feat: add an upload diff endpoint for adhoc mode. (#839)

This is part of #784.

pkg/adhoc/server/model.go

@@ -86,3 +86,8 @@ func ConverterToFormat(f ConverterFn) string {
 	}
 	return "unknown"
 }
+
+type diffModel struct {
+	Base flamebearer.FlamebearerProfile `json:"base"`
+	Diff flamebearer.FlamebearerProfile `json:"diff"`
+}

pkg/adhoc/server/server.go

@@ -56,6 +56,7 @@ func (s *server) AddRoutes(r *mux.Router) http.HandlerFunc {
 		r.HandleFunc("/v1/profile/{id:[0-9a-f]+}", s.Profile)
 		r.HandleFunc("/v1/diff/{left:[0-9a-f]+}/{right:[0-9a-f]+}", s.Diff)
 		r.HandleFunc("/v1/upload/", s.Upload)
+		r.HandleFunc("/v1/upload-diff/", s.UploadDiff)
 	}
 	return r.ServeHTTP
 }
@@ -237,6 +238,35 @@ func (s *server) Upload(w http.ResponseWriter, r *http.Request) {
 	}
 }
 
+// Upload two single profiles in native JSON format and convert to a diff profile
+func (s *server) UploadDiff(w http.ResponseWriter, r *http.Request) {
+	r.Body = http.MaxBytesReader(w, r.Body, maxBodySize)
+
+	var m diffModel
+	if err := json.NewDecoder(r.Body).Decode(&m); err != nil {
+		msg := "Unable to decode the body of the request. " +
+			"A JSON body with a a `base` and a `diff` profile field is expected."
+		s.log.WithError(err).Error(msg)
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+	r.Body.Close()
+
+	fb, err := DiffV1("", &m.Base, &m.Diff, s.maxNodes)
+	if err != nil {
+		s.log.WithError(err).Error("Unable to generate a diff profile")
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+	if err := json.NewEncoder(w).Encode(fb); err != nil {
+		s.log.WithError(err).Error("Unable to encode the response")
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+}
+
 func (s *server) convert(p profile) (*flamebearer.FlamebearerProfile, error) {
 	fname := filepath.Join(s.dataDir, p.Name)
 	f, err := os.Open(fname)