seance/backend/
redis.rs

1use std::{error::Error, fmt, num::ParseIntError, string::FromUtf8Error, time::SystemTimeError};
2
3use redis::{AsyncCommands, RedisError};
4
5use crate::{backend::SessionBackend, utils::now};
6
7/// Redis powered session backend
8#[derive(Clone)]
9pub struct RedisBackend<C> {
10    namespace: String,
11    sessions_key: String,
12    connection: C,
13}
14
15impl<C> RedisBackend<C> {
16    /// Creates a new backend
17    ///
18    /// # Arguments
19    ///
20    /// * namespace - A prefix string for keys
21    /// * connection - A redis connection manager
22    pub fn new<N>(namespace: N, connection: C) -> Self
23    where
24        N: Into<String>,
25    {
26        let namespace = namespace.into();
27        let sessions_key = format!("{namespace}:__seance_sessions");
28        Self {
29            namespace,
30            sessions_key,
31            connection,
32        }
33    }
34
35    fn get_session_key(&self, session_id: &str) -> String {
36        format!("{}:{}", self.namespace, session_id)
37    }
38}
39
40impl<C> SessionBackend for RedisBackend<C>
41where
42    C: AsyncCommands,
43{
44    type Error = RedisBackendError;
45
46    async fn get_sessions(&mut self) -> Result<Vec<String>, Self::Error> {
47        self.connection
48            .hkeys(&self.sessions_key)
49            .await
50            .map_err(RedisBackendError::GetSessions)
51    }
52
53    async fn get_session_age(&mut self, session_id: &str) -> Result<Option<u64>, Self::Error> {
54        self.connection
55            .hget(&self.sessions_key, session_id)
56            .await
57            .map_err(RedisBackendError::GetSessionAge)
58    }
59
60    async fn remove_session(&mut self, session_id: &str) -> Result<(), Self::Error> {
61        let session_key = self.get_session_key(session_id);
62        self.connection
63            .del(session_key)
64            .await
65            .map_err(RedisBackendError::RemoveSession)
66    }
67
68    async fn read_value(&mut self, session_id: &str, key: &str) -> Result<Option<Vec<u8>>, Self::Error> {
69        let session_key = self.get_session_key(session_id);
70        // Use additional variable because trait bound for FromRedisValue is not satisfied for some reason
71        let result: Option<Vec<u8>> = self
72            .connection
73            .hget(session_key, key)
74            .await
75            .map_err(RedisBackendError::ReadValue)?;
76        Ok(result)
77    }
78
79    async fn write_value(&mut self, session_id: &str, key: &str, value: &[u8]) -> Result<(), Self::Error> {
80        let session_key = self.get_session_key(session_id);
81        let len: i64 = self
82            .connection
83            .hlen(&session_key)
84            .await
85            .map_err(RedisBackendError::WriteValue)?;
86        if len == 0 {
87            let timestamp = format!("{}", now().map_err(RedisBackendError::SetSessionTimestamp)?);
88            let _: () = self
89                .connection
90                .hset(&self.sessions_key, session_id, timestamp)
91                .await
92                .map_err(RedisBackendError::WriteValue)?;
93        }
94        self.connection
95            .hset(session_key, key, value)
96            .await
97            .map_err(RedisBackendError::WriteValue)
98    }
99
100    async fn remove_value(&mut self, session_id: &str, key: &str) -> Result<(), Self::Error> {
101        let session_key = self.get_session_key(session_id);
102        self.connection
103            .hdel(session_key, key)
104            .await
105            .map_err(RedisBackendError::RemoveValue)
106    }
107}
108
109/// An error occurred in redis backend
110#[derive(Debug)]
111pub enum RedisBackendError {
112    /// Failed to get sessions list
113    GetSessions(RedisError),
114    /// Failed to get session age
115    GetSessionAge(RedisError),
116    /// Failed to parse session age
117    ParseSessionAge(ParseIntError),
118    /// Failed to parse session ID
119    ParseSessionId(FromUtf8Error),
120    /// Failed to read value
121    ReadValue(RedisError),
122    /// Failed to remove session
123    RemoveSession(RedisError),
124    /// Failed to remove value
125    RemoveValue(RedisError),
126    /// Failed to read session age
127    SessionAgeFromUtf8(FromUtf8Error),
128    /// Failed to set session timestamp
129    ///
130    /// An error occurred when getting system time
131    SetSessionTimestamp(SystemTimeError),
132    /// Failed to write value
133    WriteValue(RedisError),
134}
135
136impl fmt::Display for RedisBackendError {
137    fn fmt(&self, out: &mut fmt::Formatter) -> fmt::Result {
138        use self::RedisBackendError::*;
139        match self {
140            GetSessions(err) => write!(out, "failed to get sessions list: {err}"),
141            GetSessionAge(err) => write!(out, "failed to get session age: {err}"),
142            ParseSessionAge(err) => write!(out, "session age contains non-integer value: {err}"),
143            ParseSessionId(err) => write!(out, "session id contains non-utf8 string: {err}"),
144            ReadValue(err) => write!(out, "failed to read value: {err}"),
145            RemoveSession(err) => write!(out, "failed to remove session: {err}"),
146            RemoveValue(err) => write!(out, "failed to remove value: {err}"),
147            SessionAgeFromUtf8(err) => write!(out, "session age contains non-utf8 string: {err}"),
148            SetSessionTimestamp(err) => write!(out, "failed to set session timestamp: {err}"),
149            WriteValue(err) => write!(out, "failed to write value: {err}"),
150        }
151    }
152}
153
154impl Error for RedisBackendError {
155    fn source(&self) -> Option<&(dyn Error + 'static)> {
156        use self::RedisBackendError::*;
157        Some(match self {
158            GetSessions(err) => err,
159            GetSessionAge(err) => err,
160            ParseSessionAge(err) => err,
161            ParseSessionId(err) => err,
162            ReadValue(err) => err,
163            RemoveSession(err) => err,
164            RemoveValue(err) => err,
165            SessionAgeFromUtf8(err) => err,
166            SetSessionTimestamp(err) => err,
167            WriteValue(err) => err,
168        })
169    }
170}
seance/backend/redis.rs

seance/backend/
redis.rs
