Sign In With Ethereum

import { SiweMessage } from "siwe";
import {
  type SIWESession,
  type SIWEVerifyMessageArgs,
  type SIWECreateMessageArgs,
  createSIWEConfig,
  formatMessage,
} from "@reown/appkit-siwe";

const BASE_URL = "http://localhost:8080";

/* Function that returns the user's session - this should come from your SIWE backend */
async function getSession() {
  const res = await fetch(BASE_URL + "/session", {
    method: "GET",
    headers: {
      "Content-Type": "application/json",
    },
    credentials: "include",
  });
  if (!res.ok) {
    throw new Error("Network response was not ok");
  }

  const data = await res.json();

  const isValidData =
    typeof data === "object" &&
    typeof data.address === "string" &&
    typeof data.chainId === "number";

  return isValidData ? (data as SIWESession) : null;
}

/* Use your SIWE server to verify if the message and the signature are valid */
const verifyMessage = async ({ message, signature }: SIWEVerifyMessageArgs) => {
  try {
    const response = await fetch(BASE_URL + "/verify", {
      method: "POST",
      headers: {
        Accept: "application/json",
        "Content-Type": "application/json",
      },
      mode: "cors",
      body: JSON.stringify({ message, signature }),
      credentials: "include",
    });

    if (!response.ok) {
      return false;
    }

    const result = await response.json();
    return result === true;
  } catch (error) {
    return false;
  }
};

// Check the full example for signOut and getNonce functions ...

/* Create a SIWE configuration object */
export const siweConfig = createSIWEConfig({
  getMessageParams: async () => ({
    domain: window.location.host,
    uri: window.location.origin,
    chains: [1, 2020],
    statement: "Please sign with your account",
  }),
  createMessage: ({ address, ...args }: SIWECreateMessageArgs) =>
    formatMessage(args, address),

  getNonce: async () => {
    //This is only an example, substitute it with your actual nonce getter.
    const nonce = "YOUR_NONCE_GETTER";
    if (!nonce) {
      throw new Error("Failed to get nonce!");
    }
    return nonce;
  },
  getSession,
  verifyMessage,
  signOut: async () => {
    //Example
    // Implement your Sign out function
  },
});

import cors from "cors";
import express from "express";
import Session from "express-session";
import { generateNonce } from "siwe";
import {
  /*verifySignature,*/
  getAddressFromMessage,
  getChainIdFromMessage,
} from "@reown/appkit-siwe";
import { createPublicClient, http } from "viem";

const app = express();

const projectId = "YOUR_PROJECT_ID";

// configure cors and sessions
app.use(
  cors({
    origin: "http://localhost:5173", // frontend URL
    credentials: true,
  })
);
app.use(express.json());
app.use(
  Session({
    name: "siwe-quickstart",
    secret: "siwe-quickstart-secret",
    resave: true,
    saveUninitialized: true,
    cookie: { secure: false, sameSite: true },
  })
);

app.get("/nonce", function (_, res) {
  res.setHeader("Content-Type", "text/plain");
  res.send(generateNonce());
});

// verify the message
app.post("/verify", async (req, res) => {
  try {
    if (!req.body.message) {
      return res.status(400).json({ error: "SiweMessage is undefined" });
    }

    // save the session with the address and chainId (SIWESession)
    req.session.siwe = { address, chainId };
    req.session.save(() => res.status(200).send(true));

    const message = req.body.message;
    const signature = req.body.signature;
    const address = getAddressFromMessage(message);
    let chainId = getChainIdFromMessage(message);

    // for the moment, the verifySignature is not working with social logins and emails  with non deployed smart accounts
    // for this reason we recommend using the viem to verify the signature
    const publicClient = createPublicClient({
      transport: http(
        `https://rpc.walletconnect.org/v1/?chainId=${chainId}&projectId=${projectId}`
      ),
    });
    const isValid = await publicClient.verifyMessage({
      message,
      address,
      signature,
    });
    if (!isValid) {
      // throw an error if the signature is invalid
      throw new Error("Invalid signature");
    }
    if (chainId.includes(":")) {
      chainId = chainId.split(":")[1];
    }

    // Convert chainId to a number
    chainId = Number(chainId);

    if (isNaN(chainId)) {
      throw new Error("Invalid chainId");
    }

    // save the session with the address and chainId (SIWESession)
    req.session.siwe = { address, chainId };
    req.session.save(() => res.status(200).send(true));
  } catch (e) {
    // clean the session
    req.session.siwe = null;
    req.session.nonce = null;
    req.session.save(() => res.status(500).json({ message: e.message }));
  }
});

/// ... check the github repository for the others endpoints

// get the session
app.get("/session", (req, res) => {
  res.setHeader("Content-Type", "application/json");
  res.send(req.session.siwe);
});

import { createPublicClient, http } from "viem";

const publicClient = createPublicClient({
  transport: http(
    `https://rpc.walletconnect.org/v1/?chainId=${chainId}&projectId=${projectId}`
  ),
});
const isValid = await publicClient.verifyMessage({
  message,
  address: address as `0x${string}`,
  signature: signature as `0x${string}`,
});

// The verifySignature is not working with social logins and emails with non deployed smart accounts
// for this reason we recommend using the viem to verify the signature
// import { verifySignature } from '@reown/appkit-siwe'
// const isValid = await verifySignature({ address, message, signature, chainId, projectId })