Add inline SVG data_url preview fallback

backend/app/generator.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import html
+import base64
 import textwrap
 import uuid
 from pathlib import Path
@@ -34,6 +35,7 @@ class GenerationResult(BaseModel):
     height: int
     model_id: str
     prompt: str
+    data_url: str | None = None
 
 
 class GeneratorService:
@@ -63,23 +65,25 @@ def generate(self, request: GenerateRequest) -> GenerationResult:
             width, height = self.VIDEO_SIZES[request.video_size]
             label = f"VIDEO PREVIEW ({request.video_size})"
 
-        output_path = self._create_preview_svg(
+        output_path, svg_content = self._create_preview_svg(
             model_id=request.model_id,
             prompt=request.prompt,
             width=width,
             height=height,
             label=label,
         )
+        encoded_svg = base64.b64encode(svg_content.encode("utf-8")).decode("ascii")
         return GenerationResult(
             file_url=f"/outputs/{output_path.name}",
             media_type="image/svg+xml",
             width=width,
             height=height,
             model_id=request.model_id,
             prompt=request.prompt,
+            data_url=f"data:image/svg+xml;base64,{encoded_svg}",
         )
 
-    def _create_preview_svg(self, model_id: str, prompt: str, width: int, height: int, label: str) -> Path:
+    def _create_preview_svg(self, model_id: str, prompt: str, width: int, height: int, label: str) -> tuple[Path, str]:
         escaped_lines = textwrap.wrap(f"Prompt: {prompt}", width=60)
         text_lines = [
             label,
@@ -105,4 +109,4 @@ def _create_preview_svg(self, model_id: str, prompt: str, width: int, height: in
         file_name = f"asset_{uuid.uuid4().hex[:8]}.svg"
         path = self.output_dir / file_name
         path.write_text(svg, encoding="utf-8")
-        return path
+        return path, svg

frontend/app.js

@@ -65,7 +65,8 @@ async function generate(event) {
       body: JSON.stringify(payload),
     });
 
-    resultImage.src = `${data.file_url}?t=${Date.now()}`;
+    const cacheBustedFileUrl = `${data.file_url}?t=${Date.now()}`;
+    resultImage.src = data.data_url || cacheBustedFileUrl;
     resultImage.classList.remove('hidden');
     statusEl.textContent = `완료: ${data.model_id} / ${data.width}x${data.height}`;
   } catch (error) {

tests/test_api.py

@@ -44,3 +44,4 @@ def test_generate_image() -> None:
     assert payload["width"] == 512
     assert payload["height"] == 512
     assert payload["file_url"].startswith("/outputs/asset_")
+    assert payload["data_url"].startswith("data:image/svg+xml;base64,")