Further consolidate the libraries

api/handler/http/http.go

@@ -0,0 +1,100 @@
+// Package http is a http reverse proxy handler
+package http
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+	"net/http/httputil"
+	"net/url"
+
+	"github.com/micro/go-micro/api"
+	"github.com/micro/go-micro/api/handler"
+	"github.com/micro/go-micro/selector"
+)
+
+const (
+	Handler = "http"
+)
+
+type httpHandler struct {
+	options handler.Options
+
+	// set with different initialiser
+	s *api.Service
+}
+
+func (h *httpHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	service, err := h.getService(r)
+	if err != nil {
+		w.WriteHeader(500)
+		return
+	}
+
+	if len(service) == 0 {
+		w.WriteHeader(404)
+		return
+	}
+
+	rp, err := url.Parse(service)
+	if err != nil {
+		w.WriteHeader(500)
+		return
+	}
+
+	httputil.NewSingleHostReverseProxy(rp).ServeHTTP(w, r)
+}
+
+// getService returns the service for this request from the selector
+func (h *httpHandler) getService(r *http.Request) (string, error) {
+	var service *api.Service
+
+	if h.s != nil {
+		// we were given the service
+		service = h.s
+	} else if h.options.Router != nil {
+		// try get service from router
+		s, err := h.options.Router.Route(r)
+		if err != nil {
+			return "", err
+		}
+		service = s
+	} else {
+		// we have no way of routing the request
+		return "", errors.New("no route found")
+	}
+
+	// create a random selector
+	next := selector.Random(service.Services)
+
+	// get the next node
+	s, err := next()
+	if err != nil {
+		return "", nil
+	}
+
+	return fmt.Sprintf("http://%s:%d", s.Address, s.Port), nil
+}
+
+func (h *httpHandler) String() string {
+	return "http"
+}
+
+// NewHandler returns a http proxy handler
+func NewHandler(opts ...handler.Option) handler.Handler {
+	options := handler.NewOptions(opts...)
+
+	return &httpHandler{
+		options: options,
+	}
+}
+
+// WithService creates a handler with a service
+func WithService(s *api.Service, opts ...handler.Option) handler.Handler {
+	options := handler.NewOptions(opts...)
+
+	return &httpHandler{
+		options: options,
+		s:       s,
+	}
+}