noVnc和websockify

## websockify: WebSockets support for any application/server websockify was formerly named wsproxy and was part of the [noVNC](https://github.com/kanaka/noVNC) project. At the most basic level, websockify just translates WebSockets traffic to normal socket traffic. Websockify accepts the WebSockets handshake, parses it, and then begins forwarding traffic between the client and the target in both directions. ### News/help/contact Notable commits, announcements and news are posted to <a href="http://www.twitter.com/noVNC">@noVNC</a> If you are a websockify developer/integrator/user (or want to be) please join the <a href="https://groups.google.com/forum/?fromgroups#!forum/novnc">noVNC/websockify discussion group</a> Bugs and feature requests can be submitted via [github issues](https://github.com/kanaka/websockify/issues). If you want to show appreciation for websockify you could donate to a great non-profits such as: [Compassion International](http://www.compassion.com/), [SIL](http://www.sil.org), [Habitat for Humanity](http://www.habitat.org), [Electronic Frontier Foundation](https://www.eff.org/), [Against Malaria Foundation](http://www.againstmalaria.com/), [Nothing But Nets](http://www.nothingbutnets.net/), etc. Please tweet <a href="http://www.twitter.com/noVNC">@noVNC</a> if you do. ### WebSockets binary data Starting with websockify 0.5.0, only the HyBi / IETF 6455 WebSocket protocol is supported. There is no support for the older Base64 encoded data format. ### Encrypted WebSocket connections (wss://) To encrypt the traffic using the WebSocket 'wss://' URI scheme you need to generate a certificate and key for Websockify to load. By default, Websockify loads a certificate file name `self.pem` but the `--cert=CERT` and `--key=KEY` options can override the file name. You can generate a self-signed certificate using openssl. When asked for the common name, use the hostname of the server where the proxy will be running: ``` openssl req -new -x509 -days 365 -nodes -out self.pem -keyout self.pem ``` For a self-signed certificate to work, you need to make your client/browser understand it. You can do this by installing it as accepted certificate, or by using that same certificate for a HTTPS connection to which you navigate first and approve. Browsers generally don't give you the "trust certificate?" prompt by opening a WSS socket with invalid certificate, hence you need to have it acccept it by either of those two methods. If you have a commercial/valid SSL certificate with one ore more intermediate certificates, concat them into one file, server certificate first, then the intermediate(s) from the CA, etc. Point to this file with the `--cert` option and then also to the key with `--key`. Finally, use `--ssl-only` as needed. ### Websock Javascript library The `include/websock.js` Javascript library library provides a Websock object that is similar to the standard WebSocket object but Websock enables communication with raw TCP sockets (i.e. the binary stream) via websockify. Websock has built-in receive queue buffering; the message event does not contain actual data but is simply a notification that there is new data available. Several rQ* methods are available to read binary data off of the receive queue. The Websock API is documented on the [websock.js API wiki page](https://github.com/kanaka/websockify/wiki/websock.js) See the "Wrap a Program" section below for an example of using Websock and websockify as a browser telnet client (`wstelnet.html`). ### Additional websockify features These are not necessary for the basic operation. * Daemonizing: When the `-D` option is specified, websockify runs in the background as a daemon process. * SSL (the wss:// WebSockets URI): This is detected automatically by websockify by sniffing the first byte sent from the client and then wrapping the socket if the data starts with '\x16' or '\x80' (indicating SSL). * Session recording: This feature that allows recording of the traffic sent and received from the client to a file using the `--record` option. * Mini-webserver: websockify can detect and respond to normal web requests on the same port as the WebSockets proxy. This functionality is activated with the `--web DIR` option where DIR is the root of the web directory to serve. * Wrap a program: see the "Wrap a Program" section below. * Log files: websockify can save all logging information in a file. This functionality is activated with the `--log-file FILE` option where FILE is the file where the logs should be saved. * Authentication plugins: websockify can demand authentication for websocket connections and, if you use `--web-auth`, also for normal web requests. This functionality is activated with the `--auth-plugin CLASS` and `--auth-source ARG` options, where CLASS is usually one from auth_plugins.py and ARG is the plugin's configuration. * Token plugins: a single instance of websockify can connect clients to multiple different pre-configured targets, depending on the token sent by the client using the `token` URL parameter, or the hostname used to reach websockify, if you use `--host-token`. This functionality is activated with the `--token-plugin CLASS` and `--token-source ARG` options, where CLASS is usually one from token_plugins.py and ARG is the plugin's configuration. ### Implementations of websockify The primary implementation of websockify is in python. There are several alternate implementations in other languages (C, Node.js, Clojure, Ruby) in the `other/` subdirectory (with varying levels of functionality). In addition there are several other external projects that implement the websockify "protocol". See the alternate implementation [Feature Matrix](https://github.com/kanaka/websockify/wiki/Feature_Matrix) for more information. ### Wrap a Program In addition to proxying from a source address to a target address (which may be on a different system), websockify has the ability to launch a program on the local system and proxy WebSockets traffic to a normal TCP port owned/bound by the program. The is accomplished with a small LD_PRELOAD library (`rebind.so`) which intercepts bind() system calls by the program. The specified port is moved to a new localhost/loopback free high port. websockify then proxies WebSockets traffic directed to the original port to the new (moved) port of the program. The program wrap mode is invoked by replacing the target with `--` followed by the program command line to wrap. `./run 2023 -- PROGRAM ARGS` The `--wrap-mode` option can be used to indicate what action to take when the wrapped program exits or daemonizes. Here is an example of using websockify to wrap the vncserver command (which backgrounds itself) for use with [noVNC](https://github.com/kanaka/noVNC): `./run 5901 --wrap-mode=ignore -- vncserver -geometry 1024x768 :1` Here is an example of wrapping telnetd (from krb5-telnetd). telnetd exits after the connection closes so the wrap mode is set to respawn the command: `sudo ./run 2023 --wrap-mode=respawn -- telnetd -debug 2023` The `wstelnet.html` page demonstrates a simple WebSockets based telnet client (use 'localhost' and '2023' for the host and port respectively). ### Installing the Python implementation of websockify Download one of the releases or the latest development version, extract it and run `python setup.py install` as root in the directory where you extracted the files. Normally, this will also install numpy for better performance, if you don't have it installed already. However, numpy is optional. If you don't want to install numpy or if you can't compile it, you can edit setup.py and remove the `install_requires=['numpy'],` line before running `python setup.py install`. Afterwards, websockify should be available in your path. Run `websockify --help` to confirm it's installed correctly. ### Building the Python ssl module (for python 2.5 a