App

App inherits from _view's ViewApp, which is a base C class for defining the main ASGI entry point. More on that later, though. Most C app functions are called through accessing self inside of an App instance.

App

Bases: ViewApp

Public view.py app object.

Source code in src/view/app.py
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class App(ViewApp):
    """Public view.py app object."""

    def __init__(self, config: Config) -> None:
        """
        Args:
            config: Configuration object to be used. Automatically generated by `new_app`.
        """
        supply_parsers(self)
        self.config = config
        self._set_dev_state(config.dev)
        self._manual_routes: list[Route] = []
        self.routes: list[Route] = []
        self.loaded: bool = False
        self.running = False
        self._docs: DocsType = {}
        self.loaded_routes: list[Route] = []

        Service.log.setLevel(
            config.log.level
            if not isinstance(config.log.level, str)
            else config.log.level.upper()
        )

        if config.dev:
            if os.environ.get("VIEW_PROD") is not None:
                Service.warning("VIEW_PROD is set but dev is set to true")

            format_warnings()
            weakref.finalize(self, self._finalize)

            if config.log.pretty_tracebacks:
                install(show_locals=True)

            rich_handler = sys.excepthook

            def _hook(tp: type[B], value: B, traceback: Traceback) -> None:
                rich_handler(tp, value, traceback)
                os.environ["_VIEW_CANCEL_FINALIZERS"] = "1"

                if isinstance(value, ViewError):
                    if value.hint:
                        print(value.hint)

            sys.excepthook = _hook
            with suppress(UnsupportedOperation):
                faulthandler.enable()
        else:
            os.environ["VIEW_PROD"] = "1"

        if config.log.level == "debug":
            enable_debug()

        self.running = False

    def _finalize(self) -> None:
        if os.environ.get("_VIEW_CANCEL_FINALIZERS"):
            return

        if self.loaded:
            return

        warnings.warn(
            "load() was never called (did you forget to start the app?)"
        )
        split = self.config.app.app_path.split(":", maxsplit=1)

        if len(split) != 2:
            return

        app_name = split[1]

        print(
            make_hint(
                "Add this to your code",
                split[0],
                line=-1,
                prepend=f"\n{app_name}.run()",
            )
        )

    def _push_route(self, route: Route) -> None:
        if route in self._manual_routes:
            return

        self._manual_routes.append(route)

    def _method_wrapper(
        self,
        path: str,
        doc: str | None,
        target: Callable[..., Any],
        # i dont really feel like typing this properly
    ) -> Callable[[RouteOrCallable], Route]:
        def inner(route: RouteOrCallable) -> Route:
            new_route = target(path, doc)(route)
            self._push_route(new_route)
            return new_route

        return inner

    def get(self, path: str, *, doc: str | None = None):
        """Set a GET route."""
        return self._method_wrapper(path, doc, get)

    def post(self, path: str, *, doc: str | None = None):
        """Set a POST route."""
        return self._method_wrapper(path, doc, post)

    def delete(self, path: str, *, doc: str | None = None):
        """Set a DELETE route."""
        return self._method_wrapper(path, doc, delete)

    def patch(self, path: str, *, doc: str | None = None):
        """Set a PATCH route."""
        return self._method_wrapper(path, doc, patch)

    def put(self, path: str, *, doc: str | None = None):
        """Set a PUT route."""
        return self._method_wrapper(path, doc, put)

    def options(self, path: str, *, doc: str | None = None):
        """Set a OPTIONS route."""
        return self._method_wrapper(path, doc, options)

    def query(
        self,
        name: str,
        *tps: type[V],
        doc: str | None = None,
        default: V | None | _NoDefaultType = _NoDefault,
    ):
        """Set a query parameter.

        Args:
            name: Name of the parameter.
            tps: Types that can be passed to the server. If empty, any is used.
            doc: Description of this query parameter.
            default: Default value to be used if not supplied.
        """

        def inner(func: RouteOrCallable) -> Route:
            route = query_impl(name, *tps, doc=doc, default=default)(func)
            self._push_route(route)
            return route

        return inner

    def body(
        self,
        name: str,
        *tps: type[V],
        doc: str | None = None,
        default: V | None | _NoDefaultType = _NoDefault,
    ):
        """Set a body parameter.

        Args:
            name: Name of the parameter.
            tps: Types that can be passed to the server. If empty, any is used.
            doc: Description of this body parameter.
            default: Default value to be used if not supplied.
        """

        def inner(func: RouteOrCallable) -> Route:
            route = body_impl(name, *tps, doc=doc, default=default)(func)
            self._push_route(route)
            return route

        return inner

    async def _app(self, scope, receive, send) -> None:
        return await self.asgi_app_entry(scope, receive, send)

    def load(self, routes: list[Route] | None = None) -> None:
        """Load the app. This is automatically called most of the time and should only be called manually during manual loading.

        Args:
            routes: Routes to load into the app.
        """
        if self.loaded:
            if routes:
                finalize(routes, self)
            Internal.warning("load called twice")
            return

        if self.config.app.loader == "filesystem":
            if routes:
                warnings.warn(_ROUTES_WARN_MSG)
            load_fs(self, self.config.app.loader_path)
        elif self.config.app.loader == "simple":
            if routes:
                warnings.warn(_ROUTES_WARN_MSG)
            load_simple(self, self.config.app.loader_path)
        else:
            finalize([*(routes or ()), *self._manual_routes], self)

        self.loaded = True

        for r in self.loaded_routes:
            if not r.path:
                continue

            body = {}
            query = {}

            for i in r.inputs:
                target = body if i.is_body else query
                target[i.name] = InputDoc(
                    i.doc or "No description provided.", i.tp, i.default
                )

            self._docs[(r.method.name, r.path)] = RouteDoc(
                r.doc or "No description provided.", body, query
            )

    async def _spawn(self, coro: Coroutine[Any, Any, Any]):
        Internal.info(f"using event loop: {asyncio.get_event_loop()}")
        Internal.info(f"spawning {coro}")

        task = asyncio.create_task(coro)
        if self.config.log.hijack:
            if self.config.server.backend == "uvicorn":
                Internal.info("hijacking uvicorn")
                for log in (
                    logging.getLogger("uvicorn.error"),
                    logging.getLogger("uvicorn.access"),
                ):
                    log.addFilter(UvicornHijack())
            else:
                Internal.info("hijacking hypercorn")

        if self.config.log.fancy:
            if not self.config.log.hijack:
                raise ValueError("hijack must be enabled for fancy mode")

            enter_server()

        self.running = True
        Internal.debug("here we go!")
        await task
        self.running = False

        if self.config.log.fancy:
            exit_server()

        Internal.info("server closed")

    def _run(self, start_target: Callable[..., Any] | None = None) -> Any:
        self.load()
        Internal.info("starting server!")
        server = self.config.server.backend
        uvloop_enabled = False

        if self.config.app.uvloop is True:
            uvloop = attempt_import("uvloop")
            uvloop.install()
            uvloop_enabled = True
        elif self.config.app.uvloop == "decide":
            with suppress(MissingLibraryError):
                uvloop = attempt_import("uvloop")
                uvloop.install()
                uvloop_enabled = True

        start = start_target or asyncio.run

        if server == "uvicorn":
            uvicorn = attempt_import("uvicorn")

            config = uvicorn.Config(
                self._app,
                port=self.config.server.port,
                host=str(self.config.server.host),
                log_level="debug" if self.config.dev else "info",
                lifespan="on",
                factory=False,
                interface="asgi3",
                loop="uvloop" if uvloop_enabled else "asyncio",
                **self.config.server.extra_args,
            )
            server = uvicorn.Server(config)

            return start(self._spawn(server.serve()))

        elif server == "hypercorn":
            hypercorn = attempt_import("hypercorn")
            conf = hypercorn.Config()
            conf.loglevel = "debug" if self.config.dev else "info"
            conf.bind = [
                f"{self.config.server.host}:{self.config.server.port}",
            ]

            for k, v in self.config.server.extra_args.items():
                setattr(conf, k, v)

            return start(
                importlib.import_module("hypercorn.asyncio").serve(
                    self._app, conf
                )
            )
        else:
            raise NotImplementedError("viewserver is not implemented yet")

    def run(self, *, fancy: bool | None = None) -> None:
        """Run the app."""
        if fancy is not None:
            self.config.log.fancy = fancy

        frame = inspect.currentframe()
        assert frame, "failed to get frame"
        assert frame.f_back, "frame has no f_back"

        back = frame.f_back
        base = os.path.basename(back.f_code.co_filename)
        app_path = self.config.app.app_path
        fname = app_path.split(":")[0]
        if base != fname:
            warnings.warn(
                f"ran app from {base}, but app path is {fname} in config",
            )

        if (not os.environ.get("_VIEW_RUN")) and (
            back.f_globals.get("__name__") == "__main__"
        ):
            self._run()
        else:
            Internal.info("called run, but env or scope prevented startup")

    def run_threaded(self, *, daemon: bool = True) -> Thread:
        """Run the app in a thread."""
        thread = Thread(target=self._run, daemon=daemon)
        thread.start()
        return thread

    def run_async(
        self,
        loop: asyncio.AbstractEventLoop | None = None,
    ) -> None:
        """Run the app in an event loop."""
        self._run((loop or asyncio.get_event_loop()).run_until_complete)

    def run_task(
        self,
        loop: asyncio.AbstractEventLoop | None = None,
    ) -> asyncio.Task[None]:
        """Run the app as a task."""
        return self._run((loop or asyncio.get_event_loop()).create_task)

    start = run

    def __repr__(self) -> str:
        return f"App(config={self.config!r})"

    @asynccontextmanager
    async def test(self):
        """Open the testing context."""
        self.load()
        ctx = TestingContext(self.asgi_app_entry)
        try:
            yield ctx
        finally:
            await ctx.stop()

    @overload
    def docs(self, file: None = None) -> str:
        ...

    @overload
    def docs(self, file: TextIO) -> None:
        ...

    @overload
    def docs(
        self,
        file: Path,
        *,
        encoding: str = "utf-8",
        overwrite: bool = True,
    ) -> None:
        ...

    @overload
    def docs(
        self,
        file: str,
        *,
        encoding: str = "utf-8",
        overwrite: bool = True,
    ) -> None:
        ...

    def docs(
        self,
        file: str | TextIO | Path | None = None,
        *,
        encoding: str = "utf-8",
        overwrite: bool = True,
    ) -> str | None:
        """Generate documentation for the app."""
        self.load()
        md = markdown_docs(self._docs)

        if not file:
            return md

        if isinstance(file, str):
            if not overwrite:
                Path(file).write_text(md, encoding=encoding)
            else:
                with open(file, "w", encoding=encoding) as f:
                    f.write(md)
        elif isinstance(file, Path):
            if overwrite:
                with open(file, "w", encoding=encoding) as f:
                    f.write(md)
            else:
                file.write_text(md)
        else:
            file.write(md)

__init__(config)

Parameters:

Name Type Description Default
config Config

Configuration object to be used. Automatically generated by new_app.

required
Source code in src/view/app.py
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def __init__(self, config: Config) -> None:
    """
    Args:
        config: Configuration object to be used. Automatically generated by `new_app`.
    """
    supply_parsers(self)
    self.config = config
    self._set_dev_state(config.dev)
    self._manual_routes: list[Route] = []
    self.routes: list[Route] = []
    self.loaded: bool = False
    self.running = False
    self._docs: DocsType = {}
    self.loaded_routes: list[Route] = []

    Service.log.setLevel(
        config.log.level
        if not isinstance(config.log.level, str)
        else config.log.level.upper()
    )

    if config.dev:
        if os.environ.get("VIEW_PROD") is not None:
            Service.warning("VIEW_PROD is set but dev is set to true")

        format_warnings()
        weakref.finalize(self, self._finalize)

        if config.log.pretty_tracebacks:
            install(show_locals=True)

        rich_handler = sys.excepthook

        def _hook(tp: type[B], value: B, traceback: Traceback) -> None:
            rich_handler(tp, value, traceback)
            os.environ["_VIEW_CANCEL_FINALIZERS"] = "1"

            if isinstance(value, ViewError):
                if value.hint:
                    print(value.hint)

        sys.excepthook = _hook
        with suppress(UnsupportedOperation):
            faulthandler.enable()
    else:
        os.environ["VIEW_PROD"] = "1"

    if config.log.level == "debug":
        enable_debug()

    self.running = False

body(name, *tps, doc=None, default=_NoDefault)

Set a body parameter.

Parameters:

Name Type Description Default
name str

Name of the parameter.

required
tps type[V]

Types that can be passed to the server. If empty, any is used.

()
doc str | None

Description of this body parameter.

None
default V | None | _NoDefaultType

Default value to be used if not supplied.

_NoDefault
Source code in src/view/app.py
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def body(
    self,
    name: str,
    *tps: type[V],
    doc: str | None = None,
    default: V | None | _NoDefaultType = _NoDefault,
):
    """Set a body parameter.

    Args:
        name: Name of the parameter.
        tps: Types that can be passed to the server. If empty, any is used.
        doc: Description of this body parameter.
        default: Default value to be used if not supplied.
    """

    def inner(func: RouteOrCallable) -> Route:
        route = body_impl(name, *tps, doc=doc, default=default)(func)
        self._push_route(route)
        return route

    return inner

delete(path, *, doc=None)

Set a DELETE route.

Source code in src/view/app.py
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def delete(self, path: str, *, doc: str | None = None):
    """Set a DELETE route."""
    return self._method_wrapper(path, doc, delete)

docs(file=None, *, encoding='utf-8', overwrite=True)

Generate documentation for the app.

Source code in src/view/app.py
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def docs(
    self,
    file: str | TextIO | Path | None = None,
    *,
    encoding: str = "utf-8",
    overwrite: bool = True,
) -> str | None:
    """Generate documentation for the app."""
    self.load()
    md = markdown_docs(self._docs)

    if not file:
        return md

    if isinstance(file, str):
        if not overwrite:
            Path(file).write_text(md, encoding=encoding)
        else:
            with open(file, "w", encoding=encoding) as f:
                f.write(md)
    elif isinstance(file, Path):
        if overwrite:
            with open(file, "w", encoding=encoding) as f:
                f.write(md)
        else:
            file.write_text(md)
    else:
        file.write(md)

get(path, *, doc=None)

Set a GET route.

Source code in src/view/app.py
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def get(self, path: str, *, doc: str | None = None):
    """Set a GET route."""
    return self._method_wrapper(path, doc, get)

load(routes=None)

Load the app. This is automatically called most of the time and should only be called manually during manual loading.

Parameters:

Name Type Description Default
routes list[Route] | None

Routes to load into the app.

None
Source code in src/view/app.py
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def load(self, routes: list[Route] | None = None) -> None:
    """Load the app. This is automatically called most of the time and should only be called manually during manual loading.

    Args:
        routes: Routes to load into the app.
    """
    if self.loaded:
        if routes:
            finalize(routes, self)
        Internal.warning("load called twice")
        return

    if self.config.app.loader == "filesystem":
        if routes:
            warnings.warn(_ROUTES_WARN_MSG)
        load_fs(self, self.config.app.loader_path)
    elif self.config.app.loader == "simple":
        if routes:
            warnings.warn(_ROUTES_WARN_MSG)
        load_simple(self, self.config.app.loader_path)
    else:
        finalize([*(routes or ()), *self._manual_routes], self)

    self.loaded = True

    for r in self.loaded_routes:
        if not r.path:
            continue

        body = {}
        query = {}

        for i in r.inputs:
            target = body if i.is_body else query
            target[i.name] = InputDoc(
                i.doc or "No description provided.", i.tp, i.default
            )

        self._docs[(r.method.name, r.path)] = RouteDoc(
            r.doc or "No description provided.", body, query
        )

options(path, *, doc=None)

Set a OPTIONS route.

Source code in src/view/app.py
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def options(self, path: str, *, doc: str | None = None):
    """Set a OPTIONS route."""
    return self._method_wrapper(path, doc, options)

patch(path, *, doc=None)

Set a PATCH route.

Source code in src/view/app.py
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def patch(self, path: str, *, doc: str | None = None):
    """Set a PATCH route."""
    return self._method_wrapper(path, doc, patch)

post(path, *, doc=None)

Set a POST route.

Source code in src/view/app.py
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def post(self, path: str, *, doc: str | None = None):
    """Set a POST route."""
    return self._method_wrapper(path, doc, post)

put(path, *, doc=None)

Set a PUT route.

Source code in src/view/app.py
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def put(self, path: str, *, doc: str | None = None):
    """Set a PUT route."""
    return self._method_wrapper(path, doc, put)

query(name, *tps, doc=None, default=_NoDefault)

Set a query parameter.

Parameters:

Name Type Description Default
name str

Name of the parameter.

required
tps type[V]

Types that can be passed to the server. If empty, any is used.

()
doc str | None

Description of this query parameter.

None
default V | None | _NoDefaultType

Default value to be used if not supplied.

_NoDefault
Source code in src/view/app.py
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def query(
    self,
    name: str,
    *tps: type[V],
    doc: str | None = None,
    default: V | None | _NoDefaultType = _NoDefault,
):
    """Set a query parameter.

    Args:
        name: Name of the parameter.
        tps: Types that can be passed to the server. If empty, any is used.
        doc: Description of this query parameter.
        default: Default value to be used if not supplied.
    """

    def inner(func: RouteOrCallable) -> Route:
        route = query_impl(name, *tps, doc=doc, default=default)(func)
        self._push_route(route)
        return route

    return inner

run(*, fancy=None)

Run the app.

Source code in src/view/app.py
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def run(self, *, fancy: bool | None = None) -> None:
    """Run the app."""
    if fancy is not None:
        self.config.log.fancy = fancy

    frame = inspect.currentframe()
    assert frame, "failed to get frame"
    assert frame.f_back, "frame has no f_back"

    back = frame.f_back
    base = os.path.basename(back.f_code.co_filename)
    app_path = self.config.app.app_path
    fname = app_path.split(":")[0]
    if base != fname:
        warnings.warn(
            f"ran app from {base}, but app path is {fname} in config",
        )

    if (not os.environ.get("_VIEW_RUN")) and (
        back.f_globals.get("__name__") == "__main__"
    ):
        self._run()
    else:
        Internal.info("called run, but env or scope prevented startup")

run_async(loop=None)

Run the app in an event loop.

Source code in src/view/app.py
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def run_async(
    self,
    loop: asyncio.AbstractEventLoop | None = None,
) -> None:
    """Run the app in an event loop."""
    self._run((loop or asyncio.get_event_loop()).run_until_complete)

run_task(loop=None)

Run the app as a task.

Source code in src/view/app.py
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def run_task(
    self,
    loop: asyncio.AbstractEventLoop | None = None,
) -> asyncio.Task[None]:
    """Run the app as a task."""
    return self._run((loop or asyncio.get_event_loop()).create_task)

run_threaded(*, daemon=True)

Run the app in a thread.

Source code in src/view/app.py
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def run_threaded(self, *, daemon: bool = True) -> Thread:
    """Run the app in a thread."""
    thread = Thread(target=self._run, daemon=daemon)
    thread.start()
    return thread

test() async

Open the testing context.

Source code in src/view/app.py
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@asynccontextmanager
async def test(self):
    """Open the testing context."""
    self.load()
    ctx = TestingContext(self.asgi_app_entry)
    try:
        yield ctx
    finally:
        await ctx.stop()

Config

Configuration in view.py is handled by configzen. For information about changing the config or how files are loaded, look at their docs.

Config loading is done by the load_config function in config.py. load_config searches through the possible paths that a configuration could be found (relative to the path and directory parameters passed to it).

The possible config filenames are as follows:

load_config

Load the configuration file.

Parameters:

Name Type Description Default
path Path | None

Path to get the configuration from.

None
directory Path | None

Where to look for the configuration.

None
Source code in src/view/config.py
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def load_config(
    path: Path | None = None,
    *,
    directory: Path | None = None,
) -> Config:
    """Load the configuration file.

    Args:
        path: Path to get the configuration from.
        directory: Where to look for the configuration."""
    paths = (
        "view.toml",
        "view.json",
        "view.ini",
        "view.yaml",
        "view.yml",
        "view_config.py",
        "config.py",
    )

    if path:
        if directory:
            return Config.load(directory / path)
            # idk why someone would do this, but i guess its good to support it
        return Config.load(path)

    for i in paths:
        p = Path(i) if not directory else directory / i

        if not p.exists():
            continue

        if p.suffix == ".py":
            spec = importlib.util.spec_from_file_location(str(p))
            assert spec, "spec is none"
            mod = importlib.util.module_from_spec(spec)
            assert mod, "mod is none"
            sys.modules[p.stem] = mod
            assert spec.loader, "spec.loader is none"
            spec.loader.exec_module(mod)
            return Config.wrap_module(mod)

        return Config.load(p)

    return Config()

App Creation

A new App instance takes in a Config, which is then used to handle behavior of the app. Upon creation of a new App instance, several attributes are set.

Routing

Routes called directly on the App instance (e.g. App.get) are added to the _manual_routes attribute, which is then added to the loader when App.load() is called. Direct App routes are wrappers around things like get() in routing.py.

load() simply chooses one of the loader entry points (load_simple or load_fs) based on the config settings. For more information on the loader, look at the loader docs.