udt.diff

diff --git a/src/Namespaces.ts b/src/Namespaces.ts
index fd2e0ca..127b285 100644
--- a/src/Namespaces.ts
+++ b/src/Namespaces.ts
@@ -373,6 +373,9 @@ export const NS_OMEMO_AXOLOTL = 'eu.siacs.conversations.axolotl';
 export const NS_OMEMO_AXOLOTL_DEVICELIST = 'eu.siacs.conversations.axolotl.devicelist';
 export const NS_OMEMO_AXOLOTL_BUNDLES = 'eu.siacs.conversations.axolotl.bundles';
 
+// XEP-????
+export const NS_UDT_0 = 'urn:xmpp:udt:0';
+
 // istanbul ignore next
 export const NS_OMEMO_AXOLOTL_BUNDLE = (deviceId: string) =>
     `${NS_OMEMO_AXOLOTL_BUNDLES}:${deviceId}`;
diff --git a/src/plugins/index.ts b/src/plugins/index.ts
index 4cbc69b..8938377 100644
--- a/src/plugins/index.ts
+++ b/src/plugins/index.ts
@@ -18,6 +18,7 @@ export * from './pubsub';
 export * from './roster';
 export * from './sasl';
 export * from './sharing';
+export * from './udt';
 
 import Account from './account';
 import Avatar from './avatar';
@@ -38,6 +39,8 @@ import Roster from './roster';
 import SASL from './sasl';
 import Sharing from './sharing';
 
+import UDT from './udt';
+
 export function core(client: Agent) {
     client.use(Features);
     client.use(Disco);
@@ -61,4 +64,5 @@ export default function(client: Agent) {
     client.use(PubSub);
     client.use(Roster);
     client.use(Sharing);
+    client.use(UDT);
 }
diff --git a/src/plugins/udt.ts b/src/plugins/udt.ts
new file mode 100644
index 0000000..333b2a5
--- /dev/null
+++ b/src/plugins/udt.ts
@@ -0,0 +1,36 @@
+import { Agent } from '../';
+import * as JID from '../JID';
+import { NS_UDT_0 } from '../Namespaces';
+import { UDT, IQ } from '../protocol';
+
+declare module '../' {
+    export interface Agent {
+        sendJSON(jid: string, dataType: string, data: any): void;
+    }
+
+    export interface AgentEvents {
+        json: { from: string; dataType: string; json: any };
+    }
+}
+
+export default function(client: Agent) {
+    client.disco.addFeature(NS_UDT_0);
+
+    client.sendJSON = (jid: string, dataType: string, data: any) => {
+        client.sendMessage({
+            to: jid,
+            udt: [{ dataType, json: data }]
+        });
+    };
+
+    client.on('message', msg => {
+        if (msg.udt) {
+            for (const udt of msg.udt) {
+                client.emit('custom-data', {
+                    from: msg.from,
+                    ...udt
+                });
+            }
+        }
+    });
+}
diff --git a/src/protocol/index.ts b/src/protocol/index.ts
index 2c16820..155f8b7 100644
--- a/src/protocol/index.ts
+++ b/src/protocol/index.ts
@@ -81,6 +81,7 @@ export * from './xep0363';
 export * from './xep0380';
 export * from './xep0384';
 export * from './xrd';
+export * from './xep_udt';
 
 import RFC3921 from './rfc3921';
 import RFC4287 from './rfc4287';
@@ -163,6 +164,7 @@ import XEP0363 from './xep0363';
 import XEP0380 from './xep0380';
 import XEP0384 from './xep0384';
 import XRD from './xrd';
+import XEP_UDT from './xep_udt';
 
 const Protocol: Array<DefinitionOptions | DefinitionOptions[]> = [
     RFC3921,
@@ -245,7 +247,8 @@ const Protocol: Array<DefinitionOptions | DefinitionOptions[]> = [
     XEP0363,
     XEP0380,
     XEP0384,
-    XRD
+    XRD,
+    XEP_UDT
 ];
 
 export default Protocol;
diff --git a/src/protocol/xep_udt.ts b/src/protocol/xep_udt.ts
new file mode 100644
index 0000000..9118067
--- /dev/null
+++ b/src/protocol/xep_udt.ts
@@ -0,0 +1,44 @@
+// ====================================================================
+// XEP-????: XEP-XXXX: User-defined Data Transfer
+// --------------------------------------------------------------------
+// Source: https://xmpp.org/extensions/xep-????.html
+// Version: ???
+// ====================================================================
+
+import {
+    childJSON,
+    DefinitionOptions,
+    extendMessage,
+    pubsubItemContentAliases,
+    textJSON,
+    attribute
+} from '../jxt';
+import { NS_UDT_0, NS_JSON_0 } from '../Namespaces';
+
+declare module './' {
+    export interface Message {
+        udt?: UDT[];
+    }
+
+    export interface IQ {
+        udt?: UDT;
+    }
+}
+
+export interface UDT {
+    dataType: string;
+    json: any;
+}
+
+const Protocol: DefinitionOptions[] = [
+    {
+        namespace: NS_UDT_0,
+        element: 'udt',
+        aliases: [{ path: 'message.udt', multiple: true }, { path: 'iq.udt' }],
+        fields: {
+            dataType: attribute('datatype'),
+            json: childJSON(NS_JSON_0, 'json')
+        }
+    }
+];
+export default Protocol;