package tracking
import (
"encoding/json"
"errors"
"net/http"
"github.com/gorilla/mux"
"golang.org/x/net/context"
"github.com/go-kit/kit/examples/shipping/cargo"
kitlog "github.com/go-kit/kit/log"
kithttp "github.com/go-kit/kit/transport/http"
)
// MakeHandler returns a handler for the tracking service.
func MakeHandler(ctx context.Context, ts Service, logger kitlog.Logger) http.Handler {
r := mux.NewRouter()
opts := []kithttp.ServerOption{
kithttp.ServerErrorLogger(logger),
kithttp.ServerErrorEncoder(encodeError),
}
trackCargoHandler := kithttp.NewServer(
ctx,
makeTrackCargoEndpoint(ts),
decodeTrackCargoRequest,
encodeResponse,
opts...,
)
r.Handle("/tracking/v1/cargos/{id}", trackCargoHandler).Methods("GET")
return r
}
func decodeTrackCargoRequest(r *http.Request) (interface{}, error) {
vars := mux.Vars(r)
id, ok := vars["id"]
if !ok {
return nil, errors.New("bad route")
}
return trackCargoRequest{ID: id}, nil
}
func encodeResponse(w http.ResponseWriter, response interface{}) error {
if e, ok := response.(errorer); ok && e.error() != nil {
encodeError(w, e.error())
return nil
}
w.Header().Set("Content-Type", "application/json; charset=utf-8")
return json.NewEncoder(w).Encode(response)
}
type errorer interface {
error() error
}
// encode errors from business-logic
func encodeError(w http.ResponseWriter, err error) {
switch err {
case cargo.ErrUnknown:
w.WriteHeader(http.StatusNotFound)
case ErrInvalidArgument:
w.WriteHeader(http.StatusBadRequest)
default:
w.WriteHeader(http.StatusInternalServerError)
}
w.Header().Set("Content-Type", "application/json; charset=utf-8")
json.NewEncoder(w).Encode(map[string]interface{}{
"error": err.Error(),
})
}