"""QR code widget."""
from __future__ import annotations
import base64
import io
from typing import Any, Dict
import mcp.types as types
import qrcode
from pydantic import BaseModel, ConfigDict, Field, ValidationError
from ._base import Widget, format_validation_error, get_invocation_meta
WIDGET = Widget(
identifier="show_qr",
title="Generate QR Code",
description="""Generate a QR code from text or a URL.
Use this tool when:
- The user wants to create a QR code
- Encoding a URL, text, or data as a scannable image
- Sharing links or information visually
Args:
text: The text or URL to encode (default: "https://modelcontextprotocol.io")
fill_color: Foreground color name or hex (default: "black")
back_color: Background color name or hex (default: "white")
Returns:
A QR code image displayed in the widget.
Example:
show_qr(text="https://example.com", fill_color="#1a1a2e", back_color="#eaeaea")""",
template_uri="ui://widget/qr.html",
invoking="Generating QR code...",
invoked="QR code ready",
component_name="qr",
)
class QrInput(BaseModel):
"""Input for QR code widget."""
text: str = Field(default="https://modelcontextprotocol.io", description="Text or URL to encode")
box_size: int = Field(default=10, alias="boxSize", description="Box size in pixels")
border: int = Field(default=4, description="Border size in boxes")
error_correction: str = Field(default="M", alias="errorCorrection", description="Error correction: L(7%), M(15%), Q(25%), H(30%)")
fill_color: str = Field(default="black", alias="fillColor", description="Foreground color (hex or name)")
back_color: str = Field(default="white", alias="backColor", description="Background color (hex or name)")
model_config = ConfigDict(populate_by_name=True, extra="forbid")
INPUT_MODEL = QrInput
async def handle(widget: Widget, arguments: Dict[str, Any]) -> types.ServerResult:
try:
payload = QrInput.model_validate(arguments)
except ValidationError as e:
error_msg = format_validation_error(e, QrInput)
return types.ServerResult(types.CallToolResult(
content=[types.TextContent(type="text", text=error_msg)],
isError=True,
))
error_levels = {
"L": qrcode.constants.ERROR_CORRECT_L,
"M": qrcode.constants.ERROR_CORRECT_M,
"Q": qrcode.constants.ERROR_CORRECT_Q,
"H": qrcode.constants.ERROR_CORRECT_H,
}
# Clamp/default to valid values
text = payload.text or "https://modelcontextprotocol.io"
box_size = max(1, payload.box_size)
border = max(0, payload.border)
fill_color = payload.fill_color or "black"
back_color = payload.back_color or "white"
ec_key = (payload.error_correction or "M").upper()
qr = qrcode.QRCode(
version=1,
error_correction=error_levels.get(ec_key, qrcode.constants.ERROR_CORRECT_M),
box_size=box_size,
border=border,
)
qr.add_data(text)
qr.make(fit=True)
img = qr.make_image(fill_color=fill_color, back_color=back_color)
buffer = io.BytesIO()
img.save(buffer, format="PNG")
b64 = base64.b64encode(buffer.getvalue()).decode()
structured_content = {
"imageData": b64,
"mimeType": "image/png",
}
return types.ServerResult(types.CallToolResult(
content=[
types.TextContent(type="text", text=f"QR code generated for: {text}"),
types.ImageContent(type="image", data=b64, mimeType="image/png"),
],
structuredContent=structured_content,
_meta=get_invocation_meta(widget),
))
