server(attachments): render empty SVGs properly (closes #1378)

src/routes/api/image.spec.ts

@@ -0,0 +1,32 @@
+import { describe, expect, it } from "vitest";
+import { note } from "../../../spec/support/becca_mocking.js";
+import { renderSvgAttachment } from "./image.js";
+
+describe("Image API", () => {
+    it("renders empty SVG properly", () => {
+        const parentNote = note("note").note;
+        const response = new MockResponse();
+        renderSvgAttachment(parentNote, response as any, "attachment");
+        expect(response.headers["Content-Type"]).toBe("image/svg+xml");
+        expect(response.body).toBe(`<svg xmlns="http://www.w3.org/2000/svg"></svg>`);
+    });
+});
+
+class MockResponse {
+
+    body?: string;
+    headers: Record<string, string>;
+
+    constructor() {
+        this.headers = {};
+    }
+
+    set(name: string, value: string) {
+        this.headers[name] = value;
+    }
+
+    send(body: string) {
+        this.body = body;
+    }
+
+}

src/routes/api/image.ts

@@ -41,8 +41,8 @@ function returnImageInt(image: BNote | BRevision | null, res: Response) {
     }
 }
 
-function renderSvgAttachment(image: BNote | BRevision, res: Response, attachmentName: string) {
+export function renderSvgAttachment(image: BNote | BRevision, res: Response, attachmentName: string) {
-    let svg: string | Buffer = "<svg/>";
+    let svg: string | Buffer = `<svg xmlns="http://www.w3.org/2000/svg"></svg>`;
     const attachment = image.getAttachmentByTitle(attachmentName);
 
     if (attachment) {