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+++ b/mod_pubsub_subscription/README.markdown	Mon Mar 15 16:31:23 2021 +0100
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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