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This leverages the refactor patches to introduce the ability to disable building any client side code in the library or the client side test apps. This will be a considerable size saving for embedded server-only case. Signed-off-by: Andy Green <andy.green@linaro.org>
451 lines
15 KiB
Text
451 lines
15 KiB
Text
Using test-server as a quickstart
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---------------------------------
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You need to regenerate the autotools and libtoolize stuff for your system
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$ ./autogen.sh
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Then for a Fedora x86_86 box, the following config line was
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needed:
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./configure --prefix=/usr --libdir=/usr/lib64 --enable-openssl
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For Apple systems, Christopher Baker reported that this is needed
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(and I was told separately enabling openssl makes trouble somehow)
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./configure CC="gcc -arch i386 -arch x86_64" CXX="g++ -arch i386 -arch
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x86_64" CPP="gcc -E" CXXCPP="g++ -E" --enable-nofork
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For mingw build, I did the following to get working build, ping test is
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disabled when building this way
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1) install mingw64_w32 compiler packages from Fedora
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2) additionally install mingw64-zlib package
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3) ./configure --prefix=/usr --enable-mingw --host=x86_64-w64-mingw32
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4) make
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For uClibc, you will likely need --enable-builtin-getifaddrs
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otherwise if /usr/local/... and /usr/local/lib are OK then...
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$ ./configure
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$ make clean
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$ make
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$ sudo make install
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$ libwebsockets-test-server
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should be enough to get a test server listening on port 7861.
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Configure script options
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------------------------
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There are several other possible configure options
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--enable-nofork disables the fork into the background API
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and removes all references to fork() and
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pr_ctl() from the sources. Use it if your
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platform doesn't support forking.
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--enable-libcrypto by default libwebsockets uses its own
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built-in md5 and sha-1 implementation for
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simplicity. However the libcrypto ones
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may be faster, and in a distro context it
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may be highly desirable to use a common
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library implementation for ease of security
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upgrades. Give this configure option
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to disable the built-in ones and force use
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of the libcrypto (part of openssl) ones.
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--with-client-cert-dir=dir tells the client ssl support where to
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look for trust certificates to validate
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the remote certificate against.
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--enable-noping Don't try to build the ping test app
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It needs some unixy environment that
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may choke in other build contexts, this
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lets you cleanly stop it being built
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--enable-x-google-mux Enable experimental x-google-mux support
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in the build (see notes later in document)
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--enable-builtin-getifaddrs if your libc lacks getifaddrs, you can build an
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implementation into the library. By default your libc
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one is used.
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--without-testapps Just build the library not the test apps
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--without-client Don't build the client part of the library nor the
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test apps that need the client part. Useful to
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minimize library footprint for embedded server-only
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case
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Externally configurable important constants
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-------------------------------------------
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You can control these from configure by just setting them as commandline
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args throgh CFLAGS, eg
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./configure CFLAGS="-DLWS_MAX_ZLIB_CONN_BUFFER=8192"
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They all have defaults so you only need to take care about them if you want
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to tune them to the amount of memory available.
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- FD_HASHTABLE_MODULUS default 32: size of the file descriptor hash map,
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affects server performance with large numbers of connections, at the cost of
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increased memory consumption
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- MAX_CLIENTS default 100: total number of simultaneous connections
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allowed... reserves some memory even when not in use, so reduce for embedded
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applications that only expect one or two connections
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- LWS_MAX_HEADER_NAME_LENGTH default 64: max characters in an HTTP header
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name that libwebsockets can cope with
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- LWS_MAX_HEADER_LEN default 4096: largest HTTP header value string length
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libwebsockets can cope with
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- LWS_INITIAL_HDR_ALLOC default 256: amount of memory to allocate initially,
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tradeoff between taking too much and needless realloc
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- LWS_ADDITIONAL_HDR_ALLOC default 64: how much to additionally realloc if
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the header value string keeps coming
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- MAX_USER_RX_BUFFER default 4096: max amount of user rx data to buffer at a
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time and pass to user callback LWS_CALLBACK_RECEIVE or
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LWS_CALLBACK_CLIENT_RECEIVE. Large frames are passed to the user callback
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in chunks of this size. Tradeoff between per-connection static memory
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allocation and if you expect to deal with large frames, how much you can
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see at once which can affect efficiency.
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- MAX_BROADCAST_PAYLOAD default 4096: largest amount of user tx data we can
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broadcast at a time
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- LWS_MAX_PROTOCOLS default 10: largest amount of different protocols the
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server can serve
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- LWS_MAX_EXTENSIONS_ACTIVE default 10: largest amount of extensions we can
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choose to have active on one connection
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- SPEC_LATEST_SUPPORTED default 13: only change if you want to remove support
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for later protocol versions... unlikely
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- AWAITING_TIMEOUT default 5: after this many seconds without a response, the
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server will hang up on the client
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- CIPHERS_LIST_STRING default "DEFAULT": SSL Cipher selection. It's advisable
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to tweak the ciphers allowed to be negotiated on secure connections for
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performance reasons, otherwise a slow algorithm may be selected by the two
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endpoints and the server could expend most of its time just encrypting and
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decrypting data, severely limiting the amount of messages it will be able to
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handle per second. For example::
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"RC4-MD5:RC4-SHA:AES128-SHA:AES256-SHA:HIGH:!DSS:!aNULL"
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- SYSTEM_RANDOM_FILEPATH default "/dev/urandom": if your random device differs
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you can set it here
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- LWS_MAX_ZLIB_CONN_BUFFER maximum size a compression buffer is allowed to
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grow to before closing the connection. Default is 64KBytes.
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- LWS_SOMAXCONN maximum number of pending connect requests the listening
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socket can cope with. Default is SOMAXCONN. If you need to use synthetic
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tests that just spam hundreds of connect requests at once without dropping
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any, you can try setting this to MAX_CLIENTS and mess with your box's tcp
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config like this (courtesy Edwin van der Oetelaar)
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echo "2048 64512" > /proc/sys/net/ipv4/ip_local_port_range
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echo "1" > /proc/sys/net/ipv4/tcp_tw_recycle
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echo "1" > /proc/sys/net/ipv4/tcp_tw_reuse
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echo "10" > /proc/sys/net/ipv4/tcp_fin_timeout
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echo "65536" > /proc/sys/net/core/somaxconn
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echo "65536" > /proc/sys/net/ipv4/tcp_max_syn_backlog
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echo "262144" > /proc/sys/net/netfilter/nf_conntrack_max
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Testing server with a browser
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-----------------------------
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If you point your browser (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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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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$ libwebsockets-test-server --ssl
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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 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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Forkless operation
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------------------
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If your target device does not offer fork(), you can use
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libwebsockets from your own main loop instead. Use the
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configure option --nofork and simply call libwebsocket_service()
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from your own main loop as shown in the test app sources.
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Fragmented messages
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-------------------
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To support fragmented messages you need to check for the final
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frame of a message with libwebsocket_is_final_fragment. This
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check can be combined with libwebsockets_remaining_packet_payload
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to gather the whole contents of a message, eg:
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case LWS_CALLBACK_RECEIVE:
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{
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Client * const client = (Client *)user;
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const size_t remaining = libwebsockets_remaining_packet_payload(wsi);
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if (!remaining && libwebsocket_is_final_fragment(wsi)) {
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if (client->HasFragments()) {
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client->AppendMessageFragment(in, len, 0);
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in = (void *)client->GetMessage();
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len = client->GetMessageLength();
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}
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client->ProcessMessage((char *)in, len, wsi);
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client->ResetMessage();
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} else
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client->AppendMessageFragment(in, len, remaining);
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}
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break;
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The test app llibwebsockets-test-fraggle sources also show how to
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deal with fragmented messages.
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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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$ libwebsockets-test-client localhost
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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 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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$ libwebsockets-test-client localhost --ssl
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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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$ 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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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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$ 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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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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$ 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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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 yet.
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You use it like this
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export http_proxy=myproxy.com:3128
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libwebsockets-test-client someserver.com
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debug logging
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-------------
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By default logging of severity "warn" or "err" is enabled to stderr.
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Again by default other logging is comiled in but disabled from printing.
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If you want to eliminate the debug logging below warn 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 INFO
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8 DEBUG
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16 PARSER
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32 HEADER
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64 EXTENSION
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128 CLIENT
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Also using lws_set_log_level api you may provide a custom callback to actually
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emit the log string. By default, this points to an internal emit function
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that sends to stderr. Setting it to NULL leaves it as it is instead.
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Websocket version supported
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---------------------------
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The final IETF standard is supported along with various older ones that will
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be removed at some point, -76, -04 and -05.
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External Polling Loop support
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-----------------------------
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libwebsockets maintains an internal poll() array for all of its
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sockets, but you can instead integrate the sockets into an
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external polling array. That's needed if libwebsockets will
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cooperate with an existing poll array maintained by another
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server.
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Four callbacks LWS_CALLBACK_ADD_POLL_FD, LWS_CALLBACK_DEL_POLL_FD,
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LWS_CALLBACK_SET_MODE_POLL_FD and LWS_CALLBACK_CLEAR_MODE_POLL_FD
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appear in the callback for protocol 0 and allow interface code to
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manage socket descriptors in other poll loops.
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x-google-mux support
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--------------------
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Experimental and super-preliminary x-google-mux support is available if
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enabled in ./configure with --enable-x-google-mux. Note that when changing
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configurations, you will need to do a make distclean before, then the new
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configure and then make ; make install. Don't forget the necessary other
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flags for your platform as described at the top of the readme.
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It has the following notes:
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1) To enable it, reconfigure with --enable-x-google-mux
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2) It deviates from the google standard by sending full
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headers in the addchannel subcommand rather than just
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changed ones from original connect
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3) Quota is not implemented yet
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However despite those caveats, in fact it can run the
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test client reliably over one socket (both dumb-increment
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and lws-mirror-protocol), you can open a browser on the
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same test server too and see the circles, etc.
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It also works compatibly with deflate-stream automatically.
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2012-04-12 Andy Green <andy@warmcat.com>
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