Add support for sgnl:// proxy deep links.

app/src/main/AndroidManifest.xml

@@ -261,6 +261,8 @@
             <category android:name="android.intent.category.BROWSABLE" />
             <data android:scheme="https"
                   android:host="signal.tube" />
+            <data android:scheme="sgnl"
+                  android:host="signal.tube" />
         </intent-filter>
     </activity>
 

app/src/main/java/org/thoughtcrime/securesms/util/SignalProxyUtil.java

@@ -103,11 +103,17 @@ public final class SignalProxyUtil {
    * If this is a valid proxy deep link, this will return the embedded host. If not, it will return
    * null.
    */
-  public static @Nullable String parseHostFromProxyDeepLink(@NonNull String proxyLink) {
+  public static @Nullable String parseHostFromProxyDeepLink(@Nullable String proxyLink) {
+    if (proxyLink == null) {
+      return null;
+    }
+
     try {
       URI uri = new URI(proxyLink);
 
-      if (!"https".equalsIgnoreCase(uri.getScheme())) {
+      if (!"https".equalsIgnoreCase(uri.getScheme()) &&
+          !"sgnl".equalsIgnoreCase(uri.getScheme()))
+      {
         return null;
       }
 

app/src/test/java/org/thoughtcrime/securesms/util/SignalProxyUtilText_parseHostFromProxyDeepLink.java

@@ -0,0 +1,43 @@
+package org.thoughtcrime.securesms.util;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+
+import java.util.Arrays;
+import java.util.Collection;
+
+import static junit.framework.TestCase.assertEquals;
+
+@RunWith(Parameterized.class)
+public class SignalProxyUtilText_parseHostFromProxyDeepLink {
+
+  private final String input;
+  private final String output;
+
+  @Parameterized.Parameters
+  public static Collection<Object[]> data() {
+    return Arrays.asList(new Object[][]{
+        { "https://signal.tube/#proxy.parker.org", "proxy.parker.org" },
+        { "sgnl://signal.tube/#proxy.parker.org",  "proxy.parker.org" },
+        { "https://signal.tube/",                   null },
+        { "https://signal.tube/#",                  null },
+        { "sgnl://signal.tube/",                    null },
+        { "sgnl://signal.tube/#",                   null },
+        { "http://signal.tube/#proxy.parker.org",   null },
+        { "signal.tube/#proxy.parker.org",          null },
+        { "",                                       null },
+        { null,                                     null }
+    });
+  }
+
+  public SignalProxyUtilText_parseHostFromProxyDeepLink(String input, String output) {
+    this.input  = input;
+    this.output = output;
+  }
+
+  @Test
+  public void parse() {
+    assertEquals(output, SignalProxyUtil.parseHostFromProxyDeepLink(input));
+  }
+}