Error handling in web pages

[psperneac]

• handle errors coming from server - present in UI as snackbar and visual aid on fields that cause the error
• implement an error interface returned back to UI
• translate sql errors on backend into normal errors; instead of 500 Internal Server Error, return 'Duplicate Entry' with field description of what happened
• eg duplicate entry

  "query": "INSERT INTO `PLACE_TYPES`(`id`, `version`, `created`, `updated`, `deleted`, `type`, `name`, `description`) VALUES (?, 1, DEFAULT, DEFAULT, DEFAULT, ?, ?, ?)",
  "parameters": [
  "e3d754ed-90bf-400d-bea5-3e935ad0862c",
  "RAIL",
  "RAIL",
  "Another Rail"
  ],
  "driverError": {
  "code": "ER_DUP_ENTRY",
  "errno": 1062,
  "sqlState": "23000",
  "sqlMessage": "Duplicate entry 'RAIL' for key 'PLACE_TYPES.PLACE_TYPES_TYPE'",
  "sql": "INSERT INTO `PLACE_TYPES`(`id`, `version`, `created`, `updated`, `deleted`, `type`, `name`, `description`) VALUES ('e3d754ed-90bf-400d-bea5-3e935ad0862c', 1, DEFAULT, DEFAULT, DEFAULT, 'RAIL', 'RAIL', 'Another Rail')"
  },
  "code": "ER_DUP_ENTRY",
  "errno": 1062,
  "sqlState": "23000",
  "sqlMessage": "Duplicate entry 'RAIL' for key 'PLACE_TYPES.PLACE_TYPES_TYPE'",
  "sql": "INSERT INTO `PLACE_TYPES`(`id`, `version`, `created`, `updated`, `deleted`, `type`, `name`, `description`) VALUES ('e3d754ed-90bf-400d-bea5-3e935ad0862c', 1, DEFAULT, DEFAULT, DEFAULT, 'RAIL', 'RAIL', 'Another Rail')"
  }