1 # Copyright 2002 Katipo Communications
3 # This file is part of Koha.
5 # Koha is free software; you can redistribute it and/or modify it under the
6 # terms of the GNU General Public License as published by the Free Software
7 # Foundation; either version 2 of the License, or (at your option) any later
10 # Koha is distributed in the hope that it will be useful, but WITHOUT ANY
11 # WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
12 # A PARTICULAR PURPOSE. See the GNU General Public License for more details.
14 # You should have received a copy of the GNU General Public License along with
15 # Koha; if not, write to the Free Software Foundation, Inc., 59 Temple Place,
16 # Suite 330, Boston, MA 02111-1307 USA
22 use vars qw($VERSION $AUTOLOAD),
26 $VERSION = do { my @v = '$Revision$' =~ /\d+/g;
27 shift(@v) . "." . join("_", map {sprintf "%03d", $_ } @v); };
31 C4::Context - Maintain and manipulate the context of a Koha script
37 use C4::Context("/path/to/koha.conf");
39 $config_value = C4::Context->config("config_variable");
40 $db_handle = C4::Context->dbh;
44 When a Koha script runs, it makes use of a certain number of things:
45 configuration settings in F</etc/koha.conf>, a connection to the Koha
46 database, and so forth. These things make up the I<context> in which
49 This module takes care of setting up the context for a script:
50 figuring out which configuration file to load, and loading it, opening
51 a connection to the right database, and so forth.
53 Most scripts will only use one context. They can simply have
59 Other scripts may need to use several contexts. For instance, if a
60 library has two databases, one for a certain collection, and the other
61 for everything else, it might be necessary for a script to use two
62 different contexts to search both databases. Such scripts should use
63 the C<&set_context> and C<&restore_context> functions, below.
65 By default, C4::Context reads the configuration from
66 F</etc/koha.conf>. This may be overridden by setting the C<$KOHA_CONF>
67 environment variable to the pathname of a configuration file to use.
75 # In addition to what is said in the POD above, a Context object is a
76 # reference-to-hash with the following fields:
79 # A reference-to-hash whose keys and values are the
80 # configuration variables and values specified in the config
81 # file (/etc/koha.conf).
83 # A handle to the appropriate database for this context.
85 # Used by &set_dbh and &restore_dbh to hold other database
86 # handles for this context.
88 use constant CONFIG_FNAME => "/etc/koha.conf";
89 # Default config file, if none is specified
91 $context = undef; # Initially, no context is set
92 @context_stack = (); # Initially, no saved contexts
95 # Reads the specified Koha config file. Returns a reference-to-hash
96 # whose keys are the configuration variables, and whose values are the
97 # configuration values (duh).
98 # Returns undef in case of error.
101 my $fname = shift; # Config file to read
102 my $retval; # Return value: ref-to-hash holding the
105 open (CONF, $fname) or return undef;
109 my $var; # Variable name
110 my $value; # Variable value
113 s/#.*//; # Strip comments
114 next if /^\s*$/; # Ignore blank lines
116 # Look for a line of the form
118 if (!/^\s*(\w+)\s*=\s*(.*?)\s*$/)
120 # FIXME - Complain about bogus line
124 # Found a variable assignment
125 # FIXME - Ought to complain is this line sets a
126 # variable that was already set.
129 $retval->{$var} = $value;
139 my $conf_fname = shift; # Config file name
142 # Create a new context from the given config file name, if
143 # any, then set it as the current context.
144 $context = __PACKAGE__->new($conf_fname);
145 $context->set_context;
150 $context = new C4::Context;
151 $context = new C4::Context("/path/to/koha.conf");
153 Allocates a new context. Initializes the context from the specified
154 file, which defaults to either the file given by the C<$KOHA_CONF>
155 environment variable, or F</etc/koha.conf>.
157 C<&new> does not set this context as the new default context; for
158 that, use C<&set_context>.
165 my $conf_fname = shift; # Config file to load
168 # Figure out a good config file to load if none was specified.
169 if (!defined($conf_fname))
171 # If the $KOHA_CONF environment variable is set, use
172 # that. Otherwise, use the built-in default.
173 $conf_fname = $ENV{"KOHA_CONF"} ||
177 $self->{"config_file"} = $conf_fname;
179 # Load the desired config file.
180 $self->{"config"} = &read_config_file($conf_fname);
181 return null if !defined($self->{"config"});
183 $self->{"dbh"} = undef; # Database handle
191 $context = new C4::Context;
192 $context->set_context();
194 set_context C4::Context $context;
197 restore_context C4::Context;
199 In some cases, it might be necessary for a script to use multiple
200 contexts. C<&set_context> saves the current context on a stack, then
201 sets the context to C<$context>, which will be used in future
202 operations. To restore the previous context, use C<&restore_context>.
209 my $new_context; # The context to set
211 # Figure out whether this is a class or instance method call.
213 # We're going to make the assumption that control got here
214 # through valid means, i.e., that the caller used an instance
215 # or class method call, and that control got here through the
216 # usual inheritance mechanisms. The caller can, of course,
217 # break this assumption by playing silly buggers, but that's
218 # harder to do than doing it properly, and harder to check
220 if (ref($self) eq "")
222 # Class method. The new context is the next argument.
223 $new_context = shift;
225 # Instance method. The new context is $self.
226 $new_context = $self;
229 # Save the old context, if any, on the stack
230 push @context_stack, $context if defined($context);
232 # Set the new context
233 $context = $new_context;
236 =item restore_context
240 Restores the context set by C<&set_context>.
248 if ($#context_stack < 0)
251 die "Context stack underflow";
254 # Pop the old context and set it.
255 $context = pop @context_stack;
257 # FIXME - Should this return something, like maybe the context
258 # that was current when this was called?
263 $value = C4::Config->config("config_variable");
265 $value = C4::Config->config_variable;
267 Returns the value of a variable specified in the configuration file
268 from which the current context was created.
270 The second form is more compact, but of course may conflict with
271 method names. If there is a configuration variable called "new", then
272 C<C4::Config-E<gt>new> will not return it.
279 my $var = shift; # The config variable to return
281 return undef if !defined($context->{"config"});
282 # Presumably $self->{config} might be
283 # undefined if the config file given to &new
284 # didn't exist, and the caller didn't bother
285 # to check the return value.
287 # Return the value of the requested config variable
288 return $context->{"config"}{$var};
292 # This implements C4::Config->foo, and simply returns
293 # C4::Config->config("foo"), as described in the documentation for
299 $AUTOLOAD =~ s/.*:://; # Chop off the package name,
300 # leaving only the function name.
301 return $self->config($AUTOLOAD);
305 # Internal helper function (not a method!). This creates a new
306 # database connection from the data given in the current context, and
310 my $db_driver = $context->{"config"}{"db_scheme"} || "mysql";
311 my $db_name = $context->{"config"}{"database"};
312 my $db_host = $context->{"config"}{"hostname"};
313 my $db_user = $context->{"config"}{"user"};
314 my $db_passwd = $context->{"config"}{"pass"};
316 return DBI->connect("DBI:$db_driver:$db_name:$db_host",
317 $db_user, $db_passwd);
322 $dbh = C4::Context->dbh;
324 Returns a database handle connected to the Koha database for the
325 current context. If no connection has yet been made, this method
326 creates one, and connects to the database.
328 This database handle is cached for future use: if you call
329 C<C4::Context-E<gt>dbh> twice, you will get the same handle both
330 times. If you need a second database handle, use C<&new_dbh> and
331 possibly C<&set_dbh>.
339 # If there's already a database handle, return it.
340 return $context->{"dbh"} if defined($context->{"dbh"});
342 # No database handle yet. Create one.
343 $context->{"dbh"} = &_new_dbh();
345 return $context->{"dbh"};
350 $dbh = C4::Context->new_dbh;
352 Creates a new connection to the Koha database for the current context,
353 and returns the database handle (a C<DBI::db> object).
355 The handle is not saved anywhere: this method is strictly a
356 convenience function; the point is that it knows which database to
357 connect to so that the caller doesn't have to know.
370 $my_dbh = C4::Connect->new_dbh;
371 C4::Connect->set_dbh($my_dbh);
373 C4::Connect->restore_dbh;
375 C<&set_dbh> and C<&restore_dbh> work in a manner analogous to
376 C<&set_context> and C<&restore_context>.
378 C<&set_dbh> saves the current database handle on a stack, then sets
379 the current database handle to C<$my_dbh>.
381 C<$my_dbh> is assumed to be a good database handle.
390 # Save the current database handle on the handle stack.
391 # We assume that $new_dbh is all good: if the caller wants to
392 # screw himself by passing an invalid handle, that's fine by
394 push @{$context->{"dbh_stack"}}, $context->{"dbh"};
395 $context->{"dbh"} = $new_dbh;
400 C4::Context->restore_dbh;
402 Restores the database handle saved by an earlier call to
403 C<C4::Context-E<gt>set_dbh>.
411 if ($#{$context->{"dbh_stack"}} < 0)
414 die "DBH stack underflow";
417 # Pop the old database handle and set it.
418 $context->{"dbh"} = pop @{$context->{"dbh_stack"}};
420 # FIXME - If it is determined that restore_context should
421 # return something, then this function should, too.
434 Specifies the configuration file to read.