Ionic capture

Open the capture from an Ionic app with a local Capacitor plugin.

Markdown

Your back-end creates the process in Human Plugin with a Journey flow and a callbackUri that uses your app's URL scheme. A local Capacitor plugin opens the link from the response in Custom Tabs on Android and in ASWebAuthenticationSession on iOS. When the capture ends, the plugin resolves and the app takes over.

Keep the Human Plugin id from the create response. Your back-end reads the outcome with it.

Prerequisites

• Ionic with Capacitor 4 or later
• Xcode 14 or later, and Android Studio
• A URL scheme unique to your app, such as myapp

1. Create the process with your scheme

Your back-end sends the scheme as callbackUri:

{
  "flow": "humantoken",
  "clientId": "client-a",
  "correlationId": "order-1001",
  "credential": { "type": "DUI_TYPE_NG_BVN", "value": "<document number>" },
  "callbackUri": "myapp://callback"
}

and returns id and link to the app.

2. Define the plugin interface

// src/plugins/capture-plugin.ts
import { registerPlugin } from '@capacitor/core';

export interface CapturePlugin {
  openSession(options: { url: string }): Promise<{ callbackUrl: string }>;
}

const Capture = registerPlugin<CapturePlugin>('CapturePlugin');
export default Capture;

3. Implement the iOS plugin

import Capacitor
import AuthenticationServices

@objc(CapturePlugin)
public class CapturePlugin: CAPPlugin, ASWebAuthenticationPresentationContextProviding {
    private var session: ASWebAuthenticationSession?

    @objc func openSession(_ call: CAPPluginCall) {
        guard let urlString = call.getString("url"),
              let url = URL(string: urlString) else {
            call.reject("Invalid URL")
            return
        }

        DispatchQueue.main.async {
            let newSession = ASWebAuthenticationSession(
                url: url,
                callbackURLScheme: "myapp"
            ) { callbackURL, error in
                self.session = nil
                if let callbackURL = callbackURL {
                    call.resolve(["callbackUrl": callbackURL.absoluteString])
                } else {
                    call.reject(error?.localizedDescription ?? "Session cancelled")
                }
            }
            newSession.presentationContextProvider = self
            newSession.prefersEphemeralWebBrowserSession = true
            newSession.start()
            self.session = newSession
        }
    }

    public func presentationAnchor(for session: ASWebAuthenticationSession) -> ASPresentationAnchor {
        guard let windowScene = UIApplication.shared.connectedScenes.first as? UIWindowScene,
              let window = windowScene.windows.first else {
            return ASPresentationAnchor()
        }
        return window
    }
}

4. Implement the Android plugin

import android.content.Intent
import android.net.Uri
import androidx.browser.customtabs.CustomTabsIntent
import com.getcapacitor.JSObject
import com.getcapacitor.Plugin
import com.getcapacitor.PluginCall
import com.getcapacitor.PluginMethod
import com.getcapacitor.annotation.CapacitorPlugin

@CapacitorPlugin(name = "CapturePlugin")
class CapturePlugin : Plugin() {

    private var pendingCall: PluginCall? = null

    @PluginMethod
    fun openSession(call: PluginCall) {
        val url = call.getString("url") ?: return call.reject("Missing URL")
        pendingCall = call

        activity.runOnUiThread {
            CustomTabsIntent.Builder().build()
                .launchUrl(activity, Uri.parse(url))
        }
    }

    override fun handleOnNewIntent(intent: Intent) {
        super.handleOnNewIntent(intent)
        intent.data?.let { uri ->
            if (uri.scheme == "myapp") {
                pendingCall?.resolve(JSObject().put("callbackUrl", uri.toString()))
                pendingCall = null
            }
        }
    }
}

5. Register your scheme

iOS

In Info.plist:

<key>CFBundleURLTypes</key>
<array>
    <dict>
        <key>CFBundleURLSchemes</key>
        <array>
            <string>myapp</string>
        </array>
    </dict>
</array>

Android

In AndroidManifest.xml, inside your main <activity>:

<intent-filter>
    <action android:name="android.intent.action.VIEW" />
    <category android:name="android.intent.category.DEFAULT" />
    <category android:name="android.intent.category.BROWSABLE" />
    <data android:scheme="myapp" android:host="callback" />
</intent-filter>

In build.gradle:

implementation("androidx.browser:browser:1.5.0")

6. Start the capture

An Angular service around the plugin:

import { Injectable } from '@angular/core';
import Capture from '../plugins/capture-plugin';

@Injectable({ providedIn: 'root' })
export class CaptureService {
  /** Resolves true when the capture ended, false when the person closed it. */
  async open(link: string): Promise<boolean> {
    try {
      await Capture.openSession({ url: link });
      return true;
    } catch {
      return false;
    }
  }
}

const ended = await this.captureService.open(link);
if (ended) {
  // The capture ended. Ask your back-end to read the outcome
  // with GET /v1/processes/{id}, using the Human Plugin id.
}

Summary

File	Purpose
capture-plugin.ts	Capacitor plugin interface
CapturePlugin.swift	iOS: ASWebAuthenticationSession
CapturePlugin.kt	Android: Custom Tabs
Info.plist	iOS URL scheme
AndroidManifest.xml	Android intent filter
capture.service.ts	Angular service