Merge 'develop' changes into 'master'.

src/main/java/fr/unistra/sil/erp/back/controller/api/ApiRetrieveInfoController.java

@@ -13,6 +13,7 @@ import fr.unistra.sil.erp.back.db.DatabaseInterface;
 import java.util.List;
 import java.util.logging.Level;
 import java.util.logging.Logger;
+import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.GetMapping;
@@ -67,6 +68,8 @@ public class ApiRetrieveInfoController implements IRetrieveInfoController {
         
         if(res == null)
             throw new ApiServerErrorException("Failed to query info.");
+        else if(res.isEmpty())
+            return ResponseEntity.noContent().build();
         
         return new ResponseEntity<>(res, HttpStatus.OK);
     }