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# `tornado.platform.caresresolver` — Asynchronous DNS Resolver using C-Ares
This module contains a DNS resolver using the c-ares library (and itswrapper `pycares`).
*class *`tornado.platform.caresresolver.``CaresResolver`
Name resolver based on the c-ares library.
This is a non-blocking and non-threaded resolver. It may not producethe same results as the system resolver, but can be used for non-blockingresolution when threads cannot be used.
c-ares fails to resolve some names when `family` is `AF_UNSPEC`,so it is only recommended for use in `AF_INET` (i.e. IPv4). This isthe default for `tornado.simple_httpclient`, but other librariesmay default to `AF_UNSPEC`.
? Copyright 2009-2016, The Tornado Authors. Created using [Sphinx](http://sphinx-doc.org/) 1.3.5.
- User's guide
- Introduction
- Asynchronous and non-Blocking I/O
- Coroutines
- Queue example - a concurrent web spider
- Structure of a Tornado web application
- Templates and UI
- Authentication and security
- Running and deploying
- Web framework
- tornado.web — RequestHandler and Application classes
- tornado.template — Flexible output generation
- tornado.escape — Escaping and string manipulation
- tornado.locale — Internationalization support
- tornado.websocket — Bidirectional communication to the browser
- HTTP servers and clients
- tornado.httpserver — Non-blocking HTTP server
- tornado.httpclient — Asynchronous HTTP client
- tornado.httputil — Manipulate HTTP headers and URLs
- tornado.http1connection – HTTP/1.x client/server implementation
- Asynchronous networking
- tornado.ioloop — Main event loop
- tornado.iostream — Convenient wrappers for non-blocking sockets
- tornado.netutil — Miscellaneous network utilities
- tornado.tcpclient — IOStream connection factory
- tornado.tcpserver — Basic IOStream-based TCP server
- Coroutines and concurrency
- tornado.gen — Simplify asynchronous code
- tornado.concurrent — Work with threads and futures
- tornado.locks – Synchronization primitives
- tornado.queues – Queues for coroutines
- tornado.process — Utilities for multiple processes
- Integration with other services
- tornado.auth — Third-party login with OpenID and OAuth
- tornado.wsgi — Interoperability with other Python frameworks and servers
- tornado.platform.asyncio — Bridge between asyncio and Tornado
- tornado.platform.caresresolver — Asynchronous DNS Resolver using C-Ares
- tornado.platform.twisted — Bridges between Twisted and Tornado
- Utilities
- tornado.autoreload — Automatically detect code changes in development
- tornado.log — Logging support
- tornado.options — Command-line parsing
- tornado.stack_context — Exception handling across asynchronous callbacks
- tornado.testing — Unit testing support for asynchronous code
- tornado.util — General-purpose utilities
- Frequently Asked Questions
- Release notes
- What's new in Tornado 4.3
- What's new in Tornado 4.2.1
- What's new in Tornado 4.2
- What's new in Tornado 4.1
- What's new in Tornado 4.0.2
- What's new in Tornado 4.0.1
- What's new in Tornado 4.0
- What's new in Tornado 3.2.2
- What's new in Tornado 3.2.1
- What's new in Tornado 3.2
- What's new in Tornado 3.1.1
- What's new in Tornado 3.1
- What's new in Tornado 3.0.2
- What's new in Tornado 3.0.1
- What's new in Tornado 3.0
- What's new in Tornado 2.4.1
- What's new in Tornado 2.4
- What's new in Tornado 2.3
- What's new in Tornado 2.2.1
- What's new in Tornado 2.2
- What's new in Tornado 2.1.1
- What's new in Tornado 2.1
- What's new in Tornado 2.0
- What's new in Tornado 1.2.1
- What's new in Tornado 1.2
- What's new in Tornado 1.1.1
- What's new in Tornado 1.1
- What's new in Tornado 1.0.1
- What's new in Tornado 1.0