NCCN Guidelines MCP Server

Instructions

Download a PDF file from the specified URL, with optional NCCN login credentials.

Args:
    url: The URL of the PDF file to download
    filename: Optional custom filename for the downloaded file
    username: Optional NCCN username/email for authentication (defaults to NCCN_USERNAME env var)
    password: Optional NCCN password for authentication (defaults to NCCN_PASSWORD env var)

Returns:
    String indicating success/failure and the path to the downloaded file

Implementation Reference

• server.py:167-223 (handler)

  MCP tool handler for 'download_pdf': orchestrates authentication, directory setup, and delegates download to NCCNDownloader instance.

  @mcp.tool()
  async def download_pdf(url: str) -> str:
      """
      Download a PDF file from the specified URL, with optional NCCN login credentials.
      
      Args:
          url: The URL of the PDF file to download
          filename: Optional custom filename for the downloaded file
          username: Optional NCCN username/email for authentication (defaults to NCCN_USERNAME env var)
          password: Optional NCCN password for authentication (defaults to NCCN_PASSWORD env var)
      
      Returns:
          String indicating success/failure and the path to the downloaded file
      """
      try:
          # Ensure download directory exists
          download_path = current_dir / DOWNLOAD_DIR
          download_path.mkdir(exist_ok=True)
          
          # Use provided credentials or fall back to global configuration
          auth_username = NCCN_USERNAME
          auth_password = NCCN_PASSWORD
          
          # Create downloader instance with credentials if available
          if auth_username and auth_password:
              downloader_instance = NCCNDownloader(auth_username, auth_password)
              logger.info(f"Using NCCN authentication for user: {auth_username}")
          else:
              downloader_instance = downloader
              logger.info("No NCCN authentication configured - attempting anonymous download")
          
          # Download the PDF
          success, actual_filename = await downloader_instance.download_pdf(
              pdf_url=url,
              download_dir=str(download_path),
              username=auth_username,
              password=auth_password,
              skip_if_exists=True
          )
          
          # Update the full path with the actual filename used
          actual_full_path = download_path / actual_filename
          
          if success:
              logger.info(f"PDF downloaded successfully: {actual_full_path}")
              return f"PDF downloaded successfully: {actual_full_path} (filename: {actual_filename})"
          else:
              error_msg = f"Failed to download PDF from {url} (attempted filename: {actual_filename})."
              if not (auth_username and auth_password):
                  error_msg += " You may need to provide NCCN login credentials via environment variables (NCCN_USERNAME, NCCN_PASSWORD) or function parameters."
              logger.error(error_msg)
              return error_msg
      
      except Exception as e:
          logger.error(f"Error downloading PDF: {str(e)}")
          return f"Error downloading PDF: {str(e)}"

• nccn_login_downloader.py:204-340 (helper)

  Core implementation of PDF downloading in NCCNDownloader class, including caching check, HTTP requests, automatic login detection and handling, and recursive re-download after login.

  async def download_pdf(self, pdf_url, download_dir=None, username=None, password=None, skip_if_exists=True, max_cache_age_days=PDF_CACHE_MAX_AGE_DAYS):
      """
      Downloads a PDF file, automatically logging in if required.
      
      Args:
          pdf_url (str): URL of the PDF file.
          download_dir (str, optional): Directory to save the PDF. Defaults to current directory.
          username (str, optional): Username (email address), required if not already logged in.
          password (str, optional): Password, required if not already logged in.
          skip_if_exists (bool): Whether to skip download if the file already exists. Defaults to True.
          max_cache_age_days (int): Maximum cache file validity period (days). Defaults to PDF_CACHE_MAX_AGE_DAYS.
      
      Returns:
          tuple: (success (bool), saved_filename (str))
      """
      try:
          # Automatically extract filename from URL
          filename = os.path.basename(pdf_url)
          if not filename or not filename.endswith('.pdf'):
              filename = 'nccn_guideline.pdf'
          
          if download_dir:
              os.makedirs(download_dir, exist_ok=True)
          else:
              download_dir = os.getcwd() # Use current working directory if not specified
          
          save_path = os.path.join(download_dir, filename)
          
          # Check if file already exists and is still valid (not too old)
          if skip_if_exists:
              cache_info = check_pdf_cache_age(save_path, max_cache_age_days)
              if cache_info['exists']:
                  if cache_info['is_valid']:
                      logger.info(f"Using valid cached PDF: {save_path}")
                      logger.info(f"File size: {cache_info['size']} bytes, age: {cache_info['age_days']} days")
                      return True, filename
                  else:
                      logger.info(f"PDF cache expired ({cache_info['age_days']} days > {max_cache_age_days} days) or corrupted, re-downloading...")
              else:
                  logger.info(f"PDF not found in cache, downloading: {save_path}")
          
          logger.info(f"Downloading PDF: {pdf_url}")
          
          # Set request headers for PDF download
          pdf_headers = {
              'Accept': 'application/pdf,*/*',
              'Referer': 'https://www.nccn.org/',
          }
          
          # First, make a regular GET request to check the response
          response = await self.session.get(pdf_url, headers=pdf_headers, follow_redirects=True)
          
          logger.info(f"Response status: {response.status_code}")
          logger.info(f"Final URL: {response.url}")
          
          # Check if we were redirected to a login page
          if response.status_code == 200:
              content_type = response.headers.get('Content-Type', '')
              logger.info(f"Content-Type: {content_type}")
              
              # Check if this is actually a PDF
              if 'application/pdf' in content_type:
                  # This is a PDF, save it directly
                  with open(save_path, 'wb') as f:
                      f.write(response.content)
                  
                  file_size = os.path.getsize(save_path)
                  logger.info(f"PDF file saved to: {save_path}")
                  logger.info(f"File size: {file_size} bytes")
                  return True, filename
              
              elif 'text/html' in content_type:
                  # This is HTML, likely a login page
                  response_text = response.text
                  
                  if 'login' in response_text.lower() or 'log in' in response_text.lower():
                      logger.info("Login required detected, attempting automatic login...")
                      
                      # If login credentials are provided, attempt to log in
                      login_username = username or self.username
                      login_password = password or self.password
                      
                      if login_username and login_password:
                          if await self.login(login_username, login_password, pdf_url):
                              logger.info("Login successful, re-downloading PDF...")
                              time.sleep(1)  # Wait for login state to stabilize
                              # Recursive call, but do not pass login credentials to avoid infinite loop
                              return await self.download_pdf(pdf_url, download_dir=download_dir, skip_if_exists=skip_if_exists, max_cache_age_days=max_cache_age_days)
                          else:
                              logger.error("Automatic login failed.")
                              return False, filename
                      else:
                          logger.error("Login required but username and password not provided.")
                          return False, filename
                  else:
                      logger.warning("Received HTML response but no login form detected.")
                      logger.debug(f"Response preview: {response_text[:500]}...")
                      return False, filename
              else:
                  logger.warning(f"Unexpected content type: {content_type}")
                  return False, filename
          
          elif response.status_code == 302:
              # Handle redirect manually if needed
              redirect_url = response.headers.get('Location')
              logger.info(f"Received redirect to: {redirect_url}")
              
              # Check if redirect is to login page
              if redirect_url and 'login' in redirect_url.lower():
                  logger.info("Redirected to login page, attempting automatic login...")
                  
                  login_username = username or self.username
                  login_password = password or self.password
                  
                  if login_username and login_password:
                      if await self.login(login_username, login_password, pdf_url):
                          logger.info("Login successful, re-downloading PDF...")
                          time.sleep(1)
                          return await self.download_pdf(pdf_url, download_dir=download_dir, skip_if_exists=skip_if_exists, max_cache_age_days=max_cache_age_days)
                      else:
                          logger.error("Automatic login failed.")
                          return False, filename
                  else:
                      logger.error("Login required but username and password not provided.")
                      return False, filename
              else:
                  logger.error(f"Unexpected redirect to: {redirect_url}")
                  return False, filename
          
          else:
              logger.error(f"Download failed, status code: {response.status_code}")
              return False, filename
              
      except Exception as e:
          logger.error(f"An error occurred during download: {str(e)}")
          return False, filename

• server.py:167-167 (registration)

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

  @mcp.tool()