INTERNAL PR VidosResolver example

.gitignore

@@ -1,2 +1,3 @@
 .DS_Store
 **/**/node_modules/
+**/.env

verifier-integration/js/.env

@@ -0,0 +1,2 @@
+VIDOS_RESOLVER_URL=
+VIDOS_API_KEY=

verifier-integration/js/.env.example

@@ -0,0 +1,2 @@
+VIDOS_RESOLVER_URL=https://ugly-aqua-hummingbird-120.resolver.service.eu.vidos.dev
+VIDOS_API_KEY=24b500499e7c2f0a8634831d1b9894b74d656d3e7cd6de238d706c20a5db6d41

verifier-integration/js/VidosResolver.js

@@ -0,0 +1,117 @@
+const { Id } = require("@iden3/js-iden3-core");
+const { resolver } = require("@iden3/js-iden3-auth");
+
+/**
+ * Implementation of {@link resolver.IStateResolver} that uses Vidos resolver service to resolve states.
+ * It can serve as drop-in replacement for {@link resolver.EthStateResolver}.
+ * 
+ * @implements {resolver.IStateResolver}
+ */
+class VidosResolver {
+  /**
+   * @param {string} resolverUrl
+   * @param {string} apiKey
+   */
+  constructor(resolverUrl, apiKey) {
+    this.resolverUrl = resolverUrl;
+    this.apiKey = apiKey;
+  }
+
+  /**
+   * @param {bigint} state
+   * @returns {Promise<resolver.ResolvedState>}
+   */
+  async rootResolve(state) {
+    const stateHex = state.toString("16");
+
+    const zeroAddress = "11111111111111111111"; // 1 is 0 in base58
+    const did = `did:polygonid:polygon:amoy:${zeroAddress}?gist=${stateHex}`;
+
+    const response = await fetch(`${this.resolverUrl}/${encodeURIComponent(did)}`, {
+      method: "GET",
+      headers: {
+        Authorization: `Bearer ${this.apiKey}`,
+      },
+    });
+    const result = await response.json();
+
+    const globalInfo = result.didDocument.verificationMethod[0].global;
+    if (globalInfo == null) throw new Error('gist info not found')
+
+    if (globalInfo.root !== stateHex) {
+      throw new Error('gist info contains invalid state');
+    }
+
+    if (globalInfo.replacedByRoot !== "0") {
+      if (globalInfo.replacedAtTimestamp === "0") {
+        throw new Error('state was replaced, but replaced time unknown');
+      }
+      return {
+        latest: false,
+        state: state,
+        transitionTimestamp: globalInfo.replacedAtTimestamp,
+        genesis: false,
+      };
+    }
+
+    return {
+      latest: true,
+      state: state,
+      transitionTimestamp: 0,
+      genesis: false,
+    };
+  }
+
+  /**
+   * @param {bigint} id
+   * @param {bigint} state
+   * @returns {Promise<resolver.ResolvedState>}
+   */
+  async resolve(id, state) {
+    const iden3Id = Id.fromBigInt(id);
+    const stateHex = state.toString("16");
+
+    const did = `did:polygonid:polygon:amoy:${iden3Id.string()}`;
+
+    const didWithState = `${did}?state=${stateHex}`;
+    const response = await fetch(
+      `${this.resolverUrl}/${encodeURIComponent(didWithState)}`,
+      {
+        method: "GET",
+        headers: {
+          Authorization: `Bearer ${this.apiKey}`,
+        },
+      }
+    );
+    const result = await response.json();
+    const isGenesis = resolver.isGenesisStateId(id, state);
+
+    const stateInfo = result.didDocument.verificationMethod[0].info;
+    if (stateInfo == null) throw new Error('state info not found');
+
+    if (stateInfo.id !== did) {
+      throw new Error(`state was recorded for another identity`);
+    }
+
+    if (stateInfo.state !== stateHex) {
+      if (stateInfo.replacedAtTimestamp === "0") {
+        throw new Error(`no information about state transition`);
+      }
+      return {
+        latest: false,
+        genesis: false,
+        state: state,
+        transitionTimestamp: Number.parseInt(stateInfo.replacedAtTimestamp),
+      };
+    }
+
+    return {
+      latest: stateInfo.replacedAtTimestamp === "0",
+      genesis: isGenesis,
+      state,
+      transitionTimestamp: Number.parseInt(stateInfo.replacedAtTimestamp),
+    };
+  }
+}
+
+module.exports = VidosResolver;

verifier-integration/js/index.js

@@ -1,7 +1,9 @@
+require("dotenv").config();
 const path = require("path");
 const express = require("express");
-const { auth, resolver, protocol } = require("@iden3/js-iden3-auth");
+const { auth, resolver } = require("@iden3/js-iden3-auth");
 const getRawBody = require("raw-body");
+const VidosResolver = require("./VidosResolver");
 
 const app = express();
 const port = 8080;
@@ -85,9 +87,16 @@ async function callback(req, res) {
     ethURL,
     contractAddress
   );
+  const vidosResolver =
+    process.env.VIDOS_RESOLVER_URL && process.env.VIDOS_API_KEY
+      ? new VidosResolver(
+          process.env.VIDOS_RESOLVER_URL,
+          process.env.VIDOS_API_KEY
+        )
+      : undefined;
 
   const resolvers = {
-    ["polygon:amoy"]: ethStateResolver,
+    ["polygon:amoy"]: vidosResolver ?? ethStateResolver,
   };
 
   // fetch authRequest from sessionID

verifier-integration/js/interceptStateResolver.js

@@ -0,0 +1,36 @@
+const { resolver } = require("@iden3/js-iden3-auth");
+
+/**
+ * Wrapper around a state resolver that logs the state resolution process. Useful for debugging and learning how state resolution works.
+ * 
+ * @param {resolver.IStateResolver} resolver
+ * @returns {resolver.IStateResolver}
+ */
+function interceptStateResolver(resolver) {
+  return {
+    async resolve(id, state) {
+      try {
+        console.log("Resolving state", id, state);
+        const result = await resolver.resolve(id, state);
+        console.log("Resolved state", id, state, result);
+        return result;
+      } catch (e) {
+        console.error("Error resolving state", id, state, e);
+        throw e;
+      }
+    },
+    async rootResolve(state) {
+      try {
+        console.log("Resolving root state", state);
+        const result = await resolver.rootResolve(state);
+        console.log("Resolved root state", state, result);
+        return result;
+      } catch (e) {
+        console.error("Error resolving root state", state, e);
+        throw e;
+      }
+    },
+  };
+}
+
+module.exports = interceptStateResolver;

verifier-integration/js/package.json

@@ -1,6 +1,8 @@
 {
   "dependencies": {
     "@iden3/js-iden3-auth": "1.3.2",
-    "express": "^4.18.2"
+    "@iden3/js-iden3-core": "^1.3.1",
+    "express": "^4.18.2",
+    "dotenv": "^16.4.5"
   }
 }