1from __future__ import annotations
2
3from .mixins import UpdateDictMixin
4
5
6def csp_property(key):
7 """Return a new property object for a content security policy header.
8 Useful if you want to add support for a csp extension in a
9 subclass.
10 """
11 return property(
12 lambda x: x._get_value(key),
13 lambda x, v: x._set_value(key, v),
14 lambda x: x._del_value(key),
15 f"accessor for {key!r}",
16 )
17
18
19class ContentSecurityPolicy(UpdateDictMixin, dict):
20 """Subclass of a dict that stores values for a Content Security Policy
21 header. It has accessors for all the level 3 policies.
22
23 Because the csp directives in the HTTP header use dashes the
24 python descriptors use underscores for that.
25
26 To get a header of the :class:`ContentSecuirtyPolicy` object again
27 you can convert the object into a string or call the
28 :meth:`to_header` method. If you plan to subclass it and add your
29 own items have a look at the sourcecode for that class.
30
31 .. versionadded:: 1.0.0
32 Support for Content Security Policy headers was added.
33
34 """
35
36 base_uri = csp_property("base-uri")
37 child_src = csp_property("child-src")
38 connect_src = csp_property("connect-src")
39 default_src = csp_property("default-src")
40 font_src = csp_property("font-src")
41 form_action = csp_property("form-action")
42 frame_ancestors = csp_property("frame-ancestors")
43 frame_src = csp_property("frame-src")
44 img_src = csp_property("img-src")
45 manifest_src = csp_property("manifest-src")
46 media_src = csp_property("media-src")
47 navigate_to = csp_property("navigate-to")
48 object_src = csp_property("object-src")
49 prefetch_src = csp_property("prefetch-src")
50 plugin_types = csp_property("plugin-types")
51 report_to = csp_property("report-to")
52 report_uri = csp_property("report-uri")
53 sandbox = csp_property("sandbox")
54 script_src = csp_property("script-src")
55 script_src_attr = csp_property("script-src-attr")
56 script_src_elem = csp_property("script-src-elem")
57 style_src = csp_property("style-src")
58 style_src_attr = csp_property("style-src-attr")
59 style_src_elem = csp_property("style-src-elem")
60 worker_src = csp_property("worker-src")
61
62 def __init__(self, values=(), on_update=None):
63 dict.__init__(self, values or ())
64 self.on_update = on_update
65 self.provided = values is not None
66
67 def _get_value(self, key):
68 """Used internally by the accessor properties."""
69 return self.get(key)
70
71 def _set_value(self, key, value):
72 """Used internally by the accessor properties."""
73 if value is None:
74 self.pop(key, None)
75 else:
76 self[key] = value
77
78 def _del_value(self, key):
79 """Used internally by the accessor properties."""
80 if key in self:
81 del self[key]
82
83 def to_header(self):
84 """Convert the stored values into a cache control header."""
85 from ..http import dump_csp_header
86
87 return dump_csp_header(self)
88
89 def __str__(self):
90 return self.to_header()
91
92 def __repr__(self):
93 kv_str = " ".join(f"{k}={v!r}" for k, v in sorted(self.items()))
94 return f"<{type(self).__name__} {kv_str}>"