go-fractal is the go version of league/fractal which is is written in PHP, fractal provides a presentation and transformation layer for complex data output, the like found in RESTful APIs, and works really well with JSON. Think of this as a view layer for your JSON/YAML/etc.
go get -u github.com/ibllex/go-fractalFor the sake of simplicity, this example has been put together as though it was one file. In reality you would spread the manager initiation, data collection and JSON conversion into separate parts of your application.
package main
import (
"fmt"
"github.com/ibllex/go-fractal"
)
type Book struct {
ID int
Title string
Year int
Author string
}
func main() {
// This is the data to be converted
data := &Book{1, "Hogfather", 1998, "Philip K Dick"}
// Create a top level instance
manager := fractal.NewManager(nil)
manager.SetSerializer(&fractal.ArraySerializer{})
// This "Transformer" can be a callback or a new instance of a fractal.Transformer object
transformer := fractal.T(func(t *fractal.BaseTransformer, data fractal.Any) fractal.M {
result := fractal.M{}
if b, ok := data.(*Book); ok {
result["id"] = b.ID
result["title"] = "'" + b.Title + "'"
result["year"] = b.Year
result["author"] = b.Author
}
return result
})
// Convert the single book into an item resource
resource := fractal.NewItem(
fractal.WithData(data),
fractal.WithTransformer(transformer),
)
// Turn all of that into a JSON string
json, _ := manager.CreateData(resource, nil).ToJSON()
fmt.Println(json)
// Outputs: {"data":{"author":"Philip K Dick","id":1,"title":"'Hogfather'","year":1998}}
}package main
import (
"fmt"
"github.com/ibllex/go-fractal"
)
type Book struct {
ID int
Title string
Year int
Author string
}
func main() {
// This is the data to be converted
books := []fractal.Any{
&Book{1, "Hogfather", 1998, "Philip K Dick"},
&Book{2, "Game Of Kill Everyone", 2014, "George R. R. Satan"},
}
// Create a top level instance
manager := fractal.NewManager(nil)
manager.SetSerializer(&fractal.ArraySerializer{})
// This "Transformer" can be a callback or a new instance of a fractal.Transformer object
transformer := fractal.T(func(t *fractal.BaseTransformer, data fractal.Any) fractal.M {
result := fractal.M{}
if b, ok := data.(*Book); ok {
result["id"] = b.ID
result["title"] = "'" + b.Title + "'"
result["year"] = b.Year
result["author"] = b.Author
}
return result
})
// Convert the books into a collection resource
resource := fractal.NewCollection(
fractal.WithData(books),
fractal.WithTransformer(transformer),
)
// Turn all of that into a JSON string
json, _ := manager.CreateData(resource, nil).ToJSON()
fmt.Println(json)
// Outputs: {"data":[{"author":"Philip K Dick","id":1,"title":"'Hogfather'","year":1998},{"author":"George R. R. Satan","id":2,"title":"'Game Of Kill Everyone'","year":2014}]}
}package main
import (
"fmt"
"github.com/ibllex/go-fractal"
"github.com/ibllex/go-fractal/pagination"
)
type Book struct {
ID int
Title string
Year int
Author string
}
func main() {
// This is the data to be converted
books := []fractal.Any{
&Book{1, "Hogfather", 1998, "Philip K Dick"},
&Book{2, "Game Of Kill Everyone", 2014, "George R. R. Satan"},
}
// Create an paginator
paginator := pagination.NewLengthAwarePaginator(
books, 10, 2,
pagination.WithPath("https://www.example.com/books/?user=example"),
pagination.WithCurrentPage(2),
)
// Create a top level instance
manager := fractal.NewManager(nil)
manager.SetSerializer(&fractal.ArraySerializer{})
// This "Transformer" can be a callback or a new instance of a fractal.Transformer object
transformer := fractal.T(func(t *fractal.BaseTransformer, data fractal.Any) fractal.M {
result := fractal.M{}
if b, ok := data.(*Book); ok {
result["id"] = b.ID
result["title"] = "'" + b.Title + "'"
result["year"] = b.Year
result["author"] = b.Author
}
return result
})
// Convert the books into a collection resource with a paginator
resource := fractal.NewCollection(
fractal.WithData(books),
fractal.WithTransformer(transformer),
).SetPaginator(paginator)
// Turn all of that into a JSON string
json, _ := manager.CreateData(resource, nil).ToJSON()
fmt.Println(json)
// Outputs: {"data":[{"author":"Philip K Dick","id":1,"title":"'Hogfather'","year":1998},{"author":"George R. R. Satan","id":2,"title":"'Game Of Kill Everyone'","year":2014}],"meta":{"pagination":{"count":2,"current_page":2,"links":{"next":"https://www.example.com/books/?user=example&page=3","previous":"https://www.example.com/books/?user=example&page=1"},"per_page":2,"total":10,"total_pages":5}}}
}package main
import (
"fmt"
"log"
"net/http"
"github.com/gin-gonic/gin"
"github.com/ibllex/go-fractal"
fgin "github.com/ibllex/go-fractal/gin"
"github.com/ibllex/go-fractal/pagination"
)
type Book struct {
ID int
Title string
Year int
Author string
}
type BookTransformer struct {
*fractal.BaseTransformer
}
func (t *BookTransformer) Transform(data fractal.Any) fractal.M {
result := fractal.M{}
if b := t.toBook(data); b != nil {
result["id"] = b.ID
result["title"] = "'" + b.Title + "'"
result["year"] = b.Year
result["author"] = b.Author
}
return result
}
func (t *BookTransformer) toBook(data fractal.Any) *Book {
switch b := data.(type) {
case *Book:
return b
case Book:
return &b
}
return nil
}
func NewBookTransformer() *BookTransformer {
return &BookTransformer{&fractal.BaseTransformer{}}
}
func GetBook(c *fgin.Context) {
// This is the data to be converted
data := &Book{1, "Hogfather", 1998, "Philip K Dick"}
// Turn all of that into a JSON output
c.Item(data, NewBookTransformer())
// Outputs: {"data":{"author":"Philip K Dick","id":1,"title":"'Hogfather'","year":1998}}
}
func GetBooks(c *fgin.Context) {
// This is the data to be converted
books := []fractal.Any{
&Book{1, "Hogfather", 1998, "Philip K Dick"},
&Book{2, "Game Of Kill Everyone", 2014, "George R. R. Satan"},
}
// Create an paginator
paginator := pagination.NewLengthAwarePaginator(
books, 10, 2,
pagination.WithPath("https://www.example.com/books/?user=example"),
pagination.WithCurrentPage(2),
)
// Turn all of that into a JSON output with pagination
c.Paginator(paginator, NewBookTransformer())
// Outputs: {"data":[{"author":"Philip K Dick","id":1,"title":"'Hogfather'","year":1998},{"author":"George R. R. Satan","id":2,"title":"'Game Of Kill Everyone'","year":2014}],"meta":{"pagination":{"count":2,"current_page":2,"links":{"next":"https://www.example.com/books/?user=example\u0026page=3","previous":"https://www.example.com/books/?user=example\u0026page=1"},"per_page":2,"total":10,"total_pages":5}}}
// You can also use c.Collection() to transform a collection without pagination
// c.Collection(books, NewBookTransformer())
// Outputs: {"data":[{"author":"Philip K Dick","id":1,"title":"'Hogfather'","year":1998},{"author":"George R. R. Satan","id":2,"title":"'Game Of Kill Everyone'","year":2014}]}
}
func NotFound(c *fgin.Context) {
// A convenient way to return a 404 status,
// We also provide many other methods to return error messages easily,
// For more infomation: https://github.com/ibllex/go-fractal/blob/main/gin/context.go
c.ErrorNotFound()
// Outputs: {"message":"Not Found","status_code":404}
}
func main() {
r := gin.Default()
r.GET("/books", fgin.H(GetBooks))
r.GET("/book", fgin.H(GetBook))
r.GET("/404", fgin.H(NotFound))
srv := http.Server{
Addr: fmt.Sprintf(":%d", 8080),
Handler: r,
}
log.Printf("HTTP Service Started at %s", srv.Addr)
srv.ListenAndServe()
}This library is under the MIT license.