Model Generator

This model generator can be used to generate JsonSerializable models

Run

flutter packages run model_generator

Model file(s)

By default, the model generator looks for the model yaml file in model_generator/config.yaml. If you want to overwrite this, specify it in your pubspec.yaml file by using config_path. Example of the pubspec.yaml file if you want to use a custom model file location:

model_generator:
  config_path: my_model_dir/config.yaml

You can also specify a command line parameter to override the location for a single run. For this, use the --path command line parameter. Example:

flutter packages run model_generator --path my_other_model_dir/config.yaml

Note: Since version 6.1.0, instead of a single model file, you can specify a directory containing multiple model files. The generator will then generate models for all .yaml (or .yml) files in the directory. References across files are supported.

Default setup

Example of the pubspec.yaml file if you want to use a custom base_directory for all your models Default is /lib/model you can override it for all your models like this:

model_generator:
  base_directory: custom_models

this will write all your models to /lib/custom_models path will be added after the base_directory

FVM support

If you are using fvm for managing your flutter version. You can add an option to the model generator as well to run with fvm. add an option use_fvm and set it to true. (by default it is set to false)

model_generator:
  use_fvm: true

== and hashCode

If you want the generated models to include code for == and hashCode, you can turn it on in pubspec.yaml. Defaults to false. All fields are taken into consideration for the generated code.

model_generator:
  equals_and_hash_code: true

or to override the values per object:

UserModel:
  path: webservice/user
  equals_and_hash_code: false
  properties:
    id: int

Ignored fields

If you wish to ignore certain fields when generating the == and hashCode methods, you can mark those fields with ignore_equality: true.

Note: Models with all fields ignored will report a zero hash code and equal only on identity

UserModel:
  path: webservice/user
  equals_and_hash_code: false
  properties:
    id:
      type: int
      ignore_equality: true
    include: String

explicit_to_json

By default json_serializable will not generate the toJson methods on an other json_serializable object or list or map. With the model_generator we can enable this by default since 5.0.0 You can override it at a global level:

model_generator:
  explicit_to_json: false

or to override the values per object:

UserModel:
  path: webservice/user
  explicit_to_json: false
  properties:
    id: int

toString

If you want the generated models to include generated toString code, you can turn it on in pubspec.yaml. Defaults to false. All fields are taken into consideration for the generated code.

model_generator:
  to_string: true

or to override the values per object:

UserModel:
  path: webservice/user
  to_string: false
  properties:
    id: int

Extra imports and annotations

If you wish for extra import statements in the generated files and/or extra annotations on the generated model classes, you can specify those in pubspec.yaml

model_generator:
  extra_imports:
    - 'package:flutter/foundation.dart'
  extra_annotations:
    - '@immutable'

or to override the values per object:

UserModel:
  path: webservice/user
  extra_imports:
  extra_annotations:
    - '@someAnnotation'
  properties:
    id: int

Default values

Since version 5.6.0 default values are supported for properties. You can specify a default value for both required and optional properties by adding default_value: ... to the property definition.

Note: Default values are taken exactly how they are specified in the yaml file, this means for example that you will need to quote strings correctly, ensure imports are there, ensure the value is a constant, ...

UserModel:
  path: webservice/user
  extra_imports:
  extra_annotations:
    - '@someAnnotation'
  properties:
    id:
      type: int
      default_value: 1
    name:
      type: String
      default_value: "'an example quoted string'"

Default values and null

Since version 5.9.0 fields with default values can accept null values in json. In which case the default value will be used instead.

If you wish to control this behaviour, you can add disallow_null_for_defaults: true to either the model_generator config or the model property. Alternatively you can specify the behaviour per field by using disallow_null.

Example:

model_generator:
  disallow_null_for_defaults: true

Example 2:

UserModel:
  path: webservice/user
  disallow_null_for_defaults: true
  properties:
    id:
      type: int
      default_value: 1
    name:
      type: String
      default_value: "'an example quoted string'"

Example 3:

UserModel:
  path: webservice/user
  properties:
    id:
      type: int
      default_value: 1
    name:
      type: String
      default_value: "'an example quoted string'"
      disallow_null: true

Generics support support

If you want your models to generate code that can be used in combination with generics. use this:

model_generator:
  generate_for_generics: true

or to override the default generate_for_generics value in the pubspec.yaml

UserModel:
  path: webservice/user
  generate_for_generics: true
  converters:
    - DateTimeConverter
  properties:
    id: int

Extends

If you want your models to expand any other model use extends:

Note: It is not supported to extend custom models

UserDetails:
  path: webservice/user
  extends: UserModel
  properties:
    name: String

Builtin types

The following framework types descriptors are known out of the box:

string/String
int/integer
bool/boolean
double
date/datetime
dynamic/object/any
array
map

Default setup

Example of the model_generator/config.yaml file

UserModel:
  path: webservice/user
  converters:
    - DateTimeConverter
  properties:
    id: int
    name: String
    salary: double
    something: dynamic
    isLoggedIn:
      type: bool
      default_value: false
    roles: List<String>
    birthday: date
    addresses: List<Address>
    idToAddress: Map<String, Address>
    securityRole:
      type: String
      jsonKey: securityIndicator
    dynamicField: dynamic
    includeIfNullField:
      include_if_null: false #If this field is null, this field will not be added to your json object (used for PATCH models)
      type: String
    ignoreField:
      ignore: false #This field is ignored in the to & from json methods
      type: String
    ignoreFieldOnlyInFrom:
      includeFromJson: false #This field is ignored in the from json method
      type: String
    ignoreFieldOnlyInTo:
      includeToJson: false #This field is ignored in the to json method
      type: String
    mutableField:
      non_final: true #Field will not be marked final
      type: String
    changedAt:
      type: DateTime
    idToAddressList: Map<String, List<Address>>

Address:
  path: webservice/user #Can also be package:... and/or end with the actual file (.dart)
  properties:
    street: String

#Custom base_directory
CustomBaseDirectoryObject:
  base_directory: custom_models
  path: webservice
  properties:
    path: String

#Custom json converter. Use with converters property on models
DateTimeConverter:
  type: json_converter
  path: converter/

Inline types (since 6.0.0)

In some cases, writing the full specification for simple fields is very verbose. Since 6.0.0 it is possible to write simple fields inline, without nesting below the field name, since 7.0.0 nested lists and list in maps is also supported:

UserModel:
  properties:
    id: int
    name: String
    age: int
    is_active: bool?
    created_at: DateTime
    roles: List<string>
    customProperties: Map<String, Property>?
    customPropertiesList: Map<String, List<Property>>?

since 7.0.0 inline types are supported now even when adding extra configuration:

before:

BookCase:
  path: webservice/BookCases
  properties:
    id: int
    books:
      type: array
      items:
        type: Book
      required: false
      include_if_null: false

now:

BookCase:
  path: webservice/BookCases
  properties:
    id: int
    books:
      type: List<Book>?
      include_if_null: false

Currently all basic types are supported, simple Lists and Maps (no nullable generic parameters) as well as references to other objects. Items post-fixed with ? will be marked optional.

Enum support (as of v7.0.0 enums now support properties)

Add simple enums, the name of the enum value (MALE, FEMALE, X, Y) will be used when parsing from json

Gender:
  path: webservice/user
  type: enum
  values:
    MALE:
    FEMALE:
    X:
    Y:

By default enums will be generated with a property called jsonValue. this is the value of the enum used when parsing from json. This will only be used when there isn't already a custom jsonValue defined using 'is_json_value: true' in the properties of the enum. To turn this behavior of you can use 'use_default_json_value: false'.

Gender:
  path: webservice/user
  use_default_json_value: false
  type: enum
  values:
    MALE:
    FEMALE:
    X:
    Y:

Add enums with custom properties (currently supported types are int, double, bool and String)

Gender:
  path: webservice/user
  type: enum
  properties:
    abbreviation: String
  values:
    MALE:
      properties:
        abbreviation: m
    FEMALE:
      properties:
        abbreviation: f
    X:
      properties:
        abbreviation: x
    Y:
      properties:
        abbreviation: y

Define custom json key using is_json_value, the value of this property will then be used to parse from json

Gender:
  path: webservice/user
  type: enum
  properties:
    key:
      type: String
      is_json_value: true
    abbreviation: String
  values:
    MALE:
      properties:
        key: male
        abbreviation: m
    FEMALE:
      properties:
        key: female
        abbreviation: f
    X:
      properties:
        key: x
        abbreviation: x
    Y:
      properties:
        key: y
        abbreviation: y

Optional and default values are supported. If value isn't defined for a property then it will use the defaultValue. If a property is optional and no value is given it is null.

Gender:
  path: webservice/user
  type: enum
  properties:
    key:
      type: String
      is_json_value: true
    abbreviation:
      type: String
      default_value: m
    lastName: String?
  values:
    MALE:
      properties:
        key: male
    FEMALE:
      properties:
        key: female
        abbreviation: f
    X:
      properties:
        key: x
    Y:
      properties:
        key: y
        lastName: lastName

Generate mapping extensions

It is possible to generate an extension for the enum that can turn the enum into it's corresponding jsonValue and the reverse.

Person:
  path: test/enum/
  type: enum
  generate_extension: true
  properties:
    jsonValue: 
      is_json_value: true
      type: int
    firstName: String
    lastName: String
  values:
    MAN:
      properties:
        jsonKey: 1
        firstName: firstName1
        lastName: lastName1
    WOMAN:
      properties:
        jsonKey: 2
        firstName: firstName2
        lastName: lastName2

The above configuration will generate an enum with this extension.

extension PersonExtension on Person {
  static Person? fromJsonValue(int value) => Person.values.firstWhereOrNull((enumValue) => enumValue.jsonKey == value);

  int toJsonValue() => jsonKey;
}

Generate mapping is no longer supported as of V7.0.0, use properties instead

Use unknownEnumValue

UnknownEnumTestObject:
  path: webservice
  properties:
    path:
      unknown_enum_value: X
      type: Gender

Automatic case conversion(v7.0.0)

As of v7.0.0 by default all fields will be converted into lowercase camelcase instead of uppercase like before. You can control this behavior globally for all enums or per-enum by setting the uppercase_enums property to false ( default) or true. This only affects the name of the enum when using it in dart code. the jsonValue will still be the name you type in the config.

model_generator:
  uppercase_enums: true

or

UnknownEnumTestObject:
  path: webservice
  uppercase_enums: true
  properties:
    path:

Custom object

Support for custom objects that are not generated by the model generator.

Paths are either local to the project, package specifications (package:...) or dart:core

CustomObject:
  path: data/custom/
  type: custom

Required methods inside your class

  factory {Model_Name}.fromJson(Map<String, dynamic> json) => _${Model_Name}FromJson(json);

  Map<String, dynamic> toJson() => _${Model_Name}ToJson(this);

fromJson & toJson

Support for custom objects but use fromJson & toJson instead of full object parsing:

CustomObjectFromToJson:
  path: data/custom/
  type: custom_from_to_json

Required functions outside your class

{Model_Name} handle{Model_Name}FromJson(object) => {Model_Name}.fromJson(object);

{Original_Type} handle{Model_Name}ToJson({Model_Name} data) => data.toJson();

fromJson & toJson override

Support for custom objects but use fromJson & toJson instead of full object parsing:

UserModel:
  path: webservice/user
  properties:
    description: The time at which the user has last updated his information
    changedAt:
      type: datetime
      fromJson: handleFromJsonWithCustomCode
      toJson: handleToJsonWithCustomCode

Required functions outside your file. (extra import should be used)

JsonConverter support

You can specify custom json converters to be used for types that match

UserModel:
  path: webservice/user
  converters:
    - DateTimeConverter
  properties:
    changedAt: DateTime

Specify the custom JsonConverter object as a known type to resolve it

DateTimeConverter:
  type: json_converter
  path: converter/

Documentation support

You can specify description on models, enum, fields and on enum entries. This description will be used verbatim to generate a code comment for that class/enum/field

Example for a class:

UserModel:
  path: webservice/user
  description: The model holding user data
  converters:
    - DateTimeConverter
  properties:
    description: The time at which the user has last updated his information
    changedAt: DateTime

Example for a enum:

Person:
  path: test/enum/
  type: enum
  description: This is a enum of a person
  values:
    MAN:
      description: enum of a man
    WOMAN:
      description: enum of a woman
    OTHER:
      description: enum of a other

Static creator support

You can specify static_create on objects or globally in the pubspec.yaml file. If this is specified, a static creator method called create will be generated referencing the factory constructor. This static method can be used as a function reference. Defaults to false

UserModel:
  path: webservice/user
  static_create: true
  properties:
    changedAt: DateTime

Retrofit compute support

Retrofit has added compute function support for decoding json payload in version 3.0.0. This requires top-level functions with a certain signature. You can have model generator generate these for you by setting retrofit_compute: true in the pubspec.yaml file:

model_generator:
  retrofit_compute: true