resource

api2go-resource

This package serves as a bridge between GORM and api2go, reducing the amount of boilerplate code needed for implementing CRUD actions for GORM models.

Features

Here are some of the features that api2go-resource provides:

• Works with your existing GORM models
• Enables filtering to be limited to specific fields
• Provides hooks to enable access control and normalization

Usage

Let's suppose you have the following model definition:

type Article struct {
    ID      int64
    Title   string
    Content string
}

In order to use the model with api2go, three important methods must be implemented:

func (a *Article) GetName() string {
    return "articles"
}

func (a *Article) GetID() string {
    return strconv.FormatInt(a.ID, 10)
}

func (a *Article) SetID(id string) error {
    a.ID, _ = strconv.ParseInt(id, 10, 64)
    return nil
}

The next step is to create a Resource instance for the model:

import "github.com/nathan-osman/api2go-resource"

// db is an instance of *gorm.DB

var articleResource = &resource.Resource{
    DB:   db,
    Type: &Article{},
}

This resource can now be registered with api2go:

api := api2go.NewAPI("api")
api.AddResource(&Article{}, articleResource)

Hooks

Hooks can be used for a number of different purposes.

For example, to make a resource read-only:

func readOnly(p *resource.Params) error {
    switch p.Action {
    case resource.BeforeCreate, resource.BeforeDelete, resource.BeforeUpdate:
        return api2go.NewHTTPError(nil, "read only", http.StatusBadRequest)
    }
    return nil
}

var articleResource = &resource.Resource{
    // ...
    Hooks: []Hook{readOnly},
}

To ensure that articles are always retrieved in alphabetical order:

func alphabeticalOrder(p *resource.Params) error {
    switch p.Action {
    case resource.BeforeFindAll, resource.BeforeFindOne:
        p.DB = p.DB.Order('title')
    }
    return nil
}

var articleResource = &resource.Resource{
    // ...
    Hooks: []Hook{alphabeticalOrder},
}

To remove any extra whitespace in an article title before saving:

func trimTitle(p *resource.Params) error {
    switch p.Action {
    case resource.BeforeCreate, resource.BeforeUpdate:
        p.Obj.Title = strings.TrimSpace(p.Obj.Title)
    }
    return nil
}

var articleResource = &resource.Resource{
    // ...
    Hooks: []Hook{trimTitle},
}