model_generator

Description:

model generator

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
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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
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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
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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
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== 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
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or to override the values per object:
UserModel:
path: webservice/user
equals_and_hash_code: false
properties:
id: int
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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
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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
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or to override the values per object:
UserModel:
path: webservice/user
explicit_to_json: false
properties:
id: int
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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
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or to override the values per object:
UserModel:
path: webservice/user
to_string: false
properties:
id: int
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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'
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or to override the values per object:
UserModel:
path: webservice/user
extra_imports:
extra_annotations:
- '@someAnnotation'
properties:
id: int
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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'"
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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
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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'"
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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
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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
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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
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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
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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
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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/

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

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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;
}
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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
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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
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or
UnknownEnumTestObject:
path: webservice
uppercase_enums: true
properties:
path:
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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
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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);
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fromJson & toJson #
Support for custom objects but use fromJson & toJson instead of full object parsing:
CustomObjectFromToJson:
path: data/custom/
type: custom_from_to_json
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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();

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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
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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
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Specify the custom JsonConverter object as a known type to resolve it
DateTimeConverter:
type: json_converter
path: converter/
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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
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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
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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
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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
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