Overview
This component allows filtering incoming messages by attributes of the device. This filter is very useful if you want to apply the rule only to the certain sub-set of your device. Filter expression is a javascript expression and basically defines this sub-set. You are able to use any attribute types.
Configuration
You are able to write boolean javascript expression using following bindings:
- cs - client-side attributes map.
- ss - server-side attributes map.
- shared - shared attributes map.
If you are not sure that certain attribute is present, you can add check it’s type for undefined. For example, filter below will match if client-side attribute ‘firmware_version’ is set and equal to ‘1.0.0’
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typeof cs.firmware_version !== 'undefined' && cs.firmware_version === '1.0.0'
Example
Assuming following device attributes and their types
- firmware_version - client-side
- country - client-side
- subscription_plan - shared
- balance - server-side
The following filter will match all premium subscription devices with positive balance that are located in the USA with firmware version equal to 1.1.0
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cs.firmware_version=='1.1.0' && cs.country=='USA' && shared.subscription_plan=='premium' && ss.balance > 0
If you are not sure that all attributes are present for your device, you should use the following syntax that adds all necessary “null” checks
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typeof cs.firmware_version !== 'undefined' &&
typeof cs.country !== 'undefined' &&
typeof shared.subscription_plan !== 'undefined' &&
typeof ss.balance !== 'undefined' &&
cs.firmware_version=='1.1.0' && cs.country=='USA' && shared.subscription_plan=='premium' && ss.balance > 0
