Regular Expressions Alerts Guide

Regular Expression Pattern Syntax

Your regular expression patterns must conform to the syntax specified in the link below. http://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html When implementing regular expression patterns, the website below will be useful. http://www.regexplanet.com/advanced/java/index.html This website enables you to construct a regular expression and test the pattern across multiple inputs. Make sure to test for both false positives and false negatives. Regular expressions tend to have minor implementation or syntax differences in different languages / technology stacks. When testing out regular expressions for use in Arrayent alerts, make sure to test your pattern against the Java regular expression engine.

Inserting Attribute Values into Alert Messages

If you want to know the exact value of an attribute when the regular expression alert is triggered, you can use the Arrayent Cloud’s variable text feature. The syntax is as follows:

{device.<ATTRIBUTE NAME>}

Where <ATTRIBUTE NAME> is the name of the attribute whose value you want to insert. For example, if you want to insert the value of an attribute called error then you would use the following:

{device.error}

Continuing with the example, you could send the following message when an alert is triggered:

Error Code: {device.error}

If error was set to 10 and this value triggers the alert, then the recipient of the alert would receive the following message:

Error Code: 10

If the attribute is not valid, then the Arrayent Cloud will not substitute the template. The text will be interpreted literally. If error was not a valid attribute in your device data model, the recipient of the alert message would literally receive Error Code:{device.error}.

Examples

First, we create a Device Attribute for testing regular expression patterns. De-selecting Hardware Attribute enables us to set the value of the attribute, even when the device is offline. See Hardware Attribute to learn more. Next, we create the regular expression alert using addTrigger:

https://DevKit-api.arrayent.com:8081/zdk/services/zamapi/addTrigger?
secToken=11817-106868332&devId=184554197&attrName=message&operation=regex&
stringThreshold=H.*&address=kayce.basques@arrayent.com&msg={device.message}&
action=email&autoDisarm=true&autoDisable=false&autoDelete=false&enable=true

We’re skipping a few web service requests here. You’ll need to make a few calls before you have enough information to calladdTrigger (namely userLogin and getDeviceList). The Arrayent Cloud returns the following response:

<ns1:addTriggerResponse xmlns:ns1="http://arrayent.com/zamapi/">
 <triggerId>16144</triggerId>
</ns1:addTriggerResponse>

We could also create the alert using the Utility application. This alert is exactly the same as the addTrigger request earlier. The regular expression alert is triggered when message is set to any value that begins with H. Let’s set the value now. In our email we receive an email containing the text Hello, World!.