546f507e49* Add QR code Python MCP server example A minimal Python MCP server that generates customizable QR codes with an interactive widget UI. Features: - Generate QR codes from any text or URL - Customizable colors, size, border, and error correction - Interactive widget using MCP Apps SDK protocol - Supports both HTTP (for web clients) and stdio (for Claude Desktop) 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com> * Potential fix for code scanning alert no. 10: Client-side cross-site scripting Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com> * Add semicolon * Bind to 0.0.0.0 for Docker compatibility * Use SDK from unpkg + add CSP resourceDomains for external scripts --------- Co-authored-by: Claude <noreply@anthropic.com> Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>
102 lines
3.2 KiB
Python
102 lines
3.2 KiB
Python
"""
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QR Code MCP Server - Generates QR codes from text
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"""
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import os
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import sys
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import io
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import base64
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from pathlib import Path
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import qrcode
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import uvicorn
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from mcp.server.fastmcp import FastMCP
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from mcp.types import ImageContent
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from starlette.middleware.cors import CORSMiddleware
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WIDGET_URI = "ui://qr-server/widget.html"
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HOST = os.environ.get("HOST", "0.0.0.0") # 0.0.0.0 for Docker compatibility
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PORT = int(os.environ.get("PORT", "3108"))
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mcp = FastMCP("QR Server", port=PORT, stateless_http=True)
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@mcp.tool(meta={"ui/resourceUri": WIDGET_URI})
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def generate_qr(
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text: str,
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box_size: int = 10,
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border: int = 4,
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error_correction: str = "M",
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fill_color: str = "black",
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back_color: str = "white",
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) -> list[ImageContent]:
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"""Generate a QR code from text.
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Args:
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text: The text/URL to encode
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box_size: Size of each box in pixels (default: 10)
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border: Border size in boxes (default: 4)
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error_correction: Error correction level - L(7%), M(15%), Q(25%), H(30%)
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fill_color: Foreground color (hex like #FF0000 or name like red)
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back_color: Background color (hex like #FFFFFF or name like white)
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"""
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error_levels = {
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"L": qrcode.constants.ERROR_CORRECT_L,
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"M": qrcode.constants.ERROR_CORRECT_M,
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"Q": qrcode.constants.ERROR_CORRECT_Q,
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"H": qrcode.constants.ERROR_CORRECT_H,
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}
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qr = qrcode.QRCode(
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version=1,
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error_correction=error_levels.get(error_correction.upper(), qrcode.constants.ERROR_CORRECT_M),
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box_size=box_size,
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border=border,
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)
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qr.add_data(text)
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qr.make(fit=True)
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img = qr.make_image(fill_color=fill_color, back_color=back_color)
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buffer = io.BytesIO()
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img.save(buffer, format="PNG")
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b64 = base64.b64encode(buffer.getvalue()).decode()
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return [ImageContent(type="image", data=b64, mimeType="image/png")]
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# IMPORTANT: resourceDomains needed for CSP to allow loading SDK from unpkg.com
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# Without this, hosts enforcing CSP will block the external script import
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@mcp.resource(WIDGET_URI, mime_type="text/html")
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def widget() -> dict:
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html = Path(__file__).parent.joinpath("widget.html").read_text()
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return {
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"text": html,
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"_meta": {
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"ui": {
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"csp": {
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"resourceDomains": ["https://unpkg.com"]
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}
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}
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}
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}
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# HACK: Bypass SDK's restrictive mime_type validation
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# The SDK pattern doesn't allow ";profile=mcp-app" but MCP spec requires it for widgets
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# https://github.com/modelcontextprotocol/python-sdk/pull/1755
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for resource in mcp._resource_manager._resources.values():
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if str(resource.uri) == WIDGET_URI:
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object.__setattr__(resource, 'mime_type', 'text/html;profile=mcp-app')
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if __name__ == "__main__":
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if "--stdio" in sys.argv:
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# Claude Desktop mode
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mcp.run(transport="stdio")
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else:
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# HTTP mode for basic-host (default) - with CORS
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app = mcp.streamable_http_app()
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app.add_middleware(
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CORSMiddleware,
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allow_origins=["*"],
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allow_methods=["*"],
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allow_headers=["*"],
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)
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print(f"QR Server listening on http://{HOST}:{PORT}/mcp")
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uvicorn.run(app, host=HOST, port=PORT)
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