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swh/core/api/negotiation.py
| Show All 21 Lines | |||||
| # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | ||||
| # SOFTWARE. | # SOFTWARE. | ||||
| # | # | ||||
| from collections import defaultdict | from collections import defaultdict | ||||
| from decorator import decorator | from decorator import decorator | ||||
| from inspect import getcallargs | from inspect import getcallargs | ||||
| from typing import Any, List, Optional, Callable, \ | from typing import Any, List, Optional, Callable, Type, NoReturn, DefaultDict | ||||
| Type, NoReturn, DefaultDict | |||||
| from requests import Response | from requests import Response | ||||
| class FormatterNotFound(Exception): | class FormatterNotFound(Exception): | ||||
| pass | pass | ||||
| class Formatter: | class Formatter: | ||||
| format: Optional[str] = None | format: Optional[str] = None | ||||
| mimetypes: List[str] = [] | mimetypes: List[str] = [] | ||||
| def __init__(self, request_mimetype: Optional[str] = None) -> None: | def __init__(self, request_mimetype: Optional[str] = None) -> None: | ||||
| if request_mimetype is None or request_mimetype not in self.mimetypes: | if request_mimetype is None or request_mimetype not in self.mimetypes: | ||||
| try: | try: | ||||
| self.response_mimetype = self.mimetypes[0] | self.response_mimetype = self.mimetypes[0] | ||||
| except IndexError: | except IndexError: | ||||
| raise NotImplementedError( | raise NotImplementedError( | ||||
| "%s.mimetypes should be a non-empty list" % | "%s.mimetypes should be a non-empty list" % self.__class__.__name__ | ||||
| self.__class__.__name__) | ) | ||||
| else: | else: | ||||
| self.response_mimetype = request_mimetype | self.response_mimetype = request_mimetype | ||||
| def configure(self) -> None: | def configure(self) -> None: | ||||
| pass | pass | ||||
| def render(self, obj: Any) -> bytes: | def render(self, obj: Any) -> bytes: | ||||
| raise NotImplementedError( | raise NotImplementedError( | ||||
| "render() should be implemented by Formatter subclasses") | "render() should be implemented by Formatter subclasses" | ||||
| ) | |||||
| def __call__(self, obj: Any) -> Response: | def __call__(self, obj: Any) -> Response: | ||||
| return self._make_response( | return self._make_response( | ||||
| self.render(obj), content_type=self.response_mimetype) | self.render(obj), content_type=self.response_mimetype | ||||
| ) | |||||
| def _make_response(self, body: bytes, content_type: str) -> Response: | def _make_response(self, body: bytes, content_type: str) -> Response: | ||||
| raise NotImplementedError( | raise NotImplementedError( | ||||
| "_make_response() should be implemented by " | "_make_response() should be implemented by " | ||||
| "framework-specific subclasses of Formatter" | "framework-specific subclasses of Formatter" | ||||
| ) | ) | ||||
| class Negotiator: | class Negotiator: | ||||
| def __init__(self, func: Callable[..., Any]) -> None: | def __init__(self, func: Callable[..., Any]) -> None: | ||||
| self.func = func | self.func = func | ||||
| self._formatters: List[Type[Formatter]] = [] | self._formatters: List[Type[Formatter]] = [] | ||||
| self._formatters_by_format: DefaultDict = defaultdict(list) | self._formatters_by_format: DefaultDict = defaultdict(list) | ||||
| self._formatters_by_mimetype: DefaultDict = defaultdict(list) | self._formatters_by_mimetype: DefaultDict = defaultdict(list) | ||||
| def __call__(self, *args, **kwargs) -> Response: | def __call__(self, *args, **kwargs) -> Response: | ||||
| result = self.func(*args, **kwargs) | result = self.func(*args, **kwargs) | ||||
| format = getcallargs(self.func, *args, **kwargs).get('format') | format = getcallargs(self.func, *args, **kwargs).get('format') | ||||
| mimetype = self.best_mimetype() | mimetype = self.best_mimetype() | ||||
| try: | try: | ||||
| formatter = self.get_formatter(format, mimetype) | formatter = self.get_formatter(format, mimetype) | ||||
| except FormatterNotFound as e: | except FormatterNotFound as e: | ||||
| return self._abort(404, str(e)) | return self._abort(404, str(e)) | ||||
| return formatter(result) | return formatter(result) | ||||
| def register_formatter(self, formatter: Type[Formatter], | def register_formatter(self, formatter: Type[Formatter], *args, **kwargs) -> None: | ||||
| *args, **kwargs) -> None: | |||||
| self._formatters.append(formatter) | self._formatters.append(formatter) | ||||
| self._formatters_by_format[formatter.format].append( | self._formatters_by_format[formatter.format].append((formatter, args, kwargs)) | ||||
| (formatter, args, kwargs)) | |||||
| for mimetype in formatter.mimetypes: | for mimetype in formatter.mimetypes: | ||||
| self._formatters_by_mimetype[mimetype].append( | self._formatters_by_mimetype[mimetype].append((formatter, args, kwargs)) | ||||
| (formatter, args, kwargs)) | |||||
| def get_formatter(self, format: Optional[str] = None, | def get_formatter( | ||||
| mimetype: Optional[str] = None) -> Formatter: | self, format: Optional[str] = None, mimetype: Optional[str] = None | ||||
| ) -> Formatter: | |||||
| if format is None and mimetype is None: | if format is None and mimetype is None: | ||||
| raise TypeError( | raise TypeError( | ||||
| "get_formatter expects one of the 'format' or 'mimetype' " | "get_formatter expects one of the 'format' or 'mimetype' " | ||||
| "kwargs to be set") | "kwargs to be set" | ||||
| ) | |||||
| if format is not None: | if format is not None: | ||||
| try: | try: | ||||
| # the first added will be the most specific | # the first added will be the most specific | ||||
| formatter_cls, args, kwargs = ( | formatter_cls, args, kwargs = self._formatters_by_format[format][0] | ||||
| self._formatters_by_format[format][0]) | |||||
| except IndexError: | except IndexError: | ||||
| raise FormatterNotFound( | raise FormatterNotFound("Formatter for format '%s' not found!" % format) | ||||
| "Formatter for format '%s' not found!" % format) | |||||
| elif mimetype is not None: | elif mimetype is not None: | ||||
| try: | try: | ||||
| # the first added will be the most specific | # the first added will be the most specific | ||||
| formatter_cls, args, kwargs = ( | formatter_cls, args, kwargs = self._formatters_by_mimetype[mimetype][0] | ||||
| self._formatters_by_mimetype[mimetype][0]) | |||||
| except IndexError: | except IndexError: | ||||
| raise FormatterNotFound( | raise FormatterNotFound( | ||||
| "Formatter for mimetype '%s' not found!" % mimetype) | "Formatter for mimetype '%s' not found!" % mimetype | ||||
| ) | |||||
| formatter = formatter_cls(request_mimetype=mimetype) | formatter = formatter_cls(request_mimetype=mimetype) | ||||
| formatter.configure(*args, **kwargs) | formatter.configure(*args, **kwargs) | ||||
| return formatter | return formatter | ||||
| @property | @property | ||||
| def accept_mimetypes(self) -> List[str]: | def accept_mimetypes(self) -> List[str]: | ||||
| return [m for f in self._formatters for m in f.mimetypes] | return [m for f in self._formatters for m in f.mimetypes] | ||||
| def best_mimetype(self) -> str: | def best_mimetype(self) -> str: | ||||
| raise NotImplementedError( | raise NotImplementedError( | ||||
| "best_mimetype() should be implemented in " | "best_mimetype() should be implemented in " | ||||
| "framework-specific subclasses of Negotiator" | "framework-specific subclasses of Negotiator" | ||||
| ) | ) | ||||
| def _abort(self, status_code: int, err: Optional[str] = None) -> NoReturn: | def _abort(self, status_code: int, err: Optional[str] = None) -> NoReturn: | ||||
| raise NotImplementedError( | raise NotImplementedError( | ||||
| "_abort() should be implemented in framework-specific " | "_abort() should be implemented in framework-specific " | ||||
| "subclasses of Negotiator" | "subclasses of Negotiator" | ||||
| ) | ) | ||||
| def negotiate(negotiator_cls: Type[Negotiator], formatter_cls: Type[Formatter], | def negotiate( | ||||
| *args, **kwargs) -> Callable: | negotiator_cls: Type[Negotiator], formatter_cls: Type[Formatter], *args, **kwargs | ||||
| ) -> Callable: | |||||
| def _negotiate(f, *args, **kwargs): | def _negotiate(f, *args, **kwargs): | ||||
| return f.negotiator(*args, **kwargs) | return f.negotiator(*args, **kwargs) | ||||
| def decorate(f): | def decorate(f): | ||||
| if not hasattr(f, 'negotiator'): | if not hasattr(f, 'negotiator'): | ||||
| f.negotiator = negotiator_cls(f) | f.negotiator = negotiator_cls(f) | ||||
| f.negotiator.register_formatter(formatter_cls, *args, **kwargs) | f.negotiator.register_formatter(formatter_cls, *args, **kwargs) | ||||
| return decorator(_negotiate, f) | return decorator(_negotiate, f) | ||||
| return decorate | return decorate | ||||