Instructions

BS1400 Messenger to a webserver

Introduction

The BS1500 GP(R)S base station for the Arexx Multilogger system has built-

in messenger functionality. With the messenger it is possible source http

requests to external web servers by the base station. The http requests are

used to transport measurement data to a database via a script based web

servicelikeMySQL/ApacheorMicrosoft’sSQLServer/asp.net.Themessenger

applies given rules for each incoming measurement. A rule is an action that

is executed as soon as its accompanying condition is met. Rules are com-

posedbytheRuleEditortool,andtheresultingruleleisuploadedtothe

BS1500 were it becomes active immediately after upload. The rule action can

be an email message, a HTTP request or turning on the built-in buzzer.

Here we focus on the HTTP requests.

HTTP request

The HTTP request contains the following data:

• Request type: POST or GET

• URL: the URL of the web service, a port number can be added to

this URL, separated by a colon.

• Requestdata:auserdenedstringthatcontainstheactualdata.

This string is base64 encoded.

•

When the HTTP request type is POST, the request data string is added to the

http request, when the request type is GET, the request data string is appen-

dedtotheURLseparatedbythe‘?’character.Ontheserversidethechosen

requestmethoddeneshowthedataisextracted.

The request data string is composed by the BS1500 to contain actual measu-

rementdatabythegivenrequestdatastring.Datatags(startingwiththe‘$’

character) are replaced by the actual data, like measurement value, sensor

id etc. The resulting string is base64 encoded thereafter, and sent to the web

server as a HTTP request. The following data tags can be used: