Merge pull request #3 from gracemann365/feature/shared-lib

Phase 2: Shared-Libs & API Infra — DTO, Exception, Validation, Idempotency, Logging, HealthFeature/shared lib

Author: David Grace

api-service/pom.xml

@@ -31,11 +31,23 @@
       <artifactId>postgresql</artifactId>
       <scope>runtime</scope>
     </dependency>
+    <dependency>
+    <groupId>org.springframework.boot</groupId>
+    <artifactId>spring-boot-starter-test</artifactId>
+    <scope>test</scope>
+</dependency>
+
 
     <dependency>
     <groupId>org.flywaydb</groupId>
     <artifactId>flyway-core</artifactId>
   </dependency>
+
+  <dependency>
+        <groupId>com.openpay</groupId>
+        <artifactId>shared-libs</artifactId>
+        <version>1.0-SNAPSHOT</version>
+    </dependency>
   </dependencies>
    <build>
     <plugins>

api-service/src/main/java/com/openpay/api/config/LoggingFilter.java

@@ -0,0 +1,37 @@
+package com.openpay.api.config;
+
+import java.io.IOException;
+import java.util.UUID;
+
+import org.slf4j.MDC;
+import org.springframework.stereotype.Component;
+import org.springframework.web.filter.OncePerRequestFilter;
+
+import jakarta.servlet.FilterChain;
+import jakarta.servlet.ServletException;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+
+@Component
+public class LoggingFilter extends OncePerRequestFilter {
+
+    @Override
+    protected void doFilterInternal(
+            HttpServletRequest request,
+            HttpServletResponse response,
+            FilterChain filterChain) throws ServletException, IOException {
+
+        // Generate a unique request ID (can also use header if present)
+        String requestId = UUID.randomUUID().toString();
+
+        // Put it into MDC
+        MDC.put("requestId", requestId);
+
+        try {
+            filterChain.doFilter(request, response);
+        } finally {
+            // Always clear MDC after the request to prevent memory leaks
+            MDC.clear();
+        }
+    }
+}

api-service/src/main/java/com/openpay/api/controller/HealthController.java

@@ -0,0 +1,12 @@
+package com.openpay.api.controller;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+public class HealthController {
+    @GetMapping("/health")
+    public String health() {
+        return "UP";
+    }
+}

api-service/src/main/java/com/openpay/api/controller/StatusController.java

@@ -10,6 +10,7 @@
 
 import com.openpay.api.model.TransactionEntity;
 import com.openpay.api.repository.TransactionRepository;
+import com.openpay.shared.dto.StatusResponse;
 
 @RestController
 @RequestMapping("/transaction")
@@ -29,25 +30,9 @@ public ResponseEntity<?> getStatus(@PathVariable("id") Long id) {
             return ResponseEntity.notFound().build();
         }
 
+        // *** NO CHANGE: just use the shared StatusResponse ***
         return ResponseEntity.ok(
                 new StatusResponse(id, transaction.get().getStatus()));
     }
-
-    static class StatusResponse {
-        private Long id;
-        private String status;
-
-        public StatusResponse(Long id, String status) {
-            this.id = id;
-            this.status = status;
-        }
-
-        public Long getId() {
-            return id;
-        }
-
-        public String getStatus() {
-            return status;
-        }
-    }
+    // *** REMOVED THE INNER CLASS ***
 }

api-service/src/main/java/com/openpay/api/controller/TransactionController.java

@@ -3,11 +3,13 @@
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestHeader; 
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
 
-import com.openpay.api.dto.PaymentRequest;
 import com.openpay.api.service.TransactionService;
+import com.openpay.shared.dto.PaymentRequest;
+import com.openpay.shared.dto.StatusResponse;
 
 import jakarta.validation.Valid;
 
@@ -22,8 +24,12 @@ public TransactionController(TransactionService transactionService) {
     }
 
     @PostMapping
-    public ResponseEntity<String> initiatePayment(@Valid @RequestBody PaymentRequest request) {
-        Long id = transactionService.createTransaction(request);
-        return ResponseEntity.ok("Transaction queued with ID: " + id);
+    public ResponseEntity<StatusResponse> initiatePayment(
+            @Valid @RequestBody PaymentRequest request,
+            @RequestHeader("Idempotency-Key") String idempotencyKey) { 
+
+        Long id = transactionService.createTransaction(request, idempotencyKey); 
+        StatusResponse response = new StatusResponse(id, "QUEUED", "Transaction queued");
+        return ResponseEntity.ok(response);
     }
 }

api-service/src/main/java/com/openpay/api/handler/GlobalExceptionHandler.java

@@ -11,6 +11,9 @@
 import org.springframework.web.bind.annotation.ExceptionHandler;
 import org.springframework.web.bind.annotation.RestControllerAdvice;
 
+import com.openpay.shared.exception.InvalidUpiException;
+import com.openpay.shared.exception.OpenPayException;
+
 @RestControllerAdvice
 public class GlobalExceptionHandler {
 
@@ -49,4 +52,17 @@ public ResponseEntity<?> handleGeneric(Exception ex) {
         return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR)
                 .body(Map.of("error", "Internal server error"));
     }
+
+    // Custom Exception Handlers for invalid upi and openpay
+
+    @ExceptionHandler(InvalidUpiException.class)
+    public ResponseEntity<?> handleInvalidUpi(InvalidUpiException ex) {
+        return ResponseEntity.badRequest().body(Map.of("error", ex.getMessage()));
+    }
+
+    @ExceptionHandler(OpenPayException.class)
+    public ResponseEntity<?> handleOpenPay(OpenPayException ex) {
+        return ResponseEntity.badRequest().body(Map.of("error", ex.getMessage()));
+    }
+
 }

api-service/src/main/java/com/openpay/api/repository/IdempotencyKeyRepository.java

@@ -1,6 +1,9 @@
 package com.openpay.api.repository;
 
-import com.openpay.api.model.IdempotencyKeyEntity;
 import org.springframework.data.jpa.repository.JpaRepository;
 
-public interface IdempotencyKeyRepository extends JpaRepository<IdempotencyKeyEntity, String> {}
+import com.openpay.api.model.IdempotencyKeyEntity;
+
+public interface IdempotencyKeyRepository extends JpaRepository<IdempotencyKeyEntity, String> {
+    boolean existsByIdempotencyKey(String idempotencyKey);
+}

api-service/src/main/java/com/openpay/api/service/IdempotencyService.java

@@ -0,0 +1,6 @@
+package com.openpay.api.service;
+
+public interface IdempotencyService {
+    boolean isDuplicate(String key);
+    void saveKey(String key, Long transactionId);
+}

api-service/src/main/java/com/openpay/api/service/IdempotencyServiceImpl.java

@@ -0,0 +1,33 @@
+package com.openpay.api.service;
+
+import java.time.LocalDateTime;
+
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+import com.openpay.api.model.IdempotencyKeyEntity;
+import com.openpay.api.repository.IdempotencyKeyRepository;
+
+@Service
+public class IdempotencyServiceImpl implements IdempotencyService {
+    private final IdempotencyKeyRepository idempotencyKeyRepository;
+
+    public IdempotencyServiceImpl(IdempotencyKeyRepository idempotencyKeyRepository) {
+        this.idempotencyKeyRepository = idempotencyKeyRepository;
+    }
+
+    @Override
+    public boolean isDuplicate(String key) {
+        return idempotencyKeyRepository.existsByIdempotencyKey(key);
+    }
+
+    @Override
+    @Transactional
+    public void saveKey(String key, Long transactionId) {
+        IdempotencyKeyEntity entity = new IdempotencyKeyEntity();
+        entity.setIdempotencyKey(key);
+        entity.setTransactionId(transactionId);
+        entity.setCreatedAt(LocalDateTime.now());
+        idempotencyKeyRepository.save(entity);
+    }
+}

api-service/src/main/java/com/openpay/api/service/TransactionService.java

@@ -1,27 +1,37 @@
 package com.openpay.api.service;
 
-import com.openpay.api.dto.PaymentRequest;
+import java.time.LocalDateTime;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.stereotype.Service;
+
 import com.openpay.api.model.TransactionEntity;
 import com.openpay.api.repository.TransactionRepository;
-import org.springframework.stereotype.Service;
+import com.openpay.shared.dto.PaymentRequest;
+import com.openpay.shared.exception.OpenPayException;
 
-import java.time.LocalDateTime;
 
 @Service
 public class TransactionService {
 
     private final TransactionRepository transactionRepository;
-
-    public TransactionService(TransactionRepository transactionRepository) {
+    private final IdempotencyService idempotencyService;
+    private static final Logger log = LoggerFactory.getLogger(TransactionService.class);
+    public TransactionService(TransactionRepository transactionRepository, IdempotencyService idempotencyService) {
         this.transactionRepository = transactionRepository;
+        this.idempotencyService = idempotencyService;
     }
 
-    public Long createTransaction(PaymentRequest request) {
+    public Long createTransaction(PaymentRequest request, String idempotencyKey) {
         if (request.getSenderUpi().equalsIgnoreCase(request.getReceiverUpi())) {
-            throw new IllegalArgumentException("Sender and receiver UPI must be different");
+            throw new OpenPayException("Sender and receiver UPI must be different");
+        }
+        log.info("Creating transaction for sender={} receiver={}", request.getSenderUpi(), request.getReceiverUpi());
+        // Idempotency check
+        if (idempotencyService.isDuplicate(idempotencyKey)) {
+            throw new OpenPayException("Duplicate request");
         }
-
-        // Stub: idempotency check will go here
 
         TransactionEntity entity = new TransactionEntity();
         entity.setSenderUpi(request.getSenderUpi());
@@ -30,6 +40,10 @@ public Long createTransaction(PaymentRequest request) {
         entity.setStatus("queued");
         entity.setCreatedAt(LocalDateTime.now());
 
+        // Store idempotency key after successful transaction save
+        TransactionEntity saved = transactionRepository.save(entity);
+        idempotencyService.saveKey(idempotencyKey, saved.getId());
+
         return transactionRepository.save(entity).getId();
     }
 }