Add Mattermost driver

drivers/mattermost.groovy

@@ -0,0 +1,98 @@
+/**
+*   
+*   File: mattermost.groovy
+*   Requirements: Requires a Mattermost webhook url.
+*   Platform: Hubitat
+*   Modification History:
+*     2023-03-11    Initial Release
+*
+*  Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
+*  in compliance with the License. You may obtain a copy of the License at:
+*
+*      http://www.apache.org/licenses/LICENSE-2.0
+*
+*  Unless required by applicable law or agreed to in writing, software distributed under the License is distributed
+*  on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License
+*  for the specific language governing permissions and limitations under the License.
+*/
+
+preferences {
+    input("mm_url", "text", title: "Webhook URL:", description: "Incoming webhook URL", required: true)
+    input("mm_channel", "text", title: "Channel:", description: "Override the default channel", required: false)
+    input("mm_username", "text", title: "Username:", description: "Override the default username", required: false)
+    input("mm_icon_url", "text", title: "Icon URL:", description: "Override the default profile picture", required: false)
+    input("mm_icon_emoji", "text", title: "Icon Emoji:", description: "Override the default profile picture", required: false)
+    input("debug", "bool", title: "Enable Debug Logging", required: true, defaultValue: false)
+}
+
+metadata {
+    definition (name: "Mattermost", namespace: "jglemza-hubitat", author: "Joshua Glemza",
+               importUrl: "https://git.hwarf.com/jglemza/hubitat/raw/branch/main/drivers/mattermost.groovy") {
+        capability "Notification"
+        capability "Actuator"
+        capability "Speech Synthesis"
+    }
+}
+
+def installed() {
+    initialize()
+}
+
+def updated() {
+    initialize()   
+}
+
+def initialize() {
+}
+
+def speak(message) {
+    deviceNotification(message)
+}
+
+def deviceNotification(message) {
+  
+    def postBody = [text:message]
+
+    if(settings.mm_channel != '') {
+        postBody['channel'] = settings.mm_channel
+    }
+    
+    if(settings.mm_username != '') {
+        postBody['username'] = settings.mm_username
+    }
+    
+    if(settings.mm_icon_url != '') {
+        postBody['icon_url'] = settings.mm_icon_url
+    }
+    
+    if(settings.mm_icon_emoji != '') {
+        postBody['icon_emoji'] = settings.mm_icon_emoji
+    }
+         
+    ifDebug("Sending Message: $message [${postBody}]")
+
+    // Prepare the package to be sent
+    def params = [
+        uri: settings.mm_url,
+        body: postBody
+    ]
+    try {
+       httpPostJson(params){response ->
+            if(response.status != 202) {
+                sendPush("ERROR: 'Mattermost' received HTTP error ${response.status}.")
+                log.error "Received HTTP error ${response.status}. ${response}"
+            }
+            else {
+                ifDebug("Message queued for sending via Mattermost.")
+       }
+      }
+    } catch (e) {
+        log.error "Mattermost: Error making httpPostJson: $e"
+    }
+}
+
+private ifDebug(msg) {
+    if (settings?.debug || settings?.debug == null) {
+        log.debug 'Mattermost: ' + msg
+    }
+}