MatrixSynapse/rust/src/push/evaluator.rs

492 lines
16 KiB
Rust

// Copyright 2022 The Matrix.org Foundation C.I.C.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
use std::collections::BTreeMap;
use anyhow::{Context, Error};
use lazy_static::lazy_static;
use log::warn;
use pyo3::prelude::*;
use regex::Regex;
use super::{
utils::{get_glob_matcher, get_localpart_from_id, GlobMatchType},
Action, Condition, EventMatchCondition, FilteredPushRules, KnownCondition,
RelatedEventMatchCondition,
};
lazy_static! {
/// Used to parse the `is` clause in the room member count condition.
static ref INEQUALITY_EXPR: Regex = Regex::new(r"^([=<>]*)([0-9]+)$").expect("valid regex");
/// Used to determine which MSC3931 room version feature flags are actually known to
/// the push evaluator.
static ref KNOWN_RVER_FLAGS: Vec<String> = vec![
RoomVersionFeatures::ExtensibleEvents.as_str().to_string(),
];
/// The "safe" rule IDs which are not affected by MSC3932's behaviour (room versions which
/// declare Extensible Events support ultimately *disable* push rules which do not declare
/// *any* MSC3931 room_version_supports condition).
static ref SAFE_EXTENSIBLE_EVENTS_RULE_IDS: Vec<String> = vec![
"global/override/.m.rule.master".to_string(),
"global/override/.m.rule.roomnotif".to_string(),
"global/content/.m.rule.contains_user_name".to_string(),
];
}
enum RoomVersionFeatures {
ExtensibleEvents,
}
impl RoomVersionFeatures {
fn as_str(&self) -> &'static str {
match self {
RoomVersionFeatures::ExtensibleEvents => "org.matrix.msc3932.extensible_events",
}
}
}
/// Allows running a set of push rules against a particular event.
#[pyclass]
pub struct PushRuleEvaluator {
/// A mapping of "flattened" keys to string values in the event, e.g.
/// includes things like "type" and "content.msgtype".
flattened_keys: BTreeMap<String, String>,
/// The "content.body", if any.
body: String,
/// The number of users in the room.
room_member_count: u64,
/// The `notifications` section of the current power levels in the room.
notification_power_levels: BTreeMap<String, i64>,
/// The power level of the sender of the event, or None if event is an
/// outlier.
sender_power_level: Option<i64>,
/// The related events, indexed by relation type. Flattened in the same manner as
/// `flattened_keys`.
related_events_flattened: BTreeMap<String, BTreeMap<String, String>>,
/// If msc3664, push rules for related events, is enabled.
related_event_match_enabled: bool,
/// If MSC3931 is applicable, the feature flags for the room version.
room_version_feature_flags: Vec<String>,
/// If MSC3931 (room version feature flags) is enabled. Usually controlled by the same
/// flag as MSC1767 (extensible events core).
msc3931_enabled: bool,
}
#[pymethods]
impl PushRuleEvaluator {
/// Create a new `PushRuleEvaluator`. See struct docstring for details.
#[allow(clippy::too_many_arguments)]
#[new]
pub fn py_new(
flattened_keys: BTreeMap<String, String>,
room_member_count: u64,
sender_power_level: Option<i64>,
notification_power_levels: BTreeMap<String, i64>,
related_events_flattened: BTreeMap<String, BTreeMap<String, String>>,
related_event_match_enabled: bool,
room_version_feature_flags: Vec<String>,
msc3931_enabled: bool,
) -> Result<Self, Error> {
let body = flattened_keys
.get("content.body")
.cloned()
.unwrap_or_default();
Ok(PushRuleEvaluator {
flattened_keys,
body,
room_member_count,
notification_power_levels,
sender_power_level,
related_events_flattened,
related_event_match_enabled,
room_version_feature_flags,
msc3931_enabled,
})
}
/// Run the evaluator with the given push rules, for the given user ID and
/// display name of the user.
///
/// Passing in None will skip evaluating rules matching user ID and display
/// name.
///
/// Returns the set of actions, if any, that match (filtering out any
/// `dont_notify` actions).
pub fn run(
&self,
push_rules: &FilteredPushRules,
user_id: Option<&str>,
display_name: Option<&str>,
) -> Vec<Action> {
'outer: for (push_rule, enabled) in push_rules.iter() {
if !enabled {
continue;
}
let rule_id = &push_rule.rule_id().to_string();
let extev_flag = &RoomVersionFeatures::ExtensibleEvents.as_str().to_string();
let supports_extensible_events = self.room_version_feature_flags.contains(extev_flag);
let safe_from_rver_condition = SAFE_EXTENSIBLE_EVENTS_RULE_IDS.contains(rule_id);
let mut has_rver_condition = false;
for condition in push_rule.conditions.iter() {
has_rver_condition |= matches!(
condition,
// per MSC3932, we just need *any* room version condition to match
Condition::Known(KnownCondition::RoomVersionSupports { feature: _ }),
);
match self.match_condition(condition, user_id, display_name) {
Ok(true) => {}
Ok(false) => continue 'outer,
Err(err) => {
warn!("Condition match failed {err}");
continue 'outer;
}
}
}
// MSC3932: Disable push rules in extensible event-supporting room versions if they
// don't describe *any* MSC3931 room version condition, unless the rule is on the
// safe list.
if !has_rver_condition && !safe_from_rver_condition && supports_extensible_events {
continue;
}
let actions = push_rule
.actions
.iter()
// Filter out "dont_notify" actions, as we don't store them.
.filter(|a| **a != Action::DontNotify)
.cloned()
.collect();
return actions;
}
Vec::new()
}
/// Check if the given condition matches.
fn matches(
&self,
condition: Condition,
user_id: Option<&str>,
display_name: Option<&str>,
) -> bool {
match self.match_condition(&condition, user_id, display_name) {
Ok(true) => true,
Ok(false) => false,
Err(err) => {
warn!("Condition match failed {err}");
false
}
}
}
}
impl PushRuleEvaluator {
/// Match a given `Condition` for a push rule.
pub fn match_condition(
&self,
condition: &Condition,
user_id: Option<&str>,
display_name: Option<&str>,
) -> Result<bool, Error> {
let known_condition = match condition {
Condition::Known(known) => known,
Condition::Unknown(_) => {
return Ok(false);
}
};
let result = match known_condition {
KnownCondition::EventMatch(event_match) => {
self.match_event_match(event_match, user_id)?
}
KnownCondition::RelatedEventMatch(event_match) => {
self.match_related_event_match(event_match, user_id)?
}
KnownCondition::ContainsDisplayName => {
if let Some(dn) = display_name {
if !dn.is_empty() {
get_glob_matcher(dn, GlobMatchType::Word)?.is_match(&self.body)?
} else {
// We specifically ignore empty display names, as otherwise
// they would always match.
false
}
} else {
false
}
}
KnownCondition::RoomMemberCount { is } => {
if let Some(is) = is {
self.match_member_count(is)?
} else {
false
}
}
KnownCondition::SenderNotificationPermission { key } => {
if let Some(sender_power_level) = &self.sender_power_level {
let required_level = self
.notification_power_levels
.get(key.as_ref())
.copied()
.unwrap_or(50);
*sender_power_level >= required_level
} else {
false
}
}
KnownCondition::RoomVersionSupports { feature } => {
if !self.msc3931_enabled {
false
} else {
let flag = feature.to_string();
KNOWN_RVER_FLAGS.contains(&flag)
&& self.room_version_feature_flags.contains(&flag)
}
}
};
Ok(result)
}
/// Evaluates a `event_match` condition.
fn match_event_match(
&self,
event_match: &EventMatchCondition,
user_id: Option<&str>,
) -> Result<bool, Error> {
let pattern = if let Some(pattern) = &event_match.pattern {
pattern
} else if let Some(pattern_type) = &event_match.pattern_type {
// The `pattern_type` can either be "user_id" or "user_localpart",
// either way if we don't have a `user_id` then the condition can't
// match.
let user_id = if let Some(user_id) = user_id {
user_id
} else {
return Ok(false);
};
match &**pattern_type {
"user_id" => user_id,
"user_localpart" => get_localpart_from_id(user_id)?,
_ => return Ok(false),
}
} else {
return Ok(false);
};
let haystack = if let Some(haystack) = self.flattened_keys.get(&*event_match.key) {
haystack
} else {
return Ok(false);
};
// For the content.body we match against "words", but for everything
// else we match against the entire value.
let match_type = if event_match.key == "content.body" {
GlobMatchType::Word
} else {
GlobMatchType::Whole
};
let mut compiled_pattern = get_glob_matcher(pattern, match_type)?;
compiled_pattern.is_match(haystack)
}
/// Evaluates a `related_event_match` condition. (MSC3664)
fn match_related_event_match(
&self,
event_match: &RelatedEventMatchCondition,
user_id: Option<&str>,
) -> Result<bool, Error> {
// First check if related event matching is enabled...
if !self.related_event_match_enabled {
return Ok(false);
}
// get the related event, fail if there is none.
let event = if let Some(event) = self.related_events_flattened.get(&*event_match.rel_type) {
event
} else {
return Ok(false);
};
// If we are not matching fallbacks, don't match if our special key indicating this is a
// fallback relation is not present.
if !event_match.include_fallbacks.unwrap_or(false)
&& event.contains_key("im.vector.is_falling_back")
{
return Ok(false);
}
// if we have no key, accept the event as matching, if it existed without matching any
// fields.
let key = if let Some(key) = &event_match.key {
key
} else {
return Ok(true);
};
let pattern = if let Some(pattern) = &event_match.pattern {
pattern
} else if let Some(pattern_type) = &event_match.pattern_type {
// The `pattern_type` can either be "user_id" or "user_localpart",
// either way if we don't have a `user_id` then the condition can't
// match.
let user_id = if let Some(user_id) = user_id {
user_id
} else {
return Ok(false);
};
match &**pattern_type {
"user_id" => user_id,
"user_localpart" => get_localpart_from_id(user_id)?,
_ => return Ok(false),
}
} else {
return Ok(false);
};
let haystack = if let Some(haystack) = event.get(&**key) {
haystack
} else {
return Ok(false);
};
// For the content.body we match against "words", but for everything
// else we match against the entire value.
let match_type = if key == "content.body" {
GlobMatchType::Word
} else {
GlobMatchType::Whole
};
let mut compiled_pattern = get_glob_matcher(pattern, match_type)?;
compiled_pattern.is_match(haystack)
}
/// Match the member count against an 'is' condition
/// The `is` condition can be things like '>2', '==3' or even just '4'.
fn match_member_count(&self, is: &str) -> Result<bool, Error> {
let captures = INEQUALITY_EXPR.captures(is).context("bad 'is' clause")?;
let ineq = captures.get(1).map_or("==", |m| m.as_str());
let rhs: u64 = captures
.get(2)
.context("missing number")?
.as_str()
.parse()?;
let matches = match ineq {
"" | "==" => self.room_member_count == rhs,
"<" => self.room_member_count < rhs,
">" => self.room_member_count > rhs,
">=" => self.room_member_count >= rhs,
"<=" => self.room_member_count <= rhs,
_ => false,
};
Ok(matches)
}
}
#[test]
fn push_rule_evaluator() {
let mut flattened_keys = BTreeMap::new();
flattened_keys.insert("content.body".to_string(), "foo bar bob hello".to_string());
let evaluator = PushRuleEvaluator::py_new(
flattened_keys,
10,
Some(0),
BTreeMap::new(),
BTreeMap::new(),
true,
vec![],
true,
)
.unwrap();
let result = evaluator.run(&FilteredPushRules::default(), None, Some("bob"));
assert_eq!(result.len(), 3);
}
#[test]
fn test_requires_room_version_supports_condition() {
use std::borrow::Cow;
use crate::push::{PushRule, PushRules};
let mut flattened_keys = BTreeMap::new();
flattened_keys.insert("content.body".to_string(), "foo bar bob hello".to_string());
let flags = vec![RoomVersionFeatures::ExtensibleEvents.as_str().to_string()];
let evaluator = PushRuleEvaluator::py_new(
flattened_keys,
10,
Some(0),
BTreeMap::new(),
BTreeMap::new(),
false,
flags,
true,
)
.unwrap();
// first test: are the master and contains_user_name rules excluded from the "requires room
// version condition" check?
let mut result = evaluator.run(
&FilteredPushRules::default(),
Some("@bob:example.org"),
None,
);
assert_eq!(result.len(), 3);
// second test: if an appropriate push rule is in play, does it get handled?
let custom_rule = PushRule {
rule_id: Cow::from("global/underride/.org.example.extensible"),
priority_class: 1, // underride
conditions: Cow::from(vec![Condition::Known(
KnownCondition::RoomVersionSupports {
feature: Cow::from(RoomVersionFeatures::ExtensibleEvents.as_str().to_string()),
},
)]),
actions: Cow::from(vec![Action::Notify]),
default: false,
default_enabled: true,
};
let rules = PushRules::new(vec![custom_rule]);
result = evaluator.run(
&FilteredPushRules::py_new(rules, BTreeMap::new(), true, true),
None,
None,
);
assert_eq!(result.len(), 1);
}