1from __future__ import annotations
 2
 3from collections.abc import Callable
 4from typing import Any
 5
 6from plain.http import Response
 7from plain.utils.cache import patch_vary_headers
 8
 9from .templates import render_template_fragment
10
11
12class HTMXViewMixin:
13    def render_template(self) -> str:
14        template = self.get_template()
15        context = self.get_template_context()
16
17        if self.is_htmx_request() and self.get_htmx_fragment_name():
18            return render_template_fragment(
19                template=template._jinja_template,
20                fragment_name=self.get_htmx_fragment_name(),
21                context=context,
22            )
23
24        return template.render(context)
25
26    def get_response(self) -> Response:
27        response = super().get_response()
28        # Tell browser caching to also consider the fragment header,
29        # not just the url/cookie.
30        patch_vary_headers(
31            response, ["HX-Request", "Plain-HX-Fragment", "Plain-HX-Action"]
32        )
33        return response
34
35    def get_request_handler(self) -> Callable[..., Any]:
36        if self.is_htmx_request():
37            # You can use an htmx_{method} method on views
38            # (or htmx_{method}_{action} for specific actions)
39            method = f"htmx_{self.request.method.lower()}"
40
41            if action := self.get_htmx_action_name():
42                # If an action is specified, we throw an error if
43                # the associated method isn't found
44                return getattr(self, f"{method}_{action}")
45
46            if handler := getattr(self, method, None):
47                # If it's just an htmx post, for example,
48                # we can use a custom method or we can let it fall back
49                # to a regular post method if it's not found
50                return handler
51
52        return super().get_request_handler()
53
54    def is_htmx_request(self) -> bool:
55        return self.request.headers.get("HX-Request") == "true"
56
57    def get_htmx_fragment_name(self) -> str:
58        # A custom header that we pass with the {% htmxfragment %} tag
59        return self.request.headers.get("Plain-HX-Fragment", "")
60
61    def get_htmx_action_name(self) -> str:
62        return self.request.headers.get("Plain-HX-Action", "")