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diff --git a/doc/gfs-virtual.xml b/doc/gfs-virtual.xml
index d307f62..1250331 100644
--- a/doc/gfs-virtual.xml
+++ b/doc/gfs-virtual.xml
@@ -1,6 +1,5 @@
-
@@ -10,6 +9,13 @@
the TCP/IP binding (port+listening adddress) and/or the virtual host.
+ A backend can be configured to execute in a particular working
+ directory. Or the YAZ frontend may perform CQL to RPN conversion, thus
+ allowing traditional Z39.50 backends to be offered as a SRW/SRU
+ service. SRW/SRU Explain information for a particular backend may also
+ be specified.
+
+
For the HTTP protocol, the virtual host is specified in the Host header.
For the Z39.50 protocol, the virtual host is specified as in the
Initialize Request in the OtherInfo, OID 1.2.840.10003.10.1000.81.1.
@@ -23,7 +29,7 @@
The YAZ frontend server uses XML to describe the backend
- configurations. Command-line option -f
+ configurations. Command-line option -f
specifies filename of the XML configuration.
@@ -33,44 +39,227 @@
The listen describes listener (transport end point),
- such as TCP/IP, Unix file socket or SSL server.
+ such as TCP/IP, Unix file socket or SSL server. Content for
+ a listener:
+
+ CDATA (required)
+
+
+ The CDATA for the listen element holds the
+ listener string, such as tcp:@:210,
+ tcp:server1:2100,
+ etc.
+
+
+
+ attribute id (optional)
+
+
+ identifier for this listener. This may be referred to from
+ server sections.
+
+
+
+
+
+
+ We expect more information to be added for the listen section in
+ a future version, such as CERT file for SSL servers.
+
+
- The server describes a server and includes sub
- elements which servers as parameters for this server.
+ The server describes a server and the parameters
+ for this server type. Content for a server:
+
+ attribute id (optional)
+
+
+ Identifier for this server. Currently not used for anything,
+ but it might be for logging purposes.
+
+
+
+
+ attribute listenref (optional)
+
+
+ Specifies one or more listeners for this server. Each server ID is
+ separated by a comma.
+ If this attribute is not given, the server is accessible from all
+ listeners. In order for the server to be used for real, however, the
+ virtual host must match if specified in the configuration.
+
+
+
+
+ element config (optional)
+
+
+ Specifies the server configuration. This is equivalent
+ to the config specified using command line option
+ -c.
+
+
+
+
+ element directory (optional)
+
+
+ Specifies a working directory for this backend server. If
+ specifid, the YAZ fronend changes current working directory
+ to this directory whenever a backend of this type is
+ started (backend handler bend_start), stopped (backend handler hand_stop)
+ and initialized (bend_init).
+
+
+
+
+ element host (optional)
+
+
+ Specifies the virtual host for this server. If this is specified
+ a client must specify this host string in
+ order to use this backend.
+
+
+
+
+ element cql2rpn (optional)
+
+
+ Specifies a filename that includes CQL to RPN conversion for this
+ backend server. See &reference-tools-cql-map;
+ If given, the backend server will only "see" a Type-1/RPN query.
+
+
+
+
+ element ccl2rpn (optional)
+
+
+ Specifies a filename that includes CCL to RPN conversion for this
+ backend server. See &reference-tools-ccl-qualifiers;
+ If given, the backend server will only "see" a Type-1/RPN query.
+
+
+
+
+ element stylesheet (optional)
+
+
+ Specifies the stylesheet reference to be part of SRU HTTP responses
+ when the client does not specify one. If neither this is given, nor
+ the client specifies one, no stylesheet reference is part of the
+ SRU HTTP response.
+
+
+
+
+ element docpath (optional)
+
+
+ Specifies a path for local file access using HTTP. All URLs with
+ a leading prefix (/ exluded) that matches the value of docpath
+ are used for file access. For example, if the server is to offer
+ access in directory xsl, the docpath would be
+ xsl and all URLs of the form
+ http://host/exl will result in a local file access.
+
+
+
+
+ element explain (optional)
+
+
+ Specifies SRW/SRU ZeeRex content for this server. Copied verbatim
+ to the client. As things are now, some of the Explain content
+ seeem redundant because host information, etc. is also stored
+ elsewhere.
+
+
+
+
+ element maximumrecordsize (optional)
+
+
+ Specifies maximum record size/message size, in bytes. This
+ value also servers as maximum size of incoming
+ packages (for Record Updates etc). It's the same value as that
+ given by the -k option.
+
+
+
+
+ element retrievalinfo (optional)
+
+
+ Enables the retrieval facility supporting conversions and
+ specifications of record formats/types.
+ See for
+ more information.
+
+
+
+
+
-
- The XML below configures a server with 2 listeners and 3 backend
- servers. The server listens on port 9900 and 9901 identified
- with references "public9900" and "public9901".
- [More to be written]
+
+ The XML below configures a server that accepts connections from
+ two ports, TCP/IP port 9900 and a local UNIX file socket.
+ We name the TCP/IP server public and the
+ other server internal.
+
- tcp:@:9900
- tcp:@:9901
-
- host1
+
+ tcp:@:9900
+ unix:/var/tmp/socket
+
+ server1.mydomain
/var/www/s1
- zebra1.cfg
+ config.cfg
-
- host2
+
+ server2.mydomain
/var/www/s2
- zebra2.cfg
-
-
- /var/www/s3
- zebra3.cfg
+ config.cfg
../etc/pqf.properties
-
- explain
+
+
+ server2.mydomain
+ 9900
+ a
+
+
+ /var/www/s3
+ config.cfg
+
]]>
+
+ There are three configured backend servers. The first two
+ servers, "server1" and "server2",
+ can be reached by both listener addresses.
+ "server1" is reached by all (two) since no
+ listenref attribute is specified.
+ "server2" is reached by the two listeners specified.
+ In order to distinguish between the two, a virtual host has
+ been specified for each of server in the host
+ elements.
+
+
+ For "server2" elements for CQL to RPN conversion
+ is supported and explain information has been added (a short one here
+ to keep the example small).
+
+
+ The third server, "server3" can only be reached
+ via listener "internal".