api/router/static: allow to specify body dst (#1486)

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

api/api.go

@@ -22,7 +22,7 @@ type Api interface {
 	String() string
 }
 
-type Options struct {}
+type Options struct{}
 
 type Option func(*Options) error
 
@@ -40,6 +40,10 @@ type Endpoint struct {
 	Method []string
 	// HTTP Path e.g /greeter. Expect POSIX regex
 	Path []string
+	// Body destination
+	// "*" or "" - top level message value
+	// "string" - inner message value
+	Body string
 	// Stream flag
 	Stream bool
 }

api/handler/rpc/rpc.go

@@ -300,6 +300,7 @@ func requestPayload(r *http.Request) ([]byte, error) {
 
 	// allocate maximum
 	matches := make(map[string]interface{}, len(md))
+	bodydst := ""
 
 	// get fields from url path
 	for k, v := range md {
@@ -307,6 +308,9 @@ func requestPayload(r *http.Request) ([]byte, error) {
 		if strings.HasPrefix(k, "x-api-field-") {
 			matches[strings.TrimPrefix(k, "x-api-field-")] = v
 			delete(md, k)
+		} else if k == "x-api-body" {
+			bodydst = v
+			delete(md, k)
 		}
 	}
 
@@ -387,10 +391,34 @@ func requestPayload(r *http.Request) ([]byte, error) {
 		} else {
 			return []byte{}, nil
 		}
-
+		if bodydst == "" || bodydst == "*" {
 			if out, err = jsonpatch.MergeMergePatches(out, bodybuf); err == nil {
 				return out, nil
 			}
+		}
+		dstmap := make(map[string]interface{})
+		ps := strings.Split(bodydst, ".")
+		if len(ps) == 1 {
+			dstmap[ps[0]] = bodybuf
+		} else {
+			em := make(map[string]interface{})
+			em[ps[len(ps)-1]] = bodybuf
+			for i := len(ps) - 2; i > 0; i-- {
+				nm := make(map[string]interface{})
+				nm[ps[i]] = em
+				em = nm
+			}
+			dstmap[ps[0]] = em
+		}
+
+		bodyout, err := json.Marshal(dstmap)
+		if err != nil {
+			return nil, err
+		}
+
+		if out, err = jsonpatch.MergeMergePatches(out, bodyout); err == nil {
+			return out, nil
+		}
 
 		//fallback to previous unknown behaviour
 		return bodybuf, nil

api/router/static/static.go

@@ -191,6 +191,7 @@ func (r *staticRouter) Endpoint(req *http.Request) (*api.Service, error) {
 			Host:    ep.apiep.Host,
 			Method:  ep.apiep.Method,
 			Path:    ep.apiep.Path,
+			Body:    ep.apiep.Body,
 			Stream:  ep.apiep.Stream,
 		},
 		Services: services,
@@ -274,6 +275,7 @@ func (r *staticRouter) endpoint(req *http.Request) (*endpoint, error) {
 			for k, v := range matches {
 				md[fmt.Sprintf("x-api-field-%s", k)] = v
 			}
+			md["x-api-body"] = ep.apiep.Body
 			*req = *req.Clone(context.WithValue(ctx, metadata.MetadataKey{}, md))
 			break pathLoop
 		}
@@ -285,6 +287,7 @@ func (r *staticRouter) endpoint(req *http.Request) (*endpoint, error) {
 		// we got here, so its a match
 		return ep, nil
 	}
+
 	// no match
 	return nil, fmt.Errorf("endpoint not found for %v", req)
 }