Allow validated Obsidian links in messages

desktop/src-tauri/capabilities/default.json

@@ -17,6 +17,14 @@
     "core:window:allow-close",
     "notification:default",
     "opener:default",
+    {
+      "identifier": "opener:allow-open-url",
+      "allow": [
+        { "url": "obsidian://open[?]file=*" },
+        { "url": "obsidian://open[?]path=*" },
+        { "url": "obsidian://open[?]vault=*" }
+      ]
+    },
     "websocket:default",
     "window-state:default",
     "dialog:default",

desktop/src/shared/lib/obsidianLink.test.mjs

@@ -0,0 +1,43 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+
+import { isObsidianOpenLink } from "./obsidianLink.ts";
+
+test("accepts Obsidian open links for vault-relative and absolute targets", () => {
+  assert.equal(
+    isObsidianOpenLink(
+      "obsidian://open?vault=holistics-digest&file=agent-cowork%2Fprojects%2Fanfra%2FANFRA_SETUP_END_TO_END.canvas",
+    ),
+    true,
+  );
+  assert.equal(isObsidianOpenLink("obsidian://open?file=README.md"), true);
+  assert.equal(
+    isObsidianOpenLink("obsidian://open?path=%2Ftmp%2Fexample.md"),
+    true,
+  );
+});
+
+test("rejects non-open actions and ambiguous or extensible parameters", () => {
+  for (const link of [
+    "obsidian://new?vault=work&name=note",
+    "obsidian://search?vault=work&query=secret",
+    "obsidian://open?vault=work&file=note.md&x-success=https://example.com",
+    "obsidian://open?vault=first&vault=second",
+    "obsidian://open?vault=work&path=%2Ftmp%2Fnote.md",
+  ]) {
+    assert.equal(isObsidianOpenLink(link), false, link);
+  }
+});
+
+test("rejects malformed or unsafe open links", () => {
+  for (const link of [
+    "obsidian://open",
+    "obsidian://user@open?vault=work",
+    "obsidian://open/extra?vault=work",
+    "obsidian://open?vault=work#fragment",
+    "obsidian://open?vault=%00work",
+    "not a URL",
+  ]) {
+    assert.equal(isObsidianOpenLink(link), false, link);
+  }
+});

desktop/src/shared/lib/obsidianLink.ts

@@ -0,0 +1,53 @@
+const OBSIDIAN_OPEN_PARAMS = new Set(["file", "path", "vault"]);
+const MAX_OBSIDIAN_LINK_LENGTH = 8_192;
+
+function hasControlCharacters(value: string): boolean {
+  return Array.from(value).some((character) => {
+    const codePoint = character.codePointAt(0) ?? 0;
+    return codePoint <= 0x1f || codePoint === 0x7f;
+  });
+}
+
+/**
+ * Accept only Obsidian's read-oriented `open` action. Other Obsidian URI
+ * actions can create notes, run searches, or invoke plugin-defined behavior,
+ * so message links must never pass arbitrary `obsidian://` URLs to the OS.
+ */
+export function isObsidianOpenLink(value: string): boolean {
+  if (!value || value.length > MAX_OBSIDIAN_LINK_LENGTH) return false;
+
+  let url: URL;
+  try {
+    url = new URL(value);
+  } catch {
+    return false;
+  }
+
+  if (
+    url.protocol !== "obsidian:" ||
+    url.hostname !== "open" ||
+    (url.pathname !== "" && url.pathname !== "/") ||
+    url.username ||
+    url.password ||
+    url.port ||
+    url.hash
+  ) {
+    return false;
+  }
+
+  for (const key of url.searchParams.keys()) {
+    if (!OBSIDIAN_OPEN_PARAMS.has(key)) return false;
+  }
+  for (const key of OBSIDIAN_OPEN_PARAMS) {
+    if (url.searchParams.getAll(key).length > 1) return false;
+  }
+
+  const vault = url.searchParams.get("vault")?.trim() ?? "";
+  const file = url.searchParams.get("file")?.trim() ?? "";
+  const path = url.searchParams.get("path")?.trim() ?? "";
+  if ([vault, file, path].some(hasControlCharacters)) return false;
+
+  // `path` is the absolute-path form. `vault`/`file` address a vault-relative
+  // target and may be used individually or together.
+  return path ? !vault && !file : Boolean(vault || file);
+}

desktop/src/shared/ui/markdown.test.mjs

@@ -538,6 +538,7 @@ import ReactMarkdown, { defaultUrlTransform } from "react-markdown";
 import { isChannelLink } from "../../features/messages/lib/channelLink.ts";
 import { isMessageLink } from "../../features/messages/lib/messageLink.ts";
 import { parseEntityLink } from "../lib/entityLink.ts";
+import { isObsidianOpenLink } from "../lib/obsidianLink.ts";
 import remarkSpoilers from "../lib/remarkSpoilers.ts";
 
 const OWNER_HEX =
@@ -549,6 +550,7 @@ function buzzDeepLinkUrlTransform(value, key) {
   if (key !== "href") return defaultUrlTransform(value);
   if (isMessageLink(value) || isChannelLink(value)) return value;
   if (parseEntityLink(value).ok) return value;
+  if (isObsidianOpenLink(value)) return value;
   return defaultUrlTransform(value);
 }
 
@@ -611,6 +613,22 @@ test("messageLinkUrlTransform: passes http(s) through unchanged", () => {
   assert.match(html, /href="https:\/\/example\.com\/path"/);
 });
 
+test("buzzDeepLinkUrlTransform: preserves validated Obsidian open links", () => {
+  const link =
+    "obsidian://open?vault=holistics-digest&file=agent-cowork%2Fprojects%2Fanfra%2FANFRA_SETUP_END_TO_END.canvas";
+  const html = renderMarkdown(`[Open in Obsidian](${link})`);
+  assert.match(html, /href="obsidian:\/\/open\?/);
+  assert.doesNotMatch(html, /href=""/);
+});
+
+test("buzzDeepLinkUrlTransform: strips other Obsidian actions", () => {
+  const html = renderMarkdown(
+    "[Create note](obsidian://new?vault=holistics-digest&name=unsafe)",
+  );
+  assert.match(html, /href=""/);
+  assert.doesNotMatch(html, /obsidian:\/\/new/);
+});
+
 test("messageLinkUrlTransform: preserves legacy buzz://message href", () => {
   const html = renderMarkdown(
     "Click [here](buzz://message?channel=abc&id=xyz)",

desktop/src/shared/ui/markdown/ExternalLinkAnchor.tsx

@@ -4,6 +4,7 @@ import { toast } from "sonner";
 
 import { cn } from "@/shared/lib/cn";
 import { copyTextToClipboard } from "@/shared/lib/clipboard";
+import { isObsidianOpenLink } from "@/shared/lib/obsidianLink";
 
 import { MaskedLinkTooltip } from "./MaskedLinkTooltip";
 import {
@@ -37,6 +38,12 @@ export function ExternalLinkAnchor({
   const [menu, setMenu] = React.useState<MediaContextMenuPosition | null>(null);
   const closeMenu = React.useCallback(() => setMenu(null), []);
   useDismissMediaContextMenu(Boolean(menu), closeMenu);
+  const openHref = React.useCallback(() => {
+    if (!href) return;
+    void openUrl(href).catch(() => {
+      toast.error("Failed to open link");
+    });
+  }, [href]);
 
   const anchor = (
     <a
@@ -46,6 +53,14 @@ export function ExternalLinkAnchor({
         isLinearLink ? "linear-link" : "text-primary hover:text-primary/80",
       )}
       href={href}
+      onClick={(event) => {
+        anchorProps.onClick?.(event);
+        if (event.defaultPrevented || !href || !isObsidianOpenLink(href)) {
+          return;
+        }
+        event.preventDefault();
+        openHref();
+      }}
       onContextMenuCapture={(event) => {
         if (!href) return;
         event.preventDefault();
@@ -71,9 +86,7 @@ export function ExternalLinkAnchor({
               label: "Open link",
               onSelect: () => {
                 closeMenu();
-                void openUrl(href).catch(() => {
-                  toast.error("Failed to open link");
-                });
+                openHref();
               },
             },
             {

desktop/src/shared/ui/markdown/utils.ts

@@ -4,6 +4,7 @@ import { defaultUrlTransform } from "react-markdown";
 import { isChannelLink } from "@/features/messages/lib/channelLink";
 import { isMessageLink } from "@/features/messages/lib/messageLink";
 import { parseEntityLink } from "@/shared/lib/entityLink";
+import { isObsidianOpenLink } from "@/shared/lib/obsidianLink";
 
 export function useStableArray<T>(arr: T[]): T[] {
   const ref = React.useRef(arr);
@@ -179,12 +180,14 @@ export function isInsideHiddenSpoiler(element: Element): boolean {
  *   message-link pill renderer).
  * - `buzz://pr|issue|repo` hrefs — preserved only when `parseEntityLink`
  *   succeeds, keeping the sanitizer active against arbitrary `buzz://` URIs.
+ * - Valid `obsidian://open` hrefs — preserved for the guarded OS-opener path.
  * - Everything else delegates to `defaultUrlTransform`.
  */
 export function buzzDeepLinkUrlTransform(value: string, key: string): string {
   if (key !== "href") return defaultUrlTransform(value);
   if (isMessageLink(value) || isChannelLink(value)) return value;
   if (parseEntityLink(value).ok) return value;
+  if (isObsidianOpenLink(value)) return value;
   return defaultUrlTransform(value);
 }
 

desktop/tests/e2e/messaging.spec.ts

@@ -414,6 +414,44 @@ test("send a message and see it in timeline", async ({ page }) => {
   );
 });
 
+test("validated Obsidian link opens through the native OS opener", async ({
+  page,
+}) => {
+  const link =
+    "obsidian://open?vault=holistics-digest&file=agent-cowork%2Fprojects%2Fanfra%2FANFRA_SETUP_END_TO_END.canvas";
+
+  await page.goto("/");
+  await page.getByTestId("channel-general").click();
+  await page.getByTestId("message-input").fill(`[Open in Obsidian](${link})`);
+  await page.getByTestId("send-message").click();
+
+  const anchor = page
+    .getByTestId("message-row")
+    .last()
+    .getByRole("link", { name: "Open in Obsidian" });
+  await expect(anchor).toHaveAttribute("href", link);
+  await anchor.click();
+
+  await expect
+    .poll(() =>
+      page.evaluate(() => {
+        const calls =
+          (
+            window as Window & {
+              __BUZZ_E2E_COMMAND_LOG__?: Array<{
+                command: string;
+                payload: { url?: string };
+              }>;
+            }
+          ).__BUZZ_E2E_COMMAND_LOG__ ?? [];
+        return calls
+          .filter(({ command }) => command === "plugin:opener|open_url")
+          .map(({ payload }) => payload.url);
+      }),
+    )
+    .toContain(link);
+});
+
 test("long autolink wraps without widening the timeline", async ({ page }) => {
   await page.setViewportSize({ width: 800, height: 600 });