Skip to content

fasthx.htmy

ComponentHeader dataclass

Bases: ComponentHeader[HTMYComponentFactory[T]]

RequestComponentSelector for HTMY components that takes selects the rendered component based on a request header.

Source code in fasthx/htmy.py 
24
25
26
27
28
29
30
class ComponentHeader(_ComponentHeader[HTMYComponentFactory[T]]):
    """
    `RequestComponentSelector` for HTMY components that takes selects the rendered component
    based on a request header.
    """

    ...

CurrentRequest

HTMY context aware utility for accessing the current request.

Source code in fasthx/htmy.py 
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
class CurrentRequest:
    """
    HTMY context aware utility for accessing the current request.
    """

    @classmethod
    def to_context(cls, request: Request) -> h.MutableContext:
        """Creates an `htmy` `Context` for the given request."""
        return {Request: request}

    @classmethod
    def from_context(cls, context: h.Context) -> Request:
        """
        Loads the current `Request` instance from the given context.

        Raises:
            KeyError: If the there's no `Request` in the context.
            TypeError: If invalid data is stored for `Request`.
        """
        result = context[Request]
        if isinstance(result, Request):
            return result

        raise TypeError(f"Invalid context data for {cls.__name__}.")

from_context(context) classmethod

Loads the current Request instance from the given context.

Raises:

Type Description
KeyError

If the there's no Request in the context.
TypeError

If invalid data is stored for Request.
Source code in fasthx/htmy.py 
43
44
45
46
47
48
49
50
51
52
53
54
55
56
@classmethod
def from_context(cls, context: h.Context) -> Request:
    """
    Loads the current `Request` instance from the given context.

    Raises:
        KeyError: If the there's no `Request` in the context.
        TypeError: If invalid data is stored for `Request`.
    """
    result = context[Request]
    if isinstance(result, Request):
        return result

    raise TypeError(f"Invalid context data for {cls.__name__}.")

to_context(request) classmethod

Creates an htmy Context for the given request.

Source code in fasthx/htmy.py 
38
39
40
41
@classmethod
def to_context(cls, request: Request) -> h.MutableContext:
    """Creates an `htmy` `Context` for the given request."""
    return {Request: request}

HTMY dataclass

HTMY renderer utility with FastAPI route decorators.

The following data is added automatically to every HTMY rendering context:

  • The current Request that can be retrieved with CurrentRequest.from_context() in components.
  • All route parameters (as a RouteParams instance) that can be retrieved with RouteParams.from_context() in components.
  • Everything added through self.request_processors.
  • The default context of self.htmy.
Source code in fasthx/htmy.py 
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
@dataclass(frozen=True, slots=True)
class HTMY:
    """
    HTMY renderer utility with FastAPI route decorators.

    The following data is added automatically to every `HTMY` rendering context:

    - The current `Request` that can be retrieved with `CurrentRequest.from_context()` in components.
    - All route parameters (as a `RouteParams` instance) that can be retrieved with
      `RouteParams.from_context()` in components.
    - Everything added through `self.request_processors`.
    - The default context of `self.htmy`.
    """

    htmy: h.HTMY = field(default_factory=h.HTMY)
    """The HTMY renderer to use."""

    no_data: bool = field(default=False, kw_only=True)
    """
    If set, `hx()` routes will only accept HTMX requests.

    Note that if this property is `True`, then the `hx()` decorator's `no_data` argument
    will have no effect.
    """

    request_processors: list[RequestProcessor] = field(default_factory=list, kw_only=True)
    """
    A list of functions that expect the current request and return an `htmy` `Context` that should
    be used during rendering in addition to the default context of `self.htmy`.
    """

    def hx(
        self,
        component_selector: HTMYComponentSelector[T],
        *,
        error_component_selector: HTMYComponentSelector[Exception] | None = None,
        no_data: bool = False,
    ) -> Callable[[MaybeAsyncFunc[P, T]], Callable[P, Coroutine[None, None, T | Response]]]:
        """
        Decorator for rendering the route's result if the request was an HTMX one.

        Arguments:
            component_selector: The component selector to use.
            error_component_selector: The component selector to use for route error rendering.
            no_data: If set, the route will only accept HTMX requests.
        """
        return hx(
            self._make_render_function(component_selector),
            render_error=None
            if error_component_selector is None
            else self._make_error_render_function(error_component_selector),
            no_data=self.no_data or no_data,
        )

    def page(
        self,
        component_selector: HTMYComponentSelector[T],
        *,
        error_component_selector: HTMYComponentSelector[Exception] | None = None,
    ) -> Callable[[MaybeAsyncFunc[P, T]], Callable[P, Coroutine[None, None, T | Response]]]:
        """
        Decorator for rendering a route's result.

        This decorator triggers HTML rendering regardless of whether the request was HTMX or not.

        Arguments:
            component_selector: The component selector to use.
            error_component_selector: The component selector to use for route error rendering.
        """
        return page(
            self._make_render_function(component_selector),
            render_error=None
            if error_component_selector is None
            else self._make_error_render_function(error_component_selector),
        )

    def _make_render_function(self, component_selector: HTMYComponentSelector[T]) -> HTMLRenderer[T]:
        """Creates a render function that uses the given component selector."""

        async def render(result: T, *, context: dict[str, Any], request: Request) -> str:
            component = (
                component_selector.get_component(request, None)
                if isinstance(component_selector, RequestComponentSelector)
                else component_selector
            )
            return await self.htmy.render(component(result), self._make_render_context(request, context))

        return render

    def _make_error_render_function(
        self, component_selector: HTMYComponentSelector[Exception]
    ) -> HTMLRenderer[Exception]:
        """Creates an error renderer function that uses the given component selector."""

        async def render(result: Exception, *, context: dict[str, Any], request: Request) -> str:
            component = (
                component_selector.get_component(request, result)
                if isinstance(component_selector, RequestComponentSelector)
                else component_selector
            )
            return await self.htmy.render(component(result), self._make_render_context(request, context))

        return render

    def _make_render_context(self, request: Request, route_params: dict[str, Any]) -> h.Context:
        """Creates the HTMY rendering context."""
        # Add the current request to the context.
        result = CurrentRequest.to_context(request)

        # Add all route params to the context.
        result.update(RouteParams(route_params).to_context())

        # Run all request processors and add the result to the context.
        for cp in self.request_processors:
            result.update(cp(request))

        return result

htmy: h.HTMY = field(default_factory=h.HTMY) class-attribute instance-attribute

The HTMY renderer to use.

no_data: bool = field(default=False, kw_only=True) class-attribute instance-attribute

If set, hx() routes will only accept HTMX requests.

Note that if this property is True, then the hx() decorator's no_data argument will have no effect.

request_processors: list[RequestProcessor] = field(default_factory=list, kw_only=True) class-attribute instance-attribute

A list of functions that expect the current request and return an htmy Context that should be used during rendering in addition to the default context of self.htmy.

hx(component_selector, *, error_component_selector=None, no_data=False)

Decorator for rendering the route's result if the request was an HTMX one.

Parameters:

Name Type Description Default
component_selector HTMYComponentSelector[T]

The component selector to use.

 required
error_component_selector HTMYComponentSelector[Exception] | None

The component selector to use for route error rendering.

 None
no_data bool

If set, the route will only accept HTMX requests.

 False
Source code in fasthx/htmy.py 
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
def hx(
    self,
    component_selector: HTMYComponentSelector[T],
    *,
    error_component_selector: HTMYComponentSelector[Exception] | None = None,
    no_data: bool = False,
) -> Callable[[MaybeAsyncFunc[P, T]], Callable[P, Coroutine[None, None, T | Response]]]:
    """
    Decorator for rendering the route's result if the request was an HTMX one.

    Arguments:
        component_selector: The component selector to use.
        error_component_selector: The component selector to use for route error rendering.
        no_data: If set, the route will only accept HTMX requests.
    """
    return hx(
        self._make_render_function(component_selector),
        render_error=None
        if error_component_selector is None
        else self._make_error_render_function(error_component_selector),
        no_data=self.no_data or no_data,
    )

page(component_selector, *, error_component_selector=None)

Decorator for rendering a route's result.

This decorator triggers HTML rendering regardless of whether the request was HTMX or not.

Parameters:

Name Type Description Default
component_selector HTMYComponentSelector[T]

The component selector to use.

 required
error_component_selector HTMYComponentSelector[Exception] | None

The component selector to use for route error rendering.

 None
Source code in fasthx/htmy.py 
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
def page(
    self,
    component_selector: HTMYComponentSelector[T],
    *,
    error_component_selector: HTMYComponentSelector[Exception] | None = None,
) -> Callable[[MaybeAsyncFunc[P, T]], Callable[P, Coroutine[None, None, T | Response]]]:
    """
    Decorator for rendering a route's result.

    This decorator triggers HTML rendering regardless of whether the request was HTMX or not.

    Arguments:
        component_selector: The component selector to use.
        error_component_selector: The component selector to use for route error rendering.
    """
    return page(
        self._make_render_function(component_selector),
        render_error=None
        if error_component_selector is None
        else self._make_error_render_function(error_component_selector),
    )

RouteParams dataclass

HTMY context aware utility for accessing route parameters (resolved dependencies).

For convenience, it is a partial, readonly mapping implementation. Supported mapping methods: __contains__, __getitem___(), and get(). For more complex use-cases, you can rely on the params property.

Source code in fasthx/htmy.py 
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
@dataclass(frozen=True, slots=True)
class RouteParams:
    """
    HTMY context aware utility for accessing route parameters (resolved dependencies).

    For convenience, it is a partial, readonly mapping implementation. Supported mapping methods:
    `__contains__`, `__getitem___()`, and `get()`. For more complex use-cases, you can rely on the
    `params` property.
    """

    params: dict[str, Any]
    """Route parameters."""

    def __contains__(self, key: str) -> bool:
        """Membership test operator (`in`)."""
        return key in self.params

    def __getitem__(self, key: str) -> Any:
        """`self[key]` implementation."""
        return self.params[key]

    def get(self, key: str, default: Any = None, /) -> Any:
        """Returns the parameter with the given key."""
        return self.params.get(key, default)

    def to_context(self) -> h.MutableContext:
        """Creates an `htmy` `Context` for this instance."""
        return {RouteParams: self}

    @classmethod
    def from_context(cls, context: h.Context) -> Self:
        """
        Loads the `RouteParams` instance from the given context.

        Raises:
            KeyError: If there's no `RouteParams` in the context.
            TypeError: If invalid data is stored for `RouteParams`.
        """
        result = context[cls]
        if isinstance(result, cls):
            return result

        raise TypeError(f"Invalid context data type for {cls.__name__}.")

params: dict[str, Any] instance-attribute

Route parameters.

__contains__(key)

Membership test operator (in).

Source code in fasthx/htmy.py 
72
73
74
def __contains__(self, key: str) -> bool:
    """Membership test operator (`in`)."""
    return key in self.params

__getitem__(key)

self[key] implementation.

Source code in fasthx/htmy.py 
76
77
78
def __getitem__(self, key: str) -> Any:
    """`self[key]` implementation."""
    return self.params[key]

from_context(context) classmethod

Loads the RouteParams instance from the given context.

Raises:

Type Description
KeyError

If there's no RouteParams in the context.
TypeError

If invalid data is stored for RouteParams.
Source code in fasthx/htmy.py 
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
@classmethod
def from_context(cls, context: h.Context) -> Self:
    """
    Loads the `RouteParams` instance from the given context.

    Raises:
        KeyError: If there's no `RouteParams` in the context.
        TypeError: If invalid data is stored for `RouteParams`.
    """
    result = context[cls]
    if isinstance(result, cls):
        return result

    raise TypeError(f"Invalid context data type for {cls.__name__}.")

get(key, default=None)

Returns the parameter with the given key.

Source code in fasthx/htmy.py 
80
81
82
def get(self, key: str, default: Any = None, /) -> Any:
    """Returns the parameter with the given key."""
    return self.params.get(key, default)

to_context()

Creates an htmy Context for this instance.

Source code in fasthx/htmy.py 
84
85
86
def to_context(self) -> h.MutableContext:
    """Creates an `htmy` `Context` for this instance."""
    return {RouteParams: self}