Some while ago i searched for a rule that could download an image from the internet and save it into an item.
I found a solution from @mindstorms6 that worked for quite some time now.
With oH 4 something has changed and this rule is throwing an out of memory error.
The rule in question:
rule "Speedtest Image Update"
when
Item spdURL changed
then
val speedImage = spdURL.state + ".png"
var userImageDataBytes = newByteArrayOfSize(0)
try {
// use the built in java URL class - pass it the url to download
val url = new URL(speedImage)
// create an output stream - we'll use it for building up our downloaded bytes
val byteStreamOutput = new ByteArrayOutputStream()
// open the url as a stream - aka - start getting stuff
val inputStream = url.openStream()
// n is a variable for tracking how much data we have read off the inputStream per loop (and how much we write to the output stream)
var n = 0
// buffer is another byte array. basically we're using it as a fixed size copy byte array
var buffer = newByteArrayOfSize(1024)
do {
// read from input stream (the data at the url) into buffer - and place how many bytes were read into n
n = inputStream.read(buffer)
if (n > 0) {
// if we read more than 0 bytes - copy them from buffer into our output stream
byteStreamOutput.write(buffer, 0, n)
}
} while (n > 0) // keep doing this until we don't have anything to read.
userImageDataBytes = byteStreamOutput.toByteArray() // assemble all the bytes we wrote into an actual byte array
} catch(Throwable t) {
logError(ruleId, "Es ist ein Problem beim Download aufgetreten: " + t.toString)
}
logDebug(ruleId, "Bild Daten erhalten")
// make a new RawType with the byte array and the mime type - the open hab type Image needs a raw type
// my images are all jpeg - so this mime type is right for me
val rawType = new RawType(userImageDataBytes, "image/jpeg")
// entry.getValue is the "ImageItem" from the map. In my case - this is BrelandImage
if (rawType.toString != spdImage.state.toString) { // if this raw type isn't the same as what's already there (the toString is a kind of accurate way to test - the raw type to string is bascially mime + size - which is a bad approximation for equality - but good enough for me
spdImage.postUpdate(rawType) // update it!
logDebug(ruleId, "Bild aktualisiert")
} else {
logDebug(ruleId, "Bilder waren identisch")
}
end
The error: An error occurred while calling method 'NetworkAddressChangeListener.onChanged()' on 'org.openhab.core.io.transport.mdns.internal.MDNSClientImpl@69ce48c5': unable to create native thread: possibly out of memory or process/resource limits reached
ItĀ“s totally random when this error appears.
Sometimes itĀ“s only once a day and sometimes itĀ“s multiple times in a row.
I know itĀ“s coming from this rule as the logError for catch(Throwable t) is only used in this rule.
Is there something in oH 4 (until 4.1.1) that changed and could have an impact on this rule?
I switched to the raspberry pi 5 with openhabian v1.8c and an Sandisk Endurance card.
So atleast the rpi and sd card are brand new and canĀ“t have an impact on this.
2024-03-07 14:18:48.356 [ERROR] [internal.handler.ScriptActionHandler] - Script execution of rule with UID 'speedtest-2' failed: The name 'inputStream' cannot be resolved to an item or type; line 177, column 9, length 11 in speedtest
I assume this only works with rules from the UI and not in .rules files?
IĀ“m honest and donĀ“t know how to get this working with my rule
I just put the inputStream.close(); after userImageDataBytes = byteStreamOutput.toByteArray() inside the try { ... } phase.
Seems to work until nowā¦ iĀ“ll wait and see if itĀ“s still throwing an OutOfMemoryError.
That was for a file based rule but in jruby, so you need to install the jruby automation addon and create the file insideconf/automation/ruby/ folder, and call it something.rb. See Installation
You can do something similar in UI rule too, but the rule / trigger creation is slightly different. The rule body is the exact same.
No worries, since your rule is written in DSL it might differ a bit in certain aspects. More recent Java version allow to use try (InputStream str = open(...)) { ... } syntax which automatically close stream after leaving inner code block.
Whole point of sample I pasted is:
Declare input stream variable before try { part
Open stream inside contents of try block
Within finally part close stream, only if it was successfully opened before
It might happen that url.openStream() throws an error, then finally section has nothing to do since stream was not even created. Thatās why its necessary to have a null check.
