cmd/pkgserver: log instead of write encoding error

This message is unlikely to be useful to the user, and output may be partially written at this point, causing the error to be even less intelligible.

Signed-off-by: Ophestra <cat@gensokyo.uk>

cmd/pkgserver/api.go

@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"log"
 	"net/http"
 	"path"
 	"strconv"
@@ -32,9 +33,8 @@ func serveInfo(w http.ResponseWriter, _ *http.Request) {
 		infoPayload.Count = int(rosa.PresetUnexportedStart)
 		infoPayload.HakureiVersion = info.Version()
 	})
-	w.WriteHeader(http.StatusOK)
 	// TODO(mae): cache entire response if no additional fields are planned
-	WritePayload(w, infoPayload)
+	writeAPIPayload(w, infoPayload)
 }
 
 func (index *packageIndex) serveStatus() http.HandlerFunc {
@@ -73,7 +73,6 @@ func (index *packageIndex) serveStatus() http.HandlerFunc {
 			}
 
 			w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
-			w.WriteHeader(http.StatusOK)
 			_, err := io.Copy(w, bytes.NewReader(pk.status))
 			if err != nil {
 				http.Error(w, err.Error(), http.StatusInternalServerError)
@@ -104,7 +103,7 @@ func (index *packageIndex) serveGet() http.HandlerFunc {
 		}
 		values := index.sorts[sort][i:min(i+limit, len(index.sorts[sort]))]
 		// TODO(mae): remove count field
-		WritePayload(w, &struct {
+		writeAPIPayload(w, &struct {
 			Count  int         `json:"count"`
 			Values []*metadata `json:"values"`
 		}{len(values), values})
@@ -120,13 +119,19 @@ func apiRoutes(mux *http.ServeMux, index *packageIndex) {
 	mux.HandleFunc("GET /status/", index.serveStatus())
 }
 
-func WritePayload(w http.ResponseWriter, payload any) {
+// writeAPIPayload sets headers common to API responses and encodes payload as
+// JSON for the response body.
+func writeAPIPayload(w http.ResponseWriter, payload any) {
 	w.Header().Set("Content-Type", "application/json; charset=utf-8")
 	w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
 	w.Header().Set("Pragma", "no-cache")
 	w.Header().Set("Expires", "0")
-	err := json.NewEncoder(w).Encode(payload)
-	if err != nil {
-		http.Error(w, err.Error(), http.StatusInternalServerError)
+
+	if err := json.NewEncoder(w).Encode(payload); err != nil {
+		log.Println(err)
+		http.Error(
+			w, "cannot encode payload, contact maintainers",
+			http.StatusInternalServerError,
+		)
 	}
 }