mail4agent_server/
media.rs

1//! Media repository for attachments. Blobs are opaque bytes: in E2E rooms
2//! clients upload AES-CTR ciphertext (Matrix encrypted attachments), so the
3//! server stores ciphertext only. They follow the ciphertext-pump rule: kept
4//! for a TTL (see [`purge_expired`]) and then deleted. Plaintext uploads for
5//! public channels use the same table and the same TTL for now; a separate
6//! persistent public-media store is a named seam, not built.
7
8use rand::RngCore;
9use rusqlite::{params, Connection, OptionalExtension};
10
11/// Largest accepted upload.
12pub const MAX_UPLOAD_BYTES: usize = 25 * 1024 * 1024;
13
14/// DDL (own table, outside the event tables).
15pub fn create_media_schema(conn: &Connection) -> rusqlite::Result<()> {
16    conn.execute_batch(
17        "CREATE TABLE IF NOT EXISTS media (
18            media_id      TEXT PRIMARY KEY,
19            owner_user_id INTEGER NOT NULL,
20            content_type  TEXT NOT NULL,
21            filename      TEXT,
22            created_ms    INTEGER NOT NULL,
23            data          BLOB NOT NULL
24        );
25        CREATE INDEX IF NOT EXISTS idx_media_created ON media(created_ms);",
26    )
27}
28
29/// A fetched blob.
30pub struct Blob {
31    /// MIME type given at upload.
32    pub content_type: String,
33    /// Optional upload filename.
34    pub filename: Option<String>,
35    /// Bytes.
36    pub data: Vec<u8>,
37}
38
39/// Stores a blob and returns its media id (24 url-safe chars).
40pub fn put(conn: &Connection, owner: i64, content_type: &str, filename: Option<&str>, data: &[u8], now_ms: i64) -> rusqlite::Result<String> {
41    let mut raw = [0u8; 18];
42    rand::thread_rng().fill_bytes(&mut raw);
43    let id = base64::Engine::encode(&base64::engine::general_purpose::URL_SAFE_NO_PAD, raw);
44    conn.execute(
45        "INSERT INTO media (media_id, owner_user_id, content_type, filename, created_ms, data) VALUES (?1,?2,?3,?4,?5,?6)",
46        params![id, owner, content_type, filename, now_ms, data],
47    )?;
48    Ok(id)
49}
50
51/// Fetches a blob.
52pub fn get(conn: &Connection, media_id: &str) -> rusqlite::Result<Option<Blob>> {
53    conn.query_row("SELECT content_type, filename, data FROM media WHERE media_id = ?1", params![media_id], |r| {
54        Ok(Blob { content_type: r.get(0)?, filename: r.get(1)?, data: r.get(2)? })
55    })
56    .optional()
57}
58
59/// Deletes blobs older than `ttl_ms`. Returns how many.
60pub fn purge_expired(conn: &Connection, now_ms: i64, ttl_ms: i64) -> rusqlite::Result<usize> {
61    conn.execute("DELETE FROM media WHERE created_ms < ?1", params![now_ms - ttl_ms])
62}
63
64#[cfg(test)]
65mod tests {
66    use super::*;
67
68    #[test]
69    fn put_get_and_ttl() {
70        let c = Connection::open_in_memory().unwrap();
71        create_media_schema(&c).unwrap();
72        let id = put(&c, 1, "application/octet-stream", Some("a.bin"), &[1, 2, 3], 1_000).unwrap();
73        assert_eq!(get(&c, &id).unwrap().unwrap().data, vec![1, 2, 3]);
74        assert_eq!(purge_expired(&c, 1_500, 1_000).unwrap(), 0);
75        assert_eq!(purge_expired(&c, 5_000, 1_000).unwrap(), 1);
76        assert!(get(&c, &id).unwrap().is_none());
77    }
78}
mail4agent_server/media.rs

mail4agent_server/
media.rs
