-allow login with case insensitive emails (#6712)

Author: nayan-rafiq

app/server/appsmith-server/src/main/java/com/appsmith/server/authentication/handlers/CustomFormLoginServiceImpl.java

@@ -33,6 +33,7 @@ public CustomFormLoginServiceImpl(UserRepository repository) {
     @Override
     public Mono<UserDetails> findByUsername(String username) {
         return repository.findByEmail(username)
+                .switchIfEmpty(repository.findByCaseInsensitiveEmail(username))
                 .switchIfEmpty(Mono.error(new UsernameNotFoundException("Unable to find username: " + username)))
                 .onErrorMap(error -> {
                     log.error("Can't find user {}", username);

app/server/appsmith-server/src/test/java/com/appsmith/server/authentication/handlers/CustomFormLoginServiceImplUnitTest.java

@@ -0,0 +1,57 @@
+package com.appsmith.server.authentication.handlers;
+
+import com.appsmith.server.domains.User;
+import com.appsmith.server.repositories.UserRepository;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mockito;
+import org.springframework.boot.test.mock.mockito.MockBean;
+import org.springframework.security.core.userdetails.ReactiveUserDetailsService;
+import org.springframework.security.core.userdetails.UsernameNotFoundException;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import reactor.core.publisher.Mono;
+import reactor.test.StepVerifier;
+import static org.assertj.core.api.Assertions.assertThat;
+
+@RunWith(SpringJUnit4ClassRunner.class)
+public class CustomFormLoginServiceImplUnitTest {
+    @MockBean
+    private UserRepository repository;
+
+    private ReactiveUserDetailsService reactiveUserDetailsService;
+
+    @Before
+    public void setUp() {
+        reactiveUserDetailsService = new CustomFormLoginServiceImpl(repository);
+    }
+
+    @Test
+    public void findByUsername_WhenUserNameNotFound_ThrowsException() {
+        String sampleEmail = "sample-email@example.com";
+        Mockito.when(repository.findByEmail(sampleEmail)).thenReturn(Mono.empty());
+        Mockito.when(repository.findByCaseInsensitiveEmail(sampleEmail)).thenReturn(Mono.empty());
+
+        StepVerifier.create(reactiveUserDetailsService.findByUsername(sampleEmail))
+                .expectError(UsernameNotFoundException.class)
+                .verify();
+    }
+
+    @Test
+    public void findByUsername_WhenUserNameExistsWithOtherCase_ReturnsUser() {
+        String sampleEmail2 = "sampleEmail@example.com";
+        User user = new User();
+        user.setPassword("1234");
+        user.setEmail(sampleEmail2.toLowerCase());
+
+        Mockito.when(repository.findByEmail(sampleEmail2)).thenReturn(Mono.empty());
+        Mockito.when(repository.findByCaseInsensitiveEmail(sampleEmail2)).thenReturn(Mono.just(user));
+
+        StepVerifier.create(reactiveUserDetailsService.findByUsername(sampleEmail2))
+                .assertNext(userDetails -> {
+                    assertThat(userDetails.getUsername()).isEqualTo(sampleEmail2.toLowerCase());
+                    assertThat(userDetails.getPassword()).isEqualTo("1234");
+                })
+                .verifyComplete();
+    }
+}