feat(rln-wasm): set/get metadata api (#179)

* feat(rln-wasm): set/get metadata api

* fix(rln): imports

rln-wasm/src/lib.rs

@@ -236,6 +236,27 @@ pub fn wasm_delete_leaf(ctx: *mut RLNWrapper, index: usize) -> Result<(), String
     call_with_error_msg!(ctx, delete_leaf, "could not delete leaf".to_string(), index)
 }
 
+#[allow(clippy::not_unsafe_ptr_arg_deref)]
+#[wasm_bindgen(js_name = setMetadata)]
+pub fn wasm_set_metadata(ctx: *mut RLNWrapper, input: Uint8Array) -> Result<(), String> {
+    call_with_error_msg!(
+        ctx,
+        set_metadata,
+        "could not set metadata".to_string(),
+        &*input.to_vec()
+    )
+}
+
+#[allow(clippy::not_unsafe_ptr_arg_deref)]
+#[wasm_bindgen(js_name = getMetadata)]
+pub fn wasm_get_metadata(ctx: *mut RLNWrapper) -> Result<Uint8Array, String> {
+    call_with_output_and_error_msg!(
+        ctx,
+        get_metadata,
+        "could not get metadata".to_string()
+    )
+}
+
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[wasm_bindgen(js_name = initTreeWithLeaves)]
 pub fn wasm_init_tree_with_leaves(ctx: *mut RLNWrapper, input: Uint8Array) -> Result<(), String> {

rln-wasm/tests/rln-wasm.rs

@@ -6,8 +6,7 @@ mod tests {
     use rln::circuit::TEST_TREE_HEIGHT;
     use rln::utils::normalize_usize;
     use rln_wasm::*;
-    use wasm_bindgen::prelude::*;
-    use wasm_bindgen::JsValue;
+    use wasm_bindgen::{prelude::*, JsValue};
     use wasm_bindgen_test::wasm_bindgen_test;
 
     #[wasm_bindgen(module = "src/utils.js")]
@@ -109,4 +108,28 @@ mod tests {
         let is_proof_valid = wasm_verify_with_roots(rln_instance, proof_with_signal, roots);
         assert!(is_proof_valid.unwrap(), "verifying proof with roots failed");
     }
+
+    #[wasm_bindgen_test]
+    fn test_metadata() {
+        let tree_height = TEST_TREE_HEIGHT;
+        let circom_path = format!("../rln/resources/tree_height_{TEST_TREE_HEIGHT}/rln.wasm");
+        let zkey_path = format!("../rln/resources/tree_height_{TEST_TREE_HEIGHT}/rln_final.zkey");
+        let vk_path =
+            format!("../rln/resources/tree_height_{TEST_TREE_HEIGHT}/verification_key.json");
+        let zkey = read_file(&zkey_path).unwrap();
+        let vk = read_file(&vk_path).unwrap();
+
+        // Creating an instance of RLN
+        let rln_instance = wasm_new(tree_height, zkey, vk).unwrap();
+
+
+        let test_metadata = Uint8Array::new(&JsValue::from_str("test"));
+        // Inserting random metadata
+        wasm_set_metadata(rln_instance, test_metadata.clone()).unwrap();
+
+        // Getting metadata
+        let metadata = wasm_get_metadata(rln_instance).unwrap();
+
+        assert_eq!(metadata.to_vec(), test_metadata.to_vec());
+    }
 }

rln/src/public.rs

@@ -12,10 +12,8 @@ use ark_serialize::{CanonicalDeserialize, CanonicalSerialize, Read, Write};
 use cfg_if::cfg_if;
 use color_eyre::{Report, Result};
 use num_bigint::BigInt;
-use serde_json::{json, Value};
 use std::io::Cursor;
-use std::str::FromStr;
-use utils::{Hasher, ZerokitMerkleProof, ZerokitMerkleTree};
+use utils::{ZerokitMerkleProof, ZerokitMerkleTree};
 
 cfg_if! {
     if #[cfg(not(target_arch = "wasm32"))] {
@@ -23,6 +21,9 @@ cfg_if! {
         use std::sync::Mutex;
         use crate::circuit::{circom_from_folder, vk_from_folder, circom_from_raw, zkey_from_folder, TEST_RESOURCES_FOLDER, TEST_TREE_HEIGHT};
         use ark_circom::WitnessCalculator;
+        use serde_json::{json, Value};
+        use utils::{Hasher};
+        use std::str::FromStr;
     } else {
         use std::marker::*;
     }