api_error_parser 0.2.2

Parsing responses from api and handling errors in the Dart/Flutter

API Parser

A library for parsing responses from api and converting error codes into messages for the user.

• API response description
• Pagination
• Version
• How it works
• License

API response description

It is assumed that the response will correspond to the following specifications.

Each error from server should be in next format:

• code: a unique code of an error. Used to identify error from the dictionary.
• target: some sort of error scope. One of the following options: field - the error related to certain field, common - the error related to whole request.
• message (OPTIONAL): the error message for developers (use it only for debug purposes)
• source (OPTIONAL): a container for additional data. Arbitrary structure: ( field: resource object attribute name. Required if target set to field. )

Example:

{
"data": [
     {
       "id": 1,
       "userName": "Tom",
       "age": 21
     },
     {
       "id": 2,
       "userName": "Bob",
       "age": 22
     }
   ],
  "errors": [
    {
      "code": "insufficient_funds",
      "target": "common",
      "message": "Hi Nick, it seems that user has empty balance"
    },
    {
      "code": "invalid_punctuation",
      "target": "field",
      "source": {
        "field": "userPassword"
      },
      "message": "Hi Vova, it seems that the password provided is missing a punctuation character"
    },
    {
      "code": "invalid_password_confirmation",
      "target": "field",
      "source": {
        "field": "userPassword",
        "someAdditionalData": "bla bla bla"
      },
      "message": "Hi Lesha, it seems that the password and password confirmation fields do not match"
    }
  ]
 }

Pagination

In server response should be pagination object in the next format:

• currentPage: current returned page
• totalPage: total pages amount
• totlaRecord: total record amount
• limit: number of items per page

Example:

{
  "data": [
    {
      "id": 1
    },
    {
      "id": 2
    }
  ],
  "pagination": {
    "currentPage": 3,
    "totalPage": 10,
    "totalRecord": 92,
    "limit": 10
  }
}

Version

0.2.2

How it works

The library provides ready-made interfaces for server responses to which the object passed to the parmer must correspond.

To initialize the ErrorParser, you must pass to the constructor:

• errorMessages: Map<String, E> - the key is the error code and the value of the displayed message
• defaultErrorMessage: E - message of unknown errors
• adapters: Map<Type, ErrorMessageAdapter
• fieldErrorMessages: Map<String, Map<String, E>> - The key is the field name. The value is a table similar to errorMessages.

Api parser description:

• parse(ApiParserResponse<T> response) - returns ApiParserResponse in the states: success , empty or error
• getParserResponse(ApiResponse<T> response) - parses the server response object and returns the processed result
• getErrors(List<ErrorMessage> errors) - returns a list of processed errors
• getMessageFromCode(String errorCode) - returns the message associated with this error code
• getMessage(ErrorMessage errorMessage) - returns the processed error
• getFirstMessage(List<ErrorMessage> errors) - returns the first processed error from the list
• getFieldMessageFromCode(String field, String errorCode) - returns the first processed error from the list

Dart

final apiParser = ApiParser(
  adapters: {
    ErrorMessageEntity: SimpleErrorMessageAdapter(),
  },
  errorMessages: {
    ErrorCode.INVALID_LOGIN: Message.INVALID_LOGIN
  },
  fieldErrorMessages: {
    FIELD.EMAIL: {
      ErrorCode.INVALID_PASSWORD_CONFIRMATION: Message.PASSWORD_DO_NOT_MATCH,
    },
    FIELD.EMAIL_LENGTH: {ErrorCode.MIN: Message.EMAIL_LENGTH_MESSAGE}
  },
  defaultErrorMessage: Message.DEFAULT,
);
               
final ParserResponse<UserEntity> parserResponse = apiParser.getParserResponse(serverResponse);
                             
final ApiParserResponse<UserEntity> apiParserResponse = apiParser.parse(serverResponse); 

switch (apiParserResponse.runtimeType) {
    case  ApiParserEmptyResponse: {
      //do something
      break;
    }
    case  ApiParserErrorResponse: {
      //do something
      break;
    }
    case  ApiParserSuccessResponse: {
      //do something
      break;
    }
}
                            

License

ApiParser is released under the MIT license. See LICENSE for details.