[issue-303] Filter out addresses that do not resolve to ens

packages/backend/functions/.eslintrc.js

@@ -4,6 +4,9 @@ module.exports = {
     es6: true,
     node: true,
   },
+  parserOptions: {
+    ecmaVersion: 8,
+  },
   extends: ["plugin:prettier/recommended"],
   rules: {
     quotes: ["error", "double"],

packages/backend/functions/handlers/filterEnsAddresses.js

@@ -0,0 +1,47 @@
+const functions = require("firebase-functions");
+const ethers = require("ethers");
+
+module.exports = functions.https.onCall(async (data, context) => {
+  const { mainnetProviderUrl, addresses, importedAddresses } = data;
+
+  const lookupAddress = async (provider, address) => {
+    if (address && ethers.utils.isAddress(address)) {
+      try {
+        // Accuracy of reverse resolution is not enforced.
+        // We then manually ensure that the reported ens name resolves to address
+        const ens = await provider.lookupAddress(address);
+        const ensSplit = ens && ens.split(".");
+        const validEnsCheck = ensSplit && ensSplit[ensSplit.length - 1] === "eth";
+
+        if (address && validEnsCheck) {
+          console.log(ens);
+          return true;
+        }
+        return false;
+      } catch (e) {
+        return false;
+      }
+    }
+    return 0;
+  };
+
+  async function removeAddresses(providerUrl, addresses) {
+    const temp = [];
+    if (addresses && addresses.length > 0) {
+      for (let index = 0; index < addresses.length; index++) {
+        const element = addresses[index];
+        const provider = new ethers.providers.StaticJsonRpcProvider(providerUrl, 1);
+        let ens = await lookupAddress(provider, element);
+        if (!ens) {
+          temp.push(element);
+        }
+      }
+    }
+    return temp;
+  }
+
+  const addToblacklistAddresses = await removeAddresses(mainnetProviderUrl, addresses);
+  const removeImportedAddresses = await removeAddresses(mainnetProviderUrl, importedAddresses);
+
+  return { addToblacklistAddresses, removeImportedAddresses };
+});

packages/backend/functions/handlers/index.js

@@ -1,9 +1,11 @@
 const signRoom = require("./signRoom");
 const addRoomTx = require("./addRoomTx");
 const addRoomToken = require("./addRoomToken");
+const filterEnsAddresses = require("./filterEnsAddresses");
 
 module.exports = {
   signRoom,
   addRoomTx,
   addRoomToken,
+  filterEnsAddresses,
 };

packages/backend/functions/index.js

@@ -15,3 +15,4 @@ admin.initializeApp();
 exports.signRoom = handlers.signRoom;
 exports.addRoomTx = handlers.addRoomTx;
 exports.addRoomToken = handlers.addRoomToken;
+exports.filterEnsAddresses = handlers.filterEnsAddresses;

packages/react-app/src/utils/storage.js

@@ -45,3 +45,8 @@ export const registerTransactionForRoom = (room, hash, network) => {
 
   return addRoomTxFunction({ room, hash, network });
 };
+
+export const filterEnsAddresses = (provider, addresses) => {
+  const filterEnsAddressesFunction = httpsCallable(functions, "filterEnsAddresses");
+  return filterEnsAddressesFunction({ provider, addresses });
+};

packages/react-app/src/views/HostRoom.jsx

@@ -348,6 +348,21 @@ export default function HostRoom({
     }
   };
 
+  const handleFilterEns = async (provider, roomAddresses, localAddresses) => {
+    const data = await storage.filterEnsAddresses(provider, roomAddresses, localAddresses);
+    if (data) {
+      // Add to Blacklist
+      unList(data.addToblacklistAddresses);
+
+      //Remove Imported Addresses
+      importedAddresses.forEach((currentAddress, index) => {
+        if (data.removeImportedAddresses.includes(currentAddress)) {
+          removeImportedAddress(index - addresses.length);
+        }
+      });
+    }
+  };
+
   const reList = index => {
     const addressChanged = blacklist[index];
     const updatedAddressesList = [...blacklist];
@@ -469,6 +484,16 @@ export default function HostRoom({
                   >
                     Import Address +
                   </Button>
+                  <Button
+                    type="primary"
+                    size="small"
+                    style={{ marginLeft: 10 }}
+                    onClick={async () => {
+                      await handleFilterEns(process.env.REACT_APP_MAINNET_NETWORK, addresses, importedAddresses);
+                    }}
+                  >
+                    Filter ENS Addresses
+                  </Button>
                 </div>
 
                 <div style={{ flex: 1 }}>