Initial commit

Assisted-by: GLM 5.3

internal/admin/posts_upload.go

@@ -0,0 +1,88 @@
+// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
+// SPDX-License-Identifier: PolyForm-Noncommercial-1.0.0
+
+package admin
+
+import (
+	json "encoding/json/v2"
+	"log/slog"
+	"net/http"
+	"strconv"
+
+	"sourcedock.dev/petrbalvin/volumen/internal/i18n"
+	"sourcedock.dev/petrbalvin/volumen/internal/imagefile"
+	"sourcedock.dev/petrbalvin/volumen/internal/web"
+)
+
+// writeAdminJSON writes one JSON object response; encoding/json escapes
+// what a browser's JSON.parse requires, which a %q verb does not.
+func writeAdminJSON(w http.ResponseWriter, status int, value map[string]any) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	if err := json.MarshalWrite(w, value, json.Deterministic(true)); err != nil {
+		slog.Warn("admin: cannot encode JSON response", "error", err)
+	}
+}
+
+func (a *Admin) handleUpload(w http.ResponseWriter, r *http.Request) {
+	if !a.requireCSRF(w, r) {
+		return
+	}
+	file, header, err := r.FormFile("file")
+	if err != nil {
+		writeAdminJSONError(w, http.StatusBadRequest, "no_file", i18n.Admin.T(a.langFor(r), "No file was uploaded."))
+		return
+	}
+	defer file.Close()
+	limit := int64(a.deps.Config.Admin.MaxUploadBytes)
+	raw, err := readLimited(file, limit)
+	if err != nil {
+		writeAdminJSONError(w, http.StatusRequestEntityTooLarge, "too_large",
+			i18n.Admin.Tf(a.langFor(r),
+				"The file could not be read (limit %s bytes).",
+				strconv.FormatInt(limit, 10)))
+		return
+	}
+	if errMsg := validateImageData(raw); errMsg != "" {
+		writeAdminJSONError(w, http.StatusUnsupportedMediaType, errMsg,
+			i18n.Admin.T(a.langFor(r), "Only WebP, AVIF and SVG images are supported."))
+		return
+	}
+	url, err := a.deps.Store.StoreUpload(header.Filename, raw)
+	if err != nil {
+		writeAdminJSONError(w, http.StatusInternalServerError, "upload_failed",
+			i18n.Admin.T(a.langFor(r), "The upload could not be stored."))
+		return
+	}
+	writeAdminJSON(w, http.StatusOK, map[string]any{"url": url})
+}
+
+func writeAdminJSONError(w http.ResponseWriter, status int, code, message string) {
+	writeAdminJSON(w, status, map[string]any{"error": code, "message": message})
+}
+
+// validateImageData reports why data is not an acceptable upload. The
+// stored extension is taken from the byte signature, so the declared
+// filename's type is irrelevant: what matters is that the bytes are one
+// of the accepted image formats.
+func validateImageData(data []byte) string {
+	if imagefile.Detect(data) == "" {
+		return "invalid_signature"
+	}
+	return ""
+}
+
+func (a *Admin) handleIcon(w http.ResponseWriter, _ *http.Request) {
+	a.serveStaticSVG(w, "volumen-icon.svg")
+}
+
+func (a *Admin) serveStaticSVG(w http.ResponseWriter, name string) {
+	data, err := web.StaticFile(name)
+	if err != nil {
+		w.WriteHeader(http.StatusNotFound)
+		return
+	}
+	w.Header().Set("Content-Type", "image/svg+xml")
+	w.WriteHeader(http.StatusOK)
+	_, _ = w.Write(data)
+}