5 CGI::Auth::Flexible - web authentication optionally using cookies
9 my $verifier = CGI::Auth::Flexible->new_verifier(setting => value,...);
10 my $authreq = $verifier->new_request($cgi);
13 $authreq->check_ok() or return;
15 # sophisticated applications
16 my $divert_kind = $authreq->check_divert();
17 if ($divert_kind) { ... print diversion page and quit ... }
19 # while handling the request
20 $user = $authreq->get_username();
21 $authreq->check_mutate();
25 CGI::Auth::Flexible is a library which you can use to add a
26 forms/cookie-based login facility to a Perl web application.
28 CGI::Auth::Flexible doesn't interfere with your application's URL path
29 namespace and just needs a few (configurable) form parameter and
30 cookie name(s) for its own use. It tries to avoid making assumptions
31 about the implementation structure of your application.
33 Because CGI::Auth::Flexible is licenced under the AGPLv3, you will
34 probably need to provide a facility to allow users (even ones not
35 logged in) to download the source code for your web app. Conveniently
36 by default CGI::Auth::Flexible provides (for pure Perl webapps) a
37 mechanism for users to get the source.
39 CGI::Auth::Flexible is designed to try to stop you accidentally
40 granting access by misunderstanding the API. (Also it, of course,
41 guards against cross-site scripting.) You do need to make sure to
42 call CGI::Auth::Flexible before answering AJAX requests as well as
43 before generating HTML pages, of course, and to call it in every
44 entrypoint to your system.
48 As a minimum you need to do all of the things on this checklist, where
49 applicable. The items marked SECURITY are the ones that you might
50 forget: without them your application may appear to work, but will be
57 Call C<new_verifier> (once at application startup)
61 Call C<new_request> (once per request)
65 B<SECURITY>: Call C<check_ok> or C<check_divert> on every request, and
66 honour the return value.
70 If you're using C<check_ok>, implement either the
71 C<username_password_error> or C<login_ok> hook and provide it as
72 a setting to C<new_verifier>.
76 Provide the setting C<dir> (or provide absolute paths for all the
77 other relevant settings).
81 Call C<get_username> when you need to know who's logged in.
85 B<SECURITY>: Call C<check_mutate> or C<mutate_ok>, if you specified
86 C<promise_check_mutate>.
90 B<SECURITY>: Call C<check_nonpage> for every request which is not a page load
91 (if your application has any of those).
95 When generating URLs and forms (including AJAX requests), include the
96 hidden form parameter using C<secret_hidden_val> or
97 C<secret_hidden_html> when appropriate (see below).
101 B<SECURITY>: If you do not override the source provision facility (see
102 L</SOURCE CODE DOWNLOAD>), check that the assumptions it makes aren't
103 going to leak security-critical data.
107 Set up HTTPS on your webserver, or set the C<encrypted_only> setting
112 These points will now be covered in more detail.
114 =head2 INITIALISATION
116 Your application should, on startup (eg, when it is loaded by
118 C<< $verifier = CGI::Auth::Flexible->new_verifier(settings...) >>.
119 This call can be expensive and is best amortised.
121 The resulting verifier object can be used to process individual
122 requests, in each case with
123 C<< $authreq = CGI::Auth::Flexible->new_request($cgi) >>.
127 =head2 CHECKING AND RESPONSE GENERATION
129 If the user is logged in, your application is to handle the request.
130 Otherwise, the user needs to be presented with a login form or error
131 message, as appropriate. CGI::Auth::Flexible provides two alternative
134 =head3 Simple applications
136 The simplist usage is to call C<< $request->check_ok() >> which will
137 check the user's authentication. If the user is not logged in it will
138 generate a login form (or redirection or other appropriate page) and
139 return false; your application should not then processing that request
140 any further. If the user is logged in it will return true.
142 Various hooks are provided to customise the responses generated by
145 After C<check_ok> returns true you should go ahead and process the
146 request; you can use C<< $request->get_username >> to find out which
147 user the request came from.
149 =head2 Sophisticated applications
151 If you want to handle the control flow and to generate login forms,
152 redirections, etc., yourself, you can say
153 C<< $divert = $request->check_divert >>. This returns undef if
154 the user is logged in, or I<divert spec> if some kind of login
155 page or diversion should be generated. See L</DIVERT SPEC> below for
156 details of how to deal with the return value.
158 =head2 MUTATING OPERATIONS AND EXTERNAL LINKS
160 =head3 Mutation-ignorant applications
162 By default CGI::Auth::Flexible does not permit external links into
163 your site. All GET requests give a "click to continue" page which
164 submits a form which loads your app's main page. In this
165 configuration all your application's forms and AJAX requests should
166 use C<POST>. This restriction arises from complicated deficiencies
167 in the web's security architecture.
169 Such applications are also not able to provide user-specific CSS
170 stylesheets, javascript, favicons, etc.
172 =head3 Mutation-aware applications
174 The alternative is for your application to always make a special check
175 when the incoming request is going to do some kind of action (such as
176 modifying the user's setup, purchasing goods, or whatever) rather than
177 just retrieve and/or display information. We term such requests
180 Then non-mutating pages can be linked to from other, untrustworthy,
183 To support external links, and C<GET> requests, pass
184 C<< promise_check_mutate => 1 >> in I<settings>, and then call
185 C<< $authreq->check_mutate() >> before taking any actions. If the
186 incoming request is not suitable then C<< $authreq->check_mutate() >>
189 There have to be no mutating C<GET> requests in your application (but
190 you shouldn't have any of those anyway); if there are, they won't
191 work. (CGI::Auth::Flexible will spot them and cause them to fail,
192 rather than allow them to be insecure.)
194 =head2 GENERATING URLS, FORMS AND AJAX QUERIES
196 When you generate a URL, C<POST> form or AJAX request you may need to
197 include a secret hidden form parameter for the benefit of
198 CGI::Auth::Generic. This form parameter will be checked by
199 C<check_ok>/C<check_divert> and should be ignored by your application.
201 By default the hidden parameter is called C<caf_assochash>.
203 After calling C<check_ok> or C<check_divert> the value to put in your
204 form can be obtained from C<secret_hidden_val>; C<secret_hidden_html>
205 will generate the whole HTML C<< <input...> >> element.
207 =head3 Mutation-ignorant applications
209 For mutation-ignorant applications (see above), all forms etc. should
210 include the hidden parameter (and as discussed, they must all use
211 POST rather than GET).
213 =head3 Mutation-aware applications
215 For mutation-aware applications, whether to include the secret
216 parameter depends on the kind of request. CGI::Auth::Flexible knows
217 when it is necessary. You should find out by calling
220 If it is inconvenient to call C<need_add_hidden> at runtime, you can
221 rely instead on the following promises: All POST requests (which
222 includes all mutating requests) need the parameter. The return value
223 of need_add_hidden depends only on the $method and $reqtype
224 parameters, so you can query it once and remember the answer.
225 HTML page load GETs do not need the parameter. It is better to
226 err on the side of including the parameter.
228 If you really must, you can call C<need_add_hidden> "on the bench"
229 during development and bake the answer into your application code
230 structure. However, if you do that and a new vulnerability was
231 discovered which is fixed by changing the answer, updating
232 CGI::Auth::Flexible wouldn't be sufficient to fix it.
234 =head3 Mutation-aware applications - non-page requests
236 If your mutation-aware application supports non-page resources (AJAX
237 and JSON requests, stylesheets, favicons, etc.) it must inform
238 CGI::Auth::Flexible when it is handling such a request, by calling
241 Normally C<check_nonpage> will simply return (and you can ignore the
242 return value). However, if there is an attack (or, perhaps, a bug) it
243 will die, stopping the attack.
245 (You do not need to call C<check_nonpage> for POST requests, but it is
248 =head3 Mutation-aware applications - novel kinds of request
250 If you want to support a kind of request perhaps not yet known about
251 by CGI::Auth::Flexible, you can provide information about that new
252 request kind using C<update_get_need_add_hidden>.
256 CGI::Auth::Flexible needs to store various information in plain files;
257 it does this in the directory specified by the C<dir> parameter.
259 =head1 SOURCE CODE DOWNLOAD
261 By default, CGI::Auth::Flexible provides a facility for users to
262 download the source code for the running version of your web
265 This facility makes a number of important assumptions which you need
266 to check. Note that if the provided facility is not sufficient
267 because your application is more sophisticated than it copes with (or
268 if you disable the builtin facility), you may need to implement a
269 functioning alternative to avoid violating the AGPLv3 licence.
271 Here are the most important (default) assumptions:
277 Your app's source code is available by looking at @INC, $0 and
278 S<$ENV{'SCRIPT_FILENAME'}> (the B<source items>). See
279 C<srcdump_listitems>. Where these point to files or directories under
280 revision control, the source item is the whole containing vcs tree.
284 Specifically, there are no compiled or autogenerated Perl
285 files, Javascript resources, etc., which are not contained in one of
286 the source item directories. (Files which came with your operating
287 system install don't need to be shipped as they fall under the system
292 You have not installed any modified versions of system
293 libraries (including system-supplied Perl modules) in C</usr> outside
294 C</usr/local>. See C<srcdump_system_dir>.
298 For each source item in a dvcs, the entire dvcs history does
299 not contain anything confidential (or libellous). Also, all files which
300 contain secrets are in the dvcs's I<.ignore> file. See
301 C<srcdump_vcsscript_git> et al.
305 For each source item NOT in a dvcs, there are no confidential
306 files with the world-readable bit set (being in a world-inaccessible
307 directory is not sufficient). See C<srcdump_excludes>.
311 You have none of your app's source code in C</etc>.
315 You don't regard pathnames on your server as secret.
319 You don't intentionally load Perl code by virtue of C<.>
320 being in C<@INC> by default. (See C<srcdump_filter_cwd>.)
324 =head1 MAIN FUNCTIONS AND METHODS
328 =item C<< CGI::Auth::Flexible->new_verifier(setting => value, ...) >>
330 Initialises an instance and returns a verifier object.
331 The arguments are setting pairs like a hash initialiser.
332 See L</SETTINGS> below.
334 =item C<< $verifier->new_request($cgi) >>
336 Prepares to process a request. I<$cgi> should normally
337 be the query object from L<CGI(3perl)>. Most of the default
338 hook methods assume that it is; however if you replace enough of
339 the hook methods then you can pass any value you like and it
340 will be passed to your hooks.
342 The return value is the authentication request object (I<$authreq>)
343 which is used to check the incoming request and will contain
344 information about its credentials.
346 =item C<< $authreq->check_divert() >>
348 Checks whether the user is logged in. Returns undef if the user is
349 logged in and we should service the request. Otherwise returns a
350 divert spec (see L</DIVERT SPEC>) saying what should happen instead.
352 This method may die if it doesn't like the request, in which case
353 the request needs to be rejected.
355 =item C<< $authreq->check_ok() >>
357 Checks whether the user is logged in. Returns true if the user is
358 logged in and we should service the request.
360 Otherwise it handles the request itself, generating any appropriate
361 redirect, login form, or continuation page. It then returns false and
362 the application should not process the request further.
364 =item C<< $verifier->disconnect() >>
366 Discards the resources (open files, etc.) in the verifier object.
370 =head1 REQUEST-RELATED FUNCTIONS AND METHODS
372 All of these are only valid after C<check_divert> or C<check_ok> has
373 been called. (In the case of C<check_ok> it won't normally be sensible
374 to call these functions unless C<check_ok> returned true.)
376 =item C<< $authreq->get_divert() >>
378 Returns the value previously returned by C<check_divert>.
380 =item C<< $authreq->get_username() >>
382 Returns the name of the logged-in user. If the user was not logged
383 in (or their session had timed out, or something), returns undef.
385 =item C<< $authreq->check_mutate() >>
387 Declares to CGI::Auth::Generic that the request being handled will
388 "mutate". That is, it will modify some server-side state (eg, adding
389 items to shopping baskets, posting messages to blogs, sending emails,
392 If you have set the setting C<promise_check_mutate> you must call
393 C<check_mutate> whenever appropriate. If you haven't then it's
394 irrelevant. See L<MUTATING OPERATIONS AND EXTERNAL LINKS>.
396 C<check_mutate> will either return successfully, indicating that all
397 is well and the request should proceed, or it will die. If it dies
398 that means that the request was improper, which can only result from a
399 bug or an attack. So an "internal server error" is a suitable
402 =item C<< $authreq->check_nonpage($method, $reqtype) >>
404 Declares to CGI::Auth::Generic that the request is not a page request,
405 but rather a request of type I<$reqtype>.
407 If your application has set the setting C<promise_check_mutate>,
408 whenever it is handling anything except an HTML page loads, it must
409 call this function. See L</REQUEST TYPES>, and
410 L<GENERATING URLS, FORMS AND AJAX QUERIES>.
412 C<check_nonpage> will either return successfully, indicating that all
413 is well and the request should proceed, or it will die, like
416 =head1 RESPONSE-RELATED FUNCTIONS AND METHODS
418 =item C<< $authreq->url_with_query_params($params, [$nonpagetype]) >>
420 Convenience function which returns a url for a GET request to this
423 I<$params> is a hashref specifying the parameters and the PATH_INFO.
424 The keys are the parameter names, and the values are array refs with
425 the parameter value(s) (as strings, as yet unquoted). (They are array
426 refs because it is possible to pass multiple values for the same
427 parameter in a single request; normally each arrayref would be a
430 The request path will be the path to the application. If a parameter
431 with name C<< '' >> is supplied, it is taken as the PATH_INFO - its
432 value will be appended to the application path. (It should normally
433 start with C<< / >>, and only one value should be supplied.)
435 =item C<< something->need_add_hidden($method, $reqtype) >>
437 Enquires whether a request of type I<$reqtype> using HTTP method
438 I<$method> needs the hidden form parameter. See L</REQUEST TYPES>.
440 =item C<< something->secret_hidden_val() >>
442 Returns the value of the hidden form parameter. This should be
443 included in all POST requests to your application (and thus be a
444 hidden form parameter in all forms).
446 It should also be in some (maybe all) GET requests. If your
447 application is mutation-ignorant, it should be in all GET requests.
448 If you are mutation-aware, you need to consult C<need_add_hidden>.
450 The name of the hidden parameter is the setting C<assoc_param_name>,
451 C<caf_hassochash> by default. xxx rename param and setting
453 =item C<< something->secret_hidden_html() >>
455 Returns the HTML for an C<INPUT> element specifying the hidden form
458 =item C<< something->secret_cookie_val() >>
460 Returns the value of the secret cookie. CGI::Auth::Flexible sets this
461 cookie in the forms generated by C<check_ok>. You may also set it
462 yourself (and indeed you must do so if you use C<check_divert>).
466 =head1 OTHER FUNCTIONS AND METHODS
470 =item C<< $verifier_or_authreq->hash($data) >>
472 Hashes the supplied data using the hash function specified by the
473 C<hash_algorithm> setting, and converts the result to a string of hex
476 =item C<< something->update_get_need_add_hidden($reqtype, $value, [$force]) >>
478 Updates CGI::Auth::Generic's knowledge about the various kinds of
479 request, and whether they need the hidden form parameter. This
480 function applies only to GET requests - POST requests always use the
483 I<$reqtype> is the request type (the value which will be passed to
484 C<check_nonpage> and C<need_add_hidden>. If you are supporting a new
485 I<$reqtype> you shouuld coordinate with CGI::Auth::Flexible upstrea,
486 or other users, to assign a unique request type name.
488 This method may be called on an authreq or a verifier, in which case
489 it will affect all authreqs using the same verifier. Or it may be
490 called on the class as a whole, in which case it will affect the
491 global default list for all verifiers.
493 If I<$force> is supplied and true, this will override
494 CGI::Auth::Flexible's existing knowledge. Otherwise this new setting
495 will be ignored if CGI::Auth::Flexible already knows about the request
496 type. (When called on a verifier or authreq, it will ignore the
497 update in favour of existing knowledge recorded both globally in the
498 class or due to previous requests on the same verifier.)
500 See L</REQUEST TYPES>.
502 =item C<< CGI::Auth::Flexible::srcdump_dir_cpio($cgi,$verifier,$dumpdir,$dir,$outfn,$how,$script) >>
504 Helper function for implementing the C<srcdump_process_item> hook.
505 Generates a tarball using cpio and includes it in the prepared source
508 The arguments are mostly the same as for that hook. C<$dir> is the
509 root directory at which to start the archive. C<$how> is a short text
510 string which will be mentioned in the log.
512 C<$script> is a shell script fragment which must output a
513 nul-separated list of filenames (e.g. the output of C<find -print0>).
514 It is textually surrounded by C<( )> and will be executed with C<set -e>
515 in force. Its cwd will be C<$dir>.
517 =item C<< $verifier_or_authreq->($data) | CGI::Auth::Flexible-> >>
519 Hashes the supplied data using the hash function specified by the
520 C<hash_algorithm> setting, and converts the result to a string of hex
527 The C<$reqtype> values understood by C<check_nonpage> are strings.
534 A top-level HTML page load. May contain confidential information for
535 the benefit of the logged-in user.
539 An HTML frame. May contain confidential information for
540 the benefit of the logged-in user.
544 An HTML iframe. May contain confidential information for
545 the benefit of the logged-in user.
549 Source dump request, whether for the licence or actual source code
550 tarball; returned value is not secret.
554 CSS stylesheet. B<MUST NOT> contain any confidential data. If the
555 stylesheet depends on the user, then attackers may be able to
556 determine what stylesheet the user is using. Hopefully this is not a
561 "Favicon" - icon for display in the browser's url bar etc. We aren't
562 currently aware of a way that attackers can get a copy of this.
566 C<robots.txt>. Should not contain any confidential data (obviously).
570 Inline image, for an C<< <img src=...> >> element.
572 Unfortunately it is not possible to sensibly show top-level
573 confidential images (that is, have the user's browser directly visit a
574 url which resolves to an image rather than an HTML page with an inline
575 image). This is because images need to have a per-session hidden form
576 parameter to avoid cross-site scripting, which breaks bookmarks etc.
580 JavaScript for a C<< <script> >> element. (Possibly confidential for
585 C<< XMLHttpRequest >> returning XML data. (Possibly
586 confidential for the user.)
590 C<< XMLHttpRequest >> returning JSON data. (Possibly
591 confidential for the user.)
595 C<< XMLHttpRequest >> returning data of some other kind. (Possibly
596 confidential for the user.)
602 The return value from C<check_divert> indicates how the request should
603 be handled. It is C<undef> if all is well and the user is logged in.
605 Otherwise the return value is a hash ref with the following keys:
611 Scalar string indicating the kind of diversion required.
615 Scalar string for display to the user in relation to the diversion.
616 Has already been translated. In HTML but normally does not contain
619 =item C<CookieSecret>
621 The login cookie which should be set along with whatever response is
622 sent to the client. The value in the hash is the actual value
623 of the cookie as a string. C<undef> means no cookie setting header
624 should be sent; C<''> means the cookie should be cleared.
628 The extra hidden form parameters (and the C<PATH_INFO>) which should
629 be set when the subsequent request bounces back from the client, in
630 the form used by C<url_with_query_params>.
632 The contents of this hashref does not include the CAF-specific
633 parameters such as the secret cookie, those which follow from the kind
634 of diversion requested, etc.
636 It is correct to always include the contents of C<Params> as hidden
637 parameters in the urls for all redirections, and as hidden input
638 fields in all generated forms. The specific cases where C<Params> is
639 currently relevant are also mentioned in the text for each divert
644 The values of C<Kind> are:
648 =item C<SRCDUMP->I<item>
650 We should respond by sending our application source code. I<item>
651 (which will contain only word characters, and no lower case) is the
652 specific item to send, normally C<SOURCE> or C<LICENCE>.
654 =item C<REDIRECT-HTTPS>
656 We should respond with an HTTP redirect to the HTTPS instance of our
659 =item C<REDIRECT-LOGGEDOUT>
661 We should redirect to a page showing that the user has been logged
662 out. (Ie, to a url with one of the the C<loggedout_param_names> set.)
664 =item C<SMALLPAGE-LOGGEDOUT>
666 We should generate a page showing that the user has been logged out.
667 There can be a link on the page pointing to the login page so that the
668 user can log back in.
670 =item C<SMALLPAGE-NOCOOKIE>
672 We should generate a page reporting that the user does not have
673 cookies enabled. It should probably contain a link pointing to the
674 login page with additionally all the parameters in C<Params>. When
675 this divert spec is generated, C<Message> will explain the problem
676 with cookies so there is no need to do that again in the page body if
677 you include the contents of C<Message>.
681 The user's session was stale (this is described in C<Message>). We
682 should generate a login form.
686 The user supplied bad login credentials. The details are in
687 C<Message>. We should generate a login form (with additionally the
688 parameters from C<Params> as hidden fields).
690 =item C<LOGIN-INCOMINGLINK>
692 We should generate a login form (with the specified parameters); the
693 user is entering the site via a cross-site link but is not yet logged
698 We should generate a login form. The user is not yet logged in.
700 =item C<REDIRECT-LOGGEDIN>
702 We should redirect to our actual application, with the specified
703 parameters. (The user has just logged in.)
705 =item C<MAINPAGEONLY>
707 We should generate our main page but B<ignoring all form parameters>
708 and B<ignoring the path_info>. Most applications will find this
709 difficult to implement.
711 An alternative is to generate a small page with a form or link which
712 submits our own main page without any parameters.
714 (Applications which set C<promise_check_mutate> do not see this divert
719 C<new_verifier> and C<new_request> each take a list of settings, as
720 a list of pairs C<< key => value >> (like a Perl hash assignment).
722 The settings supplied to C<new_verifier> are stored in the verifier
723 and will apply to all authreqs made from it unless overridden in the
724 call to C<new_request>
726 When a setting is described as a hook function, it should be a
727 coderef. The first argument will be the query object from
728 L<CGI(3perl)> (strictly, it will be whatever value was passed to
729 C<new_request>). The second argument will be the authreq object (the
730 return value from C<new_request>).
731 Ie, C<< sub some_hook ($$...) { my ($cgi,$authreq,@stuff) = @_ ... >>
733 In bullet point headings, the hook functions are shown in the form
734 C<< some_hook($cgi,$authreq,@stuff) >> even though this would not be
735 legal syntax. This should be read to mean that the
736 %implicit_settings_hash{'some_hook'}($cgi,$authreq,@stuff)
737 would be a legal call. (However, the settings hash is not exposed.)
739 When a hook's default implementation is mentioned and named, that
740 function won't also be described in the section on the module's
745 =head2 GENERAL SETTINGS
749 The directory CGI::Auth::Generic should use for its data storage.
750 This is actually just a default absolute path used when the other
751 path settings are relative values.
753 Must be an absolute filename.
757 CGI::Auth::Flexible needs a database for recording users' login
758 session. This database needs to be shared across all instances of the
759 web application, so in a multi-node cluster it needs to be your actual
762 CGI::Auth::Flexible will create the table and index it needs if they
763 don't already exist, and will manage their contents. You do not need
764 to integrate them into the rest of your webapp's data storage. (In
765 particular, there is no need for transactional integrity across
766 changes made by CAF and your own application.)
768 By default, CAF uses a sqlite3 database stored on local disk in the
769 file named by C<db_path>. This will be suitable for all
770 applications which run on a single host.
772 This value, if supplied, should be a DBI handle for the database.
776 This is the DSN to pass to C<< DBI->connect >>. Used only if
777 C<db_dbh> is not supplied.
781 Path to the sqlite3 database used for CAF's session storage. The
782 default is C<caf.db>.
784 Used only if neither C<db_dbh> or C<db_dsn> are supplied.
786 If this is a relative path, it is in C<dir>.
790 Prefix for the SQL tables and indices to use (and to create, if
793 See L</DATABASE TABLES>.
797 Path to the keys file used by CAF. This arrangement will change in
798 the future. See L</BUGS>.
800 =item C<random_source>
802 Special file to read random numbers from. Should return
803 cryptographically secure (pseudo)-random bytes, unpredictable to
804 adversaries (even ones on the same machine).
806 On Linux, there is no device which is properly suitable. This is a
807 bug in Linux. You can use C</dev/random> which can block
808 unnecessarily even though the kernel PRNG has been properly seeded and
809 is fine, or C</dev/urandom> which might return values which attackers
810 can predict if the kernel PRNG has not been properly seeded.
812 The default is C</dev/urandom>.
816 Length of the assoc secret. Defaults to 128.
818 =item C<hash_algorithm>
820 Must be a string suitable for use with C<new Digest>.
821 Defaults to C<SHA-256>.
823 =item C<login_timeout>
825 A user will be logged out this many seconds after they first logged
826 in. Default: 86400 (one day).
828 =item C<login_form_timeout>
830 A login form becomes invalid this many seconds after it has been sent.
831 Default: 3600 seconds (one hour).
833 =item C<key_rollover>
835 The key used for generating assoc secrets is rolled over approximately
836 this often (in seconds). Default: 86400.
838 =item C<assoc_param_name>
840 Name of the hidden form parameter. Default: C<caf_assochash>.
844 Name of the cookie used for login sessions. Default:
847 =item C<password_param_name>
849 Name of the password field in the login form. Default: C<password>.
851 Used by C<login_ok_password> (the default C<login_ok> hook),
852 C<gen_plain_login_form> and the default C<is_login> hook.
854 =item C<username_param_names>
856 Arrayref of name(s) of username form parameters.
858 The first entry is used by C<login_ok_password> (the default
859 C<login_ok> hook) to pass to the C<username_password_error> hook and
860 used as the username if all is well.
862 All the entries are used by C<gen_plain_login_fork> (the default
863 C<gen_login_form> hook for C<check_ok>) to generate form entry fields.
865 The default is C<['username']>.
867 =item C<logout_param_names>
869 Arrayref of name(s) of form parameters indicating that the request is
872 Used by the default C<is_logout> hook.
874 If you want users to be able to explicitly log out, you need to
875 provide a logout button, something like
876 C<< <input type="submit" name="caf_logout" ...>>
878 The default is C<['caf_logout']>
880 =item C<logged_param_names>
882 Arrayref of name(s) of form parameters indicating that user has just
883 logged out. (During the logout process, the actual logout action is a
884 POST request, whose response redirects to the "you have been logged
885 out" page; these form parameters are for this second page.)
887 Used by the default C<is_loggedout> hook.
889 The first entry is used by C<check_ok> to generate the redirection.
891 The default is C<['caf_loggedout']>
893 =item C<promise_check_mutate>
895 Boolean. If true, is a declaration by the application that it is
896 mutatin-aware. See L</MUTATING OPERATIONS AND EXTERNAL LINKS>.
900 =item C<encrypted_only>
902 Boolean. If true, CAF will insist that all transactions be done over
903 an encrypted http connection. It will redirect unencrypted requests
904 to the https instance of the applicattion, and will set the encrypted
905 only flag on its cookie.
911 =item C<< get_url($cgi,$authreq) >>
913 Hook which returns the URL of this web application. By default, we
914 call C<< $cgi->url() >> for each request, but you can fix this if you
917 =item C<< is_login,is_logout,is_loggedout($cgi,$authreq) >>
919 Hook which returns a boolean indicating whether the request was,
920 respectively: a login form submission (ie, username and password); a
921 logout request (submission resulting from the user pressing the
922 "logout" button); "logged out" page (redirection from the logout
925 The default is to check whether any of the corresponding request
926 parameters (C<< login_param_names >> etc.) was supplied, using the
931 =head2 SETTINGS (HOOKS) RELATED TO THE CGI REQUEST OBJECT
935 =item C<< get_param($cgi,$authreq,$param) >>
937 Returns the value of a single-valued form parameter.
938 The default is to call C<< $cgi->param($param) >>.
939 The semantics are the same as that of C<CGI::param>.
941 =item C<< get_params($cgi,$authreq) >>
943 Returns a hash of the parameters. The return value is a hashref whose
944 keys are the parameter names and whose values are arrayrefs, one entry
945 in the arrayref for each value.
947 The default is to call C<< $cgi->Vars() >>, expect the
948 results to look like those from C<CGI::Vars>, and massage them into
949 the required form with split.
951 =item C<< get_path_info($cgi,$authreq) >>
953 Returns the PATH_INFO of the request. The default is to
954 call C<< $cgi->path_info() >>.
956 =item C<< get_cookie($cgi,$authreq) >>
958 Returns the value of the CAF cookie sent with the request, or undef if
959 none was supplied. The default is to call C<<
960 $cgi->cookie($cookie_name) >> (where C<$cookie_name> is from the
961 setting of the same name). The return value should be the scalar
964 =item C<< get_method($cgi,$authreq) >>
966 Returns the HTTP method as a string. The default is to call
967 C<< $cgi->request_method() >>.
971 =item C<< is_https($cgi,$authreq) >>
973 Returns a boolean indicating whether the request was over an encrypted
974 channel. The default is C<< !!$cgi->https() >>. See C<encrypted_only>.
978 =head2 SETTINGS RELATED TO HTML GENERATION
980 These are only used if you call C<check_ok> (or other functions
981 mentioned in this section).
983 Settings whose names are of the form C<gen_...> are hooks which each
984 return an array of strings, normally HTML strings, for use by
985 C<check_ok> (or, in turn, other hooks, or your application). These
986 are often documented simply by showing the output produced. In many
987 cases parts of the output are in turn obtained from other hooks. In
988 some cases the default implementations have been given names for
989 convenient use by your application. They will be called in array
992 We'll write C<gettext(something)> even though actually there is a hook
993 to control the translation function used.
997 =item C<handle_divert>($cgi,$authreq,$divert))
999 C<check_ok> calls this hook before producing output of its own. If
1000 you want to handle some but not all diversions yourself, you may set
1001 this hook. The hook should either do nothing and return false, or
1002 return true if it has handled the request (or arrange for the request
1003 to be handled). If the hook returns true then C<check_ok> simply
1006 =item C<gen_login_form>($cgi,$authreq,$divert))
1008 Default: a table (used mostly for layout) containing input fields for
1009 a login form. Must be within a C<< <form> >> element, but doesn't
1010 generate it. Has text fields for every entry in
1011 C<username_param_names> (in each case associated with a description
1012 C<< gettext(ucfirst $parameter_name) >>, a password field (with
1013 description C<gettext("Password")>, and a login submit button (with
1014 description C<gettext("Login")>.
1016 Default is available as the module function C<gen_plain_login_form>.
1018 =item C<gen_login_link>($cgi,$authreq))
1022 <a href="http:...">gettext(Log in again to continue.)</a>
1024 Default is available as the module function C<gen_plain_login_link>.
1026 =item C<gen_postmainpage_form>($cgi,$authreq,$params))
1028 Default: form contents (but not the C<< <form> >> element):
1030 C<$params> (in the form returned by the C<get_params> hook) as hidden
1033 <input type="submit" ... value=getext('Continue')>
1035 Default is available as the module function C<gen_postmainpage_form>.
1037 =item C<gen_start_html>($cgi,$authreq,$title)
1039 Default: C<$cgi->start_html($title)>
1041 =item C<gen_end_html>($cgi,$authreq,$title)
1043 Default: C<$cgi->end_html($title)>
1045 =item C<gen_footer_html>($cgi,$authreq)>
1050 Powered by Free / Libre / Open Source Software
1051 according to the [gen_licence_link_html].
1052 [gen_source_link_html].
1055 Default is available as the module function C<gen_plain_footer_html>.
1057 =item C<gen_licence_link_html>($cgi,$authreq)>
1059 Default: uses C<url_with_query_params> to generate a URL for
1060 downloading the licence, and returns:
1061 <a href="...">GNU Affero GPL</a>
1063 Default is available as the module function C<gen_plain_licence_link_html>.
1065 =item C<gen_source_link_html>($cgi,$authreq)>
1067 Default: uses C<url_with_query_params> to generate a URL for
1068 downloading the source, and returns:
1069 <a href="...">Source available</a>
1071 Default is available as the module function C<gen_plain_source_link_html>.
1073 =item C<form_entry_size>
1075 Size of generated text entry fields. Default is 60.
1077 =item C<dummy_param_name_prefix>
1079 Some of CAF's HTML-generating functions need to invent form parameter
1080 names. They will all start with this string. Default: C<caf__>.
1082 =head2 SETTINGS FOR SOURCE CODE DOWNLOAD FACILITY
1086 =item C<srcdump_param_name>
1088 Form parameter name used to indicate that this is a source download
1089 request. If this parameter is supplied, C<check_ok> and
1090 C<check_divert> will arrange for the applicaton source code to be
1091 delivered as the response (in C<check_ok>'s case by doing it itself
1092 and in C<check_divert>'s case by asking your application to do so.
1094 Default is C<caf_srcdump>.
1096 =item C<srcdump_path>
1098 Path to the directory used for storing pre-prepared source downloads.
1099 Defaults to C<caf-srcdump>.
1101 If this is a relative path, it is in C<dir>.
1103 =item C<srcdump_dump($cgi,$authreq,$srcobj)>
1105 Dump the source code (C<$srcobj='source'> or licence data
1106 (C<$srcobj='licence'>). The default implementation checks that
1107 C<$srcobj> has reasonable syntax and uses the files C<$srcobj.data>
1108 and C<$srcobj.ctype> with the C<dump> hook.
1110 =item C<dump($cgi,$authreq,$contenttype,$datafilehandle)>
1112 Responds to the request by sending the contents of $datafilehandle
1113 (which should just have been opened) and specifying a content type of
1116 The default implmentation uses the C<print> hook, and also calls
1117 C<$cgi->header('-type' => $contenttype>, and is available as the
1118 module function C<dump_plain>.
1120 =item C<srcdump_prepare($cgi,$verifier)>
1122 Prepares the source code for download when requested. Invoked by
1123 C<new_verifier>, always, immediately before it returns the
1124 just-created verifier object.
1126 The default implementation is the module function
1127 C<srcdump_dirscan_prepare>, which prepares a manifest, licence file
1128 and source code tarball of tarballs, as follows:
1130 It processes each entry in the return value from C<srcdump_listitems>.
1131 These are the software's include directories and any other directories
1132 containing source code. It handles C<.> specially (see
1133 C<srcdump_filter_cwd>).
1135 For each entry it looks, relative to that, for the licence as a file
1136 with a name mentioned in C<srcdump_licence_files>. The first such
1137 file found is considered to be the licence. It then calls the hook
1138 C<srcdump_process_item> for the entry.
1140 The licence, a manifest file, and all the outputs generated by the
1141 calls to C<srcdump_process_item>, are tarred up and compressed as a
1142 single source tarball.
1144 It uses the directory named by C<srcdump_path> as its directory for
1145 working and output files. It uses the filename patterns
1146 C<generate.*>, C<licence.*>, C<s.[a-z][a-z][a-z].*>, C<manifest.*>,
1147 C<source.*> in that directory.
1149 =item C<srcdump_process_item>($cgi,$verifier,$dumpdir,$item,\&outfn,\$needlicence,\%dirsdone)>
1151 Processes a single include directory or software entry, so as to
1152 include the source code found there. Called only by the default
1153 implementation of C<srcdump_prepare>.
1155 C<$dumpdir> is the directory for working and output files. C<$item>
1156 is the real (no symlinks) absolute path to the item.
1158 C<\$needlicence> is a ref to a scalar: this scalar is undef if we have
1159 already found the licence file; otherwise it is the filename to which
1160 the licence should be copied. If the referent is undef on entry,
1161 C<srcdump_process_item> needs to see if it finds the licence; if it
1162 does it should copy it to the named file and then set the scalar to
1165 C<\%dirsdone> is a ref to the hash used by C<srcdump_prepare> to avoid
1166 including a single directory more than once. If
1167 C<srcdump_process_item> decides to process a directory other than
1168 C<$item> it should check this hash with the real absolute path of the
1169 other directoy as a key: if the hash entry is true, it has already
1170 been done and should be skipped; otherwise the hash entry should be set.
1172 C<\&outfn> is a coderef which C<srcdump_process_item> should call each
1173 time it wants to generate a file which should be included as part of
1174 the source code. It should be called using one of these patterns:
1175 $outfn->("message for manifest");
1176 $outfile = $outfn->("message for manifest", "extension");
1177 The former simply prints the message into the manifest in the form
1178 none: message for manifest
1179 The latter generates and returns a filename which should then
1180 be created and filled with some appropriate data. C<"extension">
1181 should be a string for the file extension, eg C<"txt">. The output
1182 can be written directly to the named file: there is no need to
1183 write to a temporary file and rename. C<$outfn> writes the filename
1184 and the message to the manifest, in the form
1185 filename leaf: message
1186 In neither case is the actual name of C<$dir> on the system
1187 disclosed per se although of course some of the contents of some of
1188 the files in the source code dump may mention it.
1190 The default implementation is the module function
1191 C<srcdump_process_item>.
1193 It skips directories for which C<srcdump_system_dir> returns true.
1195 It then searches the item and its parent
1196 directories for a vcs metadata directory (one of the names in
1197 C<srcdump_vcs_dirs>); if found, it calls the C<srcdump_byvcs> hook
1198 (after checking and updaeing C<%dirsdone>).
1199 Otherwise it calls the C<srcdump_novcs> hook.
1201 =item C<srcdump_novcs($cgi,$verifier,$dumpdir,$item,$outfn)>
1203 Called by the default implementation of C<srcdump_process_item>, with
1204 the same arguments, if it doesn't find vcs metadata.
1206 The default implementation is the module function C<srcdump_novcs>.
1208 If C<$item> is a directory, it uses C<srcdump_dir_cpio> to prepare a
1209 tarball of all the files under C<$item> which have the world read bit
1210 set. Directories are not included (and their permissions are
1211 disregarded). The contents of C<srcdump_excludes> are excluded.
1213 If it's a plain file it uses C<srcdump_file> to include the file.
1215 =item C<srcdump_byvcs($cgi,$verifier,$dumpdir,$item,$outfn,$vcs)>
1217 Called by the default implementation of C<srcdump_process_item>, with
1218 the same arguments, if it finds vcs metadata. The additional argument
1219 C<$vcs> is derived from the entry of C<srcump_vcs_dirs> which was
1220 used: it's the first sequence of word characters, lowercased.
1222 The default implementation is the module function C<srcdump_byvcs>.
1223 It simply calls C<srcdump_dir_cpio> with a script from the setting
1224 C<srcdump_vcsscript>.
1226 =item C<srcdump_vcs_dirs>
1228 Array ref of leaf names of vcs metadata directories. Used by the
1229 default implementation of C<srcdump_process_item>. The default value
1230 is C<['.git','.hg','.bzr','.svn']>.
1232 =item C<srcdump_vcs_script>
1234 Hash ref of scripts for generating vcs metadata. Used by the default
1235 implementation of C<srcdump_byvcs>. The keys are values of C<$vcs>
1236 (see C<srcdump_byvcs>); the values are scripts as for
1237 C<srcdump_dir_cpio>.
1239 The default has an entry only for C<git>:
1241 git ls-files -z --others --exclude-from=.gitignore
1244 =item C<srcdump_excludes>
1246 Array ref of exclude glob patterns, used by the default implementation
1247 of C<srcdump_novcs>. The default value is C<['*~','*.bak','*.tmp','#*#']>.
1249 Entries must not contain C<'> or C<\>.
1251 =item C<srcdump_listitems($cgi,$verifier)>
1253 Returns an array of directories which might contain source code of the
1254 web application and which should be therefore be considered for
1255 including in the source code delivery.
1257 Used by the default implementation of C<srcdump_prepare>.
1259 Entries must be directories, plain files, or nonexistent; they may
1260 also be symlinks which resolve to one of those.
1262 If C<.> is included it may be treated specially - see
1263 C<srcdump_filter_cwd>.
1265 The default implementation returns
1266 C<(@INC, $ENV{'SCRIPT_FILENAME'}, $0)>.
1268 =item C<srcdump_system_dir($cgi,$verifier,$dir)>
1270 Determines whether C<$dir> is a "system directory", in which any
1271 source code used by the application should nevertheless not be
1272 included in the source code dump.
1274 Used by the default implementation of C<srcdump_item>.
1276 The default implementation is as follows: Things in C</etc/> are
1277 system directories. Things in C</usr/> are too, unless they are in
1278 C</usr/local/> or C</usr/lib/cgi*>.
1280 =item C<srcdump_filter_cwd>
1282 Boolean which controls the handling of C<.> if it appears in the
1283 return value from C<srcdump_listitems>. Used only by the default
1284 implementation of C<srcdump_prepare>.
1286 If set to false, C<.> is treated normally and no special action is
1289 However often the current directory may be C</>, or a data directory,
1290 or some other directory containing data which is confidential, or
1291 should not be included in the public source code distribution for
1292 other reasons. And for historical reasons Perl has C<@INC> containing
1293 C<.> by default (which is arguably dangerous and wrong).
1295 So the default this setting is true, which has the following effects:
1297 C<.> is not searched for source code even if it appears in C<@INC>.
1298 C<.> is removed from C<@INC> and C<%INC> is checked to see if any
1299 modules appear to have already been loaded by virtue of C<.> appearing
1300 in C<@INC> and if they have it is treated as a fatal error.
1302 Only the literal string C<.> is affected. If the cwd is included by
1303 any other name it is not treated specially regardless of this setting.
1307 =head1 DATABASE TABLES
1309 In a simple application, you do not need to worry about this. But if
1310 your application runs on multiple frontend hosts with a shared
1311 database, you may need to create for yourself the tables and indices
1312 used by CGI::Auth::Flexible.
1314 By default, every time CAF starts up, it attempts to execute certain
1315 fixed database statements to create the tables and indices it needs.
1316 These are run with C<$dbh->{PrintError}> set to 0. The effect with
1317 sqlite (the default database) is that the tables and indices are
1318 created iff they do not already exist, and that no spurious errors are
1321 If you use a different database, or just prefer to do things
1322 differently, you can set up the tables yourself and/or disable or
1323 modify the default setup statements, via the C<db_setup_stmts>
1326 The tables needed are:
1329 xxx document _db_setup_do
1330 xxx make _db_setup_do explicitly overrideable
1333 xxx remaining settings
1335 username_password_error
1342 xxx document cookie usage
1343 xxx document construct_cookie fn
1345 xxx document @default_db_setup_statements
1347 xxx bugs wrong default random on Linux
1348 xxx bugs wrong default random on *BSD
1349 xxx bugs keys not shared should be in db
1350 xxx rename caf_assocsecret default cookie name
1351 xxx mention relationship between login_timeout and cookies