Netcat, curl and socat for WebSockets.
$ websocat ws://echo.websocket.org
123
123
ABC
ABC
A$ websocat -s 1234
Listening on ws://127.0.0.1:1234/
ABC
123
B$ websocat ws://127.0.0.1:1234/
ABC
123
$ chromium --remote-debugging-port=9222&
$ curl -sg http://127.0.0.1:9222/json/new | grep webSocketDebuggerUrl | cut -d'"' -f4 | head -1
ws://127.0.0.1:9222/devtools/page/A331E56CCB8615EB4FCB720425A82259
$ echo 'Page.navigate {"url":"https://example.com"}' | websocat -n1 --jsonrpc ws://127.0.0.1:9222/devtools/page/A331E56CCB8615EB4FCB720425A82259
{"id":2,"result":{"frameId":"A331E56CCB8615EB4FCB720425A82259","loaderId":"EF5AAD19F2F8BB27FAF55F94FFB27DF9"}}
$ websocat --oneshot -b ws-l:127.0.0.1:1234 tcp:127.0.0.1:22&
$ websocat --oneshot -b tcp-l:127.0.0.1:1236 ws://127.0.0.1:1234/&
$ nc 127.0.0.1 1236
SSH-2.0-OpenSSH_7.4p1 Debian-10+deb9u3
qwertyu
Protocol mismatch.
A$ websocat -t ws-l:127.0.0.1:1234 broadcast:mirror:
B$ websocat ws://127.0.0.1:1234
C$ websocat ws://127.0.0.1:1234
See moreexamples.md for further examples.
- Connecting to and serving WebSockets from command line.
- Executing external program and making it communicate to WebSocket using stdin/stdout.
- Text and binary modes, converting between lines (or null-terminated records) and messages.
- Inetd mode, UNIX sockets (including abstract namespaced on Linux).
- Integration with Nginx using TCP or UNIX sockets.
- Directly using unauthenticated SOCKS5 servers for connecting to WebSockets and listening WebSocket connection.
- Auto-reconnect and connection-reuse modes.
- Linux, Windows and Mac support, with pre-built executables.
- Low-level WebSocket clients and servers with overridable underlying transport connection, e.g. calling external program to serve as a transport for websocat (for SSL, proxying, etc.).
- Buildable by rust starting from v1.30. Websocat version 1.2.0 (or from a tag) should be buildable by 1.28.0. Websocat version 1.1.0 and earlier should be buildable with Rust v1.23.0. There is legacy non-async version buildable by even older Rust.
There are multiple options for installing WebSocat. From easy to hard:
- If you're on Linux Debian or Ubuntu (or other dpkg-based), try downloading a pre-build deb package from GitHub releases and install from GUI or with command like
gdebi websocat_..._.deb - If you're on FreeBSD, you may install WebSocat with the following command:
pkg install websocat. - If you're on Mac, you can do
brew install websocat. - Download a pre-build executable and install it to PATH.
- Install the Rust toolchain and do
cargo install --features=ssl websocat. If something fails with a-syscrate, try without--features=ssl; - Build Websocat from source code (see below), then move
target/release/websocatsomewhere to the PATH.
websocat 1.5.0
Vitaly "_Vi" Shukela <vi0oss@gmail.com>
Command-line client for web sockets, like netcat/curl/socat for ws://.
USAGE:
websocat ws://URL | wss://URL (simple client)
websocat -s port (simple server)
websocat [FLAGS] [OPTIONS] <addr1> <addr2> (advanced mode)
FLAGS:
(some flags are hidden, see --help=long)
-e, --set-environment Set WEBSOCAT_* environment variables when doing exec:/cmd:/sh-c:
Currently it's WEBSOCAT_URI and WEBSOCAT_CLIENT for
request URI and client address (if TCP)
Beware of ShellShock or similar security problems.
-E, --exit-on-eof Close a data transfer direction if the other one reached EOF
--jsonrpc Format messages you type as JSON RPC 2.0 method calls. First word
becomes method name, the rest becomes parameters, possibly automatically
wrapped in [].
-0, --null-terminated Use \0 instead of \n for linemode
-1, --one-message Send and/or receive only one message. Use with --no-close and/or -u/-U.
--oneshot Serve only once. Not to be confused with -1 (--one-message)
-q Suppress all diagnostic messages, except of startup errors
-s, --server-mode Simple server mode: specify TCP port or addr:port as single argument
-S, --strict strict line/message mode: drop too long messages instead of splitting
them, drop incomplete lines.
-k, --insecure Accept invalid certificates and hostnames while connecting to TLS
-u, --unidirectional Inhibit copying data in one direction
-U, --unidirectional-reverse Inhibit copying data in the other direction (or maybe in both directions
if combined with -u)
-v Increase verbosity level to info or further
-b, --binary Send message to WebSockets as binary messages
-n, --no-close Don't send Close message to websocket on EOF
-t, --text Send message to WebSockets as text messages
OPTIONS:
(some options are hidden, see --help=long)
--socks5 <auto_socks5>
Use specified address:port as a SOCKS5 proxy. Note that proxy authentication is not supported yet. Example:
--socks5 127.0.0.1:9050
-B, --buffer-size <buffer_size> Maximum message size, in bytes [default: 65536]
-H, --header <custom_headers>...
Add custom HTTP header to websocket client request. Separate header name and value with a colon and
optionally a single space. Can be used multiple times. Note that single -H may eat multiple further
arguments, leading to confusing errors. Specify headers at the end or with equal sign like -H='X: y'.
--server-header <custom_reply_headers>...
Add custom HTTP header to websocket upgrade reply. Separate header name and value with a colon and
optionally a single space. Can be used multiple times. Note that single -H may eat multiple further
arguments, leading to confusing errors.
--header-to-env <headers_to_env>...
Forward specified incoming request header to H_* environment variable for `exec:`-like specifiers.
-h, --help <help>
See the help.
--help=short is the list of easy options and address types
--help=long lists all options and types (see [A] markers)
--help=doc also shows longer description and examples.
--conncap <max_parallel_conns> Maximum number of simultaneous connections for listening mode
--origin <origin> Add Origin HTTP header to websocket client request
--pkcs12-der <pkcs12_der>
Pkcs12 archive needed to accept SSL connections, certificate and key.
A command to output it: openssl pkcs12 -export -out output.pkcs12 -inkey key.pem -in cert.pem
Use with -s (--server-mode) option or with manually specified TLS overlays.
See moreexamples.md for more info.
--pkcs12-passwd <pkcs12_passwd> Password for --pkcs12-der pkcs12 archive. Required on Mac.
--restrict-uri <restrict_uri>
When serving a websocket, only accept the given URI, like `/ws`
This liberates other URIs for things like serving static files or proxying.
-F, --static-file <serve_static_files>...
Serve a named static file for non-websocket connections.
Argument syntax: <URI>:<Content-Type>:<file-path>
Argument example: /index.html:text/html:index.html
Directories are not and will not be supported for security reasons.
Can be specified multiple times. Recommended to specify them at the end or with equal sign like `-F=...`,
otherwise this option may eat positional arguments
--protocol <websocket_protocol> Specify this Sec-WebSocket-Protocol: header when connecting
--server-protocol <websocket_reply_protocol>
Force this Sec-WebSocket-Protocol: header when accepting a connection
--websocket-version <websocket_version> Override the Sec-WebSocket-Version value
--ping-interval <ws_ping_interval> Send WebSocket pings each this number of seconds
--ping-timeout <ws_ping_timeout>
Drop WebSocket connection if Pong message not received for this number of seconds
ARGS:
<addr1> In simple mode, WebSocket URL to connect. In advanced mode first address (there are many kinds of
addresses) to use. See --help=types for info about address types. If this is an address for
listening, it will try serving multiple connections.
<addr2> In advanced mode, second address to connect. If this is an address for listening, it will accept only
one connection.
Basic examples:
Command-line websocket client:
websocat ws://echo.websocket.org/
WebSocket server
websocat -s 8080
WebSocket-to-TCP proxy:
websocat --binary ws-l:127.0.0.1:8080 tcp:127.0.0.1:5678
Partial list of address types:
ws:// Insecure (ws://) WebSocket client. Argument is host and URL.
wss:// Secure (wss://) WebSocket client. Argument is host and URL.
ws-listen: WebSocket server. Argument is host and port to listen.
wss-listen: Listen for secure WebSocket connections on a TCP port
stdio: Same as `-`. Read input from console, print to console.
tcp: Connect to specified TCP host and port. Argument is a socket address.
tcp-listen: Listen TCP port on specified address.
ssl-listen: Listen for SSL connections on a TCP port
sh-c: Start specified command line using `sh -c` (even on Windows)
cmd: Start specified command line using `sh -c` or `cmd /C` (depending on platform)
readfile: Synchronously read a file. Argument is a file path.
writefile: Synchronously truncate and write a file.
appendfile: Synchronously append a file.
udp: Send and receive packets to specified UDP socket, from random UDP port
udp-listen: Bind an UDP socket to specified host:port, receive packet
mirror: Simply copy output to input. No arguments needed.
literalreply: Reply with a specified string for each input packet.
literal: Output a string, discard input.
Partial list of overlays:
broadcast: Reuse this connection for serving multiple clients, sending replies to all clients.
autoreconnect: Re-establish underlying connection on any error or EOF
Pre-built binaries for Linux (usual and musl), Windows, OS X and Android are available on the releases page.
- Websocat can't mix sending text and binary WebSocket messages. This also affects
mirror:specifier, making it a bit different from ws://echo.websocket.org. - Current version of Websocat don't receive notification about closed sockets. This makes serving without
-Eor-uoptions or in backpressure scenarios prone to socket leak.
- Install the Rust toolchain
cargo build --release --features=ssl.- Find the executable somewhere under
target/, e.g. intarget/release/websocat.
websocat's wss:// may fail on Android. As a workaround, download certificate bundle, for example, from https://curl.haxx.se/ca/cacert.pem and specify it explicitly:
SSL_CERT_FILE=cacert.pem /data/local/tmp/websocat wss://echo.websocket.org
Or just use --insecure option.
There is a work-in-progress reference document that contains more options and examples.
- It runs singlethreaded, but can serve multiple connections simultaneously. There is old non-async threaded version in
legacybranch of releases prior to 0.5. - IPv6 is supported, surround your IP in square brackets or use it as is, depending on context.
- Web socket usage is not obligatory, you can use any specs on both sides.
- Typically one line in binary stream correspond to one WebSocket text message. This is adjustable with options.