React Native

import { useEffect, useRef, useState } from "react";
import { Linking } from "react-native";
import { SafeAreaProvider, SafeAreaView } from "react-native-safe-area-context";
import { WebView, WebViewMessageEvent } from "react-native-webview";

const urlMapper = {
  cert: {
    sdkMobile: "https://sdk-mobile.cert.zerohash.com",
    zeroHashAppsURL: "https://web-sdk.cert.zerohash.com",
  },
  prod: {
    sdkMobile: "https://sdk-mobile.zerohash.com",
    zeroHashAppsURL: "https://web-sdk.zerohash.com",
  },
};

/**
 * List of permissions used to request a JWT in the `client_auth_token` request
 */
const permissions = [
  "crypto-buy",
  "crypto-sell",
  "crypto-withdrawals",
  "crypto-payouts",
  "fiat-deposits",
  "fiat-withdrawals",
  "fwc", // Fund
  "onboarding",
  "participant-profile",
  "update-participant",
  "crypto-account-link",
];

/**
 * You can copy and paste a JWT on jwtToken for testing. You will need to
 * implement a function to fetch the JWT from your backend and replace this variable.
 * We have an example below using fetchJwt and setToken functions.
 * */
const jwtToken = ``;

const App = () => {
  const webViewRef = useRef<WebView>(null);
  const [token, setToken] = useState<string>(jwtToken);
  useEffect(() => {
    fetchJwt();
  }, []);

  // Fetch JWT token from server
  const fetchJwt = async () => {
    const jwtPayload = {
      // The participant code you want to request the JWT for.
      participant_code: "<PARTICIPANT_CODE>",
      // The permission required for your use-case, refer to Permissions for
      // the allowed values
      permissions: ["fwc"],
    };
    try {
      const response = await fetch(`<API_URL_TO_FETCH_TOKEN>`, {
        method: "POST",
        body: JSON.stringify(jwtPayload),
      });
      const parsedResponse = await response.json();
      setToken(parsedResponse.message.token);
    } catch (e) {
      console.error("could not fetch jwt", e);
    }
  };

  // Open modal using injected JS script in webview
  const openModal = () => {
     // Replace "jwtToken" with "token" to use the token you got from your backend
    webViewRef.current?.injectJavaScript(
      `window.postMessage({ "type": "OPEN_MODAL", "payload": { "appIdentifier": "fund", "jwt": "${jwtToken}"}});true;`
    );
  };

  const handleMessage = (event: WebViewMessageEvent) => {
    try {
      // Parse message from webview event data checking nativeEvent field
      const parsedMessage = JSON.parse(event.nativeEvent.data);
      console.log("Received message:", parsedMessage);
      if (parsedMessage.type === "SDK_MOBILE_READY") {
        console.log("SDK is ready, opening modal...");
        openModal();
      }
      // Handle webview events
      // Your code here...
    } catch (e) {
      alert(
        `could not parse message: ${JSON.stringify(event.nativeEvent.data)}`
      );
    }
  };

  return (
    <SafeAreaProvider>
      <SafeAreaView style={{ flex: 1 }}>
        <WebView
          allowsInlineMediaPlayback={true}
          ref={webViewRef}
          onMessage={handleMessage}
          source={{
            // Double check the environment you are using and pick the correct URLs
            // accordingly
            uri: `${urlMapper.cert.sdkMobile}/v1?zeroHashAppsURL=${urlMapper.cert.zeroHashAppsURL}`,
          }}
          onNavigationStateChange={(event) => {
            if (!event.url.startsWith(urlMapper.cert.sdkMobile)) {
              webViewRef?.current.stopLoading();
              Linking.openURL(event.url);
            }
          }}
        />
      </SafeAreaView>
    </SafeAreaProvider>
  );
};

export default App;

import React, { useRef } from "react";
import { Platform } from "react-native";
import { WebView } from "react-native-webview";
import * as WebBrowser from "expo-web-browser";
const REDIRECT_URL = "zerohashapp://done";
// Call once to handle auth completion on app startup (iOS requirement)
WebBrowser.maybeCompleteAuthSession();
export default function PlaidWebView() {
  const webViewRef = useRef(null);
  const launchAuthSession = async (url: string) => {
    try {
      // openAuthSessionAsync opens the secure system browser (ASWebAuthenticationSession)
      const result = await WebBrowser.openAuthSessionAsync(url, REDIRECT_URL);
    } catch (e) {
      console.warn("Auth session error", e);
    }
  };

  return (
    <WebView
      ref={webViewRef}
      source={{ uri: "https://sdk-mobile.zerohash.com/v1" }}
      allowsInlineMediaPlayback
      // Interception: The core logic
      onShouldStartLoadWithRequest={(request) => {
        const url = request.url || "";
        // Check for iOS and Plaid URL patterns
        if (Platform.OS === "ios" && url.includes("plaid.com")) {
          // Prevent the WebView from loading the URL itself
          launchAuthSession(url);
          return false; 
        }
      }}
    />
  );
}