Support get android app signatures.

packages/react-native-version-check/android/build.gradle

@@ -1,7 +1,7 @@
 
 apply plugin: 'com.android.library'
 
-def DEFAULT_COMPILE_SDK_VERSION = 26
+def DEFAULT_COMPILE_SDK_VERSION = 28
 def DEFAULT_BUILD_TOOLS_VERSION = "26.0.3"
 def DEFAULT_TARGET_SDK_VERSION = 26
 def DEFAULT_MIN_SDK_VERSION = 16

packages/react-native-version-check/android/src/main/java/io/xogus/reactnative/versioncheck/RNVersionCheckModule.java

@@ -3,13 +3,20 @@
 
 import android.content.pm.PackageInfo;
 import android.content.pm.PackageManager;
+import android.content.pm.Signature;
+import android.content.pm.SigningInfo;
+import android.os.Build;
 
 import com.facebook.react.bridge.ReactApplicationContext;
 import com.facebook.react.bridge.ReactContextBaseJavaModule;
 
 import java.util.HashMap;
 import java.util.Locale;
 import java.util.Map;
+import java.util.List;
+import java.util.ArrayList;
+
+import java.security.MessageDigest;
 
 import javax.annotation.Nullable;
 
@@ -25,6 +32,36 @@ public RNVersionCheckModule(ReactApplicationContext reactContext)
         this.packageName = this.reactContext.getPackageName();
     }
 
+    private static final char[] HEX_ARRAY = "0123456789ABCDEF".toCharArray();
+    public static String bytesToHex(byte[] bytes) {
+        char[] hexChars = new char[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);
+    }
+
+    public static String signatureToSHAHex(Signature sig) {
+        try {
+            MessageDigest digest = MessageDigest.getInstance("SHA");
+            digest.update(sig.toByteArray());
+            return bytesToHex(digest.digest());            
+        }
+        catch (Exception e) {
+            return null;
+        }
+    }
+
+    public static List<String> signaturesToSHAHexList(Signature[] signatures) {
+        List<String> signatureList = new ArrayList<String>();
+        for (Signature sig : signatures) {
+            signatureList.add(signatureToSHAHex(sig));
+        }
+        return signatureList;
+    }
+
     @Override
     public @Nullable Map<String, Object> getConstants()
     {
@@ -36,12 +73,38 @@ public RNVersionCheckModule(ReactApplicationContext reactContext)
         PackageManager packageManager = this.reactContext.getPackageManager();
         try
         {
-            PackageInfo info = packageManager.getPackageInfo(packageName, 0);
+            boolean useNewAPI = Build.VERSION.SDK_INT >= Build.VERSION_CODES.P;
+            PackageInfo info = packageManager.getPackageInfo(packageName, useNewAPI ? PackageManager.GET_SIGNING_CERTIFICATES : PackageManager.GET_SIGNATURES);
+
+            List<String> signatureList;
+
+            if (useNewAPI)
+            {
+                // New signature
+                SigningInfo sig = info.signingInfo;
+                if (sig.hasMultipleSigners())
+                {
+                    // Send all with apkContentsSigners
+                    signatureList = signaturesToSHAHexList(sig.getApkContentsSigners());
+                }
+                else
+                {
+                    // Send one with signingCertificateHistory
+                    signatureList = signaturesToSHAHexList(sig.getSigningCertificateHistory());
+                }
+            }
+            else
+            {
+                signatureList = signaturesToSHAHexList(info.signatures);
+            }
+
+            constants.put("signatures", signatureList);
             constants.put("currentVersion", info.versionName);
             constants.put("currentBuildNumber", info.versionCode);
         }
         catch (PackageManager.NameNotFoundException e)
         {
+            constants.put("signatures", null);
             constants.put("currentVersion", null);
             constants.put("currentBuildNumber", null);
         }

packages/react-native-version-check/builder.js

@@ -23,6 +23,7 @@ export default (VersionInfoObject: IVersionInfo): ReactNativeVersionCheck => {
     getPackageName: VersionInfoObject.getPackageName,
     getCurrentBuildNumber: VersionInfoObject.getCurrentBuildNumber,
     getCurrentVersion: VersionInfoObject.getCurrentVersion,
+    getAppSignatures: VersionInfoObject.getAppSignatures,
 
     getStoreUrl,
     getAppStoreUrl,

packages/react-native-version-check/src/RNVersionInfo.js

@@ -6,4 +6,5 @@ export default {
   getPackageName: (): string => RNVersionCheck.packageName,
   getCurrentBuildNumber: (): number => RNVersionCheck.currentBuildNumber,
   getCurrentVersion: (): string => RNVersionCheck.currentVersion,
+  getAppSignatures: (): string[] => RNVersionCheck.signatures,
 };

packages/react-native-version-check/src/versionInfo.js

@@ -4,6 +4,7 @@ export interface IVersionInfo {
   getPackageName: () => string;
   getCurrentBuildNumber: () => number;
   getCurrentVersion: () => string;
+  getAppSignatures: () => string[];
 }
 
 let VersionInfo: ?IVersionInfo = null;