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;
41 $stopwordhash = C4::Context->stopwords;
45 When a Koha script runs, it makes use of a certain number of things:
46 configuration settings in F</etc/koha.conf>, a connection to the Koha
47 database, and so forth. These things make up the I<context> in which
50 This module takes care of setting up the context for a script:
51 figuring out which configuration file to load, and loading it, opening
52 a connection to the right database, and so forth.
54 Most scripts will only use one context. They can simply have
60 Other scripts may need to use several contexts. For instance, if a
61 library has two databases, one for a certain collection, and the other
62 for everything else, it might be necessary for a script to use two
63 different contexts to search both databases. Such scripts should use
64 the C<&set_context> and C<&restore_context> functions, below.
66 By default, C4::Context reads the configuration from
67 F</etc/koha.conf>. This may be overridden by setting the C<$KOHA_CONF>
68 environment variable to the pathname of a configuration file to use.
76 # In addition to what is said in the POD above, a Context object is a
77 # reference-to-hash with the following fields:
80 # A reference-to-hash whose keys and values are the
81 # configuration variables and values specified in the config
82 # file (/etc/koha.conf).
84 # A handle to the appropriate database for this context.
86 # Used by &set_dbh and &restore_dbh to hold other database
87 # handles for this context.
89 use constant CONFIG_FNAME => "/etc/koha.conf";
90 # Default config file, if none is specified
92 $context = undef; # Initially, no context is set
93 @context_stack = (); # Initially, no saved contexts
96 # Reads the specified Koha config file. Returns a reference-to-hash
97 # whose keys are the configuration variables, and whose values are the
98 # configuration values (duh).
99 # Returns undef in case of error.
102 my $fname = shift; # Config file to read
103 my $retval = {}; # Return value: ref-to-hash holding the
106 open (CONF, $fname) or return undef;
110 my $var; # Variable name
111 my $value; # Variable value
114 s/#.*//; # Strip comments
115 next if /^\s*$/; # Ignore blank lines
117 # Look for a line of the form
119 if (!/^\s*(\w+)\s*=\s*(.*?)\s*$/)
121 # FIXME - Complain about bogus line
125 # Found a variable assignment
126 # FIXME - Ought to complain is this line sets a
127 # variable that was already set.
130 $retval->{$var} = $value;
140 my $conf_fname = shift; # Config file name
143 # Create a new context from the given config file name, if
144 # any, then set it as the current context.
145 $context = new C4::Context($conf_fname);
146 return undef if !defined($context);
147 $context->set_context;
152 $context = new C4::Context;
153 $context = new C4::Context("/path/to/koha.conf");
155 Allocates a new context. Initializes the context from the specified
156 file, which defaults to either the file given by the C<$KOHA_CONF>
157 environment variable, or F</etc/koha.conf>.
159 C<&new> does not set this context as the new default context; for
160 that, use C<&set_context>.
167 my $conf_fname = shift; # Config file to load
170 # Figure out a good config file to load if none was specified.
171 if (!defined($conf_fname))
173 # If the $KOHA_CONF environment variable is set, use
174 # that. Otherwise, use the built-in default.
175 $conf_fname = $ENV{"KOHA_CONF"} ||
179 $self->{"config_file"} = $conf_fname;
181 # Load the desired config file.
182 $self->{"config"} = &read_config_file($conf_fname);
183 return undef if !defined($self->{"config"});
185 $self->{"dbh"} = undef; # Database handle
186 $self->{"stopwords"} = undef; # stopwords list
194 $context = new C4::Context;
195 $context->set_context();
197 set_context C4::Context $context;
200 restore_context C4::Context;
202 In some cases, it might be necessary for a script to use multiple
203 contexts. C<&set_context> saves the current context on a stack, then
204 sets the context to C<$context>, which will be used in future
205 operations. To restore the previous context, use C<&restore_context>.
212 my $new_context; # The context to set
214 # Figure out whether this is a class or instance method call.
216 # We're going to make the assumption that control got here
217 # through valid means, i.e., that the caller used an instance
218 # or class method call, and that control got here through the
219 # usual inheritance mechanisms. The caller can, of course,
220 # break this assumption by playing silly buggers, but that's
221 # harder to do than doing it properly, and harder to check
223 if (ref($self) eq "")
225 # Class method. The new context is the next argument.
226 $new_context = shift;
228 # Instance method. The new context is $self.
229 $new_context = $self;
232 # Save the old context, if any, on the stack
233 push @context_stack, $context if defined($context);
235 # Set the new context
236 $context = $new_context;
239 =item restore_context
243 Restores the context set by C<&set_context>.
251 if ($#context_stack < 0)
254 die "Context stack underflow";
257 # Pop the old context and set it.
258 $context = pop @context_stack;
260 # FIXME - Should this return something, like maybe the context
261 # that was current when this was called?
266 $value = C4::Context->config("config_variable");
268 $value = C4::Context->config_variable;
270 Returns the value of a variable specified in the configuration file
271 from which the current context was created.
273 The second form is more compact, but of course may conflict with
274 method names. If there is a configuration variable called "new", then
275 C<C4::Config-E<gt>new> will not return it.
282 my $var = shift; # The config variable to return
284 return undef if !defined($context->{"config"});
285 # Presumably $self->{config} might be
286 # undefined if the config file given to &new
287 # didn't exist, and the caller didn't bother
288 # to check the return value.
290 # Return the value of the requested config variable
291 return $context->{"config"}{$var};
296 $sys_preference = C4::Context->preference("some_variable");
298 Looks up the value of the given system preference in the
299 systempreferences table of the Koha database, and returns it. If the
300 variable is not set, or in case of error, returns the undefined value.
304 # FIXME - The preferences aren't likely to change over the lifetime of
305 # the script (and things might break if they did change), so perhaps
306 # this function should cache the results it finds.
310 my $var = shift; # The system preference to return
311 my $retval; # Return value
312 my $dbh = C4::Context->dbh; # Database handle
313 my $sth; # Database query handle
315 # Look up systempreferences.variable==$var
316 $retval = $dbh->selectrow_array(<<EOT);
318 FROM systempreferences
319 WHERE variable='$var'
326 # This implements C4::Config->foo, and simply returns
327 # C4::Context->config("foo"), as described in the documentation for
330 # FIXME - Perhaps this should be extended to check &config first, and
331 # then &preference if that fails. OTOH, AUTOLOAD could lead to crappy
332 # code, so it'd probably be best to delete it altogether so as not to
333 # encourage people to use it.
338 $AUTOLOAD =~ s/.*:://; # Chop off the package name,
339 # leaving only the function name.
340 return $self->config($AUTOLOAD);
344 # Internal helper function (not a method!). This creates a new
345 # database connection from the data given in the current context, and
349 my $db_driver = $context->{"config"}{"db_scheme"} || "mysql";
350 my $db_name = $context->{"config"}{"database"};
351 my $db_host = $context->{"config"}{"hostname"};
352 my $db_user = $context->{"config"}{"user"};
353 my $db_passwd = $context->{"config"}{"pass"};
355 return DBI->connect("DBI:$db_driver:$db_name:$db_host",
356 $db_user, $db_passwd);
361 $dbh = C4::Context->dbh;
363 Returns a database handle connected to the Koha database for the
364 current context. If no connection has yet been made, this method
365 creates one, and connects to the database.
367 This database handle is cached for future use: if you call
368 C<C4::Context-E<gt>dbh> twice, you will get the same handle both
369 times. If you need a second database handle, use C<&new_dbh> and
370 possibly C<&set_dbh>.
378 # If there's already a database handle, return it.
379 return $context->{"dbh"} if defined($context->{"dbh"});
381 # No database handle yet. Create one.
382 $context->{"dbh"} = &_new_dbh();
384 return $context->{"dbh"};
389 $dbh = C4::Context->new_dbh;
391 Creates a new connection to the Koha database for the current context,
392 and returns the database handle (a C<DBI::db> object).
394 The handle is not saved anywhere: this method is strictly a
395 convenience function; the point is that it knows which database to
396 connect to so that the caller doesn't have to know.
409 $my_dbh = C4::Connect->new_dbh;
410 C4::Connect->set_dbh($my_dbh);
412 C4::Connect->restore_dbh;
414 C<&set_dbh> and C<&restore_dbh> work in a manner analogous to
415 C<&set_context> and C<&restore_context>.
417 C<&set_dbh> saves the current database handle on a stack, then sets
418 the current database handle to C<$my_dbh>.
420 C<$my_dbh> is assumed to be a good database handle.
429 # Save the current database handle on the handle stack.
430 # We assume that $new_dbh is all good: if the caller wants to
431 # screw himself by passing an invalid handle, that's fine by
433 push @{$context->{"dbh_stack"}}, $context->{"dbh"};
434 $context->{"dbh"} = $new_dbh;
439 C4::Context->restore_dbh;
441 Restores the database handle saved by an earlier call to
442 C<C4::Context-E<gt>set_dbh>.
450 if ($#{$context->{"dbh_stack"}} < 0)
453 die "DBH stack underflow";
456 # Pop the old database handle and set it.
457 $context->{"dbh"} = pop @{$context->{"dbh_stack"}};
459 # FIXME - If it is determined that restore_context should
460 # return something, then this function should, too.
465 $dbh = C4::Context->stopwords;
467 Returns a hash with stopwords.
469 This hash is cached for future use: if you call
470 C<C4::Context-E<gt>stopwords> twice, you will get the same hash without real DB access
478 # If the hash already exists, return it.
479 return $context->{"stopwords"} if defined($context->{"stopwords"});
481 # No hash. Create one.
482 $context->{"stopwords"} = &_new_stopwords();
484 return $context->{"stopwords"};
488 # Internal helper function (not a method!). This creates a new
489 # hash with stopwords
492 my $dbh = C4::Context->dbh;
494 my $sth = $dbh->prepare("select word from stopwords");
496 while (my $stopword = $sth->fetchrow_array) {
498 $stopwordlist->{$stopword} = uc($stopword);
500 return $stopwordlist;
513 Specifies the configuration file to read.