Crate submap

source ·
Expand description

§submap

B-tree map for pub/sub services.

§Subscription map

§Usage

use submap::SubMap;

type Client = String;

let mut smap: SubMap<Client> = SubMap::new();

where “Client” is a pub/sub client type, which is usually either a channel or a structure which contains a channel or locked socket or anything else, required to work with the client.

The client type MUST provide traits Ord, Eq and Clone.

All clients must be registered in the map, before they can subscribe/unsubscribe. Use “register_client” function for this.

When “unregister_client” is called, it also automatically unsubscribes the client from all the subscribed topics.

§Separators and wildcards

SubMap supports the following masks:

  • this/is/a/topic - single topic subscription
  • this/?/a/topic - all topics which match the pattern (2nd chunk - any value)
  • this/is/* - all subtopics of “this/is”
  • * - all topics

Service symbols can be changed. E.g. let us create a subscription map with MQTT-style wildcards (+ for ? and # for *) but with the dot as the subtopic separator:

use submap::SubMap;

type Client = String;

let mut smap: SubMap<Client> =
    SubMap::new().separator('.').match_any("+").wildcard("#");

Note that “/topic/x”, “topic/x” and “topic//x” are 3 different topics. If any kind of normalization is required, it should be done manually, before calling SubMap functions.

§Formulas

SubMap also supports formulas, which are used both to subscribe to a topic by formula or to get a list of clients which match one.

Formulas are non-standard pub/sub functionality and are useful when a client want to subscribe to topics which have got e.g. some importance level. Instead of subscribing to all level topics, a client can subscribe to one topic with a formula:

use submap::SubMap;

type Client = String;

let mut smap: SubMap<Client> =
    SubMap::new().separator('/').match_any("+").wildcard("#").formula_prefix('!');
let client1 = "client1".to_owned();
smap.register_client(&client1);
smap.subscribe("some/!ge(2)/topic", &client1);
assert_eq!(smap.get_subscribers("some/1/topic").len(), 0);
assert_eq!(smap.get_subscribers("some/2/topic").len(), 1);
assert_eq!(smap.get_subscribers("some/3/topic").len(), 1);

See more: mkmf::Formula.

§Broadcast map

use submap::BroadcastMap;

type Client = String;

let mut bmap: BroadcastMap<Client> = BroadcastMap::new();

Does the opposite job - clients are registered with regular names, while “get_clients_by_mask” function returns clients, which match the mask.

Note: the default separator is dot.

§ACL map

let mut acl_map = submap::AclMap::new();

SubMap-based high-speed access control lists checker. Uses SubMap algorithm with a single unit “client” to verify various access control lists.

§Crate features

  • indexmap switches the engine to indexmap (the default is based on std::collections::BTreeMap/BTreeSet), requires Hash trait implemented for map clients.

The current engine can be obtained from

use submap::types::ENGINE;

dbg!(ENGINE); // std-btree or indexmap

§Cargo crate

https://crates.io/crates/submap

Modules§

  • digest
  • mkmf
    A module for matching keys/value keys in a map with a formula.
  • types

Structs§

Enums§