update at 2026-02-08 22:31:25

apiserver/png_renderer.py

@@ -0,0 +1,55 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+"""服务端 PNG 渲染：通过 sharp 将 SVG 转为 PNG。"""
+
+import os
+import subprocess
+
+
+def _script_path():
+    return os.path.join(os.path.dirname(__file__), "svg_to_png.js")
+
+
+def render_png_from_svg(svg_text, width, height, *, timeout_seconds=20):
+    if not svg_text or not str(svg_text).strip():
+        raise ValueError("SVG 内容为空")
+
+    script = _script_path()
+    if not os.path.isfile(script):
+        raise FileNotFoundError(f"未找到 SVG 转 PNG 脚本: {script}")
+
+    safe_width = max(1, min(4096, int(round(float(width or 0) or 0))))
+    safe_height = max(1, min(4096, int(round(float(height or 0) or 0))))
+
+    cmd = [
+        "node",
+        script,
+        "--width",
+        str(safe_width),
+        "--height",
+        str(safe_height),
+    ]
+
+    try:
+        completed = subprocess.run(
+            cmd,
+            input=str(svg_text).encode("utf-8"),
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
+            timeout=timeout_seconds,
+            check=False,
+        )
+    except FileNotFoundError as error:
+        raise RuntimeError("未找到 node，请先安装 Node.js") from error
+
+    if completed.returncode != 0:
+        stderr = completed.stderr.decode("utf-8", errors="replace").strip()
+        if "Cannot find module 'sharp'" in stderr:
+            raise RuntimeError("缺少 sharp 依赖，请在项目根目录执行: npm install")
+        raise RuntimeError(stderr or f"PNG 渲染失败，退出码: {completed.returncode}")
+
+    png_bytes = completed.stdout
+    if not png_bytes:
+        raise RuntimeError("PNG 渲染失败，返回空内容")
+
+    return png_bytes