fix(download): write error as problem details

pkg/api/download.go

@@ -9,17 +9,19 @@ import (
 	"github.com/ncarlier/readflow/pkg/service"
 )
 
+var downloadProblem = "unable to download article"
+
 // download is the handler for downloading articles.
 func download() http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		id := strings.TrimPrefix(r.URL.Path, "/articles/")
 		if id == "" {
-			http.Error(w, "missing article ID", http.StatusBadRequest)
+			helper.WriteProblemDetail(w, downloadProblem, "missing article ID", http.StatusBadRequest)
 			return
 		}
 		idArticle, ok := helper.ConvGQLStringToUint(id)
 		if !ok {
-			http.Error(w, "invalid article ID", http.StatusBadRequest)
+			helper.WriteProblemDetail(w, downloadProblem, "invalid article ID", http.StatusBadRequest)
 			return
 		}
 		// Extract and validate token parameter
@@ -32,7 +34,7 @@ func download() http.Handler {
 		// Archive the article
 		asset, err := service.Lookup().DownloadArticle(r.Context(), idArticle, format)
 		if err != nil {
-			http.Error(w, err.Error(), http.StatusInternalServerError)
+			helper.WriteProblemDetail(w, downloadProblem, err.Error(), http.StatusInternalServerError)
 			return
 		}
 

pkg/helper/error.go

@@ -0,0 +1,25 @@
+package helper
+
+import (
+	"encoding/json"
+	"net/http"
+)
+
+type problemObject struct {
+	Title  string `json:"title"`
+	Detail string `json:"detail"`
+	Status int    `json:"status"`
+}
+
+// WriteProblemDetail write error as JSON Problem Details format
+func WriteProblemDetail(w http.ResponseWriter, title string, detail string, status int) {
+	err := problemObject{
+		Title:  title,
+		Detail: detail,
+		Status: status,
+	}
+	w.Header().Set("Content-Type", "application/problem+json; charset=utf-8")
+	w.Header().Set("X-Content-Type-Options", "nosniff")
+	w.WriteHeader(status)
+	json.NewEncoder(w).Encode(err)
+}