session-trees.h File Reference

Allows a client session to configure session trees. More...

Data Structures
struct	diffusion_session_trees_put_branch_mapping_table_params_s
	Structure supplied when issuing a diffusion_session_trees_put_branch_mapping_table call. More...
struct	diffusion_session_trees_get_session_tree_branches_params_s
	Structure supplied when issuing a diffusion_session_trees_get_session_tree_branches call. More...
struct	diffusion_session_trees_get_branch_mapping_table_params_s
	Structure supplied when issuing a diffusion_session_trees_get_branch_mapping_table call. More...

Typedefs
typedef struct DIFFUSION_BRANCH_MAPPING_TABLE_BUILDER_T	DIFFUSION_BRANCH_MAPPING_TABLE_BUILDER_T
	Opaque Branch Mapping Table Builder struct.
typedef struct DIFFUSION_BRANCH_MAPPING_TABLE_T	DIFFUSION_BRANCH_MAPPING_TABLE_T
	Opaque Branch Mapping Table struct.
typedef struct DIFFUSION_BRANCH_MAPPING_T	DIFFUSION_BRANCH_MAPPING_T
	Opaque Branch Mapping struct.
typedef int(*	branch_mapping_table_set_cb) (void *context)
	callback when branch mapping table has been set on the server
typedef int(*	get_session_tree_branches_cb) (const LIST_T *session_tree_branches, void *context)
	callback when branch mapping table has been set on the server
typedef int(*	get_branch_mapping_table_cb) (const DIFFUSION_BRANCH_MAPPING_TABLE_T *table, void *context)
	callback when branch mapping table has been retrieved from the server
typedef struct diffusion_session_trees_put_branch_mapping_table_params_s	DIFFUSION_SESSION_TREES_PUT_BRANCH_MAPPING_TABLE_PARAMS_T
	Structure supplied when issuing a diffusion_session_trees_put_branch_mapping_table call.
typedef struct diffusion_session_trees_get_session_tree_branches_params_s	DIFFUSION_SESSION_TREES_GET_SESSION_TREE_BRANCHES_PARAMS_T
	Structure supplied when issuing a diffusion_session_trees_get_session_tree_branches call.
typedef struct diffusion_session_trees_get_branch_mapping_table_params_s	DIFFUSION_SESSION_TREES_GET_BRANCH_MAPPING_TABLE_PARAMS_T
	Structure supplied when issuing a diffusion_session_trees_get_branch_mapping_table call.

Functions
DIFFUSION_BRANCH_MAPPING_TABLE_BUILDER_T *	diffusion_branch_mapping_table_builder_init ()
	Initialise a new branch mapping table builder.
DIFFUSION_BRANCH_MAPPING_TABLE_BUILDER_T *	diffusion_branch_mapping_table_builder_reset (DIFFUSION_BRANCH_MAPPING_TABLE_BUILDER_T *builder)
	Reset the stored branch mappings in the branch mapping table builder.
DIFFUSION_BRANCH_MAPPING_TABLE_BUILDER_T *	diffusion_branch_mapping_table_builder_add_branch_mapping (DIFFUSION_BRANCH_MAPPING_TABLE_BUILDER_T *builder, char *session_filter, char *topic_tree_branch)
	Adds a new branch mapping with the specified values.
DIFFUSION_BRANCH_MAPPING_TABLE_T *	diffusion_branch_mapping_table_builder_create_table (DIFFUSION_BRANCH_MAPPING_TABLE_BUILDER_T *builder, char *session_tree_branch)
	Creates a branch mapping table for the specified session tree branch.
void	diffusion_branch_mapping_table_builder_free (DIFFUSION_BRANCH_MAPPING_TABLE_BUILDER_T *builder)
	Free a branch mapping table builder.
void	diffusion_branch_mapping_table_free (DIFFUSION_BRANCH_MAPPING_TABLE_T *table)
	Free a branch mapping table.
char *	diffusion_branch_mapping_table_get_session_tree_branch (DIFFUSION_BRANCH_MAPPING_TABLE_T *table)
	Get the session tree branch from a branch mapping table.
LIST_T *	diffusion_branch_mapping_table_get_branch_mappings (DIFFUSION_BRANCH_MAPPING_TABLE_T *table)
	Get the branch mappings from a branch mapping table.
void	diffusion_branch_mapping_table_free_branch_mappings (LIST_T *branch_mappings)
	Free a list containing branch mappings.
char *	diffusion_branch_mapping_get_session_filter (DIFFUSION_BRANCH_MAPPING_T *mapping)
	Get the session filter from a branch mapping.
char *	diffusion_branch_mapping_get_topic_tree_branch (DIFFUSION_BRANCH_MAPPING_T *mapping)
	Get the topic tree branch from a branch mapping.
bool	diffusion_session_trees_put_branch_mapping_table (SESSION_T *session, const DIFFUSION_SESSION_TREES_PUT_BRANCH_MAPPING_TABLE_PARAMS_T params, DIFFUSION_API_ERROR *api_error)
	Create or replace a branch mapping table.
bool	diffusion_session_trees_get_session_tree_branches (SESSION_T *session, const DIFFUSION_SESSION_TREES_GET_SESSION_TREE_BRANCHES_PARAMS_T params, DIFFUSION_API_ERROR *api_error)
	Retrieve the session tree branches of the server's branch mapping tables.
bool	diffusion_session_trees_get_branch_mapping_table (SESSION_T *session, const DIFFUSION_SESSION_TREES_GET_BRANCH_MAPPING_TABLE_PARAMS_T params, DIFFUSION_API_ERROR *api_error)
	Retrieve a branch mapping table from the server.

Detailed Description

Allows a client session to configure session trees.

A session tree is a virtual view of the topic tree presented to a session by fetch and subscription operations. Custom session trees for different sessions can be configured using declarative rules maintained by the server to meet data security, data optimisation, or personalisation and localisation requirements. Each session can be presented with a unique session tree based on its session properties.

A session tree is produced by applying branch mappings to the topic tree. Branch mappings are organised into branch mapping tables. Each branch mapping table is assigned to a unique path – the session tree branch.

A session tree is composed of session paths. Each session path is mapped via the branch mapping tables to a unique topic path.

A branch mapping table is an ordered list of (session filter, topic tree branch) pairs. For example, the branch mapping table for the session tree branch market/prices might be:

Session filter                           Topic tree branch
==============                           =================
USER_TIER is '1' or $Country is 'DE'     backend/discounted_prices
USER_TIER is '2'                         backend/standard_prices
$Principal is ''                         backend/delayed_prices

With this configuration, if an unauthenticated session (one that matches the $Principal is '' session filter) subscribes to the session path market/prices/X, and there is a topic bound to the topic path backend/delayed_prices/X, the subscription will complete. The session will receive a subscription notification under the session path market/prices/X, together with the topic properties and the value of the topic. The session is unaware that the data originates from a topic bound to a different topic path. If no topic is bound to backend/delayed_prices/X, the subscription will not resolve and the session will receive no data, even if there is a topic bound to market/prices/X.

Session trees complement the data transformation capabilities of topic views. In our example, the time delayed time feed at backend/delayed_prices could be maintained by a topic view using the delay by clause.

Branch mappings are persisted by the server and shared across a cluster, in a similar manner to topic views, security stores, and metric collectors. Branch mappings are editable using this feature, and via the management console.

For a given session and session path, at most one branch mapping applies. The applicable branch mapping is chosen as follows:

• Each branch mapping table with session tree branch that is a prefix of the session path is considered. For a given table, the first branch mapping with a session filter that matches the session's properties is the one that applies. A branch mapping table may have no applicable branch mappings for a session.
• If there are several such branch mapping tables with a branch mapping that for the session, the one with the longest prefix of the session path applies.
• If no branch mapping table has a branch mapping for the session, the session path is translated to the identical topic path.

Access control

To subscribe to or fetch from a session path, a session must be granted the appropriate path permission to the session path for the operation PATH_PERMISSION_SELECT_TOPIC, or PATH_PERMISSION_READ_TOPIC). The session doesn't require any permissions to the topic path of the topic providing the data.

To create or replace branch mappings, a session needs the PATH_PERMISSION_MODIFY_TOPIC path permission for the session tree branch of the branch mapping table, PATH_PERMISSION_EXPOSE_BRANCH path permission for the topic tree branch of each branch mapping, and (if an existing table with the same session tree branch is being replaced) PATH_PERMISSION_EXPOSE_BRANCH permission for each branch mapping of existing table.

To retrieve a branch mapping table, a session needs the PATH_PERMISSION_READ_TOPIC path permission for its session tree branch.

Since

6.7

Typedef Documentation

branch_mapping_table_set_cb

typedef int(* branch_mapping_table_set_cb) (void *context)

callback when branch mapping table has been set on the server

Parameters

context

User supplied context.

Returns

HANDLER_SUCCESS or HANDLER_FAILURE.

get_branch_mapping_table_cb

typedef int(* get_branch_mapping_table_cb) (const DIFFUSION_BRANCH_MAPPING_TABLE_T *table, void *context)

callback when branch mapping table has been retrieved from the server

Parameters

table	The branch mapping table.
context	User supplied context.

Returns

HANDLER_SUCCESS or HANDLER_FAILURE.

get_session_tree_branches_cb

typedef int(* get_session_tree_branches_cb) (const LIST_T *session_tree_branches, void *context)

callback when branch mapping table has been set on the server

Parameters

session_tree_branches	A list of session tree branches.
context	User supplied context.

Returns

HANDLER_SUCCESS or HANDLER_FAILURE.