add proxy interface and move router packages

proxy/http/http.go

@@ -0,0 +1,177 @@
+// Package http provides a micro rpc to http proxy
+package http
+
+import (
+	"bytes"
+	"context"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+	"path"
+
+	"github.com/micro/go-micro"
+	"github.com/micro/go-micro/errors"
+	"github.com/micro/go-micro/server"
+)
+
+// Router will proxy rpc requests as http POST requests. It is a server.Router
+type Router struct {
+	// The http backend to call
+	Backend string
+
+	// first request
+	first bool
+}
+
+var (
+	// The default backend
+	DefaultBackend = "http://localhost:9090"
+	// The default router
+	DefaultRouter = &Router{}
+)
+
+func getMethod(hdr map[string]string) string {
+	switch hdr["Micro-Method"] {
+	case "GET", "HEAD", "POST", "PUT", "DELETE", "CONNECT", "OPTIONS", "TRACE", "PATCH":
+		return hdr["Micro-Method"]
+	default:
+		return "POST"
+	}
+}
+
+func getEndpoint(hdr map[string]string) string {
+	ep := hdr["Micro-Endpoint"]
+	if len(ep) > 0 && ep[0] == '/' {
+		return ep
+	}
+	return ""
+}
+
+// ServeRequest honours the server.Router interface
+func (p *Router) ServeRequest(ctx context.Context, req server.Request, rsp server.Response) error {
+	if p.Backend == "" {
+		p.Backend = DefaultBackend
+	}
+
+	for {
+		// get data
+		body, err := req.Read()
+		if err == io.EOF {
+			return nil
+		}
+		if err != nil {
+			return err
+		}
+
+		// get the header
+		hdr := req.Header()
+
+		// get method
+		method := getMethod(hdr)
+
+		// get endpoint
+		endpoint := getEndpoint(hdr)
+
+		// set the endpoint
+		if len(endpoint) == 0 {
+			endpoint = p.Backend
+		} else {
+			// add endpoint to backend
+			u, err := url.Parse(p.Backend)
+			if err != nil {
+				return errors.InternalServerError(req.Service(), err.Error())
+			}
+			u.Path = path.Join(u.Path, endpoint)
+			endpoint = u.String()
+		}
+
+		// send to backend
+		hreq, err := http.NewRequest(method, endpoint, bytes.NewReader(body))
+		if err != nil {
+			return errors.InternalServerError(req.Service(), err.Error())
+		}
+
+		// set the headers
+		for k, v := range hdr {
+			hreq.Header.Set(k, v)
+		}
+
+		// make the call
+		hrsp, err := http.DefaultClient.Do(hreq)
+		if err != nil {
+			return errors.InternalServerError(req.Service(), err.Error())
+		}
+
+		// read body
+		b, err := ioutil.ReadAll(hrsp.Body)
+		hrsp.Body.Close()
+		if err != nil {
+			return errors.InternalServerError(req.Service(), err.Error())
+		}
+
+		// set response headers
+		hdr = map[string]string{}
+		for k, _ := range hrsp.Header {
+			hdr[k] = hrsp.Header.Get(k)
+		}
+		// write the header
+		rsp.WriteHeader(hdr)
+		// write the body
+		err = rsp.Write(b)
+		if err == io.EOF {
+			return nil
+		}
+		if err != nil {
+			return errors.InternalServerError(req.Service(), err.Error())
+		}
+	}
+
+	return nil
+}
+
+// NewSingleHostRouter returns a router which sends requests to a single http backend
+//
+// It is used by setting it in a new micro service to act as a proxy for a http backend.
+//
+// Usage:
+//
+// Create a new router to the http backend
+//
+// 	r := NewSingleHostRouter("http://localhost:10001")
+//
+// 	// Create your new service
+// 	service := micro.NewService(
+// 		micro.Name("greeter"),
+//		// Set the router
+//		http.WithRouter(r),
+// 	)
+//
+// 	// Run the service
+// 	service.Run()
+func NewSingleHostRouter(url string) *Router {
+	return &Router{
+		Backend: url,
+	}
+}
+
+// NewService returns a new http proxy. It acts as a micro service proxy.
+// Any request on the transport is routed to a fixed http backend.
+//
+// Usage:
+//
+// 	service := NewService(
+//		micro.Name("greeter"),
+//		// Sets the default http endpoint
+//		http.WithBackend("http://localhost:10001"),
+//	 )
+//
+func NewService(opts ...micro.Option) micro.Service {
+	// prepend router to opts
+	opts = append([]micro.Option{
+		WithRouter(DefaultRouter),
+	}, opts...)
+
+	// create the new service
+	return micro.NewService(opts...)
+}