POST Forms Messages and Validations (#70)

- return errors in forms with invalid constraints (via POST calls to the API) as a JSON body with the errors mapped as "field":"message"
- return a 400 Bad Request code in case a field in the Path Params and the Query Params (via GET calls to the API) instead of returning a 500 Internal Server Error with a 404 Not found body message
- return a 400 Bad Request code in forms with invalid constraints instead of a 500 Internal Server Error
- added custom (spanish) messages for constraints validation errors

webapp/src/main/java/ar/edu/itba/paw/webapp/exceptions/ConstraintViolationExceptionMapper.java

@@ -0,0 +1,53 @@
+package ar.edu.itba.paw.webapp.exceptions;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import javax.validation.ConstraintViolation;
+import javax.validation.ConstraintViolationException;
+import javax.ws.rs.core.Response;
+import javax.ws.rs.ext.ExceptionMapper;
+import javax.ws.rs.ext.Provider;
+
+@Provider
+public class ConstraintViolationExceptionMapper implements ExceptionMapper<ConstraintViolationException> {
+
+  private static final Logger LOGGER = LoggerFactory.getLogger(ConstraintViolationExceptionMapper.class);
+
+  private static final int LEAF_POSITION = 2;
+
+  @Override
+  public Response toResponse(final ConstraintViolationException e) {
+    LOGGER.warn("Exception: {}", (Object[]) e.getStackTrace());
+    final StringBuilder responseEntity = new StringBuilder();
+
+    responseEntity.append("{ errors: [\n");
+    for (ConstraintViolation<?> cv : e.getConstraintViolations()) {
+      final String propertyName;
+      final String[] propertyNodes = cv.getPropertyPath().toString().split("\\.");
+
+      if(propertyNodes.length == 3) {
+         propertyName = propertyNodes[LEAF_POSITION];
+      } else {
+        propertyName = propertyNodes[1];
+      }
+
+      LOGGER.debug("propertyname = " + propertyName);
+
+      responseEntity.append("{");
+      responseEntity
+              .append("\"")
+                .append(propertyName)
+              .append("\"")
+              .append(":")
+              .append("\"")
+                .append(cv.getMessage())
+              .append("\"")
+              .append("},")
+              .append("\n");
+    }
+    responseEntity.append("] }");
+    return Response.status(Response.Status.BAD_REQUEST).entity(responseEntity.toString()).build();
+  }
+
+}

webapp/src/main/java/ar/edu/itba/paw/webapp/exceptions/QueryParamExceptionMapper.java

@@ -0,0 +1,15 @@
+package ar.edu.itba.paw.webapp.exceptions;
+
+import javax.ws.rs.core.Response;
+import javax.ws.rs.ext.ExceptionMapper;
+import javax.ws.rs.ext.Provider;
+
+import static org.glassfish.jersey.server.ParamException.QueryParamException;
+
+@Provider
+public class QueryParamExceptionMapper implements ExceptionMapper<QueryParamException> {
+  @Override
+  public Response toResponse(final QueryParamException exception) {
+    return Response.status(Response.Status.BAD_REQUEST).build();
+  }
+}

webapp/src/main/resources/ValidationMessages.properties

@@ -1,9 +1,7 @@
-# Jersey Bean Validations
-
-javax.validation.constraints.Min.message=must be greater than or equal to {value}
-javax.validation.constraints.Digits=must have {integer} digits
-org.hibernate.validator.constraints.NotBlank=must not be empty
-javax.validation.constraints.NotNull=must not be null
-javax.validation.constraints.Size=must be between {min} and {max} characters long
-javax.validation.constraints.Pattern=must follow the pattern: {regexp}
+javax.validation.constraints.Min.message=debe ser igual o mayor a {value}
+javax.validation.constraints.Digits.message=debe poseer {integer} dígitos
+org.hibernate.validator.constraints.NotBlank.message=no debe estar vacío
+javax.validation.constraints.NotNull.message=no debe ser nulo
+javax.validation.constraints.Size.message=debe tener entre {min} y {max} caracteres
+javax.validation.constraints.Pattern.message=debe poseer la siguiente expresión regular: {regexp}