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Problem Details

Implementation of ProblemDetails object (for more info see https://www.rfc-editor.org/rfc/rfc7807)

• How to use
  • ProblemDetails
  • ProblemDetails.raw
  • Additional fields
  • toJson
  • fromJson

How to use

ProblemDetails

You can use unnamed factory constructor ProblemDetails to create ProblemDetails:

void main() {
  final problemDetails = ProblemDetails();
}

status is 500 by default.

ProblemDetails constructor fulfills fields: type and title based on status. But, it only works for a limited set of status values. The full set of status values you can see here .

For example:

void main() {
  final problemDetails = ProblemDetails(status: 403);

  // prints: https://www.rfc-editor.org/rfc/rfc7231#section-6.5.3
  print(problemDetails.type);

  // prints: Forbidden
  print(problemDetails.title);
}

If ProblemDetails does not have default values of type, title for a certain status, then type is set to about:blank.

void main() {
  final problemDetails = ProblemDetails(status: 1);

  // prints: about:blank
  print(problemDetails.type);
}

ProblemDetails.raw

Use ProblemDetails.raw if you want to set all values manually:

void main() {
  final problemDetails = ProblemDetails.raw(status: 403);

  // prints: null
  print(problemDetails.type);

  // prints: null
  print(problemDetails.title);
}

Additional fields

If you want to add new fields to ProblemDetails, use extensions:

void extensions() {
  var problemDetails = ProblemDetails(
    extensions: {
      'key1': 'value',
      'key2': null,
      'key3': {
        'key4': [1, 2, 3],
      },
    },
  );

  // prints:
  //  {
  //    key1: value,
  //    key2: null,
  //    key3: {
  //      key4: [1, 2, 3]
  //    }
  //  }
  print(problemDetails.extensions);
}

You can change/add a field by using addOrUpdateExtension method:

void main() {
  var problemDetails = ProblemDetails(
    extensions: {
      'key1': 'value',
      'key2': null,
      'key3': {
        'key4': [1, 2, 3],
      },
    },
  );

  problemDetails = problemDetails.addOrUpdateExtension('KEY', 'VALUE');

  // prints:
  //  {
  //    key1: value,
  //    key2: null,
  //    key3: {
  //      key4: [1, 2, 3]
  //    },
  //    'KEY': 'VALUE'
  //  }
  print(problemDetails.extensions);
}

You can change/add multiple fields by using addOrUpdateExtensions method:

void main() {
  var problemDetails = ProblemDetails(
    extensions: {
      'key1': 'value',
      'key2': null,
      'key3': {
        'key4': [1, 2, 3],
      },
    },
  );

  problemDetails = problemDetails.addOrUpdateExtensions(
    {
      'a': 1,
      'b': 2,
    },
  );

  // prints:
  //  {
  //    key1: value,
  //    key2: null,
  //    key3: {
  //      key4: [1, 2, 3]
  //    },
  //    'a': 1,
  //    'b': 2
  //  }
  print(problemDetails.extensions);
}

You can remove a field by using removeExtension method:

void main() {
  var problemDetails = ProblemDetails(
    extensions: {
      'key1': 'value',
      'key2': null,
      'key3': {
        'key4': [1, 2, 3],
      },
    },
  );

  problemDetails = problemDetails.removeExtension('key1');

  // prints:
  //  {
  //    key2: null,
  //    key3: {
  //      key4: [1, 2, 3]
  //    }
  //  }
  print(problemDetails.extensions);
}

toJson

toJson method converts ProblemDetails into Map.

NOTE: Standard fields (status, type, title, details, instance) are not included in a Map, if a field is null.

IMPORTANT: Content of extensions is put on the top level of a Map.

void main() {
  final problemDetails = ProblemDetails(
    status: 403,
    extensions: {
      'key1': 'value',
      'key2': null,
      'key3': {
        'key4': [1, 2, 3],
      },
    },
  );

  final jsonData = problemDetails.toJson();

  // prints:
  //  {
  //    status: 403,
  //    type: https://www.rfc-editor.org/rfc/rfc7231#section-6.5.3,
  //    title: Forbidden,
  //    key1: value,
  //    key2: null,
  //    key3: {
  //      key4: [1, 2, 3]
  //    }
  //  }
  print(jsonData);
}

fromJson

fromJson constructor parses Map into ProblemDetails.

IMPORTANT: Non-standard fields of ProblemDetails (i. e. all fields except status, type, title, details, instance) convert in extensions.

void main() {
  var problemDetails = ProblemDetails(
    status: 403,
    extensions: {
      'key1': 'value',
      'key2': null,
      'key3': {
        'key4': [1, 2, 3],
      },
    },
  );

  final jsonData = problemDetails.toJson();

  problemDetails = ProblemDetails.fromJson(jsonData);

  // prints:
  //  ProblemDetails {
  //    status: 403,
  //    type: https://www.rfc-editor.org/rfc/rfc7231#section-6.5.3,
  //    title: Forbidden,
  //    key1: value,
  //    key2: null,
  //    key3: {
  //      key4: [1, 2, 3]
  //    }
  //  }
  print(problemDetails);
}