use the sha2 of the key and add database migrations

src/database/mod.rs

@@ -880,6 +880,27 @@ impl KeyValueDatabase {
                 warn!("Migration: 11 -> 12 finished");
             }
 
+            if services().globals.database_version()? < 13 {
+                // Move old media files to new names
+                for (key, _) in db.mediaid_file.iter() {
+                    // we know that this method is deprecated, but we need to use it to migrate the old files
+                    // to the new location
+                    //
+                    // TODO: remove this once we're sure that all users have migrated
+                    #[allow(deprecated)]
+                    let old_path = services().globals.get_media_file_old(&key);
+                    let path = services().globals.get_media_file(&key);
+                    // move the file to the new location
+                    if old_path.exists() {
+                        tokio::fs::rename(&old_path, &path).await?;
+                    }
+                }
+
+                services().globals.bump_database_version(13)?;
+
+                warn!("Migration: 12 -> 13 finished");
+            }
+
             assert_eq!(
                 services().globals.database_version().unwrap(),
                 latest_database_version

src/service/globals/mod.rs

@@ -3,6 +3,7 @@ pub use data::Data;
 use ruma::{
     OwnedDeviceId, OwnedEventId, OwnedRoomId, OwnedServerName, OwnedServerSigningKeyId, OwnedUserId,
 };
+use sha2::Digest;
 
 use crate::api::server_server::FedDest;
 
@@ -14,14 +15,16 @@ use ruma::{
     },
     DeviceId, RoomVersionId, ServerName, UserId,
 };
-use std::sync::atomic::{self, AtomicBool};
 use std::{
     collections::{BTreeMap, HashMap},
     fs,
     future::Future,
     net::{IpAddr, SocketAddr},
     path::PathBuf,
-    sync::{Arc, Mutex, RwLock},
+    sync::{
+        atomic::{self, AtomicBool},
+        Arc, Mutex, RwLock,
+    },
     time::{Duration, Instant},
 };
 use tokio::sync::{broadcast, watch::Receiver, Mutex as TokioMutex, Semaphore};
@@ -339,6 +342,24 @@ impl Service {
     }
 
     pub fn get_media_file(&self, key: &[u8]) -> PathBuf {
+        let mut r = PathBuf::new();
+        r.push(self.config.database_path.clone());
+        r.push("media");
+        r.push(base64::encode_config(
+            // Using the hash of the key as the filename
+            // This is to prevent the total length of the path from exceeding the maximum length
+            sha2::Sha256::digest(key),
+            base64::URL_SAFE_NO_PAD,
+        ));
+        r
+    }
+
+    /// This is the old version of `get_media_file` that uses the key as the filename.
+    ///
+    /// This is deprecated and will be removed in a future release.
+    /// Please use `get_media_file` instead.
+    #[deprecated(note = "Use get_media_file instead")]
+    pub fn get_media_file_old(&self, key: &[u8]) -> PathBuf {
         let mut r = PathBuf::new();
         r.push(self.config.database_path.clone());
         r.push("media");

src/service/media/mod.rs

@@ -269,9 +269,9 @@ mod tests {
 
         fn search_file_metadata(
             &self,
-            mxc: String,
-            width: u32,
-            height: u32,
+            _mxc: String,
+            _width: u32,
+            _height: u32,
         ) -> Result<(Option<String>, Option<String>, Vec<u8>)> {
             todo!()
         }