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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, http.Header) (int, interface{}, http.Header)
}
// PostSupported is the interface that provides the Post
// method a resource must support to receive HTTP POSTs.
type PostSupported interface {
Post(url.Values, http.Header) (int, interface{}, http.Header)
}
// PutSupported is the interface that provides the Put
// method a resource must support to receive HTTP PUTs.
type PutSupported interface {
Put(url.Values, http.Header) (int, interface{}, http.Header)
}
// DeleteSupported is the interface that provides the Delete
// method a resource must support to receive HTTP DELETEs.
type DeleteSupported interface {
Delete(url.Values, http.Header) (int, interface{}, http.Header)
}
// An API manages a group of resources by routing 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
muxInitialized bool
}
// 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, http.Header) (int, interface{}, http.Header)
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, header := handler(request.Form, request.Header)
content, err := json.MarshalIndent(data, "", " ")
if err != nil {
rw.WriteHeader(http.StatusInternalServerError)
return
}
for name, values := range header {
for _, value := range values {
rw.Header().Add(name, value)
}
}
rw.WriteHeader(code)
rw.Write(content)
}
}
// Mux returns the http.ServeMux used by an API. If a ServeMux has
// does not yet exist, a new one will be created and returned.
func (api *API) Mux() *http.ServeMux {
if api.muxInitialized {
return api.mux
} else {
api.mux = http.NewServeMux()
api.muxInitialized = true
return api.mux
}
}
// 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) {
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.muxInitialized {
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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