feat: Add matrix-sdk-content-scanner crate with a ContentScannerMediaFetcher implementation

Cargo.lock

@@ -3460,6 +3460,22 @@ dependencies = [
  "web-sys",
 ]
 
+[[package]]
+name = "matrix-sdk-contentscanner"
+version = "0.18.0"
+dependencies = [
+ "assert_matches2",
+ "matrix-sdk",
+ "matrix-sdk-crypto",
+ "matrix-sdk-test",
+ "ruma",
+ "serde",
+ "tokio",
+ "tracing",
+ "uniffi",
+ "wiremock",
+]
+
 [[package]]
 name = "matrix-sdk-crypto"
 version = "0.18.0"
@@ -3561,6 +3577,7 @@ dependencies = [
  "matrix-sdk",
  "matrix-sdk-base",
  "matrix-sdk-common",
+ "matrix-sdk-contentscanner",
  "matrix-sdk-ffi-macros",
  "matrix-sdk-ui",
  "mime",

Cargo.toml

@@ -129,6 +129,7 @@ zeroize = { version = "1.8.2", default-features = false }
 matrix-sdk = { path = "crates/matrix-sdk", version = "0.18.0", default-features = false }
 matrix-sdk-base = { path = "crates/matrix-sdk-base", version = "0.18.0" }
 matrix-sdk-common = { path = "crates/matrix-sdk-common", version = "0.18.0" }
+matrix-sdk-contentscanner = { path = "crates/matrix-sdk-contentscanner", version = "0.18.0" }
 matrix-sdk-crypto = { path = "crates/matrix-sdk-crypto", version = "0.18.0" }
 matrix-sdk-ffi-macros = { path = "bindings/matrix-sdk-ffi-macros", version = "0.7.0" }
 matrix-sdk-indexeddb = { path = "crates/matrix-sdk-indexeddb", version = "0.18.0", default-features = false }

crates/matrix-sdk-contentscanner/Cargo.toml

@@ -0,0 +1,30 @@
+[package]
+authors = ["Jorge Martín Espinosa <jorgem@element.io>"]
+description = "Optional crate used to allow scanning the contents of media to prevent malware infections"
+name = "matrix-sdk-contentscanner"
+version = "0.18.0"
+edition = "2024"
+license = "Apache-2.0"
+rust-version.workspace = true
+
+[features]
+uniffi = ["dep:uniffi", "matrix-sdk/uniffi"]
+
+[dependencies]
+assert_matches2.workspace = true
+matrix-sdk = { workspace = true, features = ["testing", "e2e-encryption"] }
+matrix-sdk-crypto.workspace = true
+ruma = { workspace = true, features = ["client-api"] }
+serde.workspace = true
+tracing.workspace = true
+uniffi = { workspace = true, optional = true }
+
+[dev-dependencies]
+tokio = { workspace = true, features = ["macros"] }
+
+[target.'cfg(not(target_family = "wasm"))'.dependencies]
+matrix-sdk-test.workspace = true
+wiremock.workspace = true
+
+[lints]
+workspace = true

crates/matrix-sdk-contentscanner/src/lib.rs

@@ -0,0 +1,64 @@
+// Copyright 2026 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::sync::Arc;
+
+use matrix_sdk::locks::Mutex;
+use matrix_sdk::{
+    BoxFuture, Client, Error, IdParseError,
+    locks::Mutex,
+    media::{MediaFetcher, MediaRequestParameters},
+};
+
+#[cfg(feature = "uniffi")]
+uniffi::setup_scaffolding!();
+
+
+/// A helper component to download and scan media from a content scanner server.
+#[derive(Debug)]
+pub struct ContentScanner {
+    scanner_url: String,
+    public_server_key: Arc<Mutex<Option<String>>>,
+}
+
+impl ContentScanner {
+    /// Instantiate a new [`ContentScanner`] using the `scanner_url`.
+    pub fn new(scanner_url: impl Into<String>) -> Self {
+        Self { scanner_url: scanner_url.into(), public_server_key: Arc::new(Mutex::new(None)) }
+    }
+
+/// A media fetcher that uses the content scanner to download and scan media.
+pub struct ContentScannerMediaFetcher {
+    pub content_scanner: ContentScanner,
+}
+
+impl ContentScannerMediaFetcher {
+    /// Instantiate a new [`MediaFetcher`] using the provided `scanner_url`.
+    pub fn new(scanner_url: impl Into<String>) -> Self {
+        Self { content_scanner: ContentScanner::new(scanner_url.into()) }
+    }
+}
+
+impl MediaFetcher for ContentScannerMediaFetcher {
+    fn fetch_media_content<'a>(
+        &'a self,
+        _client: &'a Client,
+        _request: &'a MediaRequestParameters,
+    ) -> BoxFuture<'a, matrix_sdk::Result<Vec<u8>, Error>> {
+        Box::pin(async move {
+            todo!("Implement fetch_media_content")
+        })
+    }
+}
+}

crates/matrix-sdk-contentscanner/uniffi.toml

@@ -0,0 +1,5 @@
+[bindings.kotlin]
+android_cleaner = true
+# Checksums are incorrectly failing for users with 32bit (and sometimes 64bit?) devices at the moment
+# Remove once https://github.com/mozilla/uniffi-rs/issues/2740 is fixed or JNI is used instead of JNA
+omit_checksums = true