From: David Baird Date: Sun, 30 Oct 2005 16:02:35 +0000 (+0000) Subject: Added Maypole::Manual::Inheritance and Maypole::Manual::Terminology. Renamed Maypole... X-Git-Tag: 2.11~116 X-Git-Url: https://git.decadent.org.uk/gitweb/?a=commitdiff_plain;h=1b05e3ca38fdb958cf9ced4d89e1478dc1e21257;p=maypole.git Added Maypole::Manual::Inheritance and Maypole::Manual::Terminology. Renamed Maypole::Manual::Request to Maypole::Manual::Cookbook. Minor updates elsewhere to reflect name changes and new docs. Started a docs roadmap section in Maypole.pm, needs more work. git-svn-id: http://svn.maypole.perl.org/Maypole/trunk@402 48953598-375a-da11-a14b-00016c27c3ee --- diff --git a/lib/Maypole.pm b/lib/Maypole.pm index cae420f..53732c4 100644 --- a/lib/Maypole.pm +++ b/lib/Maypole.pm @@ -488,16 +488,39 @@ Maypole is a Perl web application framework similar to Java's struts. It is essentially completely abstracted, and so doesn't know anything about how to talk to the outside world. -To use it, you need to create a package which represents your entire +To use it, you need to create a driver package which represents your entire application. In our example above, this is the C package. This needs to first use L which will make your package inherit from the appropriate platform driver such as C or -C, and then call setup. This sets up the model classes and +C. Then, the driver calls C. This sets up the model classes and configures your application. The default model class for Maypole uses L to map a database to classes, but this can be changed by altering configuration. (B calling setup.) + +=head1 DOCUMENTATION ROADMAP + +The primary documentation is the Maypole manual. This lives in the +C pod documents included with the distribution. + + +=head1 DEMOS + +A couple of demos are available, usually with source code and configs. + +=over4 + +=item beerdb.riverside-cms.co.uk + +Looks to be down at the moment. + +=item beerfb.riverside-cms.co.uk + +A demo of L. This site is running on the set of Mason +templates included in the L distribution. See the +synopsis of L for an example driver + =head2 CLASS METHODS =head3 config diff --git a/lib/Maypole/Manual.pod b/lib/Maypole/Manual.pod index dc60222..d556ae9 100644 --- a/lib/Maypole/Manual.pod +++ b/lib/Maypole/Manual.pod @@ -71,6 +71,15 @@ This document also introduces the theory behind Maypole's actions and templates, showing you how to write your own so that you can have a highly customized application. +=item L - writing Maypole plugins + +Useful information for plugin authors. + +=item L - pinning down usage + +As well as defining common terms used in Maypole discussions, this document +briefly discusses the MVC-ness of Maypole. + =item L - Description of the Request Workflow This is a technical document that describes the progress of a @@ -83,7 +92,7 @@ and not to most of those who are using it. This document gives a close look at the Beer database that was introduced in L. -=item L - The Request Cookbook +=item L - The Maypole Cookbook This extensive document is Maypole's main "How do I do X?" FAQ. It provides a wide variety of cookbook-like techniques that diff --git a/lib/Maypole/Manual/About.pod b/lib/Maypole/Manual/About.pod index d78be34..6f48663 100644 --- a/lib/Maypole/Manual/About.pod +++ b/lib/Maypole/Manual/About.pod @@ -74,48 +74,6 @@ logic of your application. This is one of the reasons why Maypole lets you develop so rapidly: because most of the time, you don't need to do any development at all. -=head2 Installing Maypole - -The first thing you're going to need to do to get Maypole running is to -install it. Maypole needs an absolute shedload of Perl modules from CPAN -to do its job. I am unrepentant about this. Maypole does a lot of work, -so that you don't have to. This is called code re-use, and if we're -serious about code re-use, then Maypole should be re-using as much code -as possible in terms of Perl modules. In another sense, this gives the -impression that Maypole doesn't actually do all that much itself, -because all it's doing is gluing together already-existing code. Well, -welcome to code re-use. - -The downside of code re-use is, of course, that you then have to install -a shedload of Perl modules from CPAN. If you're using OpenBSD or -FreeBSD, the wonderful ports system will be your friend. There's a -Maypole port in C. Just type C. - -Debian users, hang in there. There's a package coming. - -For other Unices, the L or C modules will help with -this. If you don't have C installed, my recommendation is to -use C to install it and then throw -C away. In any case, one of these two should get all that -Maypole needs: - - % perl -MCPANPLUS -e 'install Maypole' - % perl -MCPAN -e 'install Maypole' - -I don't know if Maypole works on Windows. I'm not sure I care. - -You're also going to need a database server and a web server. For -databases, I recommend SQLite (if you install the C module, -you get the SQLite library for free) for prototyping and mysql for -production; heavier duty users should use Postgresql or Oracle - Maypole -should be happy with them all. Maypole is happiest when running under -Apache C, with the C module installed, but as -I said, it is a blank slate, and everything is customizable. There is a -C frontend available to run as a standalone CGI script. - -As well as the documentation embedded in the Perl modules the distribution -also includes the manual, of which this is a part. You can access it using the -perldoc command, the man command, or by browsing CPAN. =head2 The Beer Database example diff --git a/lib/Maypole/Manual/Cookbook.pod b/lib/Maypole/Manual/Cookbook.pod new file mode 100644 index 0000000..1d2395c --- /dev/null +++ b/lib/Maypole/Manual/Cookbook.pod @@ -0,0 +1,839 @@ +=head1 NAME + +Maypole::Manual::Cookbook - Maypole Cookbook + +=head1 DESCRIPTION + +Hacks; design patterns; recipes: call it what you like, this chapter is a +developing collection of techniques which can be slotted in to Maypole +applications to solve common problems or make the development process easier. + +As Maypole developers, we don't necessarily know the "best practice" for +developing Maypole applications ourselves, in the same way that Larry Wall +didn't know all about the best Perl programming style as soon as he wrote +Perl. These techniques are what we're using at the moment, but they may +be refined, modularized, or rendered irrelevant over time. But they've +certainly saved us a bunch of hours work. + +=head2 Frontend hacks + +These hacks deal with changing the way Maypole relates to the outside world; +alternate front-ends to the Apache and CGI interfaces, or subclassing chunks +of the front-end modules to alter Maypole's behaviour in particular ways. + +=head3 Separate model class modules + +You want to put all the C routines in a separate module, +so you say: + + package BeerDB::Beer; + BeerDB::Beer->has_a(brewery => "BeerDB::Brewery"); + sub foo :Exported {} + +And in F, you put: + + use BeerDB::Beer; + +It doesn't work. + +B: It doesn't work because of the timing of the module loading. +C will try to set up the C relationships +at compile time, when the database tables haven't even been set up, +since they're set up by + + BeerDB->setup("...") + +which does its stuff at runtime. There are two ways around this; you can +either move the C call to compile time, like so: + + BEGIN { BeerDB->setup("...") } + +or move the module loading to run-time (my preferred solution): + + BeerDB->setup("..."); + BeerDB::Beer->require; + +=head3 Redirecting to SSL for sensitive information + +You have a website with forms that people will be entering sensitive information into, +such as credit cards or login details. You want to make sure that they aren't sent +in plain text but over SSL instead. + +B + +The solution is a bit tricky for 2 reasons : + +Firstly -- Many browsers and web clients will change a redirected +POST request into a GET request (which displays all that sensitive information in the +browser, or access logs and possibly elsewhere) and/or drops the values on the floor. + +Secondly -- If somebody has sent that sensitive information in plain text already, then +sending it again over SSL won't solve the problem. + +Redirecting a request is actually rather simple : + +$r->redirect_request('https://www.example.com/path'); # perldoc Maypole for API + +.. as is checking the protocol : + +$r->get_protocol(); # returns 'http' or 'https' + +You should check that the action that generates the form that people will enter +the sensitive information into is https and redirect if not. + +You should also check that no information is lost when redirecting, possibly by +storing it in a session and retrieving it later - see Maypole::Plugin::Session + +=head3 Debugging with the command line + +You're seeing bizarre problems with Maypole output, and you want to test it in +some place outside of the whole Apache/mod_perl/HTTP/Internet/browser circus. + +B: Use the L module to go directly from a URL to +standard output, bypassing Apache and the network altogether. + +L is not a standalone front-end, but to allow you to debug your +applications without having to change the front-end they use, it temporarily +"borgs" an application. If you run it from the command line, you're expected +to use it like so: + + perl -MMaypole::CLI=Application -e1 'http://your.server/path/table/action' + +For example: + + perl -MMaypole::CLI=BeerDB -e1 'http://localhost/beerdb/beer/view/1?o2=desc' + +You can also use the C module programatically to create +test suites for your application. See the Maypole tests themselves or +the documentation to C for examples of this. + +Don't forget also to turn on debugging output in your application: + + package BeerDB; + use strict; + use warnings; + use Maypole::Application qw(-Debug); + +=head3 Changing how URLs are parsed + +You don't like the way Maypole URLs look, and want something that either +fits in with the rest of your site or hides the internal workings of the +system. + +B: So far we've been using the C form +of a URL as though it was "the Maypole way"; well, there is no Maypole +way. Maypole is just a framework and absolutely everything about it is +overridable. + +If we want to provide our own URL handling, the method to override in +the driver class is C. This is responsible for taking +C<$r-Epath> and filling the C, C and C slots +of the request object. Normally it does this just by splitting the path +on 'C' characters, but you can do it any way you want, including +getting the information from C form parameters or session variables. + +For instance, suppose we want our URLs to be of the form +C, we could provide a C method +like so: + + sub parse_path { + my $r = shift; + $r->path("ProductList.html") unless $r->path; + ($r->path =~ /^(.*?)([A-Z]\w+)\.html/); + $r->table(lc $1); + $r->action(lc $2); + my %query = $r->ar->args; + $self->args([ $query{id} ]); + } + +This takes the path, which already has the query parameters stripped off +and parsed, and finds the table and action portions of the filename, +lower-cases them, and then grabs the C from the query. Later methods +will confirm whether or not these tables and actions exist. + +See the L for another +example of custom URL processing. + +=head3 Maypole for mobile devices + +You want Maypole to use different templates to display on particular +browsers. + +B: There are several ways to do this, but here's the neatest +we've found. Maypole chooses where to get its templates either by +looking at the C config parameter or, if this is not +given, calling the C method to ask the front-end to +try to work it out. We can give the front-end a little bit of help, by +putting this method in our driver class: + + sub get_template_root { + my $r = shift; + my $browser = $r->headers_in->get('User-Agent'); + if ($browser =~ /mobile|palm|nokia/i) { + "/home/myapp/templates/mobile"; + } else { + "/home/myapp/templates/desktop"; + } + } + +(Maybe there's a better way to detect a mobile browser, but you get the +idea.) + +=head2 Content display hacks + +These hacks deal primarily with the presentation of data to the user, +modifying the F template or changing the way that the results of +particular actions are displayed. + +=head3 Null Action + +You need an "action" which doesn't really do anything, but just formats +up a template. + +B: There are two ways to do this, depending on what precisely +you need. If you just need to display a template, C +style, with no Maypole objects in it, then you don't need to write any +code; just create your template, and it will be available in the usual +way. + +If, on the other hand, you want to display some data, and what you're +essentially doing is a variant of the C action, then you need to +ensure that you have an exported action, as described in the +L and C"> +chapter: + + sub my_view :Exported { } + +=head3 Template Switcheroo + +An action doesn't have any data of its own to display, but needs to display +B. + +B: This is an B common hack. You've just issued an +action like C, which updates the database. You don't want +to display a page that says "Record updated" or similar. Lesser +application servers would issue a redirect to have the browser request +C> instead, but we can actually modify the Maypole +request on the fly and, after doing the update, pretend that we were +going to C> all along. We do this by setting the +objects in the C slot and changing the C