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1 : sh002i 455 ################################################################################
2 : sh002i 494 # WeBWorK mod_perl (c) 2000-2002 WeBWorK Project
3 : sh002i 455 # $Id$
4 :     ################################################################################
5 :    
6 : malsyned 313 package WeBWorK::ContentGenerator;
7 : malsyned 305
8 : sh002i 455 =head1 NAME
9 :    
10 :     WeBWorK::ContentGenerator - base class for modules that generate page content.
11 :    
12 :     =cut
13 :    
14 : malsyned 441 use strict;
15 :     use warnings;
16 : malsyned 323 use Apache::Constants qw(:common);
17 : sh002i 455 use CGI qw();
18 : sh002i 469 use URI::Escape;
19 : sh002i 526 use WeBWorK::DB::Auth;
20 : sh002i 476 use WeBWorK::Utils qw(readFile);
21 : sh002i 555 use Carp qw(cluck);
22 : malsyned 390
23 : sh002i 469 ################################################################################
24 :     # This is a very unruly file, so I'm going to use very large comments to divide
25 :     # it into logical sections.
26 :     ################################################################################
27 : malsyned 390
28 : sh002i 469 # new(Apache::Request, WeBWorK::CourseEnvironment) - create a new instance of a
29 :     # content generator. Usually only called by the dispatcher, although one might
30 :     # be able to use it for things like "sub-requests". Uh... uh... I have to think
31 :     # about that one. The dispatcher uses this idiom:
32 :     #
33 :     #
34 :     # WeBWorK::ContentGenerator::WHATEVER->new($r, $ce)->go(@whatever);
35 :     #
36 :     # and throws away the result ;)
37 :     #
38 : malsyned 305 sub new($$$) {
39 : malsyned 323 my $invocant = shift;
40 :     my $class = ref($invocant) || $invocant;
41 : malsyned 305 my $self = {};
42 :     ($self->{r}, $self->{courseEnvironment}) = @_;
43 :     bless $self, $class;
44 :     return $self;
45 :     }
46 :    
47 : sh002i 469 ################################################################################
48 :     # Invocation and template processing
49 :     ################################################################################
50 : malsyned 323
51 : sh002i 469 # go(@otherArguments) - render a page, using methods from the particular
52 :     # subclass of ContentGenerator. @otherArguments is passed to each method, so
53 :     # that the dispatcher can pass CG-specific data. The order of calls looks like
54 :     # this:
55 :     #
56 :     # * &pre_header_initialize - give subclasses a chance to do initialization
57 :     # necessary for generating the HTTP header.
58 :     # * &header - this class provides a standard HTTP header with Content-Type
59 :     # text/html. Subclasses are welcome to overload this for things like
60 :     # an image-creation content generator or a PDF generator.
61 :     # * &initialize - let subclasses do post-header initialization.
62 :     # * any "template escapes" defined in the system template and supported by
63 :     # the subclass. Generic implementations of &title and &body are provided.
64 :     #
65 :     sub go {
66 :     my $self = shift;
67 :     my $r = $self->{r};
68 :     my $courseEnvironment = $self->{courseEnvironment};
69 :    
70 :     $self->pre_header_initialize(@_) if $self->can("pre_header_initialize");
71 :     $self->header(@_);
72 :     return OK if $r->header_only;
73 : malsyned 313
74 : sh002i 469 $self->initialize(@_) if $self->can("initialize");
75 :     $self->template($courseEnvironment->{templates}->{system}, @_);
76 : malsyned 441
77 : sh002i 469 return OK;
78 :     }
79 :    
80 :     # template(STRING, @otherArguments) - parse a template, looking for escapes of
81 :     # the form <!--#NAME ARG1="FOO" ARG2="BAR"--> and calling a member function NAME
82 :     # (if available) for each NAME. The escapes are called like:
83 :     #
84 :     # $self->NAME(@otherArguments, \%escapeArguments)
85 :     #
86 :     # where @otherArguments originates in the dispatcher and %escapeArguments is
87 :     # parsed out of the escape itself (i.e. ARG1 => FOO, ARG2 => BAR)
88 :     #
89 :     sub template {
90 :     my ($self, $templateFile) = (shift, shift);
91 :     my $r = $self->{r};
92 :     my $courseEnvironment = $self->{courseEnvironment};
93 : malsyned 512 my @ifstack = (1); # Start off in printing mode
94 :     # say $ifstack[-1] to get the result of the last <#!--if-->
95 : sh002i 469
96 : sh002i 476 # so even though the variable $/ APPEARS to contain a newline,
97 :     # <TEMPLATE> is slurping the whole file into the first element of
98 :     # @template ONLY AFTER THE TRANSLATOR RUNS. WTF!!!
99 :     #
100 :     #open(TEMPLATE, $templateFile) or die "Couldn't open template $templateFile";
101 :     #my @template = <TEMPLATE>;
102 :     #close TEMPLATE;
103 :     #
104 :     # Let's try something else instead:
105 :     my @template = split /\n/, readFile($templateFile);
106 :    
107 : sh002i 469 foreach my $line (@template) {
108 :     # This is incremental regex processing.
109 :     # the /c is so that pos($line) doesn't die when the regex fails.
110 :     while ($line =~ m/\G(.*?)<!--#(\w*)((?:\s+.*?)?)-->/gc) {
111 :     my ($before, $function, $raw_args) = ($1, $2, $3);
112 : sh002i 555 my @args = ($raw_args =~ /\S/) ? cook_args($raw_args) : ();
113 :    
114 : malsyned 512 if ($ifstack[-1]) {
115 :     print $before;
116 :     }
117 : sh002i 555
118 : sh002i 558 if ($function eq "if") {
119 : malsyned 748 # a predicate can only be true if everything else on the ifstack is already true, for ANDing
120 :     push @ifstack, ($self->$function(@_, [@args]) && $ifstack[-1]);
121 : sh002i 558 } elsif ($function eq "else" and @ifstack > 1) {
122 :     $ifstack[-1] = not $ifstack[-1];
123 :     } elsif ($function eq "endif" and @ifstack > 1) {
124 :     pop @ifstack;
125 :     } elsif ($ifstack[-1]) {
126 : sh002i 562 if ($self->can($function)) {
127 :     print $self->$function(@_, {@args});
128 :     }
129 : sh002i 476 }
130 : malsyned 313 }
131 : sh002i 469
132 : malsyned 512 if ($ifstack[-1]) {
133 : sh002i 562 print substr($line, (defined pos $line) ? pos $line : 0), "\n";
134 : malsyned 512 }
135 : malsyned 313 }
136 : sh002i 469 }
137 :    
138 :     # cook_args(STRING) - parses a string of the form ARG1="FOO" ARG2="BAR". Returns
139 : malsyned 512 # a list which pairs into key/values and fits nicely in {}s.
140 : sh002i 469 #
141 :     sub cook_args($) {
142 :     my ($raw_args) = @_;
143 : malsyned 512 my @args = ();
144 : malsyned 353
145 : malsyned 508 # Boy I love m//g in scalar context! Go read the camel book, heathen.
146 :     # First, get the whole token with the quotes on both ends...
147 :     while ($raw_args =~ m/\G\s*(\w*)="((?:[^"\\]|\\.)*)"/g) {
148 :     my ($key, $value) = ($1, $2);
149 :     # ... then, rip out all the protecty backspaces
150 : malsyned 522 $value =~ s/\\(.)/$1/g;
151 : malsyned 512 push @args, $key => $value;
152 : sh002i 469 }
153 :    
154 : malsyned 512 return @args;
155 : malsyned 313 }
156 :    
157 : sh002i 558 # This is different. It probably shouldn't print anything (except in debugging cases)
158 :     # and it should return a boolean, not a string. &if is called in a nonstandard way
159 :     # by &template, with $args as an arrayref instead of a hashref. this is a hack! yay!
160 :    
161 :     # OK, this is a pluggin architecture. it iterates through attributes of the "if" tag,
162 :     # and for each predicate $p, it calls &if_$p in an object-oriented way, continuing the
163 :     # grand templating theme of an object-oriented pluggable architecture using ->can($).
164 :     sub if {
165 :     my ($self, $args) = @_[0,-1];
166 :     # A single if "or"s it's components. Nesting produces "and".
167 :    
168 :     my @args = @$args; # Hahahahaha, get it?!
169 :    
170 :     if (@args % 2 != 0) {
171 :     # flip out and kill people, but do not commit seppuku
172 :     print '<!--&if recieved an uneven number of arguments. This shouldn\'t happen, but I\'ll let it slide.-->\n';
173 :     }
174 :    
175 :     while (@args > 1) {
176 :     my ($key, $value) = (shift @args, shift @args);
177 :    
178 :     # a non-existent &if_$key is the same as a false result, but we're ORing, so it's OK
179 :     my $sub = "if_$key"; # perl doesn't like it when you try to construct a string right in a method invocation
180 :     if ($self->can("if_$key") and $self->$sub("$value")) {
181 :     return 1;
182 :     }
183 :     }
184 :    
185 :     return 0;
186 :     }
187 :    
188 : sh002i 469 ################################################################################
189 :     # Macros used by content generators to render common idioms
190 :     ################################################################################
191 :    
192 :     # pathMacro(HASHREF, LIST) - helper macro for <!--#path--> escape: the hash
193 :     # reference contains the "style", "image", and "text" arguments to the escape.
194 :     # The LIST consists of ordered key-value pairs of the form:
195 :     #
196 :     # "Page Name" => URL
197 :     #
198 :     # If the page should not have a link associated with it, the URL should be left
199 :     # empty. Authentication data is added to the URL so you don't have to. A fully-
200 :     # formed path line is returned, suitable for returning by a function
201 :     # implementing the #path escape.
202 :     #
203 :     sub pathMacro {
204 : malsyned 323 my $self = shift;
205 : sh002i 469 my %args = %{ shift() };
206 :     my @path = @_;
207 :     my $sep;
208 :     if ($args{style} eq "image") {
209 :     $sep = CGI::img({-src=>$args{image}, -alt=>$args{text}});
210 :     } else {
211 :     $sep = $args{text};
212 :     }
213 :     my $auth = $self->url_authen_args;
214 :     my @result;
215 :     while (@path) {
216 :     my $name = shift @path;
217 :     my $url = shift @path;
218 :     push @result, $url
219 :     ? CGI::a({-href=>"$url?$auth"}, $name)
220 :     : $name;
221 :     }
222 :     return join($sep, @result), "\n";
223 :     }
224 :    
225 :     sub siblingsMacro {
226 :     my $self = shift;
227 :     my @siblings = @_;
228 :     my $sep = CGI::br();
229 :     my $auth = $self->url_authen_args;
230 :     my @result;
231 :     while (@siblings) {
232 :     my $name = shift @siblings;
233 :     my $url = shift @siblings;
234 :     push @result, $url
235 :     ? CGI::a({-href=>"$url?$auth"}, $name)
236 :     : $name;
237 :     }
238 :     return join($sep, @result), "\n";
239 :     }
240 :    
241 :     sub navMacro {
242 :     my $self = shift;
243 :     my %args = %{ shift() };
244 : sh002i 692 my $tail = shift;
245 : sh002i 469 my @links = @_;
246 :     my $auth = $self->url_authen_args;
247 :     my @result;
248 :     while (@links) {
249 :     my $name = shift @links;
250 :     my $url = shift @links;
251 : malsyned 757 my $img = shift @links;
252 :     my $html = ($img && $args{style} eq "images") ? CGI::img({src=>($args{imageprefix}.$img.$args{imagesuffix}), border=>""}): $name;
253 :     unless($img && !$url) {
254 :     push @result, $url
255 :     ? CGI::a({-href=>"$url?$auth$tail"}, $html)
256 :     : $html;
257 :     }
258 : sh002i 469 }
259 :     return join($args{separator}, @result), "\n";
260 :     }
261 :    
262 :     # hidden_fields(LIST) - return hidden <INPUT> tags for each field mentioned in
263 :     # LIST (or all fields if list is empty), taking data from the current request.
264 :     #
265 :     sub hidden_fields($;@) {
266 :     my $self = shift;
267 : malsyned 323 my $r = $self->{r};
268 : sh002i 469 my @fields = @_;
269 :     @fields or @fields = $r->param;
270 : malsyned 323 my $courseEnvironment = $self->{courseEnvironment};
271 :     my $html = "";
272 :    
273 : sh002i 469 foreach my $param (@fields) {
274 : malsyned 323 my $value = $r->param($param);
275 : malsyned 447 $html .= CGI::input({-type=>"hidden",-name=>"$param",-value=>"$value"});
276 : malsyned 323 }
277 :     return $html;
278 :     }
279 :    
280 : sh002i 469 # hidden_authen_fields() - use hidden_fields to return hidden <INPUT> tags for
281 :     # request fields used in authentication.
282 :     #
283 :     sub hidden_authen_fields($) {
284 :     my $self = shift;
285 :     return $self->hidden_fields("user","effectiveUser","key");
286 :     }
287 : sh002i 425
288 : sh002i 469 # url_args(LIST) - return a URL query string (without the leading `?')
289 :     # containing values for each field mentioned in LIST, or all fields if list is
290 :     # empty. Data is taken from the current request.
291 :     #
292 :     sub url_args($;@) {
293 : sh002i 425 my $self = shift;
294 :     my $r = $self->{r};
295 :     my @fields = @_;
296 :     @fields or @fields = $r->param;
297 :     my $courseEnvironment = $self->{courseEnvironment};
298 :    
299 : sh002i 469 my @pairs;
300 : malsyned 441 foreach my $param (@fields) {
301 : sh002i 469 my $value = $r->param($param) || "";
302 :     push @pairs, uri_escape($param) . "=" . uri_escape($value);
303 : sh002i 425 }
304 : sh002i 469
305 :     return join("&", @pairs);
306 : sh002i 425 }
307 :    
308 : sh002i 469 # url_authen_args() - use url_args to return a URL query string for request
309 :     # fields used in authentication.
310 :     #
311 :     sub url_authen_args($) {
312 :     my $self = shift;
313 :     my $r = $self->{r};
314 :     return $self->url_args("user","effectiveUser","key");
315 : malsyned 390 }
316 :    
317 : sh002i 469 # print_form_data(BEGIN, MIDDLE, END, OMIT) - return a string containing request
318 :     # fields not matched by OMIT, placing BEGIN before each field name, MIDDLE
319 :     # between each field and its value, and END after each value. Values are taken
320 :     # from the current request. OMIT is a quoted reguar expression.
321 :     #
322 :     sub print_form_data {
323 :     my ($self, $begin, $middle, $end, $qr_omit) = @_;
324 :     my $return_string = "";
325 :     my $r=$self->{r};
326 :     my @form_data = $r->param;
327 :     foreach my $name (@form_data) {
328 :     next if ($qr_omit and $name =~ /$qr_omit/);
329 :     my @values = $r->param($name);
330 :     foreach my $variable (qw(begin name middle value end)) {
331 :     no strict 'refs';
332 :     ${$variable} = "" unless defined ${$variable};
333 :     }
334 :     foreach my $value (@values) {
335 :     $return_string .= "$begin$name$middle$value$end";
336 :     }
337 :     }
338 :     return $return_string;
339 : malsyned 390 }
340 :    
341 : sh002i 737 sub errorOutput($$$) {
342 :     my ($self, $error, $details) = @_;
343 :     return
344 :     CGI::h2("Software Error"),
345 :     CGI::p(<<EOF),
346 :     WeBWorK has encountered a software error while attempting to process this problem.
347 :     It is likely that there is an error in the problem itself.
348 :     If you are a student, contact your professor to have the error corrected.
349 :     If you are a professor, please consut the error output below for more informaiton.
350 :     EOF
351 :     CGI::h3("Error messages"), CGI::blockquote(CGI::pre($error)),
352 :     CGI::h3("Error context"), CGI::blockquote(CGI::pre($details));
353 :     }
354 :    
355 :     sub warningOutput($$) {
356 :     my ($self, $warnings) = @_;
357 :    
358 :     return
359 :     CGI::h2("Software Warnings"),
360 :     CGI::p(<<EOF),
361 :     WeBWorK has encountered warnings while attempting to process this problem.
362 :     It is likely that this indicates an error or ambiguity in the problem itself.
363 :     If you are a student, contact your professor to have the problem corrected.
364 :     If you are a professor, please consut the error output below for more informaiton.
365 :     EOF
366 :     CGI::h3("Warning messages"),
367 :     CGI::blockquote(CGI::pre($warnings)),
368 :     ;
369 :     }
370 :    
371 : sh002i 469 ################################################################################
372 :     # Generic versions of template escapes
373 :     ################################################################################
374 : malsyned 390
375 : sh002i 469 # Reminder: here are the template functions currently defined:
376 :     #
377 : sh002i 555 # head
378 : sh002i 469 # path
379 :     # style = text|image
380 :     # image = URL of image
381 :     # text = text separator
382 : sh002i 675 # loginstatus
383 : sh002i 505 # links
384 : sh002i 469 # siblings
385 :     # nav
386 :     # style = text|image
387 :     # imageprefix = prefix to image URL
388 :     # imagesuffix = suffix to image URL
389 :     # separator = HTML to place in between links
390 :     # title
391 :     # body
392 : malsyned 313
393 : malsyned 349 sub header {
394 : malsyned 305 my $self = shift;
395 : sh002i 469 my $r = $self->{r};
396 : malsyned 349 $r->content_type('text/html');
397 :     $r->send_http_header();
398 :     }
399 :    
400 : sh002i 682 sub loginstatus {
401 :     my $self = shift;
402 :     my $r = $self->{r};
403 :     my $user = $r->param("user");
404 :     my $eUser = $r->param("effectiveUser");
405 :     my $key = $r->param("key");
406 :     return "" unless $key;
407 : sh002i 692 my $exitURL = $r->uri() . "?user=$user&key=$key";
408 : sh002i 682 print CGI::small("Logged in as:", CGI::br(), "$user");
409 :     if ($user ne $eUser) {
410 : sh002i 692 print CGI::br(), CGI::font({-color=>'red'},
411 :     CGI::small("Acting as:", CGI::br(), "$eUser")
412 :     ),
413 :     CGI::br(), CGI::a({-href=>$exitURL},
414 :     CGI::small("Stop Acting")
415 :     );
416 : sh002i 682 }
417 :     return "";
418 :     }
419 :    
420 :     # *** drunk code. rewrite.
421 : sh002i 667 # also, this should be structured s.t. subclasses can add items to the links
422 :     # area, i.e. "stacking"
423 : sh002i 505 sub links {
424 : malsyned 353 my $self = shift;
425 : sh002i 469 my $ce = $self->{courseEnvironment};
426 : sh002i 526 my $userName = $self->{r}->param("user");
427 :     my $courseName = $ce->{courseName};
428 : sh002i 469 my $root = $ce->{webworkURLs}->{root};
429 : sh002i 526 my $permLevel = WeBWorK::DB::Auth->new($ce)->getPermissions($userName);
430 : sh002i 646 my $key = WeBWorK::DB::Auth->new($ce)->getKey($userName);
431 :     return "" unless defined $key;
432 : sh002i 526
433 : sh002i 667 # URLs to parts of the system
434 :     my $probSets = "$root/$courseName/?" . $self->url_authen_args();
435 : sh002i 644 my $prefs = "$root/$courseName/options/?" . $self->url_authen_args();
436 : sh002i 667 my $prof = "$root/$courseName/prof/?" . $self->url_authen_args();
437 :     my $help = "$ce->{webworkURLs}->{docs}?" . $self->url_authen_args();
438 :     my $logout = "$root/$courseName/logout/?" . $self->url_authen_args();
439 : sh002i 526
440 : sh002i 476 return
441 : sh002i 469 CGI::a({-href=>$probSets}, "Problem Sets"), CGI::br(),
442 : sh002i 526 CGI::a({-href=>$prefs}, "User Options"), CGI::br(),
443 : sh002i 667 ($permLevel > 0
444 :     ? CGI::a({-href=>$prof}, "Professor") . CGI::br()
445 :     : ""),
446 : sh002i 526 CGI::a({-href=>$help}, "Help"), CGI::br(),
447 : sh002i 476 CGI::a({-href=>$logout}, "Log Out"), CGI::br(),
448 :     ;
449 : malsyned 353 }
450 :    
451 : malsyned 525 # &if_can will return 1 if the current object->can("do $_[1]")
452 :     sub if_can ($$) {
453 :     my ($self, $arg) = (@_);
454 :    
455 :     if ($self->can("$arg")) {
456 :     return 1;
457 :     } else {
458 :     return 0;
459 :     }
460 :     }
461 :    
462 : malsyned 748 # Every content generator is logged in unless it says otherwise.
463 :     sub if_loggedin($$) {
464 :     my ($self, $arg) = (@_);
465 :    
466 :     return $arg;
467 :     }
468 :    
469 : malsyned 313 1;
470 : malsyned 508
471 :     __END__
472 :    
473 :     =head1 AUTHOR
474 :    
475 :     Written by Dennis Lambe Jr., malsyned (at) math.rochester.edu
476 :     and Sam Hathaway, sh002i (at) math.rochester.edu.
477 :    
478 :     =cut

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