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 $context = new C4::Context($conf_fname);
145 return undef if !defined($context);
146 $context->set_context;
151 $context = new C4::Context;
152 $context = new C4::Context("/path/to/koha.conf");
154 Allocates a new context. Initializes the context from the specified
155 file, which defaults to either the file given by the C<$KOHA_CONF>
156 environment variable, or F</etc/koha.conf>.
158 C<&new> does not set this context as the new default context; for
159 that, use C<&set_context>.
166 my $conf_fname = shift; # Config file to load
169 # Figure out a good config file to load if none was specified.
170 if (!defined($conf_fname))
172 # If the $KOHA_CONF environment variable is set, use
173 # that. Otherwise, use the built-in default.
174 $conf_fname = $ENV{"KOHA_CONF"} ||
178 $self->{"config_file"} = $conf_fname;
180 # Load the desired config file.
181 $self->{"config"} = &read_config_file($conf_fname);
182 return undef if !defined($self->{"config"});
184 $self->{"dbh"} = undef; # Database handle
192 $context = new C4::Context;
193 $context->set_context();
195 set_context C4::Context $context;
198 restore_context C4::Context;
200 In some cases, it might be necessary for a script to use multiple
201 contexts. C<&set_context> saves the current context on a stack, then
202 sets the context to C<$context>, which will be used in future
203 operations. To restore the previous context, use C<&restore_context>.
210 my $new_context; # The context to set
212 # Figure out whether this is a class or instance method call.
214 # We're going to make the assumption that control got here
215 # through valid means, i.e., that the caller used an instance
216 # or class method call, and that control got here through the
217 # usual inheritance mechanisms. The caller can, of course,
218 # break this assumption by playing silly buggers, but that's
219 # harder to do than doing it properly, and harder to check
221 if (ref($self) eq "")
223 # Class method. The new context is the next argument.
224 $new_context = shift;
226 # Instance method. The new context is $self.
227 $new_context = $self;
230 # Save the old context, if any, on the stack
231 push @context_stack, $context if defined($context);
233 # Set the new context
234 $context = $new_context;
237 =item restore_context
241 Restores the context set by C<&set_context>.
249 if ($#context_stack < 0)
252 die "Context stack underflow";
255 # Pop the old context and set it.
256 $context = pop @context_stack;
258 # FIXME - Should this return something, like maybe the context
259 # that was current when this was called?
264 $value = C4::Context->config("config_variable");
266 $value = C4::Context->config_variable;
268 Returns the value of a variable specified in the configuration file
269 from which the current context was created.
271 The second form is more compact, but of course may conflict with
272 method names. If there is a configuration variable called "new", then
273 C<C4::Config-E<gt>new> will not return it.
280 my $var = shift; # The config variable to return
282 return undef if !defined($context->{"config"});
283 # Presumably $self->{config} might be
284 # undefined if the config file given to &new
285 # didn't exist, and the caller didn't bother
286 # to check the return value.
288 # Return the value of the requested config variable
289 return $context->{"config"}{$var};
293 # This implements C4::Config->foo, and simply returns
294 # C4::Context->config("foo"), as described in the documentation for
300 $AUTOLOAD =~ s/.*:://; # Chop off the package name,
301 # leaving only the function name.
302 return $self->config($AUTOLOAD);
306 # Internal helper function (not a method!). This creates a new
307 # database connection from the data given in the current context, and
311 my $db_driver = $context->{"config"}{"db_scheme"} || "mysql";
312 my $db_name = $context->{"config"}{"database"};
313 my $db_host = $context->{"config"}{"hostname"};
314 my $db_user = $context->{"config"}{"user"};
315 my $db_passwd = $context->{"config"}{"pass"};
317 return DBI->connect("DBI:$db_driver:$db_name:$db_host",
318 $db_user, $db_passwd);
323 $dbh = C4::Context->dbh;
325 Returns a database handle connected to the Koha database for the
326 current context. If no connection has yet been made, this method
327 creates one, and connects to the database.
329 This database handle is cached for future use: if you call
330 C<C4::Context-E<gt>dbh> twice, you will get the same handle both
331 times. If you need a second database handle, use C<&new_dbh> and
332 possibly C<&set_dbh>.
340 # If there's already a database handle, return it.
341 return $context->{"dbh"} if defined($context->{"dbh"});
343 # No database handle yet. Create one.
344 $context->{"dbh"} = &_new_dbh();
346 return $context->{"dbh"};
351 $dbh = C4::Context->new_dbh;
353 Creates a new connection to the Koha database for the current context,
354 and returns the database handle (a C<DBI::db> object).
356 The handle is not saved anywhere: this method is strictly a
357 convenience function; the point is that it knows which database to
358 connect to so that the caller doesn't have to know.
371 $my_dbh = C4::Connect->new_dbh;
372 C4::Connect->set_dbh($my_dbh);
374 C4::Connect->restore_dbh;
376 C<&set_dbh> and C<&restore_dbh> work in a manner analogous to
377 C<&set_context> and C<&restore_context>.
379 C<&set_dbh> saves the current database handle on a stack, then sets
380 the current database handle to C<$my_dbh>.
382 C<$my_dbh> is assumed to be a good database handle.
391 # Save the current database handle on the handle stack.
392 # We assume that $new_dbh is all good: if the caller wants to
393 # screw himself by passing an invalid handle, that's fine by
395 push @{$context->{"dbh_stack"}}, $context->{"dbh"};
396 $context->{"dbh"} = $new_dbh;
401 C4::Context->restore_dbh;
403 Restores the database handle saved by an earlier call to
404 C<C4::Context-E<gt>set_dbh>.
412 if ($#{$context->{"dbh_stack"}} < 0)
415 die "DBH stack underflow";
418 # Pop the old database handle and set it.
419 $context->{"dbh"} = pop @{$context->{"dbh_stack"}};
421 # FIXME - If it is determined that restore_context should
422 # return something, then this function should, too.
435 Specifies the configuration file to read.