Mercurial > prosody-modules
view mod_pubsub_subscription/README.markdown @ 4651:8231774f5bfd
mod_cloud_notify_encrypted: Ensure body substring remains valid UTF-8
The `body:sub()` call risks splitting the string in the middle of a
multi-byte UTF-8 sequence. This should have been caught by util.stanza
validation, but that would have caused some havoc, at the very least causing
the notification to not be sent.
There have been no reports of this happening. Likely because this module
isn't widely deployed among users with languages that use many longer UTF-8
sequences.
The util.encodings.utf8.valid() function is O(n) where only the last
sequence really needs to be checked, but it's in C and expected to be fast.
author | Kim Alvefur <zash@zash.se> |
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date | Sun, 22 Aug 2021 13:22:59 +0200 |
parents | 97fac0ba0469 |
children |
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# Introduction This module lets you programmatically subscribe to updates from a [pubsub][xep0060] node, even if the pubsub service is remote. ## Example ``` {.lua} module:depends("pubsub_subscription"); module:add_item("pubsub-subscription", { service = "pubsub.example.com"; node = "otter_facts"; -- Callbacks: on_subscribed = function() module:log("info", "Otter facts incoming!"); end; on_item = function(event) module:log("info", "Random Otter Fact: %s", event.payload:get_text()); end; }); ``` ## Usage Ensure the module is loaded and add your subscription via the `:add_item` API. The item table MUST have `service` and `node` fields and SHOULD have one or more `on_<event>` callbacks. The JID of the pubsub service is given in `service` (could also be the JID of an user for advanced PEP usage) and the node is given in, unsurprisingly, the `node` field. The various `on_event` callback functions, if present, gets called when new events are received. The most interesting would be `on_item`, which receives incoming items. Available events are: `on_subscribed` : The subscription was successful, events may follow. `on_unsubscribed` : Subscription was removed successfully, this happens if the subscription is removed, which you would normally never do. `on_error` : If there was an error subscribing to the pubsub service. Receives a table with `type`, `condition`, `text`, and `extra` fields as argument. `on_item` : An item publication, the payload itself available in the `payload` field in the table provided as argument. The ID of the item can be found in `item.attr.id`. `on_retract` : When an item gets retracted (removed by the publisher). The ID of the item can be found in `item.attr.id` of the table argument.. `on_purge` : All the items were removed by the publisher. `on_delete` : The entire pubsub node was removed from the pubsub service. No subscription exists after this. ``` {.lua} event_payload = { -- Common prosody event entries: stanza = util.stanza; origin = util.session; -- PubSub service details service = "pubsub.example.com"; node = "otter_facts"; -- The pubsub event itself item = util.stanza; -- <item/> payload = util.stanza; -- actual payload, child of <item/> } ``` # Compatibility Should work with Prosody \>= 0.11.x