Passively capture, archive, and hoard your web browsing history, including the contents of the pages you visit, for later offline viewing, mirroring, and/or indexing. Your own personal private Wayback Machine that can also archive HTTP POST
requests and responses, as well as most other HTTP
-level data.
# Copyright (c) 2023-2024 Jan Malakhovski <oxij@oxij.org>
#
# This file is a part of `hoardy-web` project.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
"""Parsing and un-parsing of URLs, HTTP headers, HTML attributes, etc."""
import base64 as _base64
import dataclasses as _dc
import idna as _idna
import logging as _logging
import os as _os
import re as _re
import typing as _t
import urllib.parse as _up
from kisstdlib.exceptions import *
from .parser import *
def scheck(v : _t.Any, what : str, value : _t.Any, expected : _t.Any) -> None:
if value != expected:
raise CatastrophicFailure("while evaluating %s of %s, expected %s, got %s", what, repr(v), repr(expected), repr(value))
### Escaping stuff
_miniquoters : dict[str, dict[str, str]] = {}
def miniquote(x : str, blacklist : str) -> str:
"""Like `urllib.parse.quote`, with a blacklist instead of whitelist."""
miniquoter : dict[str, str]
try:
miniquoter = _miniquoters[blacklist]
except KeyError:
# build a dictionary from characters to their quotes
miniquoter = {}
for b in range(0, 32):
miniquoter[chr(b)] = "%{:02X}".format(b)
for c in "%" + blacklist:
miniquoter[c] = "%{:02X}".format(ord(c))
_miniquoters[blacklist] = miniquoter
return "".join([miniquoter.get(c, c) for c in x])
def miniescape(x : str, blacklist : str) -> str:
res = []
for c in x:
if c in blacklist:
res.append("\\" + c)
else:
res.append(c)
return "".join(res)
### URL parsing
# URL double-slash scheme
uds_str = r"http|https|ftp|ftps"
# URL auth
uauth_str = r"\S+(?::\S*)?"
# URL hostname
def uhostname_str(d : str) -> str:
return rf"[^:/?#\s{d}]+"
# URL port
uport_str = r":\d+"
# URL path
def upath_str(d : str) -> str:
return rf"/[^?#\s{d}]*"
# URL relative path
def urel_str(d : str) -> str:
return rf"[^?#\s{d}]+"
# URL query
def uquery_str(d : str) -> str:
return rf"[^#\s{d}]*"
# URL fragment/hash
def ufragment_str(d : str) -> str:
return rf"[^\s{d}]*"
# Regexp describing a URL, the second case is for common malformed path-less
# URLs like "https://example.com" (which should actually be given as
# "https://example.com/", but this is almost a universal mistake). The order
# of cases matters, since `_re.match` and co are greedy.
def url_re_str(d : str) -> str:
return rf"""(
(
(?:(?:{uds_str}):)?
//
(?:{uauth_str}@)?
(?:{uhostname_str(d)})
(?:{uport_str})?
(?:{upath_str(d)})
|
(?:(?:{uds_str}):)?
//
(?:{uauth_str}@)?
(?:{uhostname_str(d)})
(?:{uport_str})?
|
(?:{upath_str(d)})
|
(?:{urel_str(d)})
)
(\?{uquery_str(d)})?
(#{ufragment_str(d)})?
)""".replace("\n", "")
#print(url_re_str(""))
url_re = _re.compile(url_re_str(""))
def pp_to_path(parts : list[str]) -> str:
"""Turn URL path components list into a minimally-quoted path."""
return "/".join([miniquote(e, "/?") for e in parts])
def qsl_to_path(query : list[tuple[str, str]]) -> str:
"""Turn URL query components list into a minimally-quoted path."""
l = []
for k, v in query:
k = miniquote(k, "/&=")
v = miniquote(v, "/&")
if v == "":
l.append(k)
else:
l.append(k + "=" + v)
return "&".join(l)
@_dc.dataclass
class ParsedURL:
raw_url : str
scheme : str
user : str
password : str
brackets : bool
raw_hostname : str
net_hostname : str
hostname : str
opm : str
port : str
raw_path : str
oqm : str
raw_query : str
ofm : str
fragment : str
@property
def net_auth(self) -> str:
if self.user != "":
if self.password != "":
return f"{self.user}:{self.password}@"
else:
return f"{self.user}@"
else:
return ""
@property
def rhostname(self) -> str:
hparts = self.hostname.split(".")
hparts.reverse()
return ".".join(hparts)
@property
def netloc(self) -> str:
hn = self.hostname
if self.brackets: hn = "[" + hn + "]"
return "".join([self.net_auth, hn, self.opm, self.port])
@property
def net_netloc(self) -> str:
hn = self.net_hostname
if self.brackets: hn = "[" + hn + "]"
return "".join([self.net_auth, hn, self.opm, self.port])
@property
def net_url(self) -> str:
raw_path = self.raw_path
if self.raw_hostname:
nl = self.net_netloc
if nl != "": nl = "//" + nl
slash = "/" if raw_path == "" else ""
return _up.quote(f"{self.scheme}:{nl}{raw_path}{slash}{self.oqm}{self.raw_query}", safe="%/:=&?~#+!$,;'@()*[]|")
else:
return _up.quote(f"{self.scheme}:{raw_path}{self.oqm}{self.raw_query}", safe="%/:=&?~#+!$,;'@()*[]|")
@property
def url(self) -> str:
return f"{self.net_url}{self.ofm}{self.fragment}"
@property
def raw_path_parts(self) -> list[str]:
return [_up.unquote(e) for e in self.raw_path.split("/")]
@property
def npath_parts(self) -> list[str]:
parts_insecure = [e for e in self.raw_path_parts if e != ""]
# remove dots and securely interpret double dots
parts : list[str] = []
for e in parts_insecure:
if e == ".":
continue
elif e == "..":
if len(parts) > 0:
parts.pop()
continue
parts.append(e)
return parts
def filepath_parts_ext(self, default : str, extensions : list[str]) -> tuple[list[str], str]:
parts = self.npath_parts
if len(parts) == 0 or self.raw_path.endswith("/"):
return parts + [default], extensions[0] if len(extensions) > 0 else ".data"
last = parts[-1].lower()
last_name, last_ext = _os.path.splitext(last)
if last_ext == "":
return parts + [default], extensions[0] if len(extensions) > 0 else ".data"
elif last_ext in extensions:
return parts[:-1] + [last_name], last_ext
elif len(extensions) > 0:
return parts[:-1] + [last], extensions[0]
elif last_ext == ".data":
return parts[:-1] + [last_name], ".data"
else:
return parts[:-1] + [last], ".data"
@property
def query_parts(self) -> list[tuple[str, str]]:
return _up.parse_qsl(self.raw_query, keep_blank_values=True)
@property
def query_ne_parts(self) -> list[tuple[str, str]]:
return [e for e in self.query_parts if e[1] != ""]
@property
def mq_raw_path(self) -> str:
return pp_to_path(self.raw_path_parts)
@property
def mq_npath(self) -> str:
return pp_to_path(self.npath_parts)
@property
def mq_query(self) -> str:
return qsl_to_path(self.query_parts)
@property
def mq_nquery(self) -> str:
return qsl_to_path(self.query_ne_parts)
@property
def pretty_net_url(self) -> str:
if self.raw_hostname:
nl = self.netloc
if nl != "": nl = "//" + nl
slash = "/" if self.raw_path == "" else ""
return f"{self.scheme}:{nl}{self.mq_raw_path}{slash}{self.oqm}{self.mq_query}"
else:
return f"{self.scheme}:{self.mq_raw_path}{self.oqm}{self.mq_query}"
@property
def pretty_url(self) -> str:
return f"{self.pretty_net_url}{self.ofm}{self.fragment}"
@property
def pretty_net_nurl(self) -> str:
mq_npath = self.mq_npath
if self.raw_hostname:
nl = self.netloc
if nl != "": nl = "//" + nl
slash = "/" if self.raw_path.endswith("/") and len(mq_npath) > 0 else ""
return f"{self.scheme}:{nl}/{mq_npath}{slash}{self.oqm}{self.mq_nquery}"
else:
slash = "/" if self.raw_path.endswith("/") else ""
return f"{self.scheme}:{mq_npath}{slash}{self.oqm}{self.mq_nquery}"
@property
def pretty_nurl(self) -> str:
return f"{self.pretty_net_nurl}{self.ofm}{self.fragment}"
class URLParsingError(ValueError): pass
def parse_url(url : str) -> ParsedURL:
try:
scheme, netloc, path, query, fragment = _up.urlsplit(url)
except Exception:
raise URLParsingError(url)
userinfo, has_user, hostinfo = netloc.rpartition("@")
if has_user:
user , _, password = userinfo.partition(":")
user = _up.quote(_up.unquote(user), safe="")
password = _up.quote(_up.unquote(password), safe="")
else:
user = ""
password = ""
if hostinfo.startswith("["):
brackets = True
raw_hostname, has_endbracket, port = hostinfo[1:].partition("]")
if not has_endbracket or port != "" and not port.startswith(":"):
raise URLParsingError(url)
opm = ":"
port = port[1:]
else:
brackets = False
raw_hostname, opm, port = hostinfo.partition(":")
if raw_hostname == "":
net_hostname = hostname = ""
else:
# Fix common issues by rewriting hostnames like browsers do
ehostname = _up.unquote(raw_hostname).strip().replace("_", "-")
# Yes, this is a bit weird. `_idna.encode` and `_idna.decode` are not bijective.
# So, we turn `raw_hostname` into unicode `str` first.
try:
dehostname = _idna.decode(ehostname, uts46=True)
except _idna.IDNAError as err:
if ehostname[2:4] == "--":
_logging.warning("`parse_url` left `net_hostname` and related attrs of `%s` undecoded because `idna` module failed to decode `%s`: %s", url, ehostname, repr(err))
net_hostname = hostname = ehostname
else:
raise URLParsingError(url)
else:
try:
# Then encode it with uts46 enabled.
net_hostname = _idna.encode(dehostname, uts46=True).decode("ascii")
# And then decode it again to get the canonical unicode hostname for which
# encoding and decoding will be bijective
hostname = _idna.decode(net_hostname)
except _idna.IDNAError:
raise URLParsingError(url)
oqm = "?" if query != "" or (query == "" and url.endswith("?")) else ""
ofm = "#" if fragment != "" or (fragment == "" and url.endswith("#")) else ""
return ParsedURL(url, scheme, user, password,
brackets, raw_hostname, net_hostname, hostname,
opm, port,
path, oqm, query, ofm, fragment)
def test_parse_url() -> None:
def check(x : ParsedURL, name : str, value : _t.Any) -> None:
if getattr(x, name) != value:
raise CatastrophicFailure("while evaluating %s of %s, got %s, expected %s", name, x.raw_url, getattr(x, name), value)
tests1 : list[list[str| None]]
tests1 = [
["http://example.org", "http://example.org/", "http://example.org/"],
["http://example.org/", None, None],
["http://example.org/test", None, None],
["http://example.org/test/", None, None],
["http://example.org/unfinished/query?", None, None],
["http://example.org/unfinished/query?param", None, "http://example.org/unfinished/query?"],
["http://example.org/unfinished/query?param=0", None, None],
["http://example.org/unfinished/query?param=0¶m=1", None, None],
["http://example.org/web/2/https://archived.example.org", None, "http://example.org/web/2/https:/archived.example.org"],
["http://example.org/web/2/https://archived.example.org/", None, "http://example.org/web/2/https:/archived.example.org/"],
["http://example.org/web/2/https://archived.example.org/test", None, "http://example.org/web/2/https:/archived.example.org/test"],
["http://example.org/web/2/https://archived.example.org/test/", None, "http://example.org/web/2/https:/archived.example.org/test/"],
["http://example.org/web/2/https://archived.example.org/unfinished/query?", None, "http://example.org/web/2/https:/archived.example.org/unfinished/query?"],
["http://example.org/web/2/https://archived.example.org/unfinished/query?param", None, "http://example.org/web/2/https:/archived.example.org/unfinished/query?"],
["http://example.org/web/2/https://archived.example.org/unfinished/query?param=0", None, "http://example.org/web/2/https:/archived.example.org/unfinished/query?param=0"],
["http://example.org/web/2/https://archived.example.org/unfinished/query?param=0¶m=1", None, "http://example.org/web/2/https:/archived.example.org/unfinished/query?param=0¶m=1"],
# work-around for common typos
["http://%20example.org/", "http://example.org/", None],
# work-arounds for hostnames that `idna` module fails to parse
["http://ab-cd-xxxxxxxxx-yyyy.example.org/", None, None],
["http://ab--cd-xxxxxxxxx-yyyy.example.org/", None, None],
["http://ab---cd-xxxxxxxxx-yyyy.example.org/", None, None],
]
url : str | None
rest : list[str | None]
for url, *rest in tests1:
assert url is not None
x = parse_url(url)
check(x, "raw_url", url)
curl = rest[0] if rest[0] is not None else url
check(x, "net_url", curl)
check(x, "pretty_net_url", curl)
check(x, "pretty_url", curl)
nurl = rest[1] if rest[1] is not None else curl
check(x, "pretty_net_nurl", nurl)
check(x, "pretty_nurl", nurl)
tests2 : list[list[str| None]]
tests2 = [
["http://example.org#hash", "http://example.org/#hash", "http://example.org/"],
["http://example.org/#hash", "http://example.org/#hash", "http://example.org/"],
]
for url, *rest in tests2:
assert url is not None
x = parse_url(url)
check(x, "raw_url", url)
curl = rest[0] if rest[0] is not None else url
check(x, "pretty_url", curl)
check(x, "pretty_nurl", curl)
nurl = rest[1] if rest[1] is not None else url
check(x, "net_url", nurl)
check(x, "pretty_net_url", nurl)
check(x, "pretty_net_nurl", nurl)
### MIME valuess
Parameters = list[tuple[str, str]]
ParamDefault = _t.TypeVar("ParamDefault", str, None)
def get_parameter(ps : Parameters, name : str, default : ParamDefault) -> str | ParamDefault:
for n, v in ps:
if n == name:
return v
return default
def set_parameter(ps : Parameters, name : str, value : str) -> Parameters:
res = []
not_done = True
for n, v in ps:
if n == name:
if not_done:
res.append((name, value))
not_done = False
continue
res.append((n, v))
if not_done:
res.append((name, value))
return res
token_ends = r'\s\t()\[\]<>@,:;\/?="'
token_body_re = _re.compile(rf'([^{token_ends}]+)')
def parse_token(p : Parser) -> str:
return p.lexeme(token_body_re)
def parse_mime_type(p : Parser, ends : list[str] = []) -> str:
ends = [";"] + ends
try:
maintype = parse_token(p)
p.string("/")
subtype = parse_token(p)
p.opt_whitespace()
return maintype + "/" + subtype
except ParseError as err:
p.take_until_string_in(ends)
# RFC says invalid content types are to be interpreted as `text/plain`
return "text/plain"
attribute_ends = token_ends + "*'%"
attribute_body_re = _re.compile(rf'([^{attribute_ends}]+)')
def parse_attribute(p : Parser) -> str:
return p.lexeme(attribute_body_re)
extended_attribute_ends = token_ends + "*'"
extended_attribute_body_re = _re.compile(rf'([^{extended_attribute_ends}]+)')
def parse_extended_attribute(p : Parser) -> str:
return p.lexeme(extended_attribute_body_re)
qcontent_body_re = _re.compile(rf'([^"\\]*)')
qcontent_ends_str = '"\\'
def parse_value(p : Parser, ends : list[str]) -> str:
ws = p.opt_whitespace()
if p.at_eof() or p.at_string_in(ends):
raise ParseError("expected attribute value, got %s", repr(ws[0]))
try:
p.string('"')
except ParseError:
token = parse_extended_attribute(p)
else:
res = []
while not p.at_string('"'):
if p.at_string('\\'):
p.skip(1)
res.append(p.take(1))
else:
grp = p.regex(qcontent_body_re)
res.append(grp[0])
p.string('"')
p.opt_whitespace()
token = "".join(res)
return ws[0] + token
def parse_parameter(p : Parser, ends : list[str]) -> tuple[str, str]:
key = parse_attribute(p)
try:
p.string("=")
except ParseError:
value = ""
else:
value = parse_value(p, ends)
return key, value
def parse_invalid_parameter(p : Parser, ends : list[str]) -> tuple[str, str]:
key = p.take_until_string_in(ends)
return key.rstrip(), ""
def parse_mime_parameters(p : Parser, ends : list[str] = []) -> Parameters:
ends = [";"] + ends
res = []
while p.at_string(";"):
p.skip(1)
p.opt_whitespace()
if p.at_eof() or p.at_string_in(ends):
# empty parameter
continue
save = p.pos
try:
token = parse_parameter(p, ends)
except ParseError:
p.pos = save
token = parse_invalid_parameter(p, ends)
res.append(token)
return res
### `data:` URLs
def parse_data_url(value : str) -> tuple[str, Parameters, bytes]:
p = Parser(value)
p.string("data:")
if p.at_string(","):
# MDN says:
# > If omitted, defaults to `text/plain;charset=US-ASCII`
mime_type = "text/plain"
params = [("charset", "US-ASCII")]
else:
mime_type = parse_mime_type(p, [","])
params = parse_mime_parameters(p, [","])
p.string(",")
base64 = False
if len(params) > 0 and params[-1][0] == "base64":
params = params[:-1]
base64 = True
data : str | bytes
if base64:
data = _base64.b64decode(p.leftovers)
else:
data = _up.unquote_to_bytes(p.leftovers)
return mime_type, params, data
def test_parse_data_url() -> None:
def check(values : list[str], expected_mime_type : str, expected_params : Parameters, expected_data : bytes) -> None:
for value in values:
mime_type, params, data = parse_data_url(value)
scheck(value, "mime_type", mime_type, expected_mime_type)
scheck(value, "params", params, expected_params)
scheck(value, "data", data, expected_data)
check(["data:,Hello%2C%20World%21",], "text/plain", [("charset", "US-ASCII")], b"Hello, World!")
check(["data:text/plain,Hello%2C%20World%21"], "text/plain", [], b"Hello, World!")
check([
"data:text/plain;base64,SGVsbG8sIFdvcmxkIQ==",
"data:text/plain; base64,SGVsbG8sIFdvcmxkIQ==",
"data:text/plain; base64 ,SGVsbG8sIFdvcmxkIQ==",
], "text/plain", [], b"Hello, World!")
check([
"data:text/plain;charset=UTF-8;base64,SGVsbG8sIFdvcmxkIQ==",
"data:text/plain; charset=UTF-8;base64,SGVsbG8sIFdvcmxkIQ==",
"data:text/plain; charset=UTF-8 ;base64,SGVsbG8sIFdvcmxkIQ==",
], "text/plain", [("charset", "UTF-8")], b"Hello, World!")
# because RFC says invalid content types are to be interpreted as `text/plain`
check([
"data: ,Hello%2C%20World%21",
"data:bla,Hello%2C%20World%21",
], "text/plain", [], b"Hello, World!")
def unparse_data_url(mime_type : str, params : Parameters, data : bytes) -> str:
res = [
"data:",
mime_type,
]
for n, v in params:
res.append(";")
res.append(n)
if len(v) == 0:
continue
res.append('="')
res.append(miniescape(v, qcontent_ends_str))
res.append('"')
res += [
";base64,",
_base64.b64encode(data).decode("ascii"),
]
return "".join(res)
def test_unparse_data_url() -> None:
def check(value : str, *args : _t.Any) -> None:
res = unparse_data_url(*args)
scheck(args, "unparse", value, res)
back = parse_data_url(res)
scheck(value, "re-parse", back, args)
check('data:text/plain;base64,', "text/plain", [], b"")
check('data:text/html;base64,TllB', "text/html", [], b"NYA")
check('data:text/plain;charset="utf-8";base64,QUJD', "text/plain", [("charset", "utf-8")], b"ABC")
check('data:text/plain;charset="US-ASCII";token="\\"";token="\'A";base64,ZGF0YQ==', "text/plain", [("charset", 'US-ASCII'), ("token", '"'), ("token", "'A")], b"data")
### HTTP Headers
Headers = list[tuple[str, bytes]]
def get_raw_headers(headers : Headers, name : str) -> list[bytes]:
# split because browsers frequently squish headers together
return [e for k, v in headers if k.lower() == name for e in v.split(b"\n")]
def get_headers(headers : Headers, name : str) -> list[str]:
return [v.decode("ascii") for v in get_raw_headers(headers,name)]
def get_header(headers : Headers, name : str, default : str | None = None) -> str | None:
res = get_headers(headers, name)
if len(res) == 0:
return default
else:
return res[0]
def parse_content_type_header(value : str) -> tuple[str, Parameters]:
"""Parse HTTP `Content-Type` header."""
p = Parser(value)
mime_type = parse_mime_type(p)
params = parse_mime_parameters(p)
p.opt_whitespace()
p.eof()
return mime_type, params
def test_parse_content_type_header() -> None:
def check(cts : list[str], expected_mime_type : str, expected_params : Parameters) -> None:
for ct in cts:
mime_type, params = parse_content_type_header(ct)
scheck(ct, "mime_type", mime_type, expected_mime_type)
scheck(ct, "params", params, expected_params)
check(["text/plain"], "text/plain", [])
check(["text/html"], "text/html", [])
check([
"text/html;charset=utf-8",
"text/html ;charset=utf-8",
"text/html; charset=utf-8",
'text/html; charset="utf-8"',
'text/html; charset="utf-8";',
'text/html;; charset="utf-8";; ',
'text/html; ; charset="utf-8"; ; ',
], "text/html", [("charset", "utf-8")])
check([
"text/html;charset=utf-8;lang=en",
"text/html; charset=utf-8; lang=en",
'text/html; charset="utf-8"; lang=en',
'text/html; charset="utf-8"; lang=en;',
'text/html;; charset="utf-8"; lang=en;; ',
'text/html; ; charset="utf-8"; lang=en; ; ',
], "text/html", [("charset", "utf-8"), ("lang", "en")])
check([
'text/html;charset="\\"utf-8\\"";lang=en',
'text/html; charset="\\"utf-8\\""; lang=en',
], "text/html", [("charset", '"utf-8"'), ("lang", "en")])
check([
'text/html; charset="utf-8"; %%; lang=en',
'text/html; charset="utf-8"; %% ; lang=en',
], "text/html", [("charset", "utf-8"), ("%%", ""), ("lang", "en")])
# because RFC says invalid content types are to be interpreted as `text/plain`
check(["bla; charset=utf-8; lang=en"], "text/plain", [("charset", "utf-8"), ("lang", "en")])
link_url_re = _re.compile(url_re_str("<>"))
def parse_link_value(p : Parser) -> tuple[str, Parameters]:
"""Parse single sub-value of HTTP `Link` header.
"""
p.string("<")
p.opt_whitespace()
grp = p.regex(link_url_re)
p.opt_whitespace()
p.string(">")
p.opt_whitespace()
params = parse_mime_parameters(p, [","])
return grp[0], params
ParsedLinkHeader = list[tuple[str, Parameters]]
def parse_link_header(value : str) -> ParsedLinkHeader:
"""Parse HTTP `Link` header."""
p = Parser(value)
res = []
p.opt_whitespace()
token = parse_link_value(p)
res.append(token)
while p.at_string(","):
p.skip(1)
p.opt_whitespace()
if p.at_eof() or p.at_string(","):
# empty link value
continue
token = parse_link_value(p)
res.append(token)
return res
def test_parse_link_header() -> None:
def check(lhs : list[str], expected_values : _t.Any) -> None:
for lh in lhs:
values = parse_link_header(lh)
for i in range(0, len(expected_values)):
url, params = values[i]
expected_url, expected_params = expected_values[i]
scheck(lh, "url", url, expected_url)
scheck(lh, "params", params, expected_params)
scheck(lh, "the whole", values, expected_values)
check([
"<https://example.org>",
" <https://example.org>",
"<https://example.org> ",
" <https://example.org> ",
" < https://example.org > ",
], [
("https://example.org", [])
])
check([
"<https://example.org>;rel=me",
"<https://example.org>; rel=me",
" <https://example.org> ; rel=me",
], [
("https://example.org", [("rel", "me")])
])
check([
"<https://example.org>; rel=preconnect; crossorigin",
"<https://example.org>; rel=preconnect ; crossorigin ",
" <https://example.org> ; rel=preconnect ; crossorigin ,",
" <https://example.org> ; rel=preconnect ; ; crossorigin ; , ,, ",
#" , <https://example.org>; rel=preconnect; crossorigin , ",
], [
("https://example.org", [("rel", "preconnect"), ("crossorigin", "")])
])
check([
'<https://example.org/path/#hash>; rel=canonical; type="text/html"',
], [
("https://example.org/path/#hash", [("rel", "canonical"), ("type", "text/html")])
])
check([
'<https://example.org>; rel=preconnect, ' +
'<https://example.org/index.css>; as=style; rel=preload; crossorigin, ' +
'<https://example.org/index.js>;; as=script; ; rel = "preload" ; ; crossorigin; , ' +
', ' +
'<https://example.org/main.js>; as=script; rel=preload;;',
], [
('https://example.org', [('rel', 'preconnect')]),
('https://example.org/index.css', [('as', 'style'), ('rel', 'preload'), ('crossorigin', '')]),
('https://example.org/index.js', [('as', 'script'), ('rel', ' preload'), ('crossorigin', '')]),
('https://example.org/main.js', [('as', 'script'), ('rel', 'preload')])
])
def parse_refresh_header(value : str) -> tuple[int | None, str | None]:
"""Parse HTTP `Refresh` header."""
p = Parser(value)
p.opt_whitespace()
try:
grp = p.regex(natural_re)
p.opt_whitespace()
except ParseError:
secs = None
p.take_until_string(";")
else:
secs = int(grp[0])
try:
p.string(";")
p.opt_whitespace()
p.string("url=")
grp = p.regex(url_re)
except ParseError:
url = None
else:
url = grp[0]
return secs, url
def test_parse_refresh_header() -> None:
def check(rhs : list[str], expected_num : _t.Any, expected_url : _t.Any) -> None:
for rh in rhs:
num, url = parse_refresh_header(rh)
scheck(rh, "num", num, expected_num)
scheck(rh, "url", url, expected_url)
check([
"0",
" 0",
" 0 ",
], 0, None)
check([
"10;url=https://example.org/",
"10; url=https://example.org/",
"10 ;url=https://example.org/",
"10 ; url=https://example.org/",
], 10, "https://example.org/")
### HTML attribute parsing
opt_srcset_condition = _re.compile(r"(?:\s+([0-9]+(?:\.[0-9]+)?[xw]))?")
opt_srcset_sep = _re.compile(r"(\s*,)?")
def parse_srcset_attr(value : str) -> list[tuple[str, str]]:
"""Parse HTML5 srcset attribute"""
res = []
p = Parser(value)
p.opt_whitespace()
while not p.at_eof():
grp = p.regex(url_re)
if grp[1].endswith(","):
url = grp[1][:-1]
p.unread(",")
else:
url = grp[1]
grp = p.opt_regex(opt_srcset_condition)
cond = grp[0]
p.opt_whitespace()
p.opt_regex(opt_srcset_sep)
p.opt_whitespace()
if url != "":
res.append((url, cond))
#else: ignore it
p.eof()
return res
def unparse_srcset_attr(value : list[tuple[str, str]]) -> str:
"""Unparse HTML5 srcset attribute"""
return ", ".join([(f"{url} {cond}" if cond is not None else url) for url, cond in value])
def test_parse_srcset_attr() -> None:
def check(attr : str, expected_values : _t.Any) -> None:
values = parse_srcset_attr(attr)
for i in range(0, len(expected_values)):
url, cond = values[i]
expected_url, expected_cond = expected_values[i]
scheck(attr, "url", url, expected_url)
scheck(attr, "cond", cond, expected_cond)
scheck(attr, "the whole", values, expected_values)
check("https://example.org", [
("https://example.org", None),
])
check("https://example.org/1.jpg, https://example.org/2.jpg", [
("https://example.org/1.jpg", None),
("https://example.org/2.jpg", None),
])
check("https://example.org/1.jpg 2.5x, https://example.org/2.jpg", [
("https://example.org/1.jpg", "2.5x"),
("https://example.org/2.jpg", None),
])
check("""
https://example.org/1.jpg 2.5x
,
https://example.org/2.jpg
""", [
("https://example.org/1.jpg", "2.5x"),
("https://example.org/2.jpg", None),
])