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293 lines
9.2 KiB
Markdown
293 lines
9.2 KiB
Markdown
Testing server with a browser
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-----------------------------
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If you run [libwebsockets-test-server](test-server/test-server.c) and point your browser
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(eg, Chrome) to
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http://127.0.0.1:7681
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It will fetch a script in the form of `test.html`, and then run the
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script in there on the browser to open a websocket connection.
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Incrementing numbers should appear in the browser display.
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By default the test server logs to both stderr and syslog, you can control
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what is logged using `-d <log level>`, see later.
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Running test server as a Daemon
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-------------------------------
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You can use the -D option on the test server to have it fork into the
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background and return immediately. In this daemonized mode all stderr is
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disabled and logging goes only to syslog, eg, `/var/log/messages` or similar.
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The server maintains a lockfile at `/tmp/.lwsts-lock` that contains the pid
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of the master process, and deletes this file when the master process
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terminates.
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To stop the daemon, do
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```bash
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$ kill `cat /tmp/.lwsts-lock`
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```
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If it finds a stale lock (the pid mentioned in the file does not exist
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any more) it will delete the lock and create a new one during startup.
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If the lock is valid, the daemon will exit with a note on stderr that
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it was already running.
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Using SSL on the server side
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----------------------------
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To test it using SSL/WSS, just run the test server with
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```bash
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$ libwebsockets-test-server --ssl
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```
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and use the URL
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https://127.0.0.1:7681
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The connection will be entirely encrypted using some generated
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certificates that your browser will not accept, since they are
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not signed by any real Certificate Authority. Just accept the
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certificates in the browser and the connection will proceed
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in first https and then websocket wss, acting exactly the
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same.
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[test-server.c](test-server/test-server.c) is all that is needed to use libwebsockets for
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serving both the script html over http and websockets.
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Testing websocket client support
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--------------------------------
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If you run the test server as described above, you can also
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connect to it using the test client as well as a browser.
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```bash
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$ libwebsockets-test-client localhost
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```
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will by default connect to the test server on localhost:7681
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and print the dumb increment number from the server at the
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same time as drawing random circles in the mirror protocol;
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if you connect to the test server using a browser at the
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same time you will be able to see the circles being drawn.
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Testing simple echo
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-------------------
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You can test against `echo.websockets.org` as a sanity test like
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this (the client connects to port `80` by default):
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```bash
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$ libwebsockets-test-echo --client echo.websocket.org
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```
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This echo test is of limited use though because it doesn't
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negotiate any protocol. You can run the same test app as a
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local server, by default on localhost:7681
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```bash
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$ libwebsockets-test-echo
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```
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and do the echo test against the local echo server
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```bash
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$ libwebsockets-test-echo --client localhost --port 7681
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```
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If you add the `--ssl` switch to both the client and server, you can also test
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with an encrypted link.
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Testing SSL on the client side
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------------------------------
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To test SSL/WSS client action, just run the client test with
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```bash
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$ libwebsockets-test-client localhost --ssl
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```
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By default the client test applet is set to accept selfsigned
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certificates used by the test server, this is indicated by the
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`use_ssl` var being set to `2`. Set it to `1` to reject any server
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certificate that it doesn't have a trusted CA cert for.
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Using the websocket ping utility
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--------------------------------
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libwebsockets-test-ping connects as a client to a remote
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websocket server using 04 protocol and pings it like the
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normal unix ping utility.
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```bash
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$ libwebsockets-test-ping localhost
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handshake OK for protocol lws-mirror-protocol
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Websocket PING localhost.localdomain (127.0.0.1) 64 bytes of data.
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64 bytes from localhost: req=1 time=0.1ms
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64 bytes from localhost: req=2 time=0.1ms
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64 bytes from localhost: req=3 time=0.1ms
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64 bytes from localhost: req=4 time=0.2ms
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64 bytes from localhost: req=5 time=0.1ms
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64 bytes from localhost: req=6 time=0.2ms
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64 bytes from localhost: req=7 time=0.2ms
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64 bytes from localhost: req=8 time=0.1ms
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^C
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--- localhost.localdomain websocket ping statistics ---
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8 packets transmitted, 8 received, 0% packet loss, time 7458ms
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rtt min/avg/max = 0.110/0.185/0.218 ms
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$
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```
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By default it sends 64 byte payload packets using the 04
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PING packet opcode type. You can change the payload size
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using the `-s=` flag, up to a maximum of 125 mandated by the
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04 standard.
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Using the lws-mirror protocol that is provided by the test
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server, libwebsockets-test-ping can also use larger payload
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sizes up to 4096 is BINARY packets; lws-mirror will copy
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them back to the client and they appear as a PONG. Use the
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`-m` flag to select this operation.
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The default interval between pings is 1s, you can use the -i=
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flag to set this, including fractions like `-i=0.01` for 10ms
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interval.
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Before you can even use the PING opcode that is part of the
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standard, you must complete a handshake with a specified
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protocol. By default lws-mirror-protocol is used which is
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supported by the test server. But if you are using it on
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another server, you can specify the protcol to handshake with
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by `--protocol=protocolname`
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Fraggle test app
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----------------
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By default it runs in server mode
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```bash
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$ libwebsockets-test-fraggle
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libwebsockets test fraggle
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(C) Copyright 2010-2011 Andy Green <andy@warmcat.com> licensed under LGPL2.1
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Compiled with SSL support, not using it
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Listening on port 7681
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server sees client connect
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accepted v06 connection
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Spamming 360 random fragments
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Spamming session over, len = 371913. sum = 0x2D3C0AE
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Spamming 895 random fragments
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Spamming session over, len = 875970. sum = 0x6A74DA1
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...
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```
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You need to run a second session in client mode, you have to
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give the `-c` switch and the server address at least:
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```bash
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$ libwebsockets-test-fraggle -c localhost
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libwebsockets test fraggle
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(C) Copyright 2010-2011 Andy Green <andy@warmcat.com> licensed under LGPL2.1
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Client mode
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Connecting to localhost:7681
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denied deflate-stream extension
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handshake OK for protocol fraggle-protocol
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client connects to server
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EOM received 371913 correctly from 360 fragments
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EOM received 875970 correctly from 895 fragments
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EOM received 247140 correctly from 258 fragments
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EOM received 695451 correctly from 692 fragments
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...
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```
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The fraggle test sends a random number up to 1024 fragmented websocket frames
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each of a random size between 1 and 2001 bytes in a single message, then sends
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a checksum and starts sending a new randomly sized and fragmented message.
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The fraggle test client receives the same message fragments and computes the
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same checksum using websocket framing to see when the message has ended. It
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then accepts the server checksum message and compares that to its checksum.
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proxy support
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-------------
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The http_proxy environment variable is respected by the client
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connection code for both `ws://` and `wss://`. It doesn't support
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authentication.
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You use it like this
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```bash
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$ export http_proxy=myproxy.com:3128
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$ libwebsockets-test-client someserver.com
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```
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debug logging
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-------------
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By default logging of severity "notice", "warn" or "err" is enabled to stderr.
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Again by default other logging is compiled in but disabled from printing.
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If you want to eliminate the debug logging below notice in severity, use the
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`--disable-debug` configure option to have it removed from the code by the
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preprocesser.
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If you want to see more detailed debug logs, you can control a bitfield to
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select which logs types may print using the `lws_set_log_level()` api, in the
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test apps you can use `-d <number>` to control this. The types of logging
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available are (OR together the numbers to select multiple)
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- 1 ERR
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- 2 WARN
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- 4 NOTICE
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- 8 INFO
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- 16 DEBUG
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- 32 PARSER
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- 64 HEADER
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- 128 EXTENSION
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- 256 CLIENT
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- 512 LATENCY
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Websocket version supported
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---------------------------
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The final IETF standard is supported for both client and server, protocol
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version 13.
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Latency Tracking
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----------------
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Since libwebsockets runs using `poll()` and a single threaded approach, any
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unexpected latency coming from system calls would be bad news. There's now
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a latency tracking scheme that can be built in with `--with-latency` at
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configure-time, logging the time taken for system calls to complete and if
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the whole action did complete that time or was deferred.
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You can see the detailed data by enabling logging level 512 (eg, `-d 519` on
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the test server to see that and the usual logs), however even without that
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the "worst" latency is kept and reported to the logs with NOTICE severity
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when the context is destroyed.
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Some care is needed interpreting them, if the action completed the first figure
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(in us) is the time taken for the whole action, which may have retried through
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the poll loop many times and will depend on network roundtrip times. High
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figures here don't indicate a problem. The figure in us reported after "lat"
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in the logging is the time taken by this particular attempt. High figures
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here may indicate a problem, or if you system is loaded with another app at
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that time, such as the browser, it may simply indicate the OS gave preferential
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treatment to the other app during that call.
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