如何使Firebase数据库值仅对各自配对的UID可见？

Question

这是我的数据库结构：

我希望用户1的节点下的值仅对用户1可读和可写，并且用户2的节点下的值仅对用户2可读和可写，以此类推。这意味着用户1无法在其他用户的节点下读写值，反之亦然。为此，我必须为数据库设置规则。

---

以下规则是我尝试的。到目前为止，用户1只能在自己的节点下写值，而不能在其他用户的节点下写值，反之亦然，这正是我想要的。问题是用户1仍可以读取其他用户节点下的值，这是不希望的。我阅读了一些解释数据库规则的文档，但这对我来说很难理解。我尝试了多种方法来重写规则，但仍然失败。我需要帮助来解决此问题。

{
  "rules": {
    ".read": "auth.uid != null",
    ".write":"auth.uid != null",
    "Users' Input History": {
      "$user": {
      ".validate":"$user === auth.uid"
      }
    },

    "Users' Vocabulary List": {
      "$user": {
      ".validate":"$user === auth.uid"
      }
    }
  }
}

为了进行记录，我使用了规则模拟器，如下图所示。我切换了“ validated”选项，选择“ Google”作为提供者，将模拟的UID设置为“ Kad06bqeNChhjaksxgP9cVtoFMh1”（用户1），然后单击执行按钮。结果分别在第3行和第4行允许“读取”和“设置”。

---

下面是我用于用户身份验证并将值提交到数据库的代码：

GoogleSignInActivity：

public class GoogleSignInActivity extends BaseActivity implements
        View.OnClickListener {

    private static final String TAG = "GoogleActivity";
    private static final int RC_SIGN_IN = 9001;

    // [START declare_auth]
    private FirebaseAuth mAuth;
    private FirebaseAuth.AuthStateListener mAuthListener;
    // [END declare_auth]

    private GoogleSignInClient mGoogleSignInClient;
    private TextView mStatusTextView; // For displaying user's email
    private TextView mDetailTextView; // For displaying user's UID
    private TextView mScreenNameTextView; // For displaying user's display name (user.getDisplayName())


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_google_sign_in);

        // Views
        mStatusTextView = findViewById(R.id.status);
        mDetailTextView = findViewById(R.id.detail);
        mScreenNameTextView = findViewById(R.id.screen_name_textView);

        setProgressBar(R.id.progressBar);

        // Button listeners
        findViewById(R.id.signInButton).setOnClickListener(this);


        // [START config_signin]
        // Configure Google Sign In
        GoogleSignInOptions gso = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
                .requestIdToken(getString(R.string.default_web_client_id))
                .requestEmail()
                .build();
        // [END config_signin]

        mGoogleSignInClient = GoogleSignIn.getClient(this, gso);

        // [START initialize_auth]
        // Initialize Firebase Auth
        mAuth = FirebaseAuth.getInstance();
        // [END initialize_auth]



        mAuthListener = new FirebaseAuth.AuthStateListener() {
            @Override
            public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
                FirebaseUser user = firebaseAuth.getCurrentUser();
                if (user != null) {
                    // User is signed in
                    Log.d(TAG, "onAuthStateChanged:signed_in:" + user.getUid());
                    toastMessage("Successfully signed in with: " + user.getEmail());
                    mStatusTextView.setText(getString(R.string.Google_status_fmt, user.getEmail()));
                    mDetailTextView.setText(getString(R.string.Firebase_status_fmt, user.getUid()));


                            username = mDetailTextView.getText().toString();

                }
            }
        };


    }



    // [START on_start_check_user]
    @Override
    public void onStart() {
        super.onStart();
        mAuth.addAuthStateListener(mAuthListener);
        // Check if user is signed in (non-null).
        FirebaseUser currentUser = mAuth.getCurrentUser();
    }
    // [END on_start_check_user]


    @Override
    public void onStop() {
        super.onStop();
        if (mAuthListener != null) {
            mAuth.removeAuthStateListener(mAuthListener);
        }
    }


    // [START onActivityResult]
    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        // Result returned from launching the Intent from GoogleSignInApi.getSignInIntent(...);
        if (requestCode == RC_SIGN_IN) {
            Task<GoogleSignInAccount> task = GoogleSignIn.getSignedInAccountFromIntent(data);
            try {
                // Google Sign In was successful, authenticate with Firebase
                GoogleSignInAccount account = task.getResult(ApiException.class);
                firebaseAuthWithGoogle(account);

                Toast.makeText(getApplicationContext(), getResources().getString(R.string.Login_successful), Toast.LENGTH_LONG).show();


                        username = mDetailTextView.getText().toString();


            } catch (ApiException e) {
                // Google Sign In failed, update UI appropriately
                Log.w(TAG, "Google sign in failed", e);
            }
        }
    }
    // [END onActivityResult]

    // [START auth_with_google]
    private void firebaseAuthWithGoogle(GoogleSignInAccount acct) {
        Log.d(TAG, "firebaseAuthWithGoogle:" + acct.getId());
        // [START_EXCLUDE silent]
        showProgressBar();
        // [END_EXCLUDE]

        AuthCredential credential = GoogleAuthProvider.getCredential(acct.getIdToken(), null);
        mAuth.signInWithCredential(credential)
                .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
                    @Override
                    public void onComplete(@NonNull Task<AuthResult> task) {
                        if (task.isSuccessful()) {
                            // Sign in success, update UI with the signed-in user's information
                            Log.d(TAG, "signInWithCredential:success");
                            FirebaseUser user = mAuth.getCurrentUser();
                        } else {
                            // If sign in fails, display a message to the user.
                            Log.w(TAG, "signInWithCredential:failure", task.getException());
                            Snackbar.make(findViewById(R.id.main_layout), "Authentication Failed.", Snackbar.LENGTH_SHORT).show();
                        }

                        // [START_EXCLUDE]
                        hideProgressBar();
                        // [END_EXCLUDE]
                    }
                });
    }
    // [END auth_with_google]

    // [START signin]
    private void signIn() {
        Intent signInIntent = mGoogleSignInClient.getSignInIntent();
        startActivityForResult(signInIntent, RC_SIGN_IN);
    }
    // [END signin]


    @Override
    public void onClick(View v) {
        int i = v.getId();
        if (i == R.id.signInButton) {
            signIn();
        } 

    }


}

我将值推入数据库的代码：

EditText wordInputView;
String searchKeyword; 
String username;

public static DatabaseReference mRootReference = FirebaseDatabase.getInstance().getReference();
    public static DatabaseReference mChildReferenceForInputHistory = mRootReference.child("Users' Input History");
    public static DatabaseReference mChildReferenceForVocabularyList = mRootReference.child("Users' Vocabulary List");

searchKeyword = wordInputView.getText().toString();


Query query = mChildReferenceForInputHistory.child(username).orderByValue().equalTo(searchKeyword);

                query.addListenerForSingleValueEvent(new ValueEventListener() {
                    @Override
                    public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                        for (DataSnapshot snapshot: dataSnapshot.getChildren()) {
                            //If a duplicate value (searchKeyword) is found, remove it.
                            snapshot.getRef().setValue(null);  
                        }
                    }

                    @Override
                    public void onCancelled(@NonNull DatabaseError databaseError) {
                        throw databaseError.toException();
                    }
                });

                mChildReferenceForInputHistory.child(username).push().setValue(searchKeyword);



//Initialize the adapter
        userInputArrayAdapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, userInputArraylist);
        userInputListview.setAdapter(userInputArrayAdapter);
        mChildReferenceForInputHistory.addChildEventListener(new ChildEventListener() {
            @Override
            public void onChildAdded(@NonNull DataSnapshot dataSnapshot, @Nullable String previousChildKey) {

                for (DataSnapshot snapshot : dataSnapshot.getChildren()){
                    String value = snapshot.getValue(String.class);

                    userInputArraylist.add(value);


                    HashSet<String> myVocabularyArraylistHashSet = new HashSet<>();
                    myVocabularyArraylistHashSet.addAll(userInputArraylist);
                    userInputArraylist.clear();
                    userInputArraylist.addAll(myVocabularyArraylistHashSet);

                    //Alphabetic sorting
                    Collections.sort(userInputArraylist);

                    userInputArrayAdapter.notifyDataSetChanged();

                }
            }

            @Override
            public void onChildChanged(@NonNull DataSnapshot dataSnapshot, @Nullable String s) {
            }

            @Override
            public void onChildRemoved(@NonNull DataSnapshot dataSnapshot) {
            }

            @Override
            public void onChildMoved(@NonNull DataSnapshot dataSnapshot, @Nullable String s) {
            }

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {
            }
        });

Answer 1

从Firebase文档：