Create main.py

main.py

@@ -0,0 +1,272 @@
+"""
+FastAPI 版 SVG ➜ PNG 转换服务
+──────────────────────────────────────────
+与 Gradio 版本保持同等功能：
+1. 自动检测 / 定位 Inkscape
+2. 自动下载并嵌入 <image href="http/https"> 外链图片（Base64）
+3. 支持 DPI / 宽高 / 背景色 / 透明 / 导出区域 / 指定元素 ID / 简化 SVG
+4. 返回生成的 PNG 图片文件
+──────────────────────────────────────────
+运行：
+    python main.py
+接口：
+    POST /convert   ➜ Multipart 表单上传 svg_file + 各参数，返回 image/png
+    GET  /health    ➜ 简单健康检查
+"""
+
+import os
+import subprocess
+import platform
+import tempfile
+import shutil
+import uuid
+import base64
+import mimetypes
+import urllib.request
+import re
+from pathlib import Path
+from typing import Optional
+
+from fastapi import FastAPI, UploadFile, File, Form, HTTPException
+from fastapi.responses import FileResponse, JSONResponse
+
+###############################################################################
+# 1. Inkscape 检测
+###############################################################################
+def ensure_inkscape_available() -> tuple[bool, str]:
+    """检查 Inkscape 是否可用，不可用时尝试在常见路径中查找"""
+    try:
+        subprocess.run(
+            ["inkscape", "--version"],
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
+            check=True,
+        )
+        return True, "在 PATH 中找到 Inkscape"
+    except (subprocess.SubprocessError, FileNotFoundError):
+        system = platform.system()
+        common_paths: list[str] = []
+        if system == "Windows":
+            common_paths = [
+                r"C:\Program Files\Inkscape\bin\inkscape.exe",
+                r"C:\Program Files (x86)\Inkscape\bin\inkscape.exe",
+                r"C:\Program Files\Inkscape\inkscape.exe",
+                r"C:\Program Files (x86)\Inkscape\inkscape.exe",
+            ]
+        elif system == "Linux":
+            common_paths = [
+                "/usr/bin/inkscape",
+                "/usr/local/bin/inkscape",
+                "/opt/inkscape/bin/inkscape",
+            ]
+        elif system == "Darwin":  # macOS
+            common_paths = [
+                "/Applications/Inkscape.app/Contents/MacOS/inkscape",
+                "/usr/local/bin/inkscape",
+            ]
+
+        for path in common_paths:
+            if os.path.exists(path):
+                os.environ["PATH"] += os.pathsep + os.path.dirname(path)
+                return True, f"在 {path} 找到 Inkscape"
+
+        return False, "未找到 Inkscape，请安装或手动加入 PATH"
+
+###############################################################################
+# 2. 下载并嵌入外链图片
+###############################################################################
+# 匹配 <image ... href="http(s)://..."> 或 xlink:href
+IMG_TAG_PATTERN = re.compile(
+    r'<image[^>]+(?:href|xlink:href)\s*=\s*["\']([^"\']+)["\']', re.I
+)
+
+def download_and_encode(url: str) -> str:
+    """下载远程图片并转为 data URI（Base64）"""
+    try:
+        req = urllib.request.Request(url, headers={"User-Agent": "Mozilla/5.0"})
+        with urllib.request.urlopen(req, timeout=15) as resp:
+            data = resp.read()
+        mime, _ = mimetypes.guess_type(url)
+        mime = mime or "image/png"
+        b64 = base64.b64encode(data).decode("ascii")
+        return f"data:{mime};base64,{b64}"
+    except Exception as e:
+        # 失败则返回原链接（Inkscape 可能渲染空白 / 红叉）
+        print(f"[WARN] 下载外链图片失败 {url}: {e}")
+        return url
+
+def embed_external_images(svg_path: str) -> str:
+    """把 SVG 中的远程图片下载并嵌入（Base64），返回新的临时 SVG 路径"""
+    with open(svg_path, "r", encoding="utf-8") as f:
+        svg_text = f.read()
+
+    if "http://" not in svg_text and "https://" not in svg_text:
+        return svg_path  # 无外链，直接返回
+
+    def replacer(match: re.Match) -> str:
+        url = match.group(1)
+        if url.startswith(("http://", "https://")):
+            data_uri = download_and_encode(url)
+            return match.group(0).replace(url, data_uri)
+        return match.group(0)
+
+    new_svg = IMG_TAG_PATTERN.sub(replacer, svg_text)
+
+    # 若缺失 xlink 命名空间，则补上
+    if "xmlns:xlink" not in new_svg:
+        new_svg = new_svg.replace(
+            "<svg", '<svg xmlns:xlink="http://www.w3.org/1999/xlink"', 1
+        )
+
+    tmp_dir = tempfile.mkdtemp()
+    new_path = os.path.join(tmp_dir, Path(svg_path).name)
+    with open(new_path, "w", encoding="utf-8") as f:
+        f.write(new_svg)
+    return new_path
+
+###############################################################################
+# 3. 核心转换函数
+###############################################################################
+def convert_svg_to_png(
+    src_svg_path: str,
+    dpi: int = 96,
+    width: Optional[int] = None,
+    height: Optional[int] = None,
+    background_color: str = "transparent",
+    export_area: str = "page",
+    export_id: Optional[str] = None,
+    export_plain_svg: bool = False,
+) -> tuple[Optional[str], str]:
+    """调用 Inkscape CLI 将 SVG 转为 PNG，返回 (文件路径 or None, 消息)"""
+
+    ok, msg = ensure_inkscape_available()
+    if not ok:
+        return None, msg
+
+    # 预处理外链
+    processed_svg = embed_external_images(src_svg_path)
+
+    tmp_dir = tempfile.mkdtemp()
+    output_name = f"{uuid.uuid4()}.png"
+    output_path = os.path.join(tmp_dir, output_name)
+
+    cmd: list[str] = [
+        "inkscape",
+        processed_svg,
+        "--export-filename",
+        output_path,
+        "--export-dpi",
+        str(dpi),
+    ]
+    if width and width > 0:
+        cmd += ["--export-width", str(width)]
+    if height and height > 0:
+        cmd += ["--export-height", str(height)]
+    if background_color != "transparent":
+        cmd += ["--export-background", background_color]
+
+    if export_area == "drawing":
+        cmd.append("--export-area-drawing")
+    elif export_area == "page":
+        cmd.append("--export-area-page")
+    elif export_area == "id" and export_id:
+        cmd += ["--export-id", export_id]
+
+    if export_plain_svg:
+        cmd.append("--export-plain-svg")
+
+    try:
+        subprocess.run(
+            cmd,
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
+            text=True,
+            check=True,
+        )
+        if not os.path.exists(output_path):
+            return None, "未生成 PNG 文件"
+
+        # 把结果移动到项目根目录 output 目录
+        out_dir = Path(__file__).parent / "output"
+        out_dir.mkdir(exist_ok=True)
+        final_path = out_dir / output_name
+        shutil.copy2(output_path, final_path)
+        shutil.rmtree(tmp_dir, ignore_errors=True)
+        return str(final_path), "转换成功"
+    except subprocess.CalledProcessError as e:
+        return None, f"Inkscape 错误：{e.stderr}"
+    except Exception as e:
+        return None, f"未知错误：{e}"
+
+###############################################################################
+# 4. FastAPI 应用
+###############################################################################
+app = FastAPI(title="SVG ➜ PNG 转换 API", version="1.0.0")
+
+@app.get("/health", summary="健康检查")
+def health():
+    return {"status": "ok"}
+
+@app.post(
+    "/convert",
+    summary="SVG 转 PNG",
+    response_class=FileResponse,
+    responses={
+        200: {"content": {"image/png": {}}},
+        400: {"description": "请求或转换失败"},
+    },
+)
+async def convert_endpoint(
+    svg_file: UploadFile = File(..., description="SVG 文件"),
+    dpi: int = Form(96, ge=72, le=600, description="导出 DPI"),
+    width: Optional[int] = Form(None, description="导出宽度（像素，留空保持原比例）"),
+    height: Optional[int] = Form(None, description="导出高度（像素，留空保持原比例）"),
+    background_color: str = Form("#ffffff", description="背景色（透明时忽略）"),
+    transparent: bool = Form(True, description="是否透明背景"),
+    export_area: str = Form("page", regex="^(page|drawing|id)$", description="导出区域"),
+    export_id: Optional[str] = Form(None, description="当 export_area 为 id 时指定元素 ID"),
+    export_plain_svg: bool = Form(False, description="导出前是否简化 SVG"),
+):
+    """
+    使用 Inkscape 将上传的 SVG 转换为 PNG 并返回。
+    所有参数与 Gradio 版本保持一致。
+    """
+    # 保存上传文件到临时目录
+    temp_dir = tempfile.mkdtemp()
+    uploaded_path = os.path.join(temp_dir, svg_file.filename)
+    with open(uploaded_path, "wb") as f:
+        f.write(await svg_file.read())
+
+    png_path, msg = convert_svg_to_png(
+        src_svg_path=uploaded_path,
+        dpi=dpi,
+        width=width,
+        height=height,
+        background_color="transparent" if transparent else background_color,
+        export_area=export_area,
+        export_id=export_id if export_area == "id" else None,
+        export_plain_svg=export_plain_svg,
+    )
+
+    shutil.rmtree(temp_dir, ignore_errors=True)
+
+    if png_path is None:
+        raise HTTPException(status_code=400, detail=msg)
+
+    # 返回 PNG 文件流
+    return FileResponse(
+        png_path,
+        media_type="image/png",
+        filename=Path(svg_file.filename).stem + ".png",
+    )
+
+###############################################################################
+# 5. 入口
+###############################################################################
+if __name__ == "__main__":
+    import uvicorn
+
+    # 确保 output 目录存在
+    (Path(__file__).parent / "output").mkdir(exist_ok=True)
+
+    uvicorn.run("main:app", host="0.0.0.0", port=7860, reload=False)