qrcode generator

Instructions

Args:
    text: Text content to convert to QR code
    box_size: Size of each box in pixels (1-50)
    border: Number of boxes for border (0-20)
    fill_color: Foreground color
    back_color: Background color

Implementation Reference

• qrcode_mcp_server.py:20-64 (handler)

  The main handler function for the 'generate_qr_code' tool, decorated with @mcp.tool(), performs input validation and delegates QR code generation to the helper function, returning MCP ImageContent.

  @mcp.tool()
  async def generate_qr_code(
      text: str,
      box_size: int = 10,
      border: int = 4,
      fill_color: str = "black",
      back_color: str = "white",
  ) -> ImageContent:
      """Generate QR code(生成二维码图片) from text and return as image with description.
  
      Args:
          text: Text content to convert to QR code
          box_size: Size of each box in pixels (1-50)
          border: Number of boxes for border (0-20)
          fill_color: Foreground color
          back_color: Background color
      """
      if not text or not text.strip():
          raise ValueError("Text content cannot be empty")
  
      # 验证参数范围
      if not (1 <= box_size <= 50):
          raise ValueError("box_size must be between 1 and 50")
  
      if not (0 <= border <= 20):
          raise ValueError("border must be between 0 and 20")
  
      try:
          # 生成QR码的base64编码
          base64_result = text_to_qr_base64(
              text=text,
              box_size=box_size,
              border=border,
              fill_color=fill_color,
              back_color=back_color,
              image_format="JPEG",
          )
  
          # 按照MCP文档要求的格式返回图片
          return ImageContent(type="image", data=base64_result, mimeType="image/jpeg")
  
      except Exception as e:
          logger.error(f"Failed to generate QR code: {e}")
          raise RuntimeError(f"Failed to generate QR code: {str(e)}")

• qrcode_utils.py:7-65 (helper)

  Helper utility function that implements the core QR code generation logic using the qrcode library, producing a base64-encoded image string.

  def text_to_qr_base64(
      text: str,
      error_correction: int = qrcode.constants.ERROR_CORRECT_M,
      box_size: int = 10,
      border: int = 4,
      fill_color: str = "black",
      back_color: str = "white",
      image_format: str = "PNG",
  ) -> str:
      """
      将输入的字符串转换成QR码图片，并返回base64编码的字符串
  
      Args:
          text (str): 要转换的文本内容
          error_correction (int): 错误纠正级别，默认为中等级别
          box_size (int): 每个方块的像素大小，默认为10
          border (int): 边框的方块数量，默认为4
          fill_color (str): 前景色，默认为黑色
          back_color (str): 背景色，默认为白色
          image_format (str): 图片格式，默认为PNG
  
      Returns:
          str: base64编码的图片字符串
  
      Raises:
          ValueError: 当输入文本为空时
          Exception: 其他处理异常
      """
      if not text or not text.strip():
          raise ValueError("输入文本不能为空")
  
      try:
          # 创建QR码实例
          qr = qrcode.QRCode(
              version=1,  # 控制QR码的大小，1是最小的
              error_correction=error_correction,
              box_size=box_size,
              border=border,
          )
  
          # 添加数据
          qr.add_data(text)
          qr.make(fit=True)
  
          # 创建图片
          img = qr.make_image(fill_color=fill_color, back_color=back_color)
  
          # 将图片转换为字节流
          img_buffer = io.BytesIO()
          img.save(img_buffer, format=image_format)
          img_buffer.seek(0)
  
          # 转换为base64
          img_base64 = base64.b64encode(img_buffer.getvalue()).decode("utf-8")
  
          return img_base64
  
      except Exception as e:
          raise Exception(f"生成QR码时发生错误: {str(e)}")

• qrcode_mcp_server.py:20-20 (registration)

  The @mcp.tool() decorator registers the generate_qr_code function as an MCP tool.

  @mcp.tool()

• qrcode_mcp_server.py:21-27 (schema)

  Type hints and default values define the input schema for the tool parameters, with return type ImageContent.

  async def generate_qr_code(
      text: str,
      box_size: int = 10,
      border: int = 4,
      fill_color: str = "black",
      back_color: str = "white",
  ) -> ImageContent: