Add functionality to allow users to link to auth providers while being logged in

Author: aq-ikhwa-tech

server/api-service/lowcoder-server/src/main/java/org/lowcoder/api/authentication/AuthenticationController.java

@@ -46,7 +46,7 @@ public Mono<ResponseView<Boolean>> formLogin(@RequestBody FormLoginRequest formL
                                                  ServerWebExchange exchange) {
         return authenticationApiService.authenticateByForm(formLoginRequest.loginId(), formLoginRequest.password(),
                         formLoginRequest.source(), formLoginRequest.register(), formLoginRequest.authId(), orgId)
-                .flatMap(user -> authenticationApiService.loginOrRegister(user, exchange, invitationId))
+                .flatMap(user -> authenticationApiService.loginOrRegister(user, exchange, invitationId, Boolean.FALSE))
                 .thenReturn(ResponseView.success(true));
     }
 
@@ -63,7 +63,20 @@ public Mono<ResponseView<Boolean>> loginWithThirdParty(
             @RequestParam String orgId,
             ServerWebExchange exchange) {
         return authenticationApiService.authenticateByOauth2(authId, source, code, redirectUrl, orgId)
-                .flatMap(authUser -> authenticationApiService.loginOrRegister(authUser, exchange, invitationId))
+                .flatMap(authUser -> authenticationApiService.loginOrRegister(authUser, exchange, invitationId, Boolean.FALSE))
+                .thenReturn(ResponseView.success(true));
+    }
+
+    @Override
+    public Mono<ResponseView<Boolean>> linkAccountWithThirdParty(
+            @RequestParam(required = false) String authId,
+            @RequestParam(required = false) String source,
+            @RequestParam String code,
+            @RequestParam String redirectUrl,
+            @RequestParam String orgId,
+            ServerWebExchange exchange) {
+        return authenticationApiService.authenticateByOauth2(authId, source, code, redirectUrl, orgId)
+                .flatMap(authUser -> authenticationApiService.loginOrRegister(authUser, exchange, null, Boolean.TRUE))
                 .thenReturn(ResponseView.success(true));
     }
 

server/api-service/lowcoder-server/src/main/java/org/lowcoder/api/authentication/AuthenticationEndpoints.java

@@ -69,6 +69,24 @@ public Mono<ResponseView<Boolean>> loginWithThirdParty(
             @RequestParam String orgId,
             ServerWebExchange exchange);
 
+	/**
+	 * Link current account with third party auth provider
+	 */
+	@Operation(
+			tags = TAG_AUTHENTICATION,
+			operationId = "linkAccountWithTP",
+			summary = "Link current account with third party auth provider",
+			description = "Authenticate a Lowcoder User using third-party login credentials and link to the existing session/account"
+	)
+	@PostMapping("/tp/link")
+	public Mono<ResponseView<Boolean>> linkAccountWithThirdParty(
+			@RequestParam(required = false) String authId,
+			@RequestParam(required = false) String source,
+			@RequestParam String code,
+			@RequestParam String redirectUrl,
+			@RequestParam String orgId,
+			ServerWebExchange exchange);
+
 	@Operation(
 			tags = TAG_AUTHENTICATION,
 		    operationId = "logout",

server/api-service/lowcoder-server/src/main/java/org/lowcoder/api/authentication/service/AuthenticationApiService.java

@@ -16,7 +16,7 @@ public interface AuthenticationApiService {
 
     Mono<AuthUser> authenticateByOauth2(String authId, String source, String code, String redirectUrl, String orgId);
 
-    Mono<Void> loginOrRegister(AuthUser authUser, ServerWebExchange exchange, String invitationId);
+    Mono<Void> loginOrRegister(AuthUser authUser, ServerWebExchange exchange, String invitationId, boolean linKExistingUser);
 
     Mono<Boolean> enableAuthConfig(AuthConfigRequest authConfigRequest);
 

server/api-service/lowcoder-server/src/main/java/org/lowcoder/api/authentication/service/AuthenticationApiServiceImpl.java

@@ -130,8 +130,8 @@ protected Mono<AuthUser> authenticate(String authId, @Deprecated String source,
 
     @Override
     public Mono<Void> loginOrRegister(AuthUser authUser, ServerWebExchange exchange,
-            String invitationId) {
-        return updateOrCreateUser(authUser)
+                                      String invitationId, boolean linKExistingUser) {
+        return updateOrCreateUser(authUser, linKExistingUser)
                 .delayUntil(user -> ReactiveSecurityContextHolder.getContext()
                         .doOnNext(securityContext -> securityContext.setAuthentication(AuthenticationUtils.toAuthentication(user))))
                 // save token and set cookie
@@ -160,7 +160,13 @@ public Mono<Void> loginOrRegister(AuthUser authUser, ServerWebExchange exchange,
                 .then(businessEventPublisher.publishUserLoginEvent(authUser.getSource()));
     }
 
-    private Mono<User> updateOrCreateUser(AuthUser authUser) {
+    private Mono<User> updateOrCreateUser(AuthUser authUser, boolean linkExistingUser) {
+
+        if(linkExistingUser) {
+            return sessionUserService.getVisitor()
+                    .flatMap(user -> userService.addNewConnectionAndReturnUser(user.getId(), authUser.toAuthConnection()));
+        }
+
         return findByAuthUserSourceAndRawId(authUser).zipWith(findByAuthUserRawId(authUser))
                 .flatMap(tuple -> {