Portfolio plugins

Introduction

For the purposes of this tutorial, it will be assumed you want to create a plugin called "foo"

Create a new directory in portfolio/type/ with the name of your plugin, for example, portfolio/type/foo.

You need to create the standard version.php in here that you would normally create for most other plugin types in Moodle.

You can also provide a db/ directory with an install.xml and upgrade.php along the same lines. These are optional.

Create a lib.php inside this directory.

Now we're going to create the necessary subclass to make our plugin work. It must be called portfolio_plugin_foo and directly extend either portfolio_plugin_push_base, or portfolio_plugin_pull_base. The only real differences between them are that one pushes the package directly to the remote system (usually via a HTTP POST, but could be filesystem based), and the other type (pull) requires the remote system to request it. portfolio_plugin_pull_base adds just one extra further abstract function (see below)

Read the phpdoc documentation for the base classes for further information about each function, including the arguments it takes and the expected return type. The following documentation serves as an overview.

Error handling

Your code should always throw exceptions of type portfolio_plugin_exception. You should NOT call error or print_error or whatever, and also any third party exceptions should really be caught and rethrown although most of the time other exceptions will be caught too by the portfolio code (although this will trigger a warning in debug mode)

Methods you must override

Static functions

get_name

Return a localized name for this plugin. Usually just something like:

get_string('pluginname', 'portfolio_yourplugin');

This is enforced as an abstract function rather than a loose fuzzy dependence on a language string for maximum ease when developing a new plugin (it's blindly obvious you must implement it ;) )

Class methods

prepare_package

Does anything necessary to prepare the package for sending. This might be writing out a metadata manifest file, or zipping up all the files in the temporary directory. This is called after the corresponding prepare_package method in the caller (which is given the path of a temporary directory it can write files to to be found by this method)

send_package

Actually send the package to the remote system (this might be just sending an xmlrpc request to say a file is ready for the remote system to fetch, (in which case you must set the $file member variable for portfolio/file.php later, or actually transfering the file)

get_continue_url

Return a url to present to the user as a 'continue to their portfolio' link. This can return false, although then you might want to implement get_extra_finish_options.

verify_file_request_params (pull only)

When remote systems request files, access control check is delegated to the plugin, by passing the array of request parameters. Should this function return false, access to the file will be denied.

expected_time

How long a transfer can reasonably expect to take. This function is passed the estimate from the caller (which usually takes into account filesize) and can either agree with it by returning whatever it is given, or override it. There are three options, PORTFOLIO_TIME_LOW, PORTFOLIO_TIME_MODERATE, and PORTFOLIO_TIME_HIGH. The first means the user will not be asked if they want to wait for the transfer or not, they will just wait. The second and third mean they'll be given the option (and in the case of the third, advised not to)

Methods you can override

Static functions

supported_formats

The formats this plugin can support. At export time, both the plugin and the caller are polled for which formats they can support, and then the intersection is used to determine the export format. In the case that the intersection is greater than 1, the user is asked for their selection.

The available formats you can choose from are in portfolio_supported_formats and are constants PORTFOLIO_FORMAT_XXX. By default the parent class defines PORTFOLIO_FORMAT_FILE.

plugin_sanity_check

If the plugin depends on some other part of Moodle being configured in a particular way (for example if your plugin relies on using mnet for transport and mnet is off), you can override this function. It is called frequently in different places in the code, and whenever a non empty value is returned (an error code), all instances of your plugin will be set to invisible.

has_admin_config

If your plugin has some admininistrative configuration settings (rather than by the user), override this plugin to return true. You must also override admin_config_form and get_allowed_config. You can also override admin_config_validation.

get_allowed_config

Because most of the handling of the getting and setting of admin entered configuration data happens in the parent class, with no need to be overridden in the subclasses, this method is responsible for letting the parent class know what fields are allowed.

allows_multiple

By default, all plugins can have multiple instances configured. If it's only sensible for your plugin to be able to have one instance configured, override this to return false.

Class methods

has_user_config

If your plugin can be configured in the user profile section, override this function to return true. You must also override user_config_form and get_allowed_user_config. You can also override user_config_validation.

has_export_config

If your plugin can have further (user) configuration during export, override this function to return true. You must also override export_config_form, get_export_summary and get_allowed_export_config. You can additionally override export_config_validation.

admin_config_form

This function can actually be called statically or non statically, depending on whether it's for editing an existing instance of the plugin, or for creating a new one. It's passed an mform object by reference, as are the other two config form functions, to add elements to it. If you override this you don't need to handle setting the data of the elements (when editing), that's done in the caller, using get_allowed_config. You can also override admin_config_validation.

user_config_form

If your plugin has overridden has_user_config to return true, you must implement this function. It takes a moodleform object as a parameter (passed by reference) to have additional elements added to it by this function. You can also override user_config_validation.

export_config_form

If your plugin has overridden has_export_config to return true, you must implement this function. It takes a moodleform object as a parameter (passed by reference) to have additional elements added to it by this function. You can also override export_config_validation.

admin_config_validation

This follows the exact same format as the validation() function in the moodleform object. This function can be called statically or non statically.

user_config_validation

This follows the exact same format as the validation() function in the moodleform object.

export_config_validation

This follows the exact same format as the validation() function in the moodleform object.

get_export_summary

If your plugin has overridden has_export_config, you must implement this to display nicely to the user on the confirmation screen. It should return an array of config options, the keys being nice strings to display to the user and the values being the selected config values.

steal_control

During any part of the export process, a plugin can completely steal control away from portfolio/add.php. This is useful, for example, for plugins that need the user go to log into a remote system and grant an application access. It could be also used for a completely custom screen provided by the plugin. If you need this, override this function to return a url, and the user will be redirected there. When you're finished, return to $CFG->wwwroot/portfolio/add.php?postcontrol=1 and processing will continue. If you override this, it might be useful to also override post_control.

post_control

After control is returned after steal_control, post_control will be called before the next stage is processed, and passed any request parameters. For an example of how this is used, see the box.net plugin, which uses steal_control to redirect to box.net to get the user to authenticate and then box.net redirects back to a url passing an authentication token to use for the rest of the session. Since it's part of the request parameters, it's passed through to post_control, which stores whatever it needs before the next stage.

get_allowed_user_config

Because the setting and getting of user entered configuration data happens in the parent class, this method is responsible for letting the parent class know what fields are allowed.

get_allowed_export_config

Because the setting and getting of per-export config data happens in the parent class, this method is responsible for letting the parent class know what fields are allowed (note that if you store non-user entered config data you must implement this function)

instance_sanity_check

Similar to plugin_sanity_check although operates on an instance basis. Again, returning anything non empty here will be taken as an error string, and the instance set to invisible.

send_file (pull only)

Sends the file to STDOUT (the browser in the case of the download plugin but may be an external system requesting it) - this function gets called when portfolio/file.php is requested and by default just passes the contents of the file straight through to the browser, unencrypted. The other pull plugin this far is mahara, and it doesn't implement this function as the file is retrieved via an xmlrpc request and sent back encrypted and base64 encoded.

cleanup

if you've stashed anything in extra database tables, you can implement this function to clean them up. this is called on cron to cleanup expired transfers, as well as after a successful transfer.

mnet_publishes

return array of xmlrpc service methods for mnet (see mahara implementation for more detail)

Methods you shouldn't really override

Static functions

create_instance

Creates an instance of the given plugin. As well as plugin and name, this can also be passed initial admin config. Returns an object of the correct subclass.

Class methods

__construct

Constructor for the plugin. Subclasses don't need to override this.

save

Saves data stored in the object back to the database and resets the dirty flag.

delete

Deletes this instance and all configuration data associated with it completely from the database

set_export_config

I had originally made this function final in the base class, but the box.net plugin needs to override it for dependent export config that's a bit funky.