lwsws is an implementation of a very lightweight, ws-capable generic web server, which uses libwebsockets to implement everything underneath.
Just enable -DLWS_WITH_LWSWS=1 at cmake-time.
It enables libuv and plugin support automatically.
lwsws uses JSON config files, they're pure JSON but # may be used to turn the rest of the line into a comment.
There is a single file intended for global settings
/etc/lwsws/conf
# these are the server global settings
# stuff related to vhosts should go in one
# file per vhost in ../conf.d/
{
"global": {
"uid": "48", # apache user
"gid": "48", # apache user
"count-threads": "1",
"server-string": "myserver v1", # returned in http headers
"init-ssl": "yes"
}
}
and a config directory intended to take one file per vhost
/etc/lwsws/conf.d/warmcat.com
{
"vhosts": [{
"name": "warmcat.com",
"port": "443",
"interface": "eth0", # optional
"host-ssl-key": "/etc/pki/tls/private/warmcat.com.key", # if given enable ssl
"host-ssl-cert": "/etc/pki/tls/certs/warmcat.com.crt",
"host-ssl-ca": "/etc/pki/tls/certs/warmcat.com.cer",
"mounts": [{ # autoserve
"mountpoint": "/",
"origin": "file:///var/www/warmcat.com",
"default": "index.html"
}]
}]
}
One server can run many vhosts, where SSL is in use SNI is used to match the connection to a vhost and its vhost-specific SSL keys during SSL negotiation.
Listing multiple vhosts looks something like this
{
"vhosts": [ {
"name": "localhost",
"port": "443",
"host-ssl-key": "/etc/pki/tls/private/libwebsockets.org.key",
"host-ssl-cert": "/etc/pki/tls/certs/libwebsockets.org.crt",
"host-ssl-ca": "/etc/pki/tls/certs/libwebsockets.org.cer",
"mounts": [{
"mountpoint": "/",
"origin": "file:///var/www/libwebsockets.org",
"default": "index.html"
}, {
"mountpoint": "/testserver",
"origin": "file:///usr/local/share/libwebsockets-test-server",
"default": "test.html"
}],
# which protocols are enabled for this vhost, and optional
# vhost-specific config options for the protocol
#
"ws-protocols": [{
"warmcat,timezoom": {
"status": "ok"
}
}]
},
{
"name": "localhost",
"port": "7681",
"host-ssl-key": "/etc/pki/tls/private/libwebsockets.org.key",
"host-ssl-cert": "/etc/pki/tls/certs/libwebsockets.org.crt",
"host-ssl-ca": "/etc/pki/tls/certs/libwebsockets.org.cer",
"mounts": [{
"mountpoint": "/",
"origin": ">https://localhost"
}]
},
{
"name": "localhost",
"port": "80",
"mounts": [{
"mountpoint": "/",
"origin": ">https://localhost"
}]
}
]
}
That sets up three vhosts all called "localhost" on ports 443 and 7681 with SSL, and port 80 without SSL but with a forced redirect to https://localhost
The vhost name field is used to match on incoming SNI or Host: header, so it must always be the host name used to reach the vhost externally.
Vhosts may have the same name and different ports, these will each create a listening socket on the appropriate port.
Vhosts may also have the same port and different name: these will be treated as true vhosts on one listening socket and the active vhost decided at SSL negotiation time (via SNI) or if no SSL, then after the Host: header from the client has been parsed.
Vhosts by default have available the union of any initial protocols from context creation time, and any protocols exposed by plugins.
Vhosts can select which plugins they want to offer and give them per-vhost settings using this syntax
"ws-protocols": [{
"warmcat,timezoom": {
"status": "ok"
}
}]
The "x":"y" parameters like "status":"ok" are made available to the protocol during its per-vhost LWS_CALLBACK_PROTOCOL_INIT (@in is a pointer to a linked list of struct lws_protocol_vhost_options containing the name and value pointers).
host-ssl-cert, host-ssl-ca and host-ssl-key are given, then the vhost supports SSL.Each vhost may have its own certs, SNI is used during the initial connection negotiation to figure out which certs to use by the server name it's asking for from the request DNS name.
keeplive-timeout (in secs) defaults to 60 for lwsws, it may be set as a vhost option
interface lets you specify which network interface to listen on, if not given listens on all
"unix-socket": "1" causes the unix socket specified in the interface option to be used instead of an INET socket
"sts": "1" causes lwsws to send a Strict Transport Security header with responses that informs the client he should never accept to connect to this address using http. This is needed to get the A+ security rating from SSL Labs for your server.
"access-log": "filepath" sets where apache-compatible access logs will be written
Where mounts are given in the vhost definition, then directory contents may be auto-served if it matches the mountpoint.
Mount protocols are used to control what kind of translation happens
Eg, with this mountpoint
{
"mountpoint": "/",
"origin": "file:///var/www/mysite.com",
"default": "/"
}
The uri /file.jpg would serve /var/www/mysite.com/file.jpg, since / matched.
^http:// or ^https:// these cause any url matching the mountpoint to issue a redirect to the origin url
cgi:// this causes any matching url to be given to the named cgi, eg
{
"mountpoint": "/git",
"origin": "cgi:///var/www/cgi-bin/cgit",
"default": "/"
}, {
"mountpoint": "/cgit-data",
"origin": "file:///usr/share/cgit",
"default": "/"
},
would cause the url /git/myrepo to pass "myrepo" to the cgi /var/www/cgi-bin/cgit and send the results to the client.
Note: currently only a fixed set of mimetypes are supported.
{
"mountpoint": "/git",
"origin": "cgi:///var/www/cgi-bin/cgit",
"default": "/",
"cgi-env": [{
"CGIT_CONFIG": "/etc/cgitrc/libwebsockets.org"
}]
}
This allows you to customize one cgi depending on the mountpoint (and / or vhost).
"cgi-timeout": "30"
Cache policy of the files in the mount can also be set. If no options are given, the content is marked uncacheable.
{
"mountpoint": "/",
"origin": "file:///var/www/mysite.com",
"cache-max-age": "60", # seconds
"cache-reuse": "1", # allow reuse at client at all
"cache-revalidate": "1", # check it with server each time
"cache-intermediaries": "1" # allow intermediary caches to hold
}
Protcols and extensions may also be provided from "plugins", these are lightweight dynamic libraries. They are scanned for at init time, and any protocols and extensions found are added to the list given at context creation time.
Protocols receive init (LWS_CALLBACK_PROTOCOL_INIT) and destruction (LWS_CALLBACK_PROTOCOL_DESTROY) callbacks per-vhost, and there are arrangements they can make per-vhost allocations and get hold of the correct pointer from the wsi at the callback.
This allows a protocol to choose to strictly segregate data on a per-vhost basis, and also allows the plugin to handle its own initialization and context storage.
To help that happen conveniently, there are some new apis
dumb increment, mirror and status protocol plugins are provided as examples.
One provided protocol can be used to monitor the server status.
Enable the protocol like this on a vhost's ws-protocols section
"lws-server-status": {
"status": "ok",
"update-ms": "5000"
}
"update-ms" is used to control how often updated JSON is sent on a ws link.
And map the provided HTML into the vhost in the mounts section
{
"mountpoint": "/server-status",
"origin": "file:///usr/local/share/libwebsockets-test-server/server-status",
"default": "server-status.html"
}
You might choose to put it on its own vhost which has "interface": "lo", so it's not externally visible.
lwsws needs a service file like this as /usr/lib/systemd/system/lwsws.service
[Unit] Description=Libwebsockets Web Server After=syslog.target [Service] ExecStart=/usr/local/bin/lwsws StandardError=null [Install] WantedBy=multi-user.target
You can find this prepared in ./lwsws/usr-lib-systemd-system-lwsws.service
For correct operation with logrotate, /etc/logrotate.d/lwsws (if that's where we're putting the logs) should contain
/var/log/lwsws/*log {
copytruncate
missingok
notifempty
delaycompress
}
You can find this prepared in /lwsws/etc-logrotate.d-lwsws
Prepare the log directory like this
sudo mkdir /var/log/lwsws sudo chmod 700 /var/log/lwsws