🍍 api: improve abstractions

Author: database64128

api/internal/restapi/restapi.go

@@ -2,6 +2,7 @@ package restapi
 
 import (
 	"encoding/json"
+	"io"
 	"net/http"
 )
 
@@ -11,15 +12,29 @@ type HandlerFunc func(w http.ResponseWriter, r *http.Request) (status int, err e
 // EncodeResponse sets the Content-Type header field to application/json, and writes
 // to the response writer with the given status code and data encoded as JSON.
 //
-// If data is nil, the status code is written and no data is encoded.
+// If data is nil, only the status code is written and no data is encoded.
+//
+// If data is of type [io.Reader] or []byte, it is assumed to be encoded JSON
+// and is written directly to the response writer.
 func EncodeResponse(w http.ResponseWriter, status int, data any) (int, error) {
 	if data == nil {
 		w.WriteHeader(status)
 		return status, nil
 	}
 	w.Header()["Content-Type"] = []string{"application/json"}
 	w.WriteHeader(status)
-	return status, json.NewEncoder(w).Encode(data)
+	var err error
+	switch v := data.(type) {
+	case io.Reader:
+		_, err = io.Copy(w, v)
+	case *[]byte:
+		_, err = w.Write(*v)
+	case []byte:
+		_, err = w.Write(v)
+	default:
+		err = json.NewEncoder(w).Encode(v)
+	}
+	return status, err
 }
 
 // DecodeRequest decodes the request body as JSON into the provided value.

api/ssm/ssm.go

@@ -64,18 +64,21 @@ func (sm *ServerManager) requireServerStats(h func(http.ResponseWriter, *http.Re
 		name := r.PathValue("server")
 		server, ok := sm.serverByName[name]
 		if !ok {
-			return restapi.EncodeResponse(w, http.StatusNotFound, StandardError{Message: "server not found"})
+			return restapi.EncodeResponse(w, http.StatusNotFound, &serverNotFoundJSON)
 		}
 		return h(w, r, server.StatsCollector)
 	}
 }
 
-var serverInfoJSON = []byte(`{"server":"shadowsocks-go ` + shadowsocks.Version + `","apiVersion":"v1"}`)
+var (
+	serverInfoJSON                = []byte(`{"server":"shadowsocks-go ` + shadowsocks.Version + `","apiVersion":"v1"}`)
+	serverNotFoundJSON            = []byte(`{"error":"server not found"}`)
+	serverNoCredentialManagerJSON = []byte(`{"error":"The server does not support user management."}`)
+	userNotFoundJSON              = []byte(`{"error":"user not found"}`)
+)
 
 func handleGetServerInfo(w http.ResponseWriter, _ *http.Request, _ stats.Collector) (int, error) {
-	w.Header()["Content-Type"] = []string{"application/json"}
-	_, err := w.Write(serverInfoJSON)
-	return http.StatusOK, err
+	return restapi.EncodeResponse(w, http.StatusOK, &serverInfoJSON)
 }
 
 func handleGetStats(w http.ResponseWriter, r *http.Request, sc stats.Collector) (int, error) {
@@ -93,10 +96,10 @@ func (sm *ServerManager) requireServerUsers(h func(http.ResponseWriter, *http.Re
 		name := r.PathValue("server")
 		server, ok := sm.serverByName[name]
 		if !ok {
-			return restapi.EncodeResponse(w, http.StatusNotFound, StandardError{Message: "server not found"})
+			return restapi.EncodeResponse(w, http.StatusNotFound, &serverNotFoundJSON)
 		}
 		if server.CredentialManager == nil {
-			return restapi.EncodeResponse(w, http.StatusNotFound, StandardError{Message: "The server does not support user management."})
+			return restapi.EncodeResponse(w, http.StatusNotFound, &serverNoCredentialManagerJSON)
 		}
 		return h(w, r, server)
 	}
@@ -131,7 +134,7 @@ func handleGetUser(w http.ResponseWriter, r *http.Request, ms Server) (int, erro
 	username := r.PathValue("username")
 	userCred, ok := ms.CredentialManager.GetCredential(username)
 	if !ok {
-		return restapi.EncodeResponse(w, http.StatusNotFound, StandardError{Message: "user not found"})
+		return restapi.EncodeResponse(w, http.StatusNotFound, &userNotFoundJSON)
 	}
 
 	return restapi.EncodeResponse(w, http.StatusOK, response{userCred, ms.StatsCollector.Snapshot().Traffic})