bottle.py中的路由解析代码

# Routing
def compile_route(route):
    """ Compiles a route string and returns a precompiled RegexObject.

    Routes may contain regular expressions with named groups to support url parameters.
    Example:
      '/user/(?P<id>[0-9]+)' will match '/user/5' with {'id':'5'}

    A more human readable syntax is supported too.
    Example:
      '/user/:id/:action' will match '/user/5/kiss' with {'id':'5', 'action':'kiss'}
      Placeholders match everything up to the next slash.
      '/user/:id#[0-9]+#' will match '/user/5' but not '/user/tim'
      Instead of "#" you can use any single special char other than "/"
    """
    route = route.strip().lstrip('$^/ ').rstrip('$^ ')
    # 将 /user/:id#[0-9]+#/ 转换为 /user/(?P<id>[0-9]+)/
    route = re.sub(r':([a-zA-Z_]+)(?P<uniq>[^\w/])(?P<re>.+?)(?P=uniq)',r'(?P<\1>\g<re>)',route)
    # 将 /user/:id/ 转换为 /user/(?P<id>[^/]+)/
    route = re.sub(r':([a-zA-Z_]+)',r'(?P<\1>[^/]+)', route)
    return re.compile('^/%s$' % route)