Use custom message for UNIQUE constraint error message

src/api/docs/content/specs/clients.yaml

@@ -484,7 +484,7 @@ components:
             error:
               key: "database_error"
               message: "Could not add to gravity database"
-              hint: "Client already exists (UNIQUE constraint failed)"
+              hint: "The item is already present"
             took: 0.003
   parameters:
     client:

src/api/docs/content/specs/domains.yaml

@@ -526,7 +526,7 @@ components:
             error:
               key: "database_error"
               message: "Could not add to gravity database"
-              hint: "Domain already exists (UNIQUE constraint failed)"
+              hint: "The item is already present"
             took: 0.003
       regex_error:
         invalid_regex:

src/api/docs/content/specs/groups.yaml

@@ -398,7 +398,7 @@ components:
             error:
               key: "database_error"
               message: "Could not add to gravity database"
-              hint: "Group already exists (UNIQUE constraint failed)"
+              hint: "The item is already present"
             took: 0.003
 
   parameters:

src/api/docs/content/specs/lists.yaml

@@ -466,7 +466,7 @@ components:
             error:
               key: "database_error"
               message: "Could not add to gravity database"
-              hint: "List already exists (UNIQUE constraint failed)"
+              hint: "The item is already present"
             took: 0.003
   parameters:
     list:

src/database/gravity-db.c

@@ -2020,7 +2020,10 @@ bool gravityDB_addToTable(const enum gravity_list_type listtype, tablerow *row,
 	}
 	else
 	{
-		*message = sqlite3_errmsg(gravity_db);
+		if(rc == SQLITE_CONSTRAINT)
+			*message = "The item is already present";
+		else
+			*message = sqlite3_errmsg(gravity_db);
 	}
 
 	// Finalize statement and close database handle