Go chi renderer having difficult processing bound lists - go

Question

Go here. Trying to get the chi renderer to return a list of Order struct instances and getting a compiler error that I don't understand:
package myapp
import (
"net/http"
"github.com/go-chi/render"
)
type Order struct {
OrderId string
Status string
}
func (*Order) Bind(r *http.Request) error {
return nil
}
func GetAllOrderByCustomerId(dbClient DbClient, customerId string) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
// fetch all customer orders from the DB
orders,err := dbClient.FetchAllOrdersByCustomerId(customerId)
if err != nil {
log.Error("unable to fetch orders for customer", err)
render.Render(w, r, NewInternalServerError(err))
return
}
render.Bind(r, &orders)
return
}
}
When I go to compile this code I get:
fizz/buzz/myapp/order_fetcher.go:136:20: cannot use &orders (type *[]Order) as type render.Binder in argument to render.Bind:
*[]Order does not implement render.Binder (missing Bind method)
So even though I've defined a Bind for Order, it doesn't seem to automatically apply that Bind to a collection/list of Orders.
Can anyone see what I'm missing? Some endpoints will only be returning a single Order, whereas others (like this one) need to be able to return a collection/list of Orders.

Answer 1

As in the example in chi repository, you have to create a helper method to render the list of something, in your case, list of orders.
First, you have to implement the render.Renderer method then create a helper method to build a list of render.Renderer.
I've adapted your code from the example here:
type Order struct {
OrderId string
Status string
}
// Render implement render.Renderer
func (*Order) Render(w http.ResponseWriter, r *http.Request) error {
// do something
return nil
}
// newOrderList is a helper method to make list of render.Renderer
func newOrderList(orders []*Order) []render.Renderer {
list := []render.Renderer{}
for _, order := range orders {
list = append(list, order)
}
return list
}
func GetAllOrderByCustomerId(dbClient DbClient, customerId string) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
// fetch all customer orders from the DB
orders, err := dbClient.FetchAllOrdersByCustomerId(customerId)
if err != nil {
log.Error("unable to fetch orders for customer", err)
render.Render(w, r, NewInternalServerError(err))
return
}
// render list of orders
render.RenderList(w, r, newOrderList(orders))
return
}
}