Allow customizing the featureStates

Use a comma separated list of features to enable using the FEATURE_FLAGS env variable

src/api/core/mod.rs

@@ -193,7 +193,10 @@ fn version() -> Json<&'static str> {
 #[get("/config")]
 fn config() -> Json<Value> {
     let domain = crate::CONFIG.domain();
-    Json(json!({
+    let feature_flags = crate::CONFIG.feature_flags().to_lowercase();
+    let features = feature_flags.split(',').map(|f| f.trim()).collect::<Vec<_>>();
+    let mut feature_states = json!({});
+    let mut config = json!({
         // Note: The clients use this version to handle backwards compatibility concerns
         // This means they expect a version that closely matches the Bitwarden server version
         // We should make sure that we keep this updated when we support the new server features
@@ -213,15 +216,15 @@ fn config() -> Json<Value> {
           "notifications": format!("{domain}/notifications"),
           "sso": "",
         },
-        "featureStates": {
-          // Any feature flags that we want the clients to use
-          // Can check the enabled ones at:
-          // https://vault.bitwarden.com/api/config
-          "fido2-vault-credentials": true,  // Passkey support
-          "autofill-v2": false,             // Disabled because it is causing issues https://github.com/dani-garcia/vaultwarden/discussions/4052
-        },
         "object": "config",
-    }))
+    });
+    // Disabled because it is causing issues https://github.com/dani-garcia/vaultwarden/discussions/4052
+    feature_states["autofill-v2"] = serde_json::Value::Bool(false);
+    for feature in features {
+        feature_states[feature.to_string()] = serde_json::Value::Bool(true);
+    }
+    config["featureStates"] = feature_states;
+    Json(config)
 }
 
 pub fn catchers() -> Vec<Catcher> {

src/config.rs

@@ -547,6 +547,9 @@ make_config! {
         /// TOTP codes of the previous and next 30 seconds will be invalid.
         authenticator_disable_time_drift: bool, true, def, false;
 
+        /// Customize the enabled feature flags on the clients |> This is a comma separated list of feature flags to enable.
+        feature_flags: String, false, def, "fido2-vault-credentials".to_string();
+
         /// Require new device emails |> When a user logs in an email is required to be sent.
         /// If sending the email fails the login attempt will fail.
         require_device_email:   bool,   true,   def,     false;
@@ -751,6 +754,27 @@ fn validate_config(cfg: &ConfigItems) -> Result<(), Error> {
         )
     }
 
+    let feature_flags = cfg.feature_flags.to_lowercase();
+    let features = feature_flags.split(',').map(|f| f.trim()).collect::<Vec<_>>();
+    let supported_flags = vec![
+        "display-kdf-iteration-warning",
+        "fido2-vault-credentials",
+        "trusted-device-encryption",
+        "passwordless-login",
+        "autofill-v2",
+        "autofill-overlay",
+        "browser-fileless-import",
+        "item-share",
+        "flexible-collections",
+        "flexible-collections-v-1",
+        "bulk-collection-access",
+    ];
+    for feature in features {
+        if !supported_flags.contains(&feature) {
+            err!(format!("Feature flag {feature:?} is not supported."));
+        }
+    }
+
     if cfg._enable_duo
         && (cfg.duo_host.is_some() || cfg.duo_ikey.is_some() || cfg.duo_skey.is_some())
         && !(cfg.duo_host.is_some() && cfg.duo_ikey.is_some() && cfg.duo_skey.is_some())