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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(values 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(values 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(values 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(values url.Values) (int, interface{})
}
// An API manages a group of resources by routing to requests
// to the correct method on a matching resource.
//
// 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{}
}
// Abort responds to a given request with the status text associated
// with the passed in HTTP status code.
func (api *API) Abort(rw http.ResponseWriter, statusCode int) {
rw.WriteHeader(statusCode)
rw.Write([]byte(http.StatusText(statusCode)))
}
func (api *API) requestHandler(resource interface{}) http.HandlerFunc {
return func(rw http.ResponseWriter, request *http.Request) {
var err error
var data interface{} = ""
var code int = 405
method := request.Method
if request.ParseForm() != nil {
api.Abort(rw, 400)
return
}
values := request.Form
switch method {
case GET:
if r, ok := resource.(GetSupported); ok {
code, data = r.Get(values)
} else {
api.Abort(rw, 405)
return
}
case POST:
if r, ok := resource.(PostSupported); ok {
code, data = r.Post(values)
} else {
api.Abort(rw, 405)
return
}
case PUT:
if r, ok := resource.(PutSupported); ok {
code, data = r.Put(values)
} else {
api.Abort(rw, 405)
return
}
case DELETE:
if r, ok := resource.(DeleteSupported); ok {
code, data = r.Delete(values)
} else {
api.Abort(rw, 405)
return
}
default:
api.Abort(rw, 405)
return
}
content, err := json.Marshal(data)
if err != nil {
api.Abort(rw, 500)
}
rw.WriteHeader(code)
rw.Write(content)
}
}
// AddResource adds a new resource to an API. The API will route
// request matching the path to the correct HTTP method on the
// resource.
func (api *API) AddResource(resource interface{}, path string) {
if api.mux == nil {
api.mux = http.NewServeMux()
}
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)
http.ListenAndServe(portString, api.mux)
return nil
}
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