Blocking A function blocks when it waits for something to happen before returning. A function may block for many reasons: network I/O, disk I/O, mutexes, etc. In fact, every function blocks, at least a easier [https://glyph.twistedmatrix.com/2014/02/unyielding.html] to reason about by reducing the number of places where a context switch can happen. Example: async def fetch_coroutine(url): http_client root URL / is mapped to MainHandler and URLs of the form /story/ followed by a number are mapped to StoryHandler. That number is passed (as a string) to StoryHandler.get. class MainHandler(RequestHandler):

Blocking A function blocks when it waits for something to happen before returning. A function may block for many reasons: network I/O, disk I/O, mutexes, etc. In fact, every function blocks, at least a easier [https://glyph.twistedmatrix.com/2014/02/unyielding.html] to reason about by reducing the number of places where a context switch can happen. Example: async def fetch_coroutine(url): http_client root URL / is mapped to MainHandler and URLs of the form /story/ followed by a number are mapped to StoryHandler. That number is passed (as a string) to StoryHandler.get. class MainHandler(RequestHandler):

Blocking A function blocks when it waits for something to happen before returning. A function may block for many reasons: network I/O, disk I/O, mutexes, etc. In fact, every function blocks, at least a without the expense of a thread. They also make concurrency easier to reason about by reducing the number of places where a context switch can happen. Example: async def fetch_coroutine(url): http_client root URL / is mapped to MainHandler and URLs of the form /story/ followed by a number are mapped to StoryHandler. That number is passed (as a string) to StoryHandler.get. class MainHandler(RequestHandler):

Blocking A function blocks when it waits for something to happen before returning. A function may block for many reasons: network I/O, disk I/O, mutexes, etc. In fact, every function blocks, at least a easier [https://glyph.twistedmatrix.com/2014/02/unyielding.html] to reason about by reducing the number of places where a context switch can happen. Example: from tornado import gen @gen.coroutine def root URL / is mapped to MainHandler and URLs of the form /story/ followed by a number are mapped to StoryHandler. That number is passed (as a string) to StoryHandler.get. class MainHandler(RequestHandler):

Blocking A function blocks when it waits for something to happen before returning. A function may block for many reasons: network I/O, disk I/O, mutexes, etc. In fact, every function blocks, at least a without the expense of a thread. They also make concurrency easier to reason about by reducing the number of places where a context switch can happen. Example: from tornado import gen @gen.coroutine def root URL / is mapped to MainHandler and URLs of the form /story/ followed by a number are mapped to StoryHandler. That number is passed (as a string) to StoryHandler.get. class MainHandler(RequestHandler):

Blocking A function blocks when it waits for something to happen before returning. A function may block for many reasons: network I/O, disk I/O, mutexes, etc. In fact, every function blocks, at least a easier [https://glyph.twistedmatrix.com/2014/02/unyielding.html] to reason about by reducing the number of places where a context switch can happen. Example: async def fetch_coroutine(url): http_client root URL / is mapped to MainHandler and URLs of the form /story/ followed by a number are mapped to StoryHandler. That number is passed (as a string) to StoryHandler.get. class MainHandler(RequestHandler):

Blocking A function blocks when it waits for something to happen before returning. A function may block for many reasons: network I/O, disk I/O, mutexes, etc. In fact, every function blocks, at least a without the expense of a thread. They also make concurrency easier to reason about by reducing the number of places where a context switch can happen. Example: async def fetch_coroutine(url): http_client root URL / is mapped to MainHandler and URLs of the form /story/ followed by a number are mapped to StoryHandler. That number is passed (as a string) to StoryHandler.get. class MainHandler(RequestHandler):

Blocking A function blocks when it waits for something to happen before returning. A function may block for many reasons: network I/O, disk I/O, mutexes, etc. In fact, every function blocks, at least a without the expense of a thread. They also make concurrency easier to reason about by reducing the number of places where a context switch can happen. Example: async def fetch_coroutine(url): http_client root URL / is mapped to MainHandler and URLs of the form /story/ followed by a number are mapped to StoryHandler. That number is passed (as a string) to StoryHandler.get. class MainHandler(RequestHandler):

Blocking A function blocks when it waits for something to happen before returning. A function may block for many reasons: network I/O, disk I/O, mutexes, etc. In fact, every function blocks, at least a without the expense of a thread. They also make concurrency easier to reason about by reducing the number of places where a context switch can happen. Example: async def fetch_coroutine(url): http_client root URL / is mapped to MainHandler and URLs of the form /story/ followed by a number are mapped to StoryHandler. That number is passed (as a string) to StoryHandler.get. class MainHandler(RequestHandler):

Blocking A function blocks when it waits for something to happen before returning. A function may block for many reasons: network I/O, disk I/O, mutexes, etc. In fact, every function blocks, at least a without the expense of a thread. They also make concurrency easier to reason about by reducing the number of places where a context switch can happen. Example: async def fetch_coroutine(url): http_client root URL / is mapped to MainHandler and URLs of the form /story/ followed by a number are mapped to StoryHandler. That number is passed (as a string) to StoryHandler.get. class MainHandler(RequestHandler):