runScript

Description

Runs a single line of Python code as an expression. If a poll rate is specified, the function will be run repeatedly at the poll rate. This is a very powerful way for you to add extensions to the expression language. For example, one could write a project script module function called shared.weather.getTempAt(zip) that queried a web service for the current temperature at a given zipcode, and then bind the value of a label to the return value of that function.

The scriptFunction is a entered as a string and the pollRate is in milliseconds. You can optionally add any function arguments after the poll rate.

runScript Polling in Tags

The runScript function can be used in expression tags, but the poll rate doesn't work exactly the same as in an expression binding. All Tags have a Scan Class that dictates the minimum amount of time between each evaluation. The runScript poll rate only polls up to the rate of the scan class set on the tag.

For example, if an Expression Tag is configured with runScript to run at a poll rate of 60 seconds and is using the "default" (1 second) scan class, the Tag's Expression will still execute every 1 second. So a scan class rate of 60 seconds will be necessary for a runScript expression to poll at any rate between 0 and 60 seconds.

Syntax

runScript( scriptFunction, [pollRate], [arguments...] )

Examples

Code Snippet

# You could implement shared.weather.getTempAt(zip) with this Python script:
# This function would query Yahoo Weather for the temperature at
# the given zipcode and find the temperature using a regular expression
def getTempAt(woeid=0):
	import system
	import re #Regular Expression library
	try:
		# the Yahoo URL must be created with a woeid (Where On Earth ID) based on your zip code.
		# look up your woeid here: http://woeid.rosselliot.co.nz/lookup/
 
		# check if no value was entered, if so change it to Folsom CA.
		if woeid == 0:
			# the woeid for sunny Folsom, CA is:
			woeid = 12797905
 
		yahooURL = "https://query.yahooapis.com/v1/public/yql?q=select+*+from+weather.forecast+where+woeid%3D"
 
		response = system.net.httpGet(yahooURL + str(woeid))
		# NOTE - if you've never seen regular expressions before, don't worry, they look
		# confusing even to people who use them frequently.
		pattern = re.compile('.*?<yweather:condition (.*?)/>', re.DOTALL)
		match = pattern.match(response)
		if match:
			subText = match.group(1)
			temp = re.compile('.*?temp="(.*?)"').match(subText).group(1)
			return int(temp)
	except:
		system.gui.errorBox("Yahoo weather service changed")
		return -1

Expression Code Snippet

// run a shared function with this expression
runScript("shared.weather.getTempAt()", 15000) //This would bind a property to the temperature in sunny Folsom, CA, and would refresh itself every 15 seconds.

Expression Code Snippet

// run a shared function dynamically with this expression
// using string concatenation
runScript("shared.weather.getTempAt("+{Root Container.Numeric Text Field.intValue}+")", 0) // binds a property with a dynamic woeid code and does not refresh automatically

Expression Code Snippet

// run a shared function dynamically with this expression
// using optional arguments
// Note the missing "()" at the end of the scriptFunction string
runScript("shared.weather.getTempAt", 0, {Root Container.Numeric Text Field.intValue})