apigen

apigen

apigen is a tool written in go that parses go structs and generates code for querying the database based on GORM ORM.

Features

• generates services for all structs in your models unless skipped in the configuration file(apigen.toml)
• Created database connection helper with sane defaults.
• Optionally Preloads all relationships(even nested relationships) by default. Because the parser knows foreign keys and tree, we are able to do that for all foreignKey and many2many fields.
• Allows for customizing all queries by specifying optional Where, ordering, grouping, select options ...services.Options These options are passed to the callable handlers that are designed with the decorator pattern.
• Generates typescript interfaces for your models.

Installation

As a CLI tool

go install github.com/abiiranathan/apigen@latest

As a library

go get -u github.com/abiiranathan/apigen

Initialize project and create a configuration file apigen.toml

apigen init

The configuration file has the following format:

# apigen configuration file.
# Strings should use single quotes

# PreloadAll all relationships with gorm.Preload
PreloadAll = false

# PreloadDepth is the depth of the relationships to preload
# e.g Patient.Visit.Doctor will be preloaded if PreloadDepth is 3
PreloadDepth = 3

# Output preload.json
OutputJson = true

[Models]
# ModelPkg is the package name for the models to look for struct definitions
Pkgs = [
  'github.com/abiiranathan/apigen/models',
]

# Skip is a list of models to skip. Names are case sensitive
Skip = []

# ReadOnly is a list of models that should not be generated with CRUD operations
# Only Get methods will be generated for these models.
ReadOnly = []

[Output]

# OutDir is the directory to write the generated files to
OutDir = 'gen'

# ServiceName is the name of the service to generate
ServiceName = 'services'

[overrides]
# Overrides for types and fields. Forexample, here we are overriding the type
# as would appear in typescript for Sex to be an enum.
[overrides.types]
Sex = '"Male" | "Female"'

# Here we are overriding gener to of type Sex. Sex is a go type.
[overrides.fields]
gender = 'Sex'

Generate code

If apigen.toml is the root of your project.

apigen generate

Or

apigen --config config.toml generate

to specify the custom path to the configuration file.

Using the generated code

import(
    // These will point to the generated code
    "github.com/yourname/cool-api/gen/handlers"
	"github.com/yourname/cool-api/gen/services"

	"gorm.io/gorm/logger"
)

func main() {
	db, err := services.PostgresConnection(dsn, "Africa/kampala", logger.Silent, os.Stdout)
	if err != nil {
		panic(err)
	}

	err = db.AutoMigrate(&models.User{})
	if err != nil {
		log.Fatalf("Error performing database migrations: %v\n", err)
	}

	svc := services.NewService(db)
    users, err := svc.Users.GetAll()
}