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package sleepy
import (
"encoding/json"
"errors"
"fmt"
"net/http"
"net/url"
)
const (
GET = "GET"
POST = "POST"
PUT = "PUT"
DELETE = "DELETE"
)
// GetSupported is the interface that provides the Get
// method a resource must support to receive HTTP GETs.
type GetSupported interface {
Get(url.Values) (int, interface{})
}
// PostSupported is the interface that provides the Post
// method a resource must support to receive HTTP POST.
type PostSupported interface {
Post(url.Values) (int, interface{})
}
// PutSupported is the interface that provides the Put
// method a resource must support to receive HTTP PUT.
type PutSupported interface {
Put(url.Values) (int, interface{})
}
// DeleteSupported is the interface that provides the Delete
// method a resource must support to receive HTTP DELETE.
type DeleteSupported interface {
Delete(url.Values) (int, interface{})
}
// An API manages a group of resources by routing to requests
// to the correct method on a matching resource and marshalling
// the returned data to JSON for the HTTP response.
//
// You can instantiate multiple APIs on separate ports. Each API
// will manage its own set of resources.
type API struct {
mux *http.ServeMux
}
// NewAPI allocates and returns a new API.
func NewAPI() *API {
return &API{}
}
func (api *API) requestHandler(resource interface{}) http.HandlerFunc {
return func(rw http.ResponseWriter, request *http.Request) {
if request.ParseForm() != nil {
rw.WriteHeader(http.StatusBadRequest)
return
}
var handler func(url.Values) (int, interface{})
switch request.Method {
case GET:
if resource, ok := resource.(GetSupported); ok {
handler = resource.Get
}
case POST:
if resource, ok := resource.(PostSupported); ok {
handler = resource.Post
}
case PUT:
if resource, ok := resource.(PutSupported); ok {
handler = resource.Put
}
case DELETE:
if resource, ok := resource.(DeleteSupported); ok {
handler = resource.Delete
}
}
if handler == nil {
rw.WriteHeader(http.StatusMethodNotAllowed)
return
}
code, data := handler(request.Form)
content, err := json.Marshal(data)
if err != nil {
rw.WriteHeader(http.StatusInternalServerError)
}
rw.WriteHeader(code)
rw.Write(content)
}
}
// AddResource adds a new resource to an API. The API will route
// requests that match one of the given paths to the matching HTTP
// method on the resource.
func (api *API) AddResource(resource interface{}, paths ...string) {
if api.mux == nil {
api.mux = http.NewServeMux()
}
for _, path := range paths {
api.mux.HandleFunc(path, api.requestHandler(resource))
}
}
// Start causes the API to begin serving requests on the given port.
func (api *API) Start(port int) error {
if api.mux == nil {
return errors.New("You must add at least one resource to this API.")
}
portString := fmt.Sprintf(":%d", port)
return http.ListenAndServe(portString, api.mux)
}
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