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.\" This file is part of Vmod-sql -*- nroff -*-
.\" Copyright (C) 2013 Sergey Poznyakoff
.\"
.\" Vmod-sql is free software; you can redistribute it and/or modify
.\" it under the terms of the GNU General Public License as published by
.\" the Free Software Foundation; either version 3, or (at your option)
.\" any later version.
.\"
.\" Vmod-sql is distributed in the hope that it will be useful,
.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
.\" GNU General Public License for more details.
.\"
.\" You should have received a copy of the GNU General Public License
.\" along with vmod-sql.  If not, see <http://www.gnu.org/licenses/>.
.TH VMOD-SQL 1 "October 19, 2013" "VMOD-SQL" "User Reference"
.SH NAME
vmod-sql \- SQL access for Varnish Cache
.SH SYNOPSIS
.B import sql;
.PP
.BI "INT sql.connect(STRING " dbtype ", STRING " params ");"
.PP
.BI "VOID sql.connect_init(STRING " dbtype ", STRING " params ");"
.PP
.BI "BOOL sql.query(INT " cd ", STRING " query ", STRING " params ");"
.PP
.BI "STRING sql.result(INT " cd ", INT " row ", INT " col ");"
.PP
.BI "INT sql.affected(INT " cd ");"
.PP
.BI "VOID sql.disconnect(INT " cd ");"
.PP
.BI "INT sql.ntuples(INT " cd ");"
.PP
.BI "INT sql.nfields(INT " cd ");"
.PP
.SH DESCRIPTION
.B Vmod-sql
provides functions for accessing SQL databases from
.B Varnish
configuration files.  It supports
.B MySQL
and
.BR PostgreSQL .
.PP
Connection to a database is initiated by
.B sql.connect
function, which returns integer value, called 
.BR "connection descriptor" " (" cd ).
This descriptor is passed as the first argument to the rest of
the module's functions to identify the connection.
.PP
The first argument to
.B sql.connect
specifies the database type to use.  The valid values are \fBmysql\fR
(for \fBMySQL\fR) and \fBpgsql\fR (for \fBPostgreSQL\fR).
.PP
The
.I params
argument configures the connection.  It is a list of
\fINAME\fB=\fIVALUE\fR assignments separated with semicolons.
The \fIVALUE\fR can be any sequence of characters, excepting white space
and semicolon.  If any of these have to appear in it, they must either
be escaped by prepending them with a backslash, or the entire
\fIVALUE\fR must be enclosed in a pair of (single or double) quotes.
The following \fBescape sequences\fR are allowed for use in \fIVALUE\fR:
.PP
.nf
.ta 8n 18n 42n
.ul
	Sequence	Expansion	ASCII
	\fB\\\\\fR	\fB\\\fR	134
	\fB\\"\fR	\fB"\fR	042
	\fB\\a\fR	audible bell	007	
	\fB\\b\fR	backspace	010
	\fB\\f\fR	form-feed	014
	\fB\\n\fR	new line	012
	\fB\\r\fR	charriage return	015
	\fB\\t\fR	horizontal tabulation	011
	\fB\\v\fR	vertical tabulation	013
.fi
.sp
Any other character following a backslash is output verbatim.
.sp
The valid parameters are:
.TP
\fBdebug\fR=\fIN\fR
Set debugging level.  \fIN\fR is a decimal number.
.TP
\fBserver\fR=\fIHOST\fR
Name or IP address of the database server to connect to.  If not
defined, localhost (\fB127.0.0.1\fR) is assumed.  For \fBMySQL\fR
databases, if \fIHOST\fR begins with a slash (\fB/\fR), its value is
taken to be the full pathname of the local UNIX socket to connect to.
.TP
\fBport\fR=\fINUM\fR
Port number on the \fBserver\fR to connect to.  Default is \fB3306\fR
for \fBMySQL\fR and \fB5432\fR for \fBPostgres\fR.
.TP
\fBdatabase=\fINAME\fR
The database name.
.TP
\fBconfig\fR=\fIFILE\fR
(\fBMySQL\fR-specific) Read credentials from the \fBMySQL\fR options
file \fIFILE\fR.
.TP
\fBgroup\fR=\fINAME\fR
(\fBMySQL\fR-specific) Read credentials from section \fINAME\fR of the
options file supplied with the \fBconfig\fR parameter.  Default
section name is \fBclient\fR.
.TP
\fBcacert\fR=\fIFILE\fR
Use secure connection to the database server via SSL.  The \fIFILE\fR
is a full pathname to the certificate authority file.
.TP
\fBoptions\fR=\fISTRING\fR
(\fBPostgres\fR-specific) Connection options.
.TP
\fBuser\fR=\fINAME\fR
Database user name.
.TP
\fBpassword\fR=\fISTRING\fR
Password to access the database.
.PP
Up to 16 connections can be opened simultaneously (see the
.B BUGS
section).
.PP
On error, the function returns -1.  On success, the returned 
descriptor will be the lowest-numbered descriptor not currently
open for any connection.
.PP
The function
.B sql.connect0
is equivalent to
.BR sql.connect ,
but succeeds only if the connection is assigned the descriptor
\fB0\fR.  This function is provided as a shortcut to use when only
one database connection is needed.
.PP
The function
.B sql.disconnect
closes an existing database connection identified by descriptor
.BR cd .
.PP
The function
.B sql.query
performs a database query given as its first argument.  The second
argument is a list of variable assignments separated with
semicolons, similarly to the \fIparams\fR argument described above.
Each assignment has the form \fINAME\fB=\fIVALUE\fR.
.PP
Before being executed, the query is expanded by replacing each
occurrence of \fB$\fINAME\fR construct (a \fBvariable reference\fR)
with the corresponding \fIVALUE\fR from the \fIparams\fR argument.
Similarly to the shell syntax, the variable reference can be written
as \fB${\fINAME\fB}\fR.  This latter form can be used in contexts
where the variable name is immediately followed by another letter, to
prevent it from being counted as a part of the name.
.PP
Each expanded reference is then escaped to prevent SQL injection.
.PP
The function returns \fBTRUE\fR on success.
.PP
The result of the most recently executed query can be examined
using the following functions:
.TP
.BI "INT sql.ntuples(INT " cd ");"
Returns the number of tuples (rows) returned by the query.
.TP
.BI "INT sql.nfields(INT " cd ");"
Returns the number of fields in each tuple returned by the query.
.TP
.BI "INT sql.affected(INT " cd ");"
If the most recent query updated the database, returns the number of
affected rows.
.PP
The values returned by the most recent query can be retrieved
using the
.B sql.result
function.  The desired value is identified by the row and column
number (both 0-based).
.PP
.SH EXAMPLES
The following \fBvcl\fR fragment can be used to keep a statistics
of visits for each URL:
.PP
.EX
vcl_init {
    sql.connect0("mysql", "config=/etc/db.cnf");
}

vcl_recv {
    if (sql.query(0,
                  {"UPDATE counter SET count=count+1
		    WHERE url='$url'"},
		   "url=" + req.url)) {
        sql.query(0,
                  "INSERT INTO counter values ('$url', 1)",
		  "url=" + req.url)
    }
}
.EE
.\" The MANCGI variable is set by man.cgi script on Ulysses.
.\" The download.inc file contains the default DOWNLOAD section
.\" for man-based doc pages.
.if "\V[MANCGI]"WEBDOC" \{\
.	ds package vmod-sql
.	ds version 1.0
.	so download.inc
\}
.SH "SEE ALSO"
.BR vmod-dbrw (3),
.BR vcl (7),
.BR varnishd (1).
.PP
.ie "\V[MANCGI]"WEBDOC" \{\
Complete documentation for
.B vmod-sql
in various formats is
.URL http://puszcza.gnu.org.ua/software/vmod-sql/manual.html "available online" .
\}
.el \{\
The full documentation for
.B vmod-sql
is maintained as a Texinfo
manual.  If the
.B info
program and
.B vmod-sql
module are properly installed at your site, the  command
.PP
.nf
.in +4
.B info vmod-sql
.in
.fi
.PP
should give you access to the complete manual.
\}
.SH BUGS
Maximum number of simultaneously opened connections is limited to 16.
To change this value, define \fBMAXCONN\fR when configuring the
package, e.g.:
.PP
.EX
./configure CPPFLAGS=-DMAXCONN=32
.EE
.PP
.SH AUTHORS
Sergey Poznyakoff
.SH "BUG REPORTS"
Report bugs to <gray@gnu.org>.
.SH COPYRIGHT
Copyright \(co 2013 Sergey Poznyakoff
.br
.na
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
.br
.ad
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
.\" Local variables:
.\" eval: (add-hook 'write-file-hooks 'time-stamp)
.\" time-stamp-start: ".TH [A-Z_][A-Z0-9_.-]* [0-9] \""
.\" time-stamp-format: "%:B %:d, %:y"
.\" time-stamp-end: "\""
.\" time-stamp-line-limit: 20
.\" end:

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