zulip/zerver/models/linkifiers.py

136 lines
5.0 KiB
Python

from re import Pattern
import re2
import uri_template
from django.core.exceptions import ValidationError
from django.db import models
from django.db.models import CASCADE
from django.db.models.signals import post_delete, post_save
from django.utils.translation import gettext as _
from typing_extensions import override
from zerver.lib import cache
from zerver.lib.cache import cache_delete, cache_with_key
from zerver.lib.per_request_cache import (
flush_per_request_cache,
return_same_value_during_entire_request,
)
from zerver.lib.types import LinkifierDict
from zerver.models.realms import Realm
def filter_pattern_validator(value: str) -> Pattern[str]:
try:
# Do not write errors to stderr (this still raises exceptions)
options = re2.Options()
options.log_errors = False
regex = re2.compile(value, options=options)
except re2.error as e:
if len(e.args) >= 1:
if isinstance(e.args[0], str): # nocoverage
raise ValidationError(_("Bad regular expression: {regex}").format(regex=e.args[0]))
if isinstance(e.args[0], bytes):
raise ValidationError(
_("Bad regular expression: {regex}").format(regex=e.args[0].decode())
)
raise ValidationError(_("Unknown regular expression error")) # nocoverage
return regex
def url_template_validator(value: str) -> None:
"""Validate as a URL template"""
if not uri_template.validate(value):
raise ValidationError(_("Invalid URL template."))
class RealmFilter(models.Model):
"""Realm-specific regular expressions to automatically linkify certain
strings inside the Markdown processor. See "Custom filters" in the settings UI.
"""
realm = models.ForeignKey(Realm, on_delete=CASCADE)
pattern = models.TextField()
url_template = models.TextField(validators=[url_template_validator])
# Linkifiers are applied in a message/topic in order; the processing order
# is important when there are overlapping patterns.
order = models.IntegerField(default=0)
class Meta:
unique_together = ("realm", "pattern")
@override
def __str__(self) -> str:
return f"{self.realm.string_id}: {self.pattern} {self.url_template}"
@override
def clean(self) -> None:
"""Validate whether the set of parameters in the URL template
match the set of parameters in the regular expression.
Django's `full_clean` calls `clean_fields` followed by `clean` method
and stores all ValidationErrors from all stages to return as JSON.
"""
# Extract variables present in the pattern
pattern = filter_pattern_validator(self.pattern)
group_set = set(pattern.groupindex.keys())
# Do not continue the check if the url template is invalid to begin with.
# The ValidationError for invalid template will only be raised by the validator
# set on the url_template field instead of here to avoid duplicates.
if not uri_template.validate(self.url_template):
return
# Extract variables used in the URL template.
template_variables_set = set(uri_template.URITemplate(self.url_template).variable_names)
# Report patterns missing in linkifier pattern.
missing_in_pattern_set = template_variables_set - group_set
if len(missing_in_pattern_set) > 0:
name = min(missing_in_pattern_set)
raise ValidationError(
_("Group %(name)r in URL template is not present in linkifier pattern."),
params={"name": name},
)
missing_in_url_set = group_set - template_variables_set
# Report patterns missing in URL template.
if len(missing_in_url_set) > 0:
# We just report the first missing pattern here. Users can
# incrementally resolve errors if there are multiple
# missing patterns.
name = min(missing_in_url_set)
raise ValidationError(
_("Group %(name)r in linkifier pattern is not present in URL template."),
params={"name": name},
)
def get_linkifiers_cache_key(realm_id: int) -> str:
return f"{cache.KEY_PREFIX}:all_linkifiers_for_realm:{realm_id}"
@return_same_value_during_entire_request
@cache_with_key(get_linkifiers_cache_key, timeout=3600 * 24 * 7)
def linkifiers_for_realm(realm_id: int) -> list[LinkifierDict]:
return [
LinkifierDict(
pattern=linkifier.pattern,
url_template=linkifier.url_template,
id=linkifier.id,
)
for linkifier in RealmFilter.objects.filter(realm_id=realm_id).order_by("order")
]
def flush_linkifiers(*, instance: RealmFilter, **kwargs: object) -> None:
realm_id = instance.realm_id
cache_delete(get_linkifiers_cache_key(realm_id))
flush_per_request_cache("linkifiers_for_realm")
post_save.connect(flush_linkifiers, sender=RealmFilter)
post_delete.connect(flush_linkifiers, sender=RealmFilter)