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YAWS.CONF(5) |
User Commands |
YAWS.CONF(5) |
/usr/local/etc/yaws/yaws.conf - Configuration file for the Yaws web server
Yaws is fast lightweight web server. It reads a configuration file called
yaws.conf to control its operations. The configuration contains two distinct
parts: a global part which affects all the virtual hosts and a server part
where options for each virtual host is supplied.
- logdir = [+]Directory
- All Yaws logs will be written to files in this directory. If specified
with +, Yaws will attempt to create the directory if it does not
exist. There are several different log files written by Yaws:
report.log - this is a text file that contains all
error logger printouts from Yaws.
<Host>.access - for each virtual host served by
Yaws, a file <Host>.access will be written that contains an access
log in NCSA combined/XLF/ELF log format. (See
http://www.w3.org/TR/WD-logfile.html for more details on Extended Log
File Format.)
<Host>.auth - for each virtual host served by
Yaws, a file <Host>.auth will be written which contains all http
auth related messages.
trace_<YYYYMMDD_hhmmss> - Trace files are written
in this subdirectory, suffixed by the creation date.
trace.<Pid>.http - this file contains the
HTTP trace if that is enabled, where <Pid> is the process id handling
the TCP connection.
trace.<Pid>.traffic - this file contains the traffic
trace if that is enabled, where <Pid> is the process id handling the
TCP connection.
- Note that <Host>.access and <Host>.auth files will be used
only if the directive logger_mod is not set or set to yaws_log. The
default value for logdir is "."
- ebin_dir = Directory
- This directive adds Directory to the Erlang search path. It is possible to
have several of these commands in the configuration file. The default
value is "yaws_dir"/examples/ebin
- src_dir = Directory
- This directive defines a Directory as a source directory. Yaws will
compile all erlang modules found in this directory and all its
subdirectories. The compilation occurs when the configuration is loaded or
reloaded. The include_dir directives are used to search for
includes files. Multiple src_dir directives may be used. There is
no such directory configured by default.
- id = String
- It is possible to run multiple Yaws servers on the same machine. We use
the id of a Yaws server to control it using the different control commands
such as:
# /usr/local/bin/yaws --id foobar --stop
To stop the Yaws server with id "foobar". Each Yaws
server will write its internal data into a file called
$HOME/.yaws/yaws/ID where ID is the identity of the server. Yaws also
creates a file called $HOME/.yaws/yaws/ID/CTL which contains the port
number where the server is listening for control commands. The default
id is "default".
- server_signature = String
- This directive sets the "Server: " output header to the custom
value. The default value is "yaws/%VSN%, Yet Another Web
Server".
- include_dir = Directory
- This directive adds Directory to the path of directories where the Erlang
compiler searches for include files. We need to use this if we want to
include .hrl files in our Yaws Erlang code. It is possible to have several
of these commands in the configuration file. The default value is
"yaws_dir"/examples/include.
- max_num_cached_files = Integer
- Yaws will cache small files such as commonly accessed GIF images in RAM.
This directive sets a maximum number on the number of cached files. The
default value is 400.
- max_num_cached_bytes = Integer
- This directive controls the total amount of RAM which can maximally be
used for cached RAM files. The default value is 1000000, 1
megabyte.
- max_size_cached_file = Integer
- This directive sets a maximum size on the files that are RAM cached by
Yaws. The default value is 8000, 8 kBytes.
- cache_refresh_secs = Integer
- The RAM cache is used to serve pages that sit in the cache. An entry sits
in cache at most cache_refresh_secs number of seconds. The default is
30. This means that when the content is updated under the docroot,
that change doesn't show until 30 seconds have passed. While developing a
Yaws site, it may be convenient to set this value to 0. If the debug flag
(-d) is passed to the Yaws start script, this value is automatically set
to 0.
- trace = false | traffic | http
- This enables traffic or http tracing. Tracing is also possible to enable
with a command line flag to Yaws. Default is false.
- auth_log = true | false
- Deprecated and ignored. Now, this target must be set in server
part.
- max_connections = nolimit | Integer
- Set this value to control the maximum number of connections from HTTP
clients into the server. This is implemented by closing the last socket if
the limit threshold is reached.
- keepalive_maxuses = nolimit | Integer
- Normally, Yaws does not restrict the number of times a connection is kept
alive using keepalive. Setting this parameter to an integer X will ensure
that connections are closed once they have been used X times. This can be
a useful to guard against long running connections collecting too much
garbage in the Erlang VM.
- process_options = undefined | Proplist
- Set process spawn options for client acceptor processes. Options must be
specified as a quoted string of either the atom undefined or as a
proplist of valid process options. The supported options are
fullsweep_after, min_heap_size, and
min_bin_vheap_size, each taking an associated integer value. Other
process options are ignored. The proplist may also be empty. See
erlang:spawn_opt/4 for details on these options.
- large_file_chunk_size = Integer
- Set the chunk size used by Yaws to send large files. The default value is
10240.
- large_file_sendfile = erlang | disable
- Set the version of sendfile method to use to send large files:
erlang - use file:sendfile/5.
disable - use gen_tcp:send/2.
The default value is erlang.
- acceptor_pool_size = Integer
- Set the size of the pool of cached acceptor processes. The specified value
must be greater than or equal to 0. The default value is 8.
Specifying a value of 0 effectively disables the process pool.
- log_wrap_size = Integer
- The logs written by Yaws are all wrap logs, the default value at the size
where they wrap around and the original gets renamed to File.old is
1000000, 1 megabyte. This value can be changed.
If we set the value to 0 the logs will never wrap. If we want to use Yaws in
combination with a more traditional log wrapper such as logrotate, set the
size to 0 and Yaws will reopen the logfiles once they have be
renamed/removed.
- log_resolve_hostname = true | false
- By default the client host IP is not resolved in the access logs.
- fail_on_bind_err = true | false
- Fail completely or not if Yaws fails to bind a listen socket Default is
true.
- enable_soap = true | false
- If true, a soap server will be started at startup of Yaws. Default is
false.
- soap_srv_mods = ListOfModuleSetting
- If enable_soap is true, a startup Yaws will invoke
yaws_soap_srv:setup() to setup modules set here. ModuleSetting is
either a triad like <Mod, HandlerFunc, WsdlFile> or a
quadruple form like <Mod, HandlerFunc, WsdlFile,
Prefix> which specifies the prefix. A prefix will be
used as argument of yaws_soap_lib:initModel() and then be used as a
XML namespace prefix. Note, the WsdlFile here should be an
absolute-path file in local file systems.
For example, we can specify
soap_srv_mods=<Mod1, Handler, Wsdl1> <Mod2, Handler, Wsdl2, Prefix> ...
- php_exe_path = Path
- this target is deprecated and useless. use 'php_handler' target in
server part instead.
The name of (and possibly path to) the php executable used to interpret php
scripts (if allowed). Default is php_exe_path = php-cgi.
- copy_error_log = true | false
- Enable or disable copying of the error log. When we run in embedded mode,
there may very well be some other systems process that is responsible for
writing the errorlog to a file whereas when we run in normal standalone
mode, we typically want the Erlang errorlog written to a report.log file.
Default value is true.
- ysession_mod = Module
- Allows specifying a different Yaws session storage mechanism instead of an
ETS table. One of the drawbacks of the default yaws_session_server
implementation is that server side cookies are lost when the server
restarts. Specifying a different module here will pass all write/read
operations to this module (it must implement appropriate callbacks).
- ysession_cookiegen = Module
- Allows specifying a different Yaws session cookie generator than the
built-in default. Module is expected to provide a
new_cookie/0 function that returns a session cookie in the form of
a list. Such a cookie generator module must be careful to return a unique
cookie each time it's called.
- ysession_idle_timeout = Integer
- Controls Yaws session idle cleanup. If a server has been idle for
ysession_idle_timeout milliseconds, check all Yaws sessions and
remove any that have timed out. The default ysession_idle_timeout
value is 2*60*1000 (2 minutes).
- ysession_long_timeout = Integer
- Controls Yaws session periodic cleanup. Every ysession_long_timeout
milliseconds, check all Yaws sessions and remove any that have timed out.
The default ysession_long_timeout value is 60*60*1000 (1 hour).
- runmod = ModuleName
- At startup Yaws will invoke ModuleName:start() in a separate
process. It is possible to have several runmods. This is useful if we want
to reuse the Yaws startup shell script for our own application.
- pick_first_virthost_on_nomatch = true | false
- When Yaws gets a request, it extracts the Host header from the client
request to choose a virtual server amongst all servers with the same
IP/Port pair. This configuration parameter decides whether Yaws should
pick the first server (as defined in the yaws.conf file) if no name match
or not. If this is false and no Host header is present in the request,
Yaws returns a 400 Bad Request as required by the HTTP standard. In real
live hosting scenarios we typically want this to be false, whereas in
testing/development scenarios it may be convenient to set it to true.
Default is true.
- keepalive_timeout = TimeInMilliseconds | infinity
- If the HTTP session will be kept alive (i.e., not immediately closed) it
will close after keepalive_timeout milliseconds unless a new request is
received in that time. The default value is 30000. The value
infinity is legal but not recommended.
- subconfig = File
- Load specified config file. Absolute paths or relative ones to the
configuration location are allowed. Unix-style wildcard strings can be
used to include several files at once. See filelib:wildcard/1 for
details. Hidden files, starting by a dot, will be ignored. For example:
subconfig = /etc/yaws/global.conf
subconfig = /etc/yaws/vhosts/*.conf
Or, relatively to the configuration location:
subconfig = global.conf
subconfig = vhosts/*.conf
- subconfigdir = Directory
- Load all config files found in the specified directory. The given
Directory can be an absolute path or relative to the configuration
location. Hidden files, starting by a dot, will be ignored.
- x_forwarded_for_log_proxy_whitelist =
ListOfUpstreamProxyServerIps
- this target is deprecated and will be ignored.
- default_type = MimeType
- Defines the default MIME type to be used where Yaws cannot determine it by
its MIME types mappings. Default is text/plain.
- default_charset = Charset
- Defines the default charset to be added when a response content-type is
text/*. By default, no charset is added.
- mime_types_file = File
- Overrides the default mime.types file included with Yaws. This file
must use the following format:
# Lines beginning with a '#' or a whitespace are ignored
# blank lines are also ignored
<MIME type> <space separated file extensions>
The default file is located at
${PREFIX}/lib/yaws/priv/mime.types. You should not edit this file
because it may be replaced when you upgrade your server.
- add_types = ListOfTypes
- Specifies one or more mappings between MIME types and file extensions.
More than one extension can be assigned to a MIME type. ListOfTypes
is defined as follows:
add_types = <MimeType1, Ext> <MimeType2, Ext1 Ext2 ...> ...
The mappings defined using this directive will overload all
other definitions. If a file extension is defined several times, only
the last one is kept. Multiple add_types directives may be
used.
- add_charsets = ListOfCharsets
- Specifies one or more mappings between charsets and file extensions. More
than one extension can be assigned to a charset. ListOfCharsets is
defined as follows:
add_charsets = <Charset1, Ext> <Charset2, Ext1 Ext2 ...> ...
The mappings defined using this directive will overload all
other definitions. If a file extension is defined several times, only
the last one is kept. Multiple add_charsets directives may be
used.
- sni = disable | enable | strict
- Enables or disables the TLS SNI (Server Name Indication) support.
When disabled (or not supported), all virtual servers in the
same group (same IP/Port) must share the same SSL configuration,
especially the same SSL certificate. Only the HTTP Host header will be
considered to find the right virtual server.
When enabled, SSL configuration can be different from one
virtual server to another; each one can have its own SSL certificate. In
this case, if a client provides a SNI hostname, it will be used to find
the right virtual server. To accept the SNI information from the client,
the first virtual server -- the default one, see
pick_first_virthost_on_nomatch -- must include TLS as a
permitted protocol.
If the sni directive is set to enable, non-SNI
clients are allowed. For such clients, virtual servers are selected as
if Yaws did not have SNI support. If it is set to strict, SNI
hostname is mandatory to access a SSL virtual server. But in all cases,
when SNI support is enabled, if a client provides a SNI hostname, it
must match the HTTP Host header (which is mandatory too). Note
that the first virtual server (the default one) will be used for any
request where the provided SNI hostname doesn't match any of virtual
server names. So, it is important that the first virtual server have the
most restrictive access control, otherwise clients can access restricted
resources by sending a request for any unknown hostname. (This isn't
actually any different from using virtual servers without SNI support.)
If you're using self-signed certificates, be sure to also set the
depth configuration variable to 0 to avoid following certificate
chains.
The sni directive is a global one, so if you set it to
strict, non-SNI clients will be refused for all SSL
groups. See require_sni directive from the server part to
mitigate this requirement.
Default is disable.
Yaws can virthost several web servers on the same IP address as well as several
web servers on different IP addresses. This includes SSL servers.
Each virtual host is defined within a matching pair of
<server ServerName> and </server>. The ServerName
will be the name of the webserver.
The following directives are allowed inside a server
definition.
- port = Port
- This makes the server listen on Port. Default is 8000.
- listen = IpAddress
- This makes the server listen on IpAddress. When virthosting several
servers on the same ip/port address, if the browser doesn't send a Host:
field, Yaws will pick the first server specified in the config
file. If the specified IP address is 0.0.0.0 Yaws will listen on all local
IP addresses on the specified port. Default is 127.0.0.1. Multiple
listen directives may be used to specify several addresses to
listen on.
- listen_backlog = Integer
- This sets the TCP listen backlog for the server to define the maximum
length the queue of pending connections may grow to. The default is 1024.
- <listen_opts> ... </listen_opts>
- Defines extra options to be set on the listen socket and, by inheritance,
on accepted sockets. See inet:setopts/2 for details. Supported
options are:
buffer = Integer (default: same as
inet:setopts/2)
delay_send = true | false (default: same as
inet:setopts/2)
linger = Integer | false (default: same as
inet:setopts/2)
nodelay = true | false (default: same as
inet:setopts/2)
priority = Integer (default: same as
inet:setopts/2)
sndbuf = Integer (default: same as
inet:setopts/2)
recbuf = Integer (default: same as
inet:setopts/2)
send_timeout = Integer | infinity (default: same as
inet:setopts/2)
send_timeout_close = true | false (default: same as
inet:setopts/2)
- server_signature = String
- This directive sets the "Server: " output header to the custom
value and overloads the global one for this virtual server.
- subconfig = File
- Same as subconfig directive of the global part, but here files
should only contain directives allowed in the server part.
- subconfigdir = Directory
- Same as subconfigdir directive of the global part, but here files
should only contain directives allowed in server part.
- rhost = Host[:Port]
- This forces all local redirects issued by the server to go to Host. This
is useful when Yaws listens to a port which is different from the port
that the user connects to. For example, running Yaws as a non-privileged
user makes it impossible to listen to port 80, since that port can only be
opened by a privileged user. Instead Yaws listens to a high port number
port, 8000, and iptables are used to redirect traffic to port 80 to port
8000 (most NAT:ing firewalls will also do this for you).
- rmethod = http | https
- This forces all local redirects issued by the server to use this method.
This is useful when an SSL off-loader, or stunnel, is used in front of
Yaws.
- auth_log = true | false
- Enable or disable the auth log for this virtual server. Default is
true.
- access_log = true | false
- Setting this directive to false turns off traffic logging for this virtual
server. The default value is true.
- logger_mod = Module
- It is possible to set a special module that handles access and auth
logging. The default is to log all web server traffic to
<Host>.access and <Host>.auth files in the configured or
default logdir.
This module must implement the behaviour yaws_logger. Default value
is yaws_log.
The following functions should be exported:
Module:open_log(ServerName, Type, LogDir)
When Yaws is started, this function is called for this
virtual server. If the initialization is successful, the function must return
{true,State} and if an error occurred, it must return
false.
- Module:close_log(ServerName, Type, State)
This function is called for this virtual server when Yaws
is stopped.
- Module:wrap_log(ServerName, Type, State, LogWrapSize)
This function is used to rotate log files. It is
regularly called by Yaws and must return the possibly updated internal
NewState.
- Module:write_log(ServerName, Type, State, Infos)
When it needs to log a message, Yaws will call this
function. The parameter Infos is {Ip,Req,InHdrs,OutHdrs,Time} for an
access log and {Ip,Path,Item} for an auth log, where:
Ip - IP address of the accessing client (as a tuple).
Req - the HTTP method, URI path, and HTTP version of the
request (as a #http_request{} record).
InHdrs - the HTTP headers which were received from the WWW
client (as a #headers{} record).
OutHdrs - the HTTP headers sent to the WWW client (as a
#outh{} record)
Path - the URI path of the request (as a string).
Item - the result of an authentication request. May be
{ok,User}, 403 or {401,Realm}.
Time - The time taken to serve the request, in
microseconds.
- For all of these callbacks, ServerName is the virtual server's
name, Type is the atom access or auth and State is the
internal state of the logger.
- shaper = Module
- Defines a module to control access to this virtual server. Access can be
controlled based on the IP address of the client. It is also possible to
throttle HTTP requests based on the client's download rate. This module
must implement the behaviour yaws_shaper.
There is no such module configured by default.
- dir_listings = true | true_nozip | false
- Setting this directive to false disallows the automatic dir listing
feature of Yaws. A status code 403 Forbidden will be sent. Set to
true_nozip to avoid the auto-generated all.zip entries. Default is
false.
- extra_cgi_vars = .....
- Add additional CGI or FastCGI variables. For example:
<extra_cgi_vars dir='/path/to/some/scripts'>
var = val
...
</extra_cgi_vars>
- statistics = true | false
- Turns on/off statistics gathering for a virtual server. Default is
false.
- fcgi_app_server = Host:Port
- The hostname and TCP port number of a FastCGI application server. To
specify an IPv6 address, put it inside square brackets (ex:
"[::1]:9000"). The TCP port number is not optional. There is no
default value.
- fcgi_trace_protocol = true | false
- Enable or disable tracing of FastCGI protocol messages as info log
messages. Disabled by default.
- fcgi_log_app_error = true | false
- Enable or disable logging of application error messages (output to stderr
and non-zero exit value). Disabled by default.
- deflate = true | false
- Turns on or off deflate compression for a server. Default is false.
- <deflate> ... </deflate>
- This begins and ends the deflate compression configuration for this
server. The following items are allowed within a matching pair of
<deflate> and </deflate> delimiters.
min_compress_size = nolimit | Integer
Defines the smallest response size that will be
compressed. If nolimit is not used, the specified value must be strictly
positive. The default value is nolimit.
- compression_level = none | default | best_compression | best_speed |
0..9
Defines the compression level to be used. 0
(none), gives no compression at all, 1 (best_speed) gives best
speed and 9 (best_compression) gives best compression. The default
value is default.
- window_size = 9..15
Specifies the zlib compression window size. It should be
in the range 9 through 15. Larger values of this parameter result in better
compression at the expense of memory usage. The default value is
15.
- mem_level = 1..9
Specifies how much memory should be allocated for the
internal compression state. mem_level=1 uses minimum memory but is slow
and reduces compression ratio; mem_level=9 uses maximum memory for
optimal speed. The default value is 8.
- strategy = default | filtered | huffman_only
This parameter is used to tune the compression algorithm.
See zlib(3erl) for more details on the strategy parameter. The
default value is default.
- use_gzip_static = true | false
If true, Yaws will try to serve precompressed versions of
static files. It will look for precompressed files in the same location as
original files that end in ".gz". Only files that do not fit in the
cache are concerned. The default value is false.
- mime_types = ListOfTypes | defaults | all
Restricts the deflate compression to particular MIME
types. The special value all enable it for all types (It is a synonym
of `*/*'). MIME types into ListOfTypes must have the form
`type/subtype' or `type/*' (indicating all subtypes of that type). Here is an
example:
mime_types = default image/*
mime_types = application/xml application/xhtml+xml application/rss+xml
By default, the following MIME types are compressed (if
deflate is set to true): text/*, application/rtf,
application/msword, application/pdf, application/x-dvi,
application/javascript. Multiple mime_types directives can be
used.
- docroot = Directory ...
- This makes the server serve all its content from Directory.
It is possible to pass a space-separated list of directories as docroot. If
this is the case, the various directories will be searched in order for
the requested file. This also works with the ssi and yssi constructs where
the full list of directories will be searched for files to ssi/yssi
include. Multiple docroot directives can be used. You need at least one
valid docroot, invalid docroots are skipped with their associated auth
structures.
- auth_skip_docroot = true | false
- If true, the docroot will not be searched for .yaws_auth files.
This is useful when the docroot is quite large and the time to search it
is prohibitive when Yaws starts up. Defaults to false.
- partial_post_size = Integer | nolimit
- When a Yaws file receives large POSTs, the amount of data received in each
chunk is determined by this parameter. The default value is 10240.
Setting it to nolimit is potentially dangerous.
- dav = true | false
- Turns on the DAV protocol for this server. The dav support in Yaws is
highly limited. If dav is turned on, .yaws processing of .yaws pages is
turned off. Default is false. The socket read timeout is supplied
by the keepalive_timeout setting. If the read is not done within the
timeout, the POST will fail.
- tilde_expand = true|false
- If this value is set to false Yaws will never do tilde expansion. The
default is false. tilde_expansion is the mechanism whereby a URL on
the form http://www.foo.com/~username is changed into a request where the
docroot for that particular request is set to the directory
~username/public_html/.
- allowed_scripts = ListOfSuffixes
- The allowed script types for this server. Recognized are `yaws', `cgi',
`fcgi', `php'. Default is allowed_scripts = yaws php cgi fcgi.
Note: for fcgi scripts, the FastCGI application server is only
called if a local file with the .fcgi extension exists. However, the
contents of the local .fcgi file are ignored.
- tilde_allowed_scripts = ListOfSuffixes
- The allowed script types for this server when executing files in a users
public_html folder Recognized are `yaws', `cgi', `fcgi', `php'. Default is
tilde_allowed_scripts = i.e. empty
- index_files = ListOfResources
- This directive sets the list of resources to look for, when a directory is
requested by the client. If the last entry begins with a `/', and none of
the earlier resources are found, Yaws will perform a redirect to this uri.
Default is index_files = index.yaws index.html index.php.
- appmods = ListOfModuleNames
- If any of the names in ListOfModuleNames appear as components in the path
for a request, the path request parsing will terminate and that module
will be called. There is also an alternate syntax for specifying the
appmods if we don't want our internal erlang module names to be exposed in
the URL paths. We can specify
appmods = <Path1, Module1> <Path2, Modules2> ...
Assume for example that we have the URL
http://www.hyber.org/myapp/foo/bar/baz?user=joe while we have the module
foo defined as an appmod, the function foo:out(Arg) will be invoked
instead of searching the filesystems below the point foo.
The Arg argument will have the missing path part supplied in its
appmoddata field.
It is also possible to exclude certain directories from appmod
processing. This is particulaly interesting for '/' appmods. Here is an
example:
appmods = </, myapp exclude_paths icons js top/static>
The above configuration will invoke the 'myapp' erlang module
on everything except any file found in directories 'icons', 'js' and
'top/static' relative to the docroot.
- dispatchmod = DispatchModule
- Set DispatchModule as a server-specific request dispatching module.
Yaws expects DispatchModule to export a dispatch/1 function.
When it receives a request, Yaws passes an #arg{} record to the
dispatch module's dispatch/1 function, which returns one of the
following atom results:
done - this indicates the dispatch module handled
the request itself and already sent the response, and Yaws should resume
watching for new requests on the connection
closed - same as done but the DispatchModule
also closed the connection
continue - the dispatch module has decided not to handle
the request, and instead wants Yaws to perform its regular request
dispatching
- Note that when DispatchModule handles a request itself, Yaws does
not support tracing, increment statistics counters or allow traffic
shaping for that request. It does however still keep track of maximum
keepalive uses on the connection.
- errormod_404 = Module
- It is possible to set a special module that handles 404 Not Found
messages. The function Module:out404(Arg, GC, SC) will be invoked.
The arguments are
Arg - a #arg{} record
GC - a #gconf{} record (defined in yaws.hrl)
SC - a #sconf{} record (defined in yaws.hrl)
- The function can and must do the same things that a normal out/1
does.
- errormod_401 = Module
- It is possible to set a special module that handles 401 Unauthorized
messages. This can for example be used to display a login page instead.
The function Module:out401(Arg, Auth, Realm) will be invoked. The
arguments are
Arg - a #arg{} record
Auth - a #auth{} record
Realm - a string
- The function can and must do the same things that a normal out/1
does.
- errormod_crash = Module
- It is possible to set a special module that handles the HTML generation of
server crash messages. The default is to display the entire formatted
crash message in the browser. This is good for debugging but not in
production.
The function Module:crashmsg(Arg, SC, Str) will be called. The
Str is the real crash message formatted as a string.
The function must return, {content,MimeType,Cont} or {html,
Str} or {ehtml, Term}. That data will be shipped to the client.
- expires = ListOfExpires
- Controls the setting of the Expires HTTP header and the
max-age directive of the Cache-Control HTTP header in server
responses for specific MIME types. The expiration date can be set as
relative to either the time the source file was last modified; as the time
of the client access; or as always in order to empty the cache altogether.
ListOfExpires is defined as follows:
expires = <MimeType1, access+Seconds> <MimeType2, modify+Seconds> <MimeType3, always> ...
A MimeType can also have a wildcard as subtype or both as
subtype and type, like type/* or */*.
These HTTP headers are an instruction to the client about the
document's validity and persistence. If cached, the document may be
fetched from the cache rather than from the source until this time has
passed. After that, the cache copy is considered "expired" and
invalid, and a new copy must be obtained from the source. Here is an
example:
expires = <image/gif, access+2592000> <image/png, access+2592000>
expires = <image/jpeg, access+2592000> <text/css, access+2592000>
expires = <text/*, always>
and here is another:
expires = <*/*, always>
- arg_rewrite_mod = Module
- It is possible to install a module that rewrites all the Arg #arg{}
records at an early stage in the Yaws server. This can be used to do
various things such as checking a cookie, rewriting paths etc. An
arg_rewrite_mod must export an arg_rewrite/1 function taking and
returning an #arg{} record. If the function wants to return a response, it
must set the #arg.state field of its return value to an instance of the
#rewrite_response{} record.
The module yaws_vdir can be used in case you want to
serve static content that is not located in your docroot. See the
example at the bottom of this man page for how to use the opaque
+ vdir elements to instruct the yaws_vdir module what
paths to rewrite.
- start_mod = Module
- Defines a user provided callback module. At startup of the server,
Module:start/1 will be called. The #sconf{} record (defined in yaws.hrl)
will be used as the input argument. This makes it possible for a user
application to synchronize the startup with the Yaws server as well as
getting hold of user specific configuration data, see the explanation for
the <opaque> context.
- revproxy = Prefix Url [intercept_mod Module]
- Make Yaws a reverse proxy. Prefix is a path inside our own docroot
and Url argument is a URL pointing to a website we want to
"mount" under the Prefix path. This example:
revproxy = /tmp/foo http://yaws.hyber.org
makes the hyber website appear under /tmp/foo.
It is possible to have multiple reverse proxies inside the
same server.
You can optionally configure an interception module for each
reverse proxy, allowing your application to examine and modify requests
and HTTP headers as they pass through the proxy from client to backend
server and also examine and modify responses and HTTP headers as they
return from the backend server through the proxy to the client.
You specify an interception module by including the optional
intercept_mod keyword followed by Module, which should be
the name of your interception module.
An interception module is expected to export two functions:
rewrite_request/2 and rewrite_response/2. The two
arguments passed to rewrite_request/2 function are a
#http_request{} record and a #headers{} record, whereas
rewrite_response/2 function takes a #http_response{}
record and also a #headers{} record. You can find definitions for
these record types in the yaws_api.hrl header file. Each function
can examine each record instance and can either return each original
instance or can return a modified copy of each instance in its response.
The rewrite_request/2 function should return a tuple of the
following form:
{ok, #http_request{}, #headers{}}
and the rewrite_response/2 function should similarly
return a tuple of the following form:
{ok, #http_response{}, #headers{}}
A #headers{} record can easily be manipulated in an
interceptor using the functions listed below:
yaws_api:set_header/2, yaws_api:set_header/3
yaws_api:get_header/2, yaws_api:get_header/3
yaws_api:delete_header/2
Any failures in your interception module's functions will
result in HTTP status code 500, indicating an internal server error.
- fwdproxy = true|false
- Make Yaws a forward proxy. By enabling this option you can use Yaws as a
proxy for outgoing web traffic, typically by configuring the proxy
settings in a web-browser to explicitly target Yaws as its proxy server.
- servername = Name
- If we're virthosting several servers and want to force a server to match
specific Host: headers we can do this with the "servername"
directive. This name doesn't necessarily have to be the same as the the
name inside <server Name> in certain NAT scenarios. Rarely used
feature.
- serveralias = ListOfNames
-
This directive sets the alternate names for a virtual host. A
server alias may contain wildcards:
'*' matches any sequence of zero or more characters
'?' matches one character unless that character is a period ('.')
- Multiple serveralias directives may be used. Here is an example:
<server server.domain.com>
serveralias = server server2.domain.com server2
serveralias = *.server.domain.com *.server?.domain.com
...
</server>
- php_handler = <Type, Spec>
- Set handler to interpret .php files. It can be one of the following
definitions:
php_handler = <cgi, Filename> - The name of (and
possibly path to) the php executable used to interpret php scripts (if
allowed).
php_handler = <fcgi, Host:Port> - Use the
specified fastcgi server to interpret .php files (if allowed).
Yaws does not start the PHP interpreter in fastcgi mode
for you. To run PHP in fastcgi mode, call it with the -b option. For example:
php5-cgi -b '127.0.0.1:54321'
This starts a php5 in fastcgi mode listening on the local network
interface. To make use of this PHP server from Yaws, specify:
php_handler = <fcgi, 127.0.0.1:54321>
If you need to specify an IPv6 address, use square brackets:
php_handler = <fcgi, [::1]:54321>
The PHP interpreter needs read access to the files it is to serve.
Thus, if you run it in a different security context than Yaws itself, make
sure it has access to the .php files.
Please note that anyone who is able to connect to the php fastcgi server
directly can use it to read any file to which it has read access. You should
consider this when setting up a system with several mutually untrusted
instances of php.
- php_handler = <extern, Module:Function |
Node:Module:Function> - Use an external handler, possibly on
another node, to interpret .php files (if allowed).
To interpret a .php file, the function
Module:Function(Arg) will be invoked (Evaluated inside a rpc call if a
Node is specified), where Arg is an #arg{} record.
The function must do the same things that a normal out/1 does.
- Default value is <cgi, "/usr/bin/php-cgi">.
- phpfcgi = Host:Port
- this target is deprecated. use 'php_handler' target in server part
instead.
Using this directive is the same as: php_handler = <fcgi, Host:Port>.
- default_type = MimeType
- Overloads the global default_type value for this virtual
server.
- default_charset = Charset
- Overloads the global default_charset value for this virtual server.
- mime_types_file = File
- Overloads the global mime_type_file value for this virtual server.
Mappings defined in File will not overload those defined by
add_types directives in the global part.
- add_types = ListOfTypes
- Overloads the global add_types values for this virtual server. If a
mapping is defined in the global part and redefined in a server part using
this directive, then it is replaced. Else it is kept.
- add_charsets = ListOfCharsets
- Overloads the global add_charsets values for this virtual server.
If a mapping is defined in the global part and redefined in a server part
using this directive, then it is replaced. Else it is kept.
- nslookup_pref = [inet | inet6]
- For fcgi servers and revproxy URLs, define the name resolution preference.
For example, to perform only IPv4 name resolution, use [inet]. To do both
IPv4 and IPv6 but try IPv6 first, use [inet6, inet]. Default value is
[inet].
- <ssl> ... </ssl>
-
This begins and ends an SSL configuration for this server.
It's possible to virthost several SSL servers on the same IP/Port. If
SNI support is disabled or not supported, they must share the same
certificate configuration. In this situation, it is complicated to
virthost several SSL servers on the same IP/Port since the certificate
is typically bound to a domainname in the common name part of the
certificate. One solution to this problem is to have a certificate with
multiple subjectAltNames. If SNI support is enabled, SSL servers on the
same IP/Port can have their own SSL configuration with a different SSL
certificate for each one. See the global sni directive.
The SNI support was introduced in the SSL application in
Erlang/OTP 18.0. It is an extension to the TLS protocol (RFC 4366),
which allows the client to include the requested hostname in the first
message of its SSL handshake.
See also
http://wiki.cacert.org/VhostTaskForce#Interoperability_Test for browser
compatibility.
keyfile = File
Specifies which file contains the private key for the
certificate. If not specified then the certificate file will be used.
- certfile = File
Specifies which file contains the certificate for the
server.
- cacertfile = File
A file containing trusted certificates to use during
client authentication and to use when attempting to build the server
certificate chain. The list is also used in the list of acceptable client CAs
passed to the client when a certificate is requested.
- dhfile = File
A file containing PEM-encoded Diffie-Hellman parameters
to be used by the server if a cipher suite using Diffie-Hellman key exchange
is negotiated. If not specified, default parameters are used.
- verify = verify_none | verify_peer
Specifies the level of verification the server does on
client certs. Setting verify_none means that the x509 validation will
be skipped (no certificate request is sent to the client), verify_peer
means that a certificate request is sent to the client (x509 validation is
performed.
You might want to use fail_if_no_peer_cert in combination
with verify_peer.
- fail_if_no_peer_cert = true | false
If verify is set to verify_peer and set to
true the connection will fail if the client does not send a certificate
(i.e. an empty certificate). If set to false the server will fail only
if an invalid certificate is supplied (an empty certificate is considered
valid).
- depth = Int
Specifies the depth of certificate chains the server is
prepared to follow when verifying client certs. For the OTP new SSL
implementation it is also used to specify how far the server (Yaws in our
case) shall follow the SSL certificates we present to the clients. Hence,
using self-signed certs, we typically need to set this to 0.
- password = String
If the private key is encrypted on disc, this password is
the 3DES key to decrypt it.
- ciphers = String
This string specifies the SSL cipher string. The syntax
of the SSL cipher string is a 4-tuple representation of the map returned by
ssl:cipher_suites/2,3: {#{key_exchange}, #{cipher}, #{mac}, #{prf}}.
ciphers = "[{dhe_rsa,aes_256_cbc,sha,default_prf}, \
{dhe_dss,aes_256_cbc,sha,default_prf}]"
In older versions of Yaws, a cipher tuple lacked the #{prf}
element. When Yaws reads a cipher of the old format from configuration, it
attempts to convert it to a 4-tuple by adding default_prf for the
#{prf} element. Be aware that this may not work for all ciphers; if
it fails, manual intervention is needed to properly configure the ciphers in
the new format.
- eccs = String
This string specifies the supported Elliptic Curve
Cryptography (ECC). It must be a subset of ssl:eccs(). For PCI DSS
compliance (which is the main reason why you would want to change this), set
it on a single line to:
eccs = "[sect571r1, sect571k1, secp521r1, brainpoolP512r1, \
sect409k1, sect409r1, brainpoolP384r1, secp384r1, \
sect283k1, sect283r1, brainpoolP256r1, secp256k1, \
secp256r1, sect239k1, xsect233k1, sect233r1, \
secp224k1, secp224r1]"
- secure_renegotiate = true | false
Specifies whether to reject renegotiation attempt that
does not live up to RFC 5746. By default secure_renegotiate is set to
false i.e. secure renegotiation will be used if possible but it will fallback
to unsecure renegotiation if the peer does not support RFC 5746.
- client_renegotiation = true | false
Enables or disables the Erlang/OTP SSL application client
renegotiation option. Defaults to true. See the ssl manual page at
http://www.erlang.org/doc/man/ssl.html for more details.
- honor_cipher_order = true | false
If true (the default), use the server's preference for
cipher selection. If false, use the client's preference.
- protocol_version = ProtocolList
Specifies the list of SSL protocols that will be
supported. If not set, defaults to all protocols supported by the erlang
ssl application. For example, to support only TLS versions 1.3, 1.2,
1.1, and 1:
protocol_version = tlsv1.3, tlsv1.2, tlsv1.1, tlsv1
- require_sni = true | false
If true,the server will reject non-SNI clients and
clients providing an unknown SNI hostname (this last remark is only relevant
for the first virtual server of a SSL group). This directive is ignored if SNI
support is disabled (or not supported).
Default is false.
- <redirect> ... </redirect>
- Defines a redirect mapping. The following items are allowed within a
matching pair of <redirect> and </redirect> delimiters.
We can have a series of redirect rules in one of the formats
below:
Path = URL
Path = code
Path = code URL
Path must be an url-decoded path beginning with a
slash. URL may be either a relative URL (a path beginning with a
slash), or an absolute URL. In the first case, the
scheme:hostname:port of the current server will be added. All
accesses to Path will be redirected to URL/Path (or
scheme:hostname:port/URL/Path if URL is relative).
URL must be url-encoded. Note that the original path is appended
to the redirected URL.
For example, assume we have the following redirect
configuration:
<redirect>
/foo = http://www.mysite.org/zapp
/bar = /tomato.html
</redirect>
Assuming this config resides on a site called http://abc.com,
we have the following redirects:
http://abc.com/foo -> http://www.mysite.org/zapp/foo
http://abc.com/foo/test -> http://www.mysite.org/zapp/foo/test
http://abc.com/bar -> http://abc.com/tomato.html/bar
http://abc.com/bar/x/y/z -> http://abc.com/tomato.html/bar/x/y/z
By default, Yaws will perform a 302 redirect. The HTTP status
code can be changed using the code parameter. Note that the
status code must be known by Yaws.
- •
- For 3xx status codes, the URL parameter must be present and will be
used to build the new location.
- •
- For other status codes (1xx, 2xx, 4xx and 5xx), it can be omitted. In the
absence of URL, Yaws will return a generic response with the
specified status code.
- •
- Otherwise, the URL parameter must be a relative URL and will be
used to customize the response.
Sometimes we do not want to have the original path
appended to the redirected path. To get that behaviour we specify the config
with '==' instead of '='.
<redirect>
/foo == http://www.mysite.org/zapp
/bar = /tomato.html
</redirect>
Now a request for http://abc.com/foo/x/y/z simply gets redirected
to http://www.mysite.org/zapp. This is typically used when we simply want a
static redirect at some place in the docroot.
When we specify a relative URL as the target for the redirect, the
redirect will be to the current http(s) server.
- <auth> ... </auth>
- Defines an auth structure. The following items are allowed within a
matching pair of <auth> and </auth> delimiters.
docroot = Docroot
If a docroot is defined, this auth structure will be
tested only for requests in the specified docroot. No docroot configured means
all docroots. If two auth structures are defined, one with a docroot and one
with no docroot, the first of both overrides the second one for requests in
the configured docroot.
- dir = Dir
Makes Dir to be controlled by WWW-authenticate headers.
In order for a user to have access to WWW-Authenticate controlled directory,
the user must supply a password. The Dir must be specified relative to the
docroot. Multiple dir can be used. If no dir is set, the default value,
"/", will be used.
- realm = Realm
In the directory defined here, the WWW-Authenticate Realm
is set to this value.
- authmod = AuthMod
If an auth module is defined then AuthMod:auth(Arg, Auth)
will be called for all access to the directory. The auth/2 function should
return one of: true, false, {false, Realm}, {appmod, Mod}. If {appmod, Mod} is
returned then a call to Mod:out401(Arg, Auth, Realm) will be used to deliver
the content. If errormod_401 is defined, the call to Mod will be ignored.
(Mod:out(Arg) is deprecated).
This can, for example, be used to implement cookie authentication.
The auth() callback would check if a valid cookie header is present, if not
it would return {appmod, ?MODULE} and the out401/1 function in the same
module would return {redirect_local, "/login.html"}.
- user = User:Password | "User:{Algo}Hash" |
"User:{Algo}$Salt$Hash"
Inside this directory, the user User has access if
the user supplies the password Password in the popup dialogue presented
by the browser. It is also possible to provide a hashed password, encoded in
base64. In that case, the algorithm used to hash the password must be set.
Algo must be one of the following algorithms:
md5 | ripemd160 | sha | sha224 | sha256 | sha384 | sha512
It is possible to use salted hashes. If so, the Salt must
be provided, encoded in base64. We can specify multiple users inside a
single <auth> </auth> pair.
- pam service = pam-service
If the item pam is part of the auth structure,
Yaws will also try to authenticate the user using "pam" using the
pam service indicated. Usual services are typically found under
/etc/pam.d. Usual values are "system-auth" etc.
pam authentication is performed by an Erlang port program which is
typically installed as suid root by the Yaws install script.
- allow = all | ListOfHost
The allow directive affects which hosts can access
an area of the server. Access can be controlled by IP address or IP address
range. If all is specified, then all hosts are allowed access, subject to the
configuration of the deny and order directives. To allow only
particular hosts or groups of hosts to access the server, the host can be
specified in any of the following formats:
A full IP address
allow = 10.1.2.3
allow = 192.168.1.104, 192.168.1.205
A network/netmask pair
allow = 10.1.0.0/255.255.0.0
A network/nnn CIDR specification
allow = 10.1.0.0/16
- deny = all | ListOfHost
This directive allows access to the server to be
restricted based on IP address. The arguments for the deny directive
are identical to the arguments for the allow directive.
- order = Ordering
The order directive, along with allow and
deny directives, controls a three-pass access control system. The first
pass processes either all allow or all deny directives, as
specified by the order directive. The second pass parses the rest of
the directives ( deny or allow). The third pass applies to all
requests which do not match either of the first two.
Ordering is one of (Default value is deny,allow):
- allow,deny
- First, all allow directives are evaluated; at least one must match,
or the request is rejected. Next, deny directives are evaluated. If
any matches, the request is rejected. Last, any requests which do not
match an allow or a deny directive are denied by default.
- deny,allow
- First, all deny directives are evaluated; if any matched, the
request is denied unless it also matches an allow directive. Any
requests which do not match any allow or deny directives are
permitted.
- <opaque> ... </opaque>
- This begins and ends an opaque configuration context for this server,
where 'Key = Value' directives can be specified. These directives are
ignored by Yaws (hence the name opaque), but can be accessed as a list of
tuples {Key,Value} stored in the #sconf.opaque record entry. See
also the description of the start_mod directive.
This mechanism can be used to pass data from a surrounding
application into the individual .yaws pages.
- strip_undefined_bindings = true | false
- Change the behavior of the {bindings, [...]} directive to treat all
undefined keys found in returned out/1 content as if they were
defined with an empty value, resulting in all undefined bindings
effectively being stripped out of returned content. By default,
strip_undefined_bindings is false, which means undefined bindings
are ignored and their text is left as is in returned content.
This setting applies only for out/1 content, not to
static pages or other returned content.
- <extra_response_headers> ...
</extra_response_headers>
- This begins and ends a configuration context for extra response headers
for this server, where directives for adding headers, erasing headers, and
modules for handling extra response headers can be specified as follows:
- add Hdr = Value
- Add Hdr with value Value to the response, but only if the
response status code is one of these values:
200 OK
201 Created
204 No Content
206 Partial Content
301 Moved Permanently
302 Found
303 See Other
304 Not Modified
307 Temporary Redirect
308 Permanent Redirect
For any other status code, Hdr is not added.
- always add Hdr = Value
- Unconditionally add Hdr with value Value to the response,
regardless of the response status code.
- erase Hdr
- Remove Hdr and its associated value from the response.
- extramod = Module
- Specifies a module to call to process extra response headers. Yaws calls
Module:extra_response_headers/3 passing the following arguments:
- Response headers
- An Erlang map holding the response headers with header name strings as
keys and strings as header values
- Arg
- An #arg{} record representing the request. In cases where an
extramod module is called following the invocation of an appmod,
the #arg{} record field appmod_name indicates the name of
the appmod that serviced the request, allowing the extramod to
return extra HTTP headers appropriate for that appmod.
- {StatusCode,Version}
- A tuple where StatusCode is the numeric HTTP status code for the
response, and Version is a tuple specifying the HTTP version, e.g.
{1,1} for HTTP 1.1.
The Module:extra_response_headers/3 function should return
either the original header map or a modified map where headers have been
added, changed, or deleted. Added headers are not subject to the status code
restrictions for the add extra response header directive, but the
function can call
yaws_api:http_extra_response_headers_add_status_codes/0 to retrieve
the list of the status codes for which adding headers is normally
allowed.
For response headers that can have multiple settings, such as
Set-Cookie, multiple values can be specified in the extra response
header map by using a value of {multi, [Value]} where [Value]
is a list of one or more header values. The Set-Cookie header is a
standard special case for which Yaws converts a multi header into a
separate Set-Cookie header for each value; for other headers, Yaws converts
a multi header into a single HTTP header with a comma-separated
value.
Note that extra response headers do not apply to responses
returned directly by any DispatchModule.
- options_asterisk_methods = Methods
- Setting options_asterisk_methods to a comma-separated list of HTTP
Methods makes Yaws respond to an OPTIONS request that
specifies a literal * as the target with a 200 OK status and
an Allow header listing the specified Methods. If the
configuration does not explicitly specify options_asterisk_methods,
Yaws defaults to responding to OPTIONS * requests with a 200
OK status and an Allow header listing these HTTP methods:
GET, HEAD, POST, PUT, DELETE, OPTIONS
RFC 7231 section 4.3 lists the standard HTTP method names:
GET, HEAD, POST, PUT, DELETE, CONNECT, OPTIONS, TRACE
An options_asterisk_methods setting can include any of
these HTTP method names as well as PATCH. PATCH is not
mentioned in RFC 7231 but Yaws supports it. Yaws does not implement
CONNECT, but it supports it in options_asterisk_methods
because it's possible to implement support for it using a
dispatchmod.
If options_asterisk_methods is set to an empty value,
Yaws responds to OPTIONS * requests with status 400 Bad
Request.
The following example defines a single server on port 80.
logdir = /var/log/yaws
<server www.mydomain.org>
port = 80
listen = 192.168.128.31
docroot = /var/yaws/www
</server>
And this example shows a similar setup but two web servers on the
same IP address.
logdir = /var/log/yaws
<server www.mydomain.org>
port = 80
listen = 192.168.128.31
docroot = /var/yaws/www
</server>
<server www.funky.org>
port = 80
listen = 192.168.128.31
docroot = /var/yaws/www_funky_org
</server>
An example with www-authenticate and no access logging at all.
logdir = /var/log/yaws
<server www.mydomain.org>
port = 80
listen = 192.168.128.31
docroot = /var/yaws/www
access_log = false
<auth>
dir = secret/dir1
realm = foobar
user = jonny:verysecretpwd
user = benny:thequestion
user = ronny:havinganamethatendswithy
</auth>
</server>
An example specifying a user defined module to be called at
startup, as well as some user specific configuration.
<server www.funky.org>
port = 80
listen = 192.168.128.31
docroot = /var/yaws/www_funky_org
start_mod = btt
<opaque>
mydbdir = /tmp
mylogdir = /tmp/log
</opaque>
</server>
An example specifying the GSSAPI/SPNEGO module (authmod_gssapi) to
be used for authentication. This module requires egssapi version 0.1~pre2 or
later available at http://www.hem.za.org/egssapi/.
The Kerberos5 keytab is specified as 'keytab = File' directive in
opaque. This keytab should contain the keys of the HTTP service principal,
'HTTP/www.funky.org' in this example.
<server www.funky.org>
port = 80
listen = 192.168.128.31
docroot = /var/yaws/www_funky_org
start_mod = authmod_gssapi
<auth>
authmod = authmod_gssapi
dir = secret/dir1
</auth>
<opaque>
keytab = /etc/yaws/http.keytab
</opaque>
</server>
And finally a slightly more complex example with two servers on
the same IP, and one SSL server on a different IP.
When there are more than one server on the same IP, and they have
different names the server must be able to choose one of them if the client
doesn't send a Host: header. Yaws will choose the first one defined in the
conf file.
logdir = /var/log/yaws
max_num_cached_files = 8000
max_num_cached_bytes = 6000000
<server www.mydomain.org>
port = 80
listen = 192.168.128.31
docroot = /var/yaws/www
</server>
<server www.funky.org>
port = 80
listen = 192.168.128.31
docroot = /var/yaws/www_funky_org
</server>
<server www.funky.org>
port = 443
listen = 192.168.128.32
docroot = /var/yaws/www_funky_org
<ssl>
keyfile = /etc/funky.key
certfile = /etc/funky.cert
password = gazonk
</ssl>
</server>
Finally an example with virtual directories, vdirs.
<server server.domain>
port = 80
listen = 192.168.128.31
docroot = /var/yaws/www
arg_rewrite_mod = yaws_vdir
<opaque>
vdir = "/virtual1/ /usr/local/somewhere/notrelated/to/main/docroot"
vdir = "/myapp/ /some/other/path can include/spaces"
vdir = "/icons/ /usr/local/www/yaws/icons"
</opaque>
</server>
The first defined vdir can then be accessed at or under
http://server.domain/virtual1/ or http://server.domain/virtual1
Written by Claes Wikstrom
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