Upload text blobs with explicit charset=utf-8 so browsers decode UTF-8 correctly (em dashes rendered as mojibake on charset-less text/plain); keep NIP-94 m tag as the bare semantic MIME type

package.json

@@ -2,7 +2,7 @@
   "name": "nostr-publish",
   "displayName": "Nostr Publish",
   "description": "Publish files to Nostr from Codium/VSCode. Phase 0: raw unsigned event JSON. Phase 1: long-form notes (.md). Phase 2: signer (Rust n_signer port) signing backend.",
-  "version": "0.1.2",
+  "version": "0.1.3",
   "publisher": "laantungir",
   "license": "MIT",
   "repository": {

src/extension.ts

@@ -1860,6 +1860,20 @@ function resolveBlossomServers(): string[] {
   return [];
 }
 
+/**
+ * Append an explicit `charset=utf-8` parameter to `text/*` MIME types.
+ *
+ * Blossom servers store the upload `Content-Type` and echo it verbatim when
+ * serving the blob. Without a charset parameter, browsers fall back to
+ * Windows-1252 for text responses, rendering UTF-8 content as mojibake (an
+ * em dash `—` shows as `â€"`). Non-text types are returned unchanged.
+ */
+function withUtf8Charset(mime: string): string {
+  if (!mime.startsWith("text/")) return mime;
+  if (/;\s*charset=/i.test(mime)) return mime;
+  return `${mime}; charset=utf-8`;
+}
+
 /**
  * Shared upload + publish core for both the quick upload and header-based
  * publish commands.
@@ -1870,11 +1884,15 @@ function resolveBlossomServers(): string[] {
  * 4. Builds a kind 1063 NIP-94 event from the first successful descriptor.
  * 5. Signs and publishes the 1063 event to the enabled relays.
  *
- * Markdown bodies are uploaded as `text/plain` (browsers render text/plain
- * inline; no mainstream browser displays text/markdown, and servers send
- * `X-Content-Type-Options: nosniff` which forbids guessing). The kind 1063
- * event's `m` tag still advertises `text/markdown` so Nostr clients that
- * render markdown can detect the file's true semantic type.
+ * Markdown bodies are uploaded as `text/plain; charset=utf-8` (browsers
+ * render text/plain inline; no mainstream browser displays text/markdown,
+ * and servers send `X-Content-Type-Options: nosniff` which forbids
+ * guessing). The explicit charset is required: Blossom servers echo the
+ * upload `Content-Type` verbatim when serving the blob, and without it
+ * browsers fall back to Windows-1252, rendering UTF-8 text as mojibake
+ * (e.g. an em dash `—` becomes `â€"`). The kind 1063 event's `m` tag still
+ * advertises the bare semantic type (`text/markdown`) so Nostr clients
+ * that render markdown can detect the file's true type.
  */
 async function uploadAndPublishMetadata(
   state: StateService,
@@ -1885,9 +1903,14 @@ async function uploadAndPublishMetadata(
 ): Promise<void> {
   // Hybrid MIME handling: markdown uploads go out as text/plain for
   // browser-renderability; the semantic type is preserved for the m tag.
+  // Text bodies carry an explicit charset=utf-8 (see withUtf8Charset).
   const isMarkdown = mime === "text/markdown";
-  const uploadMime = isMarkdown ? "text/plain" : mime;
-  const semanticMime = isMarkdown ? "text/markdown" : undefined;
+  const uploadMime = withUtf8Charset(isMarkdown ? "text/plain" : mime);
+  // The m tag must carry the bare semantic MIME (no charset parameter):
+  // markdown → text/markdown; other text types → the bare type, since the
+  // server-reported descriptor type echoes the charset-annotated upload
+  // Content-Type. Binary types pass through unchanged (no override needed).
+  const semanticMime = isMarkdown || uploadMime !== mime ? mime : undefined;
 
   // Require sign-in.
   let signer = getSigner(state, config);

src/nostr/nip94.ts

@@ -16,12 +16,16 @@ export interface FileMetadataInput {
   /**
    * Override for the `m` tag (the file's semantic MIME type).
    *
-   * Markdown blobs are uploaded as `text/plain` so browsers render them
-   * inline (no mainstream browser displays `text/markdown`, and
-   * `X-Content-Type-Options: nosniff` forbids guessing). The server then
-   * reports `type: text/plain` in the descriptor. This override keeps the
-   * Nostr `m` tag advertising the true semantic type (`text/markdown`) so
-   * clients that render markdown can still detect it.
+   * Markdown blobs are uploaded as `text/plain; charset=utf-8` so browsers
+   * render them inline (no mainstream browser displays `text/markdown`, and
+   * `X-Content-Type-Options: nosniff` forbids guessing). Text uploads carry
+   * an explicit charset because Blossom servers echo the upload
+   * `Content-Type` verbatim when serving blobs — without it browsers fall
+   * back to Windows-1252 and render UTF-8 text as mojibake. The server then
+   * reports the charset-annotated type (e.g. `text/plain; charset=utf-8`) in
+   * the descriptor. This override keeps the Nostr `m` tag advertising the
+   * bare semantic type (`text/markdown`, `text/plain`, …) so clients that
+   * render markdown can still detect it.
    */
   mimeType?: string;
 }