Trying some Rx spice

app/src/main/java/chat/rocket/android/api/rest/DefaultServerPolicyApi.java

@@ -8,13 +8,12 @@ import java.io.IOException;
 import okhttp3.Call;
 import okhttp3.OkHttpClient;
 import okhttp3.Request;
-import okhttp3.Response;
 import okhttp3.ResponseBody;
+import rx.Emitter;
+import rx.Observable;
 
 public class DefaultServerPolicyApi implements ServerPolicyApi {
 
-  private static final String SECURE_PROTOCOL = "https://";
-  private static final String INSECURE_PROTOCOL = "http://";
   private static final String API_INFO_PATH = "/api/info";
 
   private final OkHttpClient client;
@@ -26,13 +25,23 @@ public class DefaultServerPolicyApi implements ServerPolicyApi {
   }
 
   @Override
-  public void getApiInfoSecurely(@NonNull Callback callback) {
-    client.newCall(createRequest(SECURE_PROTOCOL)).enqueue(getOkHttpCallback(callback));
+  public Observable<Response<JSONObject>> getApiInfoSecurely() {
+    return getApiInfo(SECURE_PROTOCOL);
   }
 
   @Override
-  public void getApiInfoInsecurely(@NonNull Callback callback) {
-    client.newCall(createRequest(INSECURE_PROTOCOL)).enqueue(getOkHttpCallback(callback));
+  public Observable<Response<JSONObject>> getApiInfoInsecurely() {
+    return getApiInfo(INSECURE_PROTOCOL);
+  }
+
+  private Observable<Response<JSONObject>> getApiInfo(@NonNull String protocol) {
+    return Observable.fromEmitter(responseEmitter -> {
+      final Call call = client.newCall(createRequest(protocol));
+
+      call.enqueue(getOkHttpCallback(responseEmitter, protocol));
+
+      responseEmitter.setCancellation(call::cancel);
+    }, Emitter.BackpressureMode.LATEST);
   }
 
   private Request createRequest(@NonNull String protocol) {
@@ -42,31 +51,36 @@ public class DefaultServerPolicyApi implements ServerPolicyApi {
         .build();
   }
 
-  private okhttp3.Callback getOkHttpCallback(@NonNull Callback callback) {
+  private okhttp3.Callback getOkHttpCallback(@NonNull Emitter<Response<JSONObject>> emitter,
+                                             @NonNull String protocol) {
     return new okhttp3.Callback() {
       @Override
       public void onFailure(Call call, IOException ioException) {
-        callback.onNetworkError();
+        emitter.onError(ioException);
       }
 
       @Override
-      public void onResponse(Call call, Response response) throws IOException {
+      public void onResponse(Call call, okhttp3.Response response) throws IOException {
         if (!response.isSuccessful()) {
-          callback.onResponseError();
+          emitter.onNext(new Response<>(false, protocol, null));
+          emitter.onCompleted();
           return;
         }
 
         final ResponseBody body = response.body();
         if (body == null || body.contentLength() == 0) {
-          callback.onResponseError();
+          emitter.onNext(new Response<>(false, protocol, null));
+          emitter.onCompleted();
           return;
         }
 
         try {
-          callback.onSuccess(new JSONObject(body.string()));
+          emitter.onNext(new Response<>(true, protocol, new JSONObject(body.string())));
         } catch (Exception e) {
-          callback.onResponseError();
+          emitter.onNext(new Response<>(false, protocol, null));
         }
+
+        emitter.onCompleted();
       }
     };
   }

app/src/main/java/chat/rocket/android/api/rest/Response.java

+package chat.rocket.android.api.rest;
+
+public class Response<T> {
+  private final boolean successful;
+  private final String protocol;
+  private final T data;
+
+  public Response(boolean successful, String protocol, T data) {
+    this.successful = successful;
+    this.protocol = protocol;
+    this.data = data;
+  }
+
+  public boolean isSuccessful() {
+    return successful;
+  }
+
+  public String getProtocol() {
+    return protocol;
+  }
+
+  public T getData() {
+    return data;
+  }
+}

app/src/main/java/chat/rocket/android/api/rest/ServerPolicyApi.java

 package chat.rocket.android.api.rest;
 
-import android.support.annotation.NonNull;
 import org.json.JSONObject;
 
-public interface ServerPolicyApi {
-
-  void getApiInfoSecurely(@NonNull Callback callback);
+import rx.Observable;
 
-  void getApiInfoInsecurely(@NonNull Callback callback);
+public interface ServerPolicyApi {
 
-  interface Callback {
-    void onSuccess(JSONObject jsonObject);
+  String SECURE_PROTOCOL = "https://";
+  String INSECURE_PROTOCOL = "http://";
 
-    void onResponseError();
+  Observable<Response<JSONObject>> getApiInfoSecurely();
 
-    void onNetworkError();
-  }
+  Observable<Response<JSONObject>> getApiInfoInsecurely();
 }

app/src/main/java/chat/rocket/android/fragment/server_config/InputHostnameFragment.java

@@ -11,11 +11,14 @@ import chat.rocket.android.api.rest.DefaultServerPolicyApi;
 import chat.rocket.android.api.rest.ServerPolicyApi;
 import chat.rocket.android.helper.LogcatIfError;
 import chat.rocket.android.helper.OkHttpHelper;
+import chat.rocket.android.helper.ServerPolicyApiValidationHelper;
 import chat.rocket.android.helper.ServerPolicyHelper;
 import chat.rocket.android.helper.TextUtils;
 import chat.rocket.android.model.ServerConfig;
 import chat.rocket.android.realm_helper.RealmObjectObserver;
 import chat.rocket.android.realm_helper.RealmStore;
+import rx.android.schedulers.AndroidSchedulers;
+import rx.schedulers.Schedulers;
 
 /**
  * Input server host.
@@ -51,28 +54,26 @@ public class InputHostnameFragment extends AbstractServerConfigFragment {
   private void handleConnect() {
     final String hostname = ServerPolicyHelper.enforceHostname(getHostname());
 
-    ServerPolicyApi serverPolicyApi =
+    final ServerPolicyApi serverPolicyApi =
         new DefaultServerPolicyApi(OkHttpHelper.getClientForUploadFile(), hostname);
 
-    ServerPolicyHelper.isApiVersionValid(serverPolicyApi,
-        new ServerPolicyHelper.Callback() {
-          @Override
-          public void isValid(boolean usesSecureConnection) {
-            getActivity().runOnUiThread(() -> onServerValid(hostname, usesSecureConnection));
-          }
-
-          @Override
-          public void isNotValid() {
-            getActivity().runOnUiThread(() ->
-                showError(getString(R.string.input_hostname_invalid_server_message)));
-          }
-
-          @Override
-          public void onNetworkError() {
-            getActivity().runOnUiThread(() ->
-                showError(getString(R.string.connection_error_try_later)));
-          }
-        });
+    final ServerPolicyApiValidationHelper validationHelper =
+        new ServerPolicyApiValidationHelper(serverPolicyApi);
+
+    ServerPolicyHelper.isApiVersionValid(validationHelper)
+        .subscribeOn(Schedulers.io())
+        .observeOn(AndroidSchedulers.mainThread())
+        .subscribe(
+            serverValidation -> {
+              if (serverValidation.isValid()) {
+                onServerValid(hostname, serverValidation.usesSecureConnection());
+              } else {
+                showError(getString(R.string.input_hostname_invalid_server_message));
+              }
+            },
+            throwable -> {
+              showError(getString(R.string.connection_error_try_later));
+            });
   }
 
   @Override

app/src/main/java/chat/rocket/android/helper/ServerPolicyApiValidationHelper.java

@@ -2,67 +2,23 @@ package chat.rocket.android.helper;
 
 import android.support.annotation.NonNull;
 
-import org.json.JSONObject;
-
 import chat.rocket.android.api.rest.ServerPolicyApi;
+import rx.Observable;
 
 public class ServerPolicyApiValidationHelper {
 
-  public static void getApiVersion(@NonNull ServerPolicyApi serverPolicyApi,
-                                   @NonNull Callback callback) {
-    trySecurely(serverPolicyApi, new Callback() {
-      @Override
-      public void onSuccess(boolean usesSecureConnection, JSONObject apiInfo) {
-        callback.onSuccess(usesSecureConnection, apiInfo);
-      }
-
-      @Override
-      public void onResponseError() {
-        callback.onResponseError();
-      }
-
-      @Override
-      public void onNetworkError() {
-        tryInsecurely(serverPolicyApi, callback);
-      }
-    });
-  }
-
-  private static void trySecurely(@NonNull ServerPolicyApi serverPolicyApi,
-                                  @NonNull Callback callback) {
-    serverPolicyApi.getApiInfoSecurely(getServerPolicyApiCallback(true, callback));
-  }
-
-  private static void tryInsecurely(@NonNull ServerPolicyApi serverPolicyApi,
-                                    @NonNull Callback callback) {
-    serverPolicyApi.getApiInfoInsecurely(getServerPolicyApiCallback(false, callback));
-  }
-
-  private static ServerPolicyApi.Callback getServerPolicyApiCallback(boolean isSecureConnection,
-                                                                     @NonNull Callback callback) {
-    return new ServerPolicyApi.Callback() {
-      @Override
-      public void onSuccess(JSONObject jsonObject) {
-        callback.onSuccess(isSecureConnection, jsonObject);
-      }
+  private final ServerPolicyApi serverPolicyApi;
 
-      @Override
-      public void onResponseError() {
-        callback.onResponseError();
-      }
-
-      @Override
-      public void onNetworkError() {
-        callback.onNetworkError();
-      }
-    };
+  public ServerPolicyApiValidationHelper(@NonNull ServerPolicyApi serverPolicyApi) {
+    this.serverPolicyApi = serverPolicyApi;
   }
 
-  interface Callback {
-    void onSuccess(boolean usesSecureConnection, JSONObject apiInfo);
-
-    void onResponseError();
-
-    void onNetworkError();
+  public Observable<ServerPolicyHelper.ServerInfo> getApiVersion() {
+    return serverPolicyApi.getApiInfoSecurely()
+        .onErrorResumeNext(serverPolicyApi.getApiInfoInsecurely())
+        .map(response -> new ServerPolicyHelper.ServerInfo(
+            response.getProtocol().equals(ServerPolicyApi.SECURE_PROTOCOL),
+            response.getData()
+        ));
   }
 }

app/src/main/java/chat/rocket/android/helper/ServerPolicyHelper.java

@@ -4,7 +4,7 @@ import android.support.annotation.NonNull;
 
 import org.json.JSONObject;
 
-import chat.rocket.android.api.rest.ServerPolicyApi;
+import rx.Observable;
 
 public class ServerPolicyHelper {
 
@@ -19,29 +19,12 @@ public class ServerPolicyHelper {
     return removeTrailingSlash(removeProtocol(enforceDefaultHost(hostname)));
   }
 
-  public static void isApiVersionValid(@NonNull ServerPolicyApi serverPolicyApi,
-                                       @NonNull Callback callback) {
-    ServerPolicyApiValidationHelper.getApiVersion(serverPolicyApi,
-        new ServerPolicyApiValidationHelper.Callback() {
-          @Override
-          public void onSuccess(boolean usesSecureConnection, JSONObject apiInfo) {
-            if (isValid(apiInfo)) {
-              callback.isValid(usesSecureConnection);
-              return;
-            }
-            callback.isNotValid();
-          }
-
-          @Override
-          public void onResponseError() {
-            callback.isNotValid();
-          }
-
-          @Override
-          public void onNetworkError() {
-            callback.onNetworkError();
-          }
-        });
+  public static Observable<ServerValidation> isApiVersionValid(
+      @NonNull ServerPolicyApiValidationHelper serverPolicyApiValidationHelper) {
+    return serverPolicyApiValidationHelper.getApiVersion()
+        .map(serverInfo ->
+            new ServerValidation(isValid(serverInfo.getApiInfo()),
+                serverInfo.usesSecureConnection()));
   }
 
   @NonNull
@@ -89,11 +72,39 @@ public class ServerPolicyHelper {
     return versionParts.length >= 3 && Integer.parseInt(versionParts[1]) >= 49;
   }
 
-  public interface Callback {
-    void isValid(boolean usesSecureConnection);
+  public static class ServerInfo {
+    private final boolean secureConnection;
+    private final JSONObject apiInfo;
 
-    void isNotValid();
+    public ServerInfo(boolean secureConnection, JSONObject apiInfo) {
+      this.secureConnection = secureConnection;
+      this.apiInfo = apiInfo;
+    }
+
+    public boolean usesSecureConnection() {
+      return secureConnection;
+    }
+
+    public JSONObject getApiInfo() {
+      return apiInfo;
+    }
+  }
 
-    void onNetworkError();
+  public static class ServerValidation {
+    private final boolean valid;
+    private final boolean secureConnection;
+
+    public ServerValidation(boolean valid, boolean secureConnection) {
+      this.valid = valid;
+      this.secureConnection = secureConnection;
+    }
+
+    public boolean isValid() {
+      return valid;
+    }
+
+    public boolean usesSecureConnection() {
+      return secureConnection;
+    }
   }
 }