Support multiple IOTA networks in the Resolver

identity_resolver/src/error.rs

@@ -68,4 +68,7 @@ pub enum ErrorCause {
     /// The method that is unsupported.
     method: String,
   },
+  /// No client attached to the specific network.
+  #[error("none of the attached clients support the network {0}")]
+  UnsupportedNetwork(String),
 }

identity_resolver/src/resolution/resolver.rs

@@ -249,6 +249,8 @@ impl<DOC: 'static> Resolver<DOC, SingleThreadedCommand<DOC>> {
 
 #[cfg(feature = "iota")]
 mod iota_handler {
+  use crate::ErrorCause;
+
   use super::Resolver;
   use identity_document::document::CoreDocument;
   use identity_iota_core::IotaClientExt;
@@ -277,6 +279,59 @@ mod iota_handler {
 
       self.attach_handler(IotaDID::METHOD.to_owned(), handler);
     }
+
+    /// Convenience method for attaching multiple handlers responsible for resolving IOTA DIDs
+    /// on multiple networks.
+    ///
+    ///
+    /// # Arguments
+    ///
+    /// * `clients` - A collection of tuples where each tuple contains the name of the network name and its
+    ///   corresponding client.
+    ///
+    /// # Examples
+    ///
+    /// ```ignore
+    /// // Assume `smr_client` and `iota_client` are instances IOTA clients `iota_sdk::client::Client`.
+    /// attach_multiple_iota_handlers(vec![("smr", smr_client), ("iota", iota_client)]);
+    /// ```
+    ///
+    /// # See Also
+    /// - [`attach_handler`](Self::attach_handler).
+    ///
+    /// # Note
+    ///
+    /// - Using `attach_iota_handler` or `attach_handler` for the IOTA method would override all
+    /// clients added in this method.
+    /// - This function does not validate the provided configuration. Ensure that the provided
+    /// network name corresponds with the client, possibly by using `client.network_name()`.
+    pub fn attach_multiple_iota_handlers<CLI>(&mut self, clients: Vec<(&'static str, CLI)>)
+    where
+      CLI: IotaClientExt + Send + Sync + 'static,
+    {
+      let arc_clients: Arc<Vec<(&str, CLI)>> = Arc::new(clients);
+
+      let handler = move |did: IotaDID| {
+        let future_client = arc_clients.clone();
+        async move {
+          let did_network = did.network_str();
+          let client: &CLI = future_client
+            .as_ref()
+            .iter()
+            .find(|(network, _)| *network == did_network)
+            .map(|(_, client)| client)
+            .ok_or(crate::Error::new(ErrorCause::UnsupportedNetwork(
+              did_network.to_string(),
+            )))?;
+          client
+            .resolve_did(&did)
+            .await
+            .map_err(|err| crate::Error::new(ErrorCause::HandlerError { source: Box::new(err) }))
+        }
+      };
+
+      self.attach_handler(IotaDID::METHOD.to_owned(), handler);
+    }
   }
 }