feat: app-grade viewport for hosted HTML apps

server/html_site.py

@@ -256,6 +256,48 @@ def stage_html_app(data: bytes, filename: str, name: str, apps_dir: Path) -> dic
         raise
 
 
+_VIEWPORT_META_RE = re.compile(
+    r'<meta[^>]*\bname\s*=\s*["\']?viewport["\']?[^>]*>', re.IGNORECASE)
+_HEAD_OPEN_RE = re.compile(r'<head[^>]*>', re.IGNORECASE)
+_CONTENT_ATTR_RE = re.compile(r'content\s*=\s*["\']([^"\']*)["\']', re.IGNORECASE)
+_VIEWPORT_KEYS = {"width", "initial-scale", "minimum-scale", "maximum-scale",
+                  "user-scalable", "viewport-fit"}
+_APP_VIEWPORT = ("width=device-width,initial-scale=1,maximum-scale=1,"
+                 "user-scalable=no,viewport-fit=cover")
+
+
+def appify_index_html(data: bytes) -> bytes:
+    """Patch a hosted page's viewport so it presents like an installed app:
+    edge-to-edge under iOS chrome and no browser-style pinch zoom. Other
+    viewport keys are preserved; everything else is untouched."""
+    try:
+        html = data.decode("utf-8")
+    except UnicodeDecodeError:
+        return data
+    head = _HEAD_OPEN_RE.search(html)
+    if not head:
+        return data
+    head_close = html.lower().find("</head>", head.end())
+    scope = head_close if head_close != -1 else min(len(html), head.end() + 8192)
+    region = html[head.end():scope]
+    m = _VIEWPORT_META_RE.search(region)
+    if m:
+        content_m = _CONTENT_ATTR_RE.search(m.group(0))
+        extra = []
+        if content_m:
+            for piece in content_m.group(1).split(","):
+                piece = piece.strip()
+                if piece and piece.split("=", 1)[0].strip().lower() not in _VIEWPORT_KEYS:
+                    extra.append(piece)
+        content = _APP_VIEWPORT + ("," + ",".join(extra) if extra else "")
+        meta = f'<meta name="viewport" content="{content}">'
+        html = html[:head.end()] + region[:m.start()] + meta + region[m.end():] + html[scope:]
+    else:
+        meta = f'<meta name="viewport" content="{_APP_VIEWPORT}">'
+        html = html[:head.end()] + meta + html[head.end():]
+    return html.encode("utf-8")
+
+
 def resolve_site_file(site_dir: Path, rel_path: str) -> Optional[Path]:
     """Resolve a served path inside a site dir; directories fall back to
     ``index.html``. Returns None when the path does not exist or escapes."""

server/main.py

@@ -24,7 +24,7 @@
 import httpx
 from fastapi import FastAPI, File, Form, HTTPException, Request, UploadFile
 from fastapi.staticfiles import StaticFiles
-from fastapi.responses import HTMLResponse, FileResponse, JSONResponse, RedirectResponse, PlainTextResponse
+from fastapi.responses import HTMLResponse, FileResponse, JSONResponse, RedirectResponse, PlainTextResponse, Response
 from fastapi.middleware.cors import CORSMiddleware
 from pydantic import BaseModel
 from typing import Dict, List, Optional
@@ -1815,6 +1815,15 @@ async def serve_app_site(app_id: str, request: Request, file_path: str = ""):
     if path is None:
         raise HTTPException(404, "Site file not found")
     history_store.record_visit(app_id, "site")
+    if path.suffix.lower() in (".html", ".htm"):
+        # Hosted HTML gets an app-grade viewport (edge-to-edge, no pinch zoom)
+        # so installed Web Clips don't look like a browser page.
+        patched = html_site.appify_index_html(path.read_bytes())
+        return Response(
+            patched,
+            media_type="text/html; charset=utf-8",
+            headers={"Cache-Control": "public, max-age=3600"},
+        )
     return FileResponse(
         path,
         media_type=html_site.mime_for(path),

tests/test_html_site.py

@@ -187,6 +187,25 @@ def test_mime_types(self):
         self.assertEqual(html_site.mime_for(Path("a.png")), "image/png")
         self.assertEqual(html_site.mime_for(Path("a.xyz")), "application/octet-stream")
 
+    def test_appify_merges_existing_viewport(self):
+        out = html_site.appify_index_html(
+            b'<html><head><meta name="viewport" content="width=device-width,initial-scale=1,shrink-to-fit=no"></head></html>')
+        text = out.decode()
+        self.assertIn('user-scalable=no', text)
+        self.assertIn('viewport-fit=cover', text)
+        self.assertIn('maximum-scale=1', text)
+        self.assertIn('shrink-to-fit=no', text)
+
+    def test_appify_inserts_missing_viewport(self):
+        out = html_site.appify_index_html(b'<html><head><title>x</title></head></html>')
+        self.assertIn('name="viewport"', out.decode())
+
+    def test_appify_leaves_non_html_and_headless(self):
+        blob = b'\x89PNG binary \x00\x01'
+        self.assertEqual(html_site.appify_index_html(blob), blob)
+        no_head = b'just text'
+        self.assertEqual(html_site.appify_index_html(no_head), no_head)
+
     def test_extract_site_meta(self):
         meta = html_site.extract_site_meta(self.site)
         self.assertEqual(meta["title"], "My Html App")