In case you would go to executeCommandLine together with curl this Can't get InfluxDB data to Grafana when seetting my own timestamp - #2 by kosken post shows a possible implementation for that call ( just focus on the call to the curl function ).
With regard to the http binding I am not that well experienced 
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But what is the content of ( val ) output ? Shouldn’t that contain information about the error in case somethign is wrong ? Does it report success or a problem ? Is there any information in the influxdb log files that could help ?