core\access\get_user_capability_course_helper Class Reference

Helper functions to implement the complex get_user_capability_course function. More...

Static Public Member Functions
static	get_sql ($userid, $capability)
	Gets SQL to restrict a query to contexts in which the user has a capability. More...

Static Protected Member Functions
static	any_path_is_above ($prohibitpaths, $otherpath)
	Test if a context path $otherpath is the same as, or underneath, any of $prohibitpaths. More...
static	calculate_permission_tree (array $pathroleperms)
	Calculates a permission tree based on an array of information about role permissions. More...
static	create_sql ($parent)
	Creates SQL suitable for restricting by contexts listed in the given permission tree. More...
static	get_capability_info_at_each_context ($userid, $capability)
	Based on the given user's access data (roles) and system role definitions, works out an array of capability values at each relevant context for the given user and capability. More...
static	get_tree ($userid, $capability)
	Gets a permission tree for the given user and capability, representing the value of that capability at different contexts across the system. More...
static	path_is_above ($parentpath, $otherpath)
	Test if a context path $otherpath is the same as, or underneath, $parentpath. More...
static	remove_duplicate_nodes ($parent)
	Removes duplicate nodes of a tree - where a child node has the same permission as its parent. More...
static	remove_negative_subtrees ($root)
	Given a permission tree (in calculate_permission_tree format), removes any subtrees that are negative from the root. More...

Detailed Description

Helper functions to implement the complex get_user_capability_course function.

Copyright

2017 The Open University

License

http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

Member Function Documentation

any_path_is_above()

static core\access\get_user_capability_course_helper::any_path_is_above (   $prohibitpaths,   $otherpath  )

staticprotected

Test if a context path $otherpath is the same as, or underneath, any of $prohibitpaths.

Parameters

array	$prohibitpaths	array keys are context paths.
string	$otherpath	the path of another context.

Return values

int	releavant $roleid if $otherpath is underneath (or equal to) any of the $prohibitpaths, 0 otherwise (so, can be used as a bool).

calculate_permission_tree()

static core\access\get_user_capability_course_helper::calculate_permission_tree ( array  $pathroleperms )

staticprotected

Calculates a permission tree based on an array of information about role permissions.

The input parameter must be in the format returned by get_capability_info_at_each_context.

The output is the root of a tree of stdClass objects with the fields 'path' (a context path), 'allow' (true or false), and 'children' (an array of similar objects).

Parameters

array

$pathroleperms

Array of permissions

Return values

stdClass

Root object of permission tree

create_sql()

static core\access\get_user_capability_course_helper::create_sql (   $parent )

staticprotected

Creates SQL suitable for restricting by contexts listed in the given permission tree.

This function relies on the permission tree being in the format created by get_tree. Specifically, all the children of the root element must be set to 'allow' permission, children of those children must be 'not allow', children of those grandchildren 'allow', etc.

Parameters

stdClass

$parent

Root node of permission tree

Return values

array

Two-element array of SQL (containing ? placeholders) and then a params array

get_capability_info_at_each_context()

static core\access\get_user_capability_course_helper::get_capability_info_at_each_context (   $userid,   $capability  )

staticprotected

Based on the given user's access data (roles) and system role definitions, works out an array of capability values at each relevant context for the given user and capability.

This is organised by the effective context path (the one at which the capability takes effect) and then by role id. Note, however, that the resulting array only has the information that will be needed later. If there are Prohibits present in some roles, then they cannot be overridden by other roles or role overrides in lower contexts, therefore, such information, if any, is absent from the results.

Parameters

int	$userid	User id
string	$capability	Capability e.g. 'moodle/course:view'

Return values

array

Array of capability constants, indexed by context path and role id

get_sql()

static core\access\get_user_capability_course_helper::get_sql (   $userid,   $capability  )

static

Gets SQL to restrict a query to contexts in which the user has a capability.

This returns an array with two elements (SQL containing ? placeholders, and a params array). The SQL is intended to be used as part of a WHERE clause. It relies on the prefix 'x' being used for the Moodle context table.

If the user does not have the permission anywhere at all (so that there is no point doing the query) then the two returned values will both be false.

Parameters

int	$userid	User id
string	$capability	Capability e.g. 'moodle/course:view'

Return values

array

Two-element array of SQL (containing ? placeholders) and then a params array

get_tree()

static core\access\get_user_capability_course_helper::get_tree (   $userid,   $capability  )

staticprotected

Gets a permission tree for the given user and capability, representing the value of that capability at different contexts across the system.

The tree will be simplified as far as possible.

The output is the root of a tree of stdClass objects with the fields 'path' (a context path), 'allow' (true or false), and 'children' (an array of similar objects).

Parameters

int	$userid	User id
string	$capability	Capability e.g. 'moodle/course:view'

Return values

stdClass

Root node of tree

path_is_above()

static core\access\get_user_capability_course_helper::path_is_above (   $parentpath,   $otherpath  )

staticprotected

Test if a context path $otherpath is the same as, or underneath, $parentpath.

Parameters

string	$parentpath	the path of the parent context.
string	$otherpath	the path of another context.

Return values

bool	true if $otherpath is underneath (or equal to) $parentpath.

remove_duplicate_nodes()

static core\access\get_user_capability_course_helper::remove_duplicate_nodes (   $parent )

staticprotected

Removes duplicate nodes of a tree - where a child node has the same permission as its parent.

Parameters

stdClass

$parent

Tree root node

remove_negative_subtrees()

static core\access\get_user_capability_course_helper::remove_negative_subtrees (   $root )

staticprotected

Given a permission tree (in calculate_permission_tree format), removes any subtrees that are negative from the root.

For example, if a top-level node of the permission tree has 'false' permission then it is meaningless because the default permission is already false; this function will remove it. However, if there is a child within that node that is positive, then that will need to be kept.

Parameters

stdClass

$root

Root object

Return values

stdClass

Filtered tree root

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The documentation for this class was generated from the following file:

• lib/classes/access/get_user_capability_course_helper.php