feat(iOS, Android): add AppUUID Lib for plugins

android/capacitor/src/main/java/com/getcapacitor/AppUUID.java

@@ -0,0 +1,65 @@
+package com.getcapacitor;
+
+import android.content.Context;
+import android.content.SharedPreferences;
+import androidx.appcompat.app.AppCompatActivity;
+import java.nio.charset.StandardCharsets;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.util.Objects;
+import java.util.UUID;
+
+public final class AppUUID {
+
+    private static final String KEY = "CapacitorAppUUID";
+
+    public static String getAppUUID(AppCompatActivity activity) throws Exception {
+        assertAppUUID(activity);
+        return readUUID(activity);
+    }
+
+    public static void regenerateAppUUID(AppCompatActivity activity) throws Exception {
+        try {
+            String uuid = generateUUID();
+            writeUUID(activity, uuid);
+        } catch (NoSuchAlgorithmException ex) {
+            throw new Exception("Capacitor App UUID could not be generated.");
+        }
+    }
+
+    private static void assertAppUUID(AppCompatActivity activity) throws Exception {
+        String uuid = readUUID(activity);
+        if (uuid.equals("")) {
+            regenerateAppUUID(activity);
+        }
+    }
+
+    private static String generateUUID() throws NoSuchAlgorithmException {
+        MessageDigest salt = MessageDigest.getInstance("SHA-256");
+        salt.update(UUID.randomUUID().toString().getBytes(StandardCharsets.UTF_8));
+        return bytesToHex(salt.digest());
+    }
+
+    private static String readUUID(AppCompatActivity activity) {
+        SharedPreferences sharedPref = activity.getPreferences(Context.MODE_PRIVATE);
+        return sharedPref.getString(KEY, "");
+    }
+
+    private static void writeUUID(AppCompatActivity activity, String uuid) {
+        SharedPreferences sharedPref = activity.getPreferences(Context.MODE_PRIVATE);
+        SharedPreferences.Editor editor = sharedPref.edit();
+        editor.putString(KEY, uuid);
+        editor.apply();
+    }
+
+    private static String bytesToHex(byte[] bytes) {
+        byte[] HEX_ARRAY = "0123456789ABCDEF".getBytes(StandardCharsets.US_ASCII);
+        byte[] hexChars = new byte[bytes.length * 2];
+        for (int j = 0; j < bytes.length; j++) {
+            int v = bytes[j] & 0xFF;
+            hexChars[j * 2] = HEX_ARRAY[v >>> 4];
+            hexChars[j * 2 + 1] = HEX_ARRAY[v & 0x0F];
+        }
+        return new String(hexChars, StandardCharsets.UTF_8);
+    }
+}

ios/Capacitor/Capacitor.xcodeproj/project.pbxproj

@@ -7,6 +7,7 @@
 	objects = {
 
 /* Begin PBXBuildFile section */
+		0F83E885285A332E006C43CB /* AppUUID.swift in Sources */ = {isa = PBXBuildFile; fileRef = 0F83E884285A332D006C43CB /* AppUUID.swift */; };
 		2F81F5C926FB7CB400DD35BE /* CAPBridgeViewController+CDVScreenOrientationDelegate.h in Headers */ = {isa = PBXBuildFile; fileRef = 2F81F5C726FB7CB400DD35BE /* CAPBridgeViewController+CDVScreenOrientationDelegate.h */; };
 		2F81F5CA26FB7CB400DD35BE /* CAPBridgeViewController+CDVScreenOrientationDelegate.m in Sources */ = {isa = PBXBuildFile; fileRef = 2F81F5C826FB7CB400DD35BE /* CAPBridgeViewController+CDVScreenOrientationDelegate.m */; };
 		373A69C1255C9360000A6F44 /* NotificationHandlerProtocol.swift in Sources */ = {isa = PBXBuildFile; fileRef = 373A69C0255C9360000A6F44 /* NotificationHandlerProtocol.swift */; };
@@ -138,6 +139,7 @@
 /* End PBXCopyFilesBuildPhase section */
 
 /* Begin PBXFileReference section */
+		0F83E884285A332D006C43CB /* AppUUID.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AppUUID.swift; sourceTree = "<group>"; };
 		2F81F5C726FB7CB400DD35BE /* CAPBridgeViewController+CDVScreenOrientationDelegate.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = "CAPBridgeViewController+CDVScreenOrientationDelegate.h"; sourceTree = "<group>"; };
 		2F81F5C826FB7CB400DD35BE /* CAPBridgeViewController+CDVScreenOrientationDelegate.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = "CAPBridgeViewController+CDVScreenOrientationDelegate.m"; sourceTree = "<group>"; };
 		373A69C0255C9360000A6F44 /* NotificationHandlerProtocol.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NotificationHandlerProtocol.swift; sourceTree = "<group>"; };
@@ -355,6 +357,7 @@
 				373A69F1255C95D0000A6F44 /* NotificationRouter.swift */,
 				62E79C562638AF7500414164 /* assets */,
 				A71289E527F380A500DADDF3 /* Router.swift */,
+				0F83E884285A332D006C43CB /* AppUUID.swift */,
 			);
 			path = Capacitor;
 			sourceTree = "<group>";
@@ -616,6 +619,7 @@
 				62FABD1A25AE5C01007B3814 /* Array+Capacitor.swift in Sources */,
 				62959B172524DA7800A3D7F1 /* JSExport.swift in Sources */,
 				373A69C1255C9360000A6F44 /* NotificationHandlerProtocol.swift in Sources */,
+				0F83E885285A332E006C43CB /* AppUUID.swift in Sources */,
 				625AF1ED258963C700869675 /* WebViewAssetHandler.swift in Sources */,
 				62959B3C2524DA7800A3D7F1 /* CAPBridgeDelegate.swift in Sources */,
 				62959B2F2524DA7800A3D7F1 /* DefaultPlugins.m in Sources */,

ios/Capacitor/Capacitor/AppUUID.swift

@@ -0,0 +1,53 @@
+import CommonCrypto
+import Foundation
+
+private func hexString(_ iterator: Array<UInt8>.Iterator) -> String {
+    return iterator.map { String(format: "%02x", $0) }.joined()
+}
+
+extension Data {
+    public var sha256: String {
+        var digest = [UInt8](repeating: 0, count: Int(CC_SHA256_DIGEST_LENGTH))
+        self.withUnsafeBytes { bytes in
+            _ = CC_SHA256(bytes.baseAddress, CC_LONG(self.count), &digest)
+        }
+        return hexString(digest.makeIterator())
+    }
+}
+
+public class AppUUID {
+    private static let key: String = "CapacitorAppUUID"
+
+    public static func getAppUUID() -> String {
+        assertAppUUID()
+        return readUUID()
+    }
+
+    public static func regenerateAppUUID() {
+        let uuid = generateUUID()
+        writeUUID(uuid)
+    }
+
+    private static func assertAppUUID() {
+        let uuid = readUUID()
+        if uuid == "" {
+            regenerateAppUUID()
+        }
+    }
+
+    private static func generateUUID() -> String {
+        let uuid: String = UUID.init().uuidString
+        return uuid.data(using: .utf8)!.sha256
+    }
+
+    private static func readUUID() -> String {
+        let defaults = UserDefaults.standard
+        return defaults.string(forKey: key) ?? ""
+    }
+
+    private static func writeUUID(_ uuid: String) {
+        let defaults = UserDefaults.standard
+        defaults.set(uuid, forKey: key)
+    }
+
+}