespace.

169

170``{% module *expr* %}``

171 Renders a `~tornado.web.UIModule`. The output of the ``UIModule`` is

172 not escaped::

173

174 {% module Template("foo.html", arg=42) %}

175

176 ``UIModules`` are a feature of the `tornado.web.RequestHandler`

177 class (and specifically its ``render`` method) and will not work

178 when the template system is used on its own in other contexts.

179

180``{% raw *expr* %}``

181 Outputs the result of the given expression without autoescaping.

182

183``{% set *x* = *y* %}``

184 Sets a local variable.

185

186``{% try %}...{% except %}...{% else %}...{% finally %}...{% end %}``

187 Same as the python ``try`` statement.

188

189``{% while *condition* %}... {% end %}``

190 Same as the python ``while`` statement. ``{% break %}`` and

191 ``{% continue %}`` may be used inside the loop.

192

193``{% whitespace *mode* %}``

194 Sets the whitespace mode for the remainder of the current file

195 (or until the next ``{% whitespace %}`` directive). See

196 `filter_whitespace` for available options. New in Tornado 4.3.

197"""

198

199import datetime

200from io import StringIO

201import linecache

202import os.path

203import posixpath

204import re

205import threading

206

207from tornado import escape

208from tornado.log import app_log

209from tornado.util import ObjectDict, exec_in, unicode_type

210

211from typing import Any, Union, Callable, List, Dict, Iterable, Optional, TextIO

212import typing

213

214if typing.TYPE_CHECKING:

215 from typing import Tuple, ContextManager # noqa: F401

216

217_DEFAULT_AUTOESCAPE = "xhtml_escape"

218

219

220class _UnsetMarker:

221 pass

222

223

224_UNSET = _UnsetMarker()

225

226

227def filter_whitespace(mode: str, text: str) -> str:

228 """Transform whitespace in ``text`` according to ``mode``.

229

230 Available modes are:

231

232 * ``all``: Return all whitespace unmodified.

233 * ``single``: Collapse consecutive whitespace with a single whitespace

234 character, preserving newlines.

235 * ``oneline``: Collapse all runs of whitespace into a single space

236 character, removing all newlines in the process.

237

238 .. versionadded:: 4.3

239 """

240 if mode == "all":

241 return text

242 elif mode == "single":

243 text = re.sub(r"([\t ]+)", " ", text)

244 text = re.sub(r"(\s*\n\s*)", "\n", text)

245 return text

246 elif mode == "oneline":

247 return re.sub(r"(\s+)", " ", text)

248 else:

249 raise Exception("invalid whitespace mode %s" % mode)

250

251

252class Template(object):

253 """A compiled template.

254

255 We compile into Python from the given template_string. You can generate

256 the template from variables with generate().

257 """

258

259 # note that the constructor's signature is not extracted with

260 # autodoc because _UNSET looks like garbage. When changing

261 # this signature update website/sphinx/template.rst too.

262 def __init__(

263 self,

264 template_string: Union[str, bytes],

265 name: str = "<string>",

266 loader: Optional["BaseLoader"] = None,

267 compress_whitespace: Union[bool, _UnsetMarker] = _UNSET,

268 autoescape: Optional[Union[str, _UnsetMarker]] = _UNSET,

269 whitespace: Optional[str] = None,

270 ) -> None:

271 """Construct a Template.

272

273 :arg str template_string: the contents of the template file.

274 :arg str name: the filename from which the template was loaded

275 (used for error message).

276 :arg tornado.template.BaseLoader loader: the `~tornado.template.BaseLoader` responsible

277 for this template, used to resolve ``{% include %}`` and ``{% extend %}`` directives.

278 :arg bool compress_whitespace: Deprecated since Tornado 4.3.

279 Equivalent to ``whitespace="single"`` if true and

280 ``whitespace="all"`` if false.

281 :arg str autoescape: The name of a function in the template

282 namespace, or ``None`` to disable escaping by default.

283 :arg str whitespace: A string specifying treatment of whitespace;

284 see `filter_whitespace` for options.

285

286 .. versionchanged:: 4.3

287 Added ``whitespace`` parameter; deprecated ``compress_whitespace``.

288 """

289 self.name = escape.native_str(name)

290

291 if compress_whitespace is not _UNSET:

292 # Convert deprecated compress_whitespace (bool) to whitespace (str).

293 if whitespace is not None:

294 raise Exception("cannot set both whitespace and compress_whitespace")

295 whitespace = "single" if compress_whitespace else "all"

296 if whitespace is None:

297 if loader and loader.whitespace:

298 whitespace = loader.whitespace

299 else:

300 # Whitespace defaults by filename.

301 if name.endswith(".html") or name.endswith(".js"):

302 whitespace = "single"

303 else:

304 whitespace = "all"

305 # Validate the whitespace setting.

306 assert whitespace is not None

307 filter_whitespace(whitespace, "")

308

309 if not isinstance(autoescape, _UnsetMarker):

310 self.autoescape = autoescape # type: Optional[str]

311 elif loader:

312 self.autoescape = loader.autoescape

313 else:

314 self.autoescape = _DEFAULT_AUTOESCAPE

315

316 self.namespace = loader.namespace if loader else {}

317 reader = _TemplateReader(name, escape.native_str(template_string), whitespace)

318 self.file = _File(self, _parse(reader, self))

319 self.code = self._generate_python(loader)

320 self.loader = loader

321 try:

322 # Under python2.5, the fake filename used here must match

323 # the module name used in __name__ below.

324 # The dont_inherit flag prevents template.py's future imports

325 # from being applied to the generated code.

326 self.compiled = compile(

327 escape.to_unicode(self.code),

328 "%s.generated.py" % self.name.replace(".", "_"),

329 "exec",

330 dont_inherit=True,

331 )

332 except Exception:

333 formatted_code = _format_code(self.code).rstrip()

334 app_log.error("%s code:\n%s", self.name, formatted_code)

335 raise

336

337 def generate(self, **kwargs: Any) -> bytes:

338 """Generate this template with the given arguments."""

339 namespace = {

340 "escape": escape.xhtml_escape,

341 "xhtml_escape": escape.xhtml_escape,

342 "url_escape": escape.url_escape,

343 "json_encode": escape.json_encode,

344 "squeeze": escape.squeeze,

345 "linkify": escape.linkify,

346 "datetime": datetime,

347 "_tt_utf8": escape.utf8, # for internal use

348 "_tt_string_types": (unicode_type, bytes),

349 # __name__ and __loader__ allow the traceback mechanism to find

350 # the generated source code.

351 "__name__": self.name.replace(".", "_"),

352 "__loader__": ObjectDict(get_source=lambda name: self.code),

353 }

354 namespace.update(self.namespace)

355 namespace.update(kwargs)

356 exec_in(self.compiled, namespace)

357 execute = typing.cast(Callable[[], bytes], namespace["_tt_execute"])

358 # Clear the traceback module's cache of source data now that

359 # we've generated a new template (mainly for this module's

360 # unittests, where different tests reuse the same name).

361 linecache.clearcache()

362 return execute()

363

364 def _generate_python(self, loader: Optional["BaseLoader"]) -> str:

365 buffer = StringIO()

366 try:

367 # named_blocks maps from names to _NamedBlock objects

368 named_blocks = {} # type: Dict[str, _NamedBlock]

369 ancestors = self._get_ancestors(loader)

370 ancestors.reverse()

371 for ancestor in ancestors:

372 ancestor.find_named_blocks(loader, named_blocks)

373 writer = _CodeWriter(buffer, named_blocks, loader, ancestors[0].template)

374 ancestors[0].generate(writer)

375 return buffer.getvalue()

376 finally:

377 buffer.close()

378

379 def _get_ancestors(self, loader: Optional["BaseLoader"]) -> List["_File"]:

380 ancestors = [self.file]

381 for chunk in self.file.body.chunks:

382 if isinstance(chunk, _ExtendsBlock):

383 if not loader:

384 raise ParseError(

385 "{% extends %} block found, but no " "template loader"

386 )

387 template = loader.load(chunk.name, self.name)

388 ancestors.extend(template._get_ancestors(loader))

389 return ancestors

390

391

392class BaseLoader(object):

393 """Base class for template loaders.

394

395 You must use a template loader to use template constructs like

396 ``{% extends %}`` and ``{% include %}``. The loader caches all

397 templates after they are loaded the first time.

398 """

399

400 def __init__(

401 self,

402 autoescape: str = _DEFAULT_AUTOESCAPE,

403 namespace: Optional[Dict[str, Any]] = None,

404 whitespace: Optional[str] = None,

405 ) -> None:

406 """Construct a template loader.

407

408 :arg str autoescape: The name of a function in the template

409 namespace, such as "xhtml_escape", or ``None`` to disable

410 autoescaping by default.

411 :arg dict namespace: A dictionary to be added to the default template

412 namespace, or ``None``.

413 :arg str whitespace: A string specifying default behavior for

414 whitespace in templates; see `filter_whitespace` for options.

415 Default is "single" for files ending in ".html" and ".js" and

416 "all" for other files.

417

418 .. versionchanged:: 4.3

419 Added ``whitespace`` parameter.

420 """

421 self.autoescape = autoescape

422 self.namespace = namespace or {}

423 self.whitespace = whitespace

424 self.templates = {} # type: Dict[str, Template]

425 # self.lock protects self.templates. It's a reentrant lock

426 # because templates may load other templates via `include` or

427 # `extends`. Note that thanks to the GIL this code would be safe

428 # even without the lock, but could lead to wasted work as multiple

429 # threads tried to compile the same template simultaneously.

430 self.lock = threading.RLock()

431

432 def reset(self) -> None:

433 """Resets the cache of compiled templates."""

434 with self.lock:

435 self.templates = {}

436

437 def resolve_path(self, name: str, parent_path: Optional[str] = None) -> str:

438 """Converts a possibly-relative path to absolute (used internally)."""

439 raise NotImplementedError()

440

441 def load(self, name: str, parent_path: Optional[str] = None) -> Template:

442 """Loads a template."""

443 name = self.resolve_path(name, parent_path=parent_path)

444 with self.lock:

445 if name not in self.templates:

446 self.templates[name] = self._create_template(name)

447 return self.templates[name]

448

449 def _create_template(self, name: str) -> Template:

450 raise NotImplementedError()

451

452

453class Loader(BaseLoader):

454 """A template loader that loads from a single root directory."""

455

456 def __init__(self, root_directory: str, **kwargs: Any) -> None:

457 super().__init__(**kwargs)

458 self.root = os.path.abspath(root_directory)

459

460 def resolve_path(self, name: str, parent_path: Optional[str] = None) -> str:

461 if (

462 parent_path

463 and not parent_path.startswith("<")

464 and not parent_path.startswith("/")

465 and not name.startswith("/")

466 ):

467 current_path = os.path.join(self.root, parent_path)

468 file_dir = os.path.dirname(os.path.abspath(current_path))

469 relative_path = os.path.abspath(os.path.join(file_dir, name))

470 if relative_path.startswith(self.root):

471 name = relative_path[len(self.root) + 1 :]

472 return name

473

474 def _create_template(self, name: str) -> Template:

475 path = os.path.join(self.root, name)

476 with open(path, "rb") as f:

477 template = Template(f.read(), name=name, loader=self)

478 return template

479

480

481class DictLoader(BaseLoader):

482 """A template loader that loads from a dictionary."""

483

484 def __init__(self, dict: Dict[str, str], **kwargs: Any) -> None:

485 super().__init__(**kwargs)

486 self.dict = dict

487

488 def resolve_path(self, name: str, parent_path: Optional[str] = None) -> str:

489 if (

490 parent_path

491 and not parent_path.startswith("<")

492 and not parent_path.startswith("/")

493 and not name.startswith("/")

494 ):

495 file_dir = posixpath.dirname(parent_path)

496 name = posixpath.normpath(posixpath.join(file_dir, name))

497 return name

498

499 def _create_template(self, name: str) -> Template:

500 return Template(self.dict[name], name=name, loader=self)

501

502

503class _Node(object):

504 def each_child(self) -> Iterable["_Node"]:

505 return ()

506

507 def generate(self, writer: "_CodeWriter") -> None:

508 raise NotImplementedError()

509

510 def find_named_blocks(

511 self, loader: Optional[BaseLoader], named_blocks: Dict[str, "_NamedBlock"]

512 ) -> None:

513 for child in self.each_child():

514 child.find_named_blocks(loader, named_blocks)

515

516

517class _File(_Node):

518 def __init__(self, template: Template, body: "_ChunkList") -> None:

519 self.template = template

520 self.body = body

521 self.line = 0

522

523 def generate(self, writer: "_CodeWriter") -> None:

524 writer.write_line("def _tt_execute():", self.line)

525 with writer.indent():

526 writer.write_line("_tt_buffer = []", self.line)

527 writer.write_line("_tt_append = _tt_buffer.append", self.line)

528 self.body.generate(writer)

529 writer.write_line("return _tt_utf8('').join(_tt_buffer)", self.line)

530

531 def each_child(self) -> Iterable["_Node"]:

532 return (self.body,)

533

534

535class _ChunkList(_Node):

536 def __init__(self, chunks: List[_Node]) -> None:

537 self.chunks = chunks

538

539 def generate(self, writer: "_CodeWriter") -> None:

540 for chunk in self.chunks:

541 chunk.generate(writer)

542

543 def each_child(self) -> Iterable["_Node"]:

544 return self.chunks

545

546

547class _NamedBlock(_Node):

548 def __init__(self, name: str, body: _Node, template: Template, line: int) -> None:

549 self.name = name

550 self.body = body

551 self.template = template

552 self.line = line

553

554 def each_child(self) -> Iterable["_Node"]:

555 return (self.body,)

556

557 def generate(self, writer: "_CodeWriter") -> None:

558 block = writer.named_blocks[self.name]

559 with writer.include(block.template, self.line):

560 block.body.generate(writer)

561

562 def find_named_blocks(

563 self, loader: Optional[BaseLoader], named_blocks: Dict[str, "_NamedBlock"]

564 ) -> None:

565 named_blocks[self.name] = self

566 _Node.find_named_blocks(self, loader, named_blocks)

567

568

569class _ExtendsBlock(_Node):

570 def __init__(self, name: str) -> None:

571 self.name = name

572

573

574class _IncludeBlock(_Node):

575 def __init__(self, name: str, reader: "_TemplateReader", line: int) -> None:

576 self.name = name

577 self.template_name = reader.name

578 self.line = line

579

580 def find_named_blocks(

581 self, loader: Optional[BaseLoader], named_blocks: Dict[str, _NamedBlock]

582 ) -> None:

583 assert loader is not None

584 included = loader.load(self.name, self.template_name)

585 included.file.find_named_blocks(loader, named_blocks)

586

587 def generate(self, writer: "_CodeWriter") -> None:

588 assert writer.loader is not None

589 included = writer.loader.load(self.name, self.template_name)

590 with writer.include(included, self.line):

591 included.file.body.generate(writer)

592

593

594class _ApplyBlock(_Node):

595 def __init__(self, method: str, line: int, body: _Node) -> None:

596 self.method = method

597 self.line = line

598 self.body = body

599

600 def each_child(self) -> Iterable["_Node"]:

601 return (self.body,)

602

603 def generate(self, writer: "_CodeWriter") -> None:

604 method_name = "_tt_apply%d" % writer.apply_counter

605 writer.apply_counter += 1

606 writer.write_line("def %s():" % method_name, self.line)

607 with writer.indent():

608 writer.write_line("_tt_buffer = []", self.line)

609 writer.write_line("_tt_append = _tt_buffer.append", self.line)

610 self.body.generate(writer)

611 writer.write_line("return _tt_utf8('').join(_tt_buffer)", self.line)

612 writer.write_line(

613 "_tt_append(_tt_utf8(%s(%s())))" % (self.method, method_name), self.line

614 )

615

616

617class _ControlBlock(_Node):

618 def __init__(self, statement: str, line: int, body: _Node) -> None:

619 self.statement = statement

620 self.line = line

621 self.body = body

622

623 def each_child(self) -> Iterable[_Node]:

624 return (self.body,)

625

626 def generate(self, writer: "_CodeWriter") -> None:

627 writer.write_line("%s:" % self.statement, self.line)

628 with writer.indent():

629 self.body.generate(writer)

630 # Just in case the body was empty

631 writer.write_line("pass", self.line)

632

633

634class _IntermediateControlBlock(_Node):

635 def __init__(self, statement: str, line: int) -> None:

636 self.statement = statement

637 self.line = line

638

639 def generate(self, writer: "_CodeWriter") -> None:

640 # In case the previous block was empty

641 writer.write_line("pass", self.line)

642 writer.write_line("%s:" % self.statement, self.line, writer.indent_size() - 1)

643

644

645class _Statement(_Node):

646 def __init__(self, statement: str, line: int) -> None:

647 self.statement = statement

648 self.line = line

649

650 def generate(self, writer: "_CodeWriter") -> None:

651 writer.write_line(self.statement, self.line)

652

653

654class _Expression(_Node):

655 def __init__(self, expression: str, line: int, raw: bool = False) -> None:

656 self.expression = expression

657 self.line = line

658 self.raw = raw

659

660 def generate(self, writer: "_CodeWriter") -> None:

661 writer.write_line("_tt_tmp = %s" % self.expression, self.line)

662 writer.write_line(

663 "if isinstance(_tt_tmp, _tt_string_types):" " _tt_tmp = _tt_utf8(_tt_tmp)",

664 self.line,

665 )

666 writer.write_line("else: _tt_tmp = _tt_utf8(str(_tt_tmp))", self.line)

667 if not self.raw and writer.current_template.autoescape is not None:

668 # In python3 functions like xhtml_escape return unicode,

669 # so we have to convert to utf8 again.

670 writer.write_line(

671 "_tt_tmp = _tt_utf8(%s(_tt_tmp))" % writer.current_template.autoescape,

672 self.line,

673 )

674 writer.write_line("_tt_append(_tt_tmp)", self.line)

675

676

677class _Module(_Expression):

678 def __init__(self, expression: str, line: int) -> None:

679 super().__init__("_tt_modules." + expression, line, raw=True)

680

681

682class _Text(_Node):

683 def __init__(self, value: str, line: int, whitespace: str) -> None:

684 self.value = value

685 self.line = line

686 self.whitespace = whitespace

687

688 def generate(self, writer: "_CodeWriter") -> None:

689 value = self.value

690

691 # Compress whitespace if requested, with a crude heuristic to avoid

692 # altering preformatted whitespace.

693 if "<pre>" not in value:

694 value = filter_whitespace(self.whitespace, value)

695

696 if value:

697 writer.write_line("_tt_append(%r)" % escape.utf8(value), self.line)

698

699

700class ParseError(Exception):

701 """Raised for template syntax errors.

702

703 ``ParseError`` instances have ``filename`` and ``lineno`` attributes

704 indicating the position of the error.

705

706 .. versionchanged:: 4.3

707 Added ``filename`` and ``lineno`` attributes.

708 """

709

710 def __init__(

711 self, message: str, filename: Optional[str] = None, lineno: int = 0

712 ) -> None:

713 self.message = message

714 # The names "filename" and "lineno" are chosen for consistency

715 # with python SyntaxError.

716 self.filename = filename

717 self.lineno = lineno

718

719 def __str__(self) -> str:

720 return "%s at %s:%d" % (self.message, self.filename, self.lineno)

721

722

723class _CodeWriter(object):

724 def __init__(

725 self,

726 file: TextIO,

727 named_blocks: Dict[str, _NamedBlock],

728 loader: Optional[BaseLoader],

729 current_template: Template,

730 ) -> None:

731 self.file = file

732 self.named_blocks = named_blocks

733 self.loader = loader

734 self.current_template = current_template

735 self.apply_counter = 0

736 self.include_stack = [] # type: List[Tuple[Template, int]]

737 self._indent = 0

738

739 def indent_size(self) -> int:

740 return self._indent

741

742 def indent(self) -> "ContextManager":

743 class Indenter(object):

744 def __enter__(_) -> "_CodeWriter":

745 self._indent += 1

746 return self

747

748 def __exit__(_, *args: Any) -> None:

749 assert self._indent > 0

750 self._indent -= 1

751

752 return Indenter()

753

754 def include(self, template: Template, line: int) -> "ContextManager":

755 self.include_stack.append((self.current_template, line))

756 self.current_template = template

757

758 class IncludeTemplate(object):

759 def __enter__(_) -> "_CodeWriter":

760 return self

761

762 def __exit__(_, *args: Any) -> None:

763 self.current_template = self.include_stack.pop()[0]

764

765 return IncludeTemplate()

766

767 def write_line(

768 self, line: str, line_number: int, indent: Optional[int] = None

769 ) -> None:

770 if indent is None:

771 indent = self._indent

772 line_comment = " # %s:%d" % (self.current_template.name, line_number)

773 if self.include_stack:

774 ancestors = [

775 "%s:%d" % (tmpl.name, lineno) for (tmpl, lineno) in self.include_stack

776 ]

777 line_comment += " (via %s)" % ", ".join(reversed(ancestors))

778 print(" " * indent + line + line_comment, file=self.file)

779

780

781class _TemplateReader(object):

782 def __init__(self, name: str, text: str, whitespace: str) -> None:

783 self.name = name

784 self.text = text

785 self.whitespace = whitespace

786 self.line = 1

787 self.pos = 0

788

789 def find(self, needle: str, start: int = 0, end: Optional[int] = None) -> int:

790 assert start >= 0, start

791 pos = self.pos

792 start += pos

793 if end is None:

794 index = self.text.find(needle, start)

795 else:

796 end += pos

797 assert end >= start

798 index = self.text.find(needle, start, end)

799 if index != -1:

800 index -= pos

801 return index

802

803 def consume(self, count: Optional[int] = None) -> str:

804 if count is None:

805 count = len(self.text) - self.pos

806 newpos = self.pos + count

807 self.line += self.text.count("\n", self.pos, newpos)

808 s = self.text[self.pos : newpos]

809 self.pos = newpos

810 return s

811

812 def remaining(self) -> int:

813 return len(self.text) - self.pos

814

815 def __len__(self) -> int:

816 return self.remaining()

817

818 def __getitem__(self, key: Union[int, slice]) -> str:

819 if isinstance(key, slice):

820 size = len(self)

821 start, stop, step = key.indices(size)

822 if start is None:

823 start = self.pos

824 else:

825 start += self.pos

826 if stop is not None:

827 stop += self.pos

828 return self.text[slice(start, stop, step)]

829 elif key < 0:

830 return self.text[key]

831 else:

832 return self.text[self.pos + key]

833

834 def __str__(self) -> str:

835 return self.text[self.pos :]

836

837 def raise_parse_error(self, msg: str) -> None:

838 raise ParseError(msg, self.name, self.line)

839

840

841def _format_code(code: str) -> str:

842 lines = code.splitlines()

843 format = "%%%dd %%s\n" % len(repr(len(lines) + 1))

844 return "".join([format % (i + 1, line) for (i, line) in enumerate(lines)])

845

846

847def _parse(

848 reader: _TemplateReader,

849 template: Template,

850 in_block: Optional[str] = None,

851 in_loop: Optional[str] = None,

852) -> _ChunkList:

853 body = _ChunkList([])

854 while True:

855 # Find next template directive

856 curly = 0

857 while True:

858 curly = reader.find("{", curly)

859 if curly == -1 or curly + 1 == reader.remaining():

860 # EOF

861 if in_block:

862 reader.raise_parse_error(

863 "Missing {%% end %%} block for %s" % in_block

864 )

865 body.chunks.append(

866 _Text(reader.consume(), reader.line, reader.whitespace)

867 )

868 return body

869 # If the first curly brace is not the start of a special token,

870 # start searching from the character after it

871 if reader[curly + 1] not in ("{", "%", "#"):

872 curly += 1

873 continue

874 # When there are more than 2 curlies in a row, use the

875 # innermost ones. This is useful when generating languages

876 # like latex where curlies are also meaningful

877 if (

878 curly + 2 < reader.remaining()

879 and reader[curly + 1] == "{"

880 and reader[curly + 2] == "{"

881 ):

882 curly += 1

883 continue

884 break

885

886 # Append any text before the special token

887 if curly > 0:

888 cons = reader.consume(curly)

889 body.chunks.append(_Text(cons, reader.line, reader.whitespace))

890

891 start_brace = reader.consume(2)

892 line = reader.line

893

894 # Template directives may be escaped as "{{!" or "{%!".

895 # In this case output the braces and consume the "!".

896 # This is especially useful in conjunction with jquery templates,

897 # which also use double braces.

898 if reader.remaining() and reader[0] == "!":

899 reader.consume(1)

900 body.chunks.append(_Text(start_brace, line, reader.whitespace))

901 continue

902

903 # Comment

904 if start_brace == "{#":

905 end = reader.find("#}")

906 if end == -1:

907 reader.raise_parse_error("Missing end comment #}")

908 contents = reader.consume(end).strip()

909 reader.consume(2)

910 continue

911

912 # Expression

913 if start_brace == "{{":

914 end = reader.find("}}")

915 if end == -1:

916 reader.raise_parse_error("Missing end expression }}")

917 contents = reader.consume(end).strip()

918 reader.consume(2)

919 if not contents:

920 reader.raise_parse_error("Empty expression")

921 body.chunks.append(_Expression(contents, line))

922 continue

923

924 # Block

925 assert start_brace == "{%", start_brace

926 end = reader.find("%}")

927 if end == -1:

928 reader.raise_parse_error("Missing end block %}")

929 contents = reader.consume(end).strip()

930 reader.consume(2)

931 if not contents:

932 reader.raise_parse_error("Empty block tag ({% %})")

933

934 operator, space, suffix = contents.partition(" ")

935 suffix = suffix.strip()

936

937 # Intermediate ("else", "elif", etc) blocks

938 intermediate_blocks = {

939 "else": set(["if", "for", "while", "try"]),

940 "elif": set(["if"]),

941 "except": set(["try"]),

942 "finally": set(["try"]),

943 }

944 allowed_parents = intermediate_blocks.get(operator)

945 if allowed_parents is not None:

946 if not in_block:

947 reader.raise_parse_error(

948 "%s outside %s block" % (operator, allowed_parents)

949 )

950 if in_block not in allowed_parents:

951 reader.raise_parse_error(

952 "%s block cannot be attached to %s block" % (operator, in_block)

953 )

954 body.chunks.append(_IntermediateControlBlock(contents, line))

955 continue

956

957 # End tag

958 elif operator == "end":

959 if not in_block:

960 reader.raise_parse_error("Extra {% end %} block")

961 return body

962

963 elif operator in (

964 "extends",

965 "include",

966 "set",

967 "import",

968 "from",

969 "comment",

970 "autoescape",

971 "whitespace",

972 "raw",

973 "module",

974 ):

975 if operator == "comment":

976 continue

977 if operator == "extends":

978 suffix = suffix.strip('"').strip("'")

979 if not suffix:

980 reader.raise_parse_error("extends missing file path")

981 block = _ExtendsBlock(suffix) # type: _Node

982 elif operator in ("import", "from"):

983 if not suffix:

984 reader.raise_parse_error("import missing statement")

985 block = _Statement(contents, line)

986 elif operator == "include":

987 suffix = suffix.strip('"').strip("'")

988 if not suffix:

989 reader.raise_parse_error("include missing file path")

990 block = _IncludeBlock(suffix, reader, line)

991 elif operator == "set":

992 if not suffix:

993 reader.raise_parse_error("set missing statement")

994 block = _Statement(suffix, line)

995 elif operator == "autoescape":

996 fn = suffix.strip() # type: Optional[str]

997 if fn == "None":

998 fn = None

999 template.autoescape = fn

1000 continue

1001 elif operator == "whitespace":

1002 mode = suffix.strip()

1003 # Validate the selected mode

1004 filter_whitespace(mode, "")

1005 reader.whitespace = mode

1006 continue

1007 elif operator == "raw":

1008 block = _Expression(suffix, line, raw=True)

1009 elif operator == "module":

1010 block = _Module(suffix, line)

1011 body.chunks.append(block)

1012 continue

1013

1014 elif operator in ("apply", "block", "try", "if", "for", "while"):

1015 # parse inner body recursively

1016 if operator in ("for", "while"):

1017 block_body = _parse(reader, template, operator, operator)

1018 elif operator == "apply":

1019 # apply creates a nested function so syntactically it's not

1020 # in the loop.

1021 block_body = _parse(reader, template, operator, None)

1022 else:

1023 block_body = _parse(reader, template, operator, in_loop)

1024

1025 if operator == "apply":

1026 if not suffix:

1027 reader.raise_parse_error("apply missing method name")

1028 block = _ApplyBlock(suffix, line, block_body)

1029 elif operator == "block":

1030 if not suffix:

1031 reader.raise_parse_error("block missing name")

1032 block = _NamedBlock(suffix, block_body, template, line)

1033 else:

1034 block = _ControlBlock(contents, line, block_body)

1035 body.chunks.append(block)

1036 continue

1037

1038 elif operator in ("break", "continue"):

1039 if not in_loop:

1040 reader.raise_parse_error(

1041 "%s outside %s block" % (operator, set(["for", "while"]))

1042 )

1043 body.chunks.append(_Statement(contents, line))

1044 continue

1045

1046 else:

1047 reader.raise_parse_error("unknown operator: %r" % operator)