Nesting from a Hot Folder

Wasatch SoftRIP includes very simple nesting from a hot folder. Jobs are arranged side-by-side, and when a row is filled, the row is output. This can be appropriate when all jobs are the same size, but is of limited or no use in other situations. Automation Option is the solution.

The script below supports all of the nesting options available on the Layout Tab of the user interface. This is particularly useful for sitations that involve nesting jobs of mixed sizes. The script periodically tests the contents of the Print Queue, using a nesting algorithm such as "TIGHTEST". When the result exceeds a specified height, it prints the layout.

To use this, configure a basic Wasatch hot folder for RIP Only". Jobs landing there will be RIP'ed and placed into the Print Queue, and held there. Run this script. It will periodically test nesting of the jobs that have accumulated in the Print Queue. It will perform output when the result of nesting exceeds "printWhenThisHeightIsExceeded".

It clears the Print Queue following output, each time it outputs a layout. This script uses the "printQueueLayout.dyn" feature of XML Access to test nesting of the current Print Queue.

Python 3 Source Code

# This script will run Wasatch nesting on the contents of the print queue, and return the height of the resulting layout.
#
# If the height of the layout exceeds 'printWhenThisHeightIsExceeded', it will submit the layout for printing.
#
# Because this version operates on the print queue only, printing starts immediately and rotation is not allowed to the nesting algorithm.
#
import urllib.request
import xml.etree.ElementTree as ET
import time
import sys

wasatchSoftRIP = '127.0.0.1:80'  # just localhost in this example
printUnit = 1
copies = 1 # in this simple example, the same copy count is applied to every item in the print queue
nestType = 'TIGHTEST' # must be one of "SIMPLE", "EASYCUT", "SUPEREASYCUT", "TIGHTEST"
printWhenThisHeightIsExceeded = 3 # inches (short for quick tests)
frequency = 60 # seconds - check the print queue every 'frequency' seconds (the nesting calculation can be costly, so don't make this too frequent)
 
def getLayout(printUnit):
    url = 'http://' + wasatchSoftRIP + '/printQueueLayout.dyn?PRINTUNIT=' + str(printUnit) + '&NEST=' + nestType + '&COPIES=' + str(copies)
    try:
        p = urllib.request.urlopen(url)
        mybytes = p.read()  
        p.close()
    except:
        print("Could not access server")
        sys.exit("no server") 
        return 0.0

xml = mybytes.decode("utf-8")
            
    xmlRoot = ET.fromstring(xml) # parse the XML retured by SoftRIP
    return xml, float(xmlRoot.find('LAYOUT').attrib['height'])
 
def printLayout(xml):
    url = 'http://' + wasatchSoftRIP + '/xmlSubmission.dyn?'
    url += urllib.parse.quote_plus(xml)  # escape all special characters in data
    try:
        p = urllib.request.urlopen(url)
        mybytes = p.read()
        p.close()
        print("Success")
    except:
        print("Failure")

def layoutAlreadyInQueue(printUnit):
    url = 'http://' + wasatchSoftRIP + '/xmlQueueStatus.dyn?PRINTUNIT=' + str(printUnit)
    try:
        p = urllib.request.urlopen(url)
        mybytes = p.read()  
        p.close()
    except:
        return True # not true, but might as well be

x = mybytes.decode("utf-8")
    if 'Not configured' in x:
        return True  # not true, but might as well be

xmlRoot = ET.fromstring(x) # parse the XML
    prtQueue = xmlRoot.find('PRINTQUEUE')
    for item in prtQueue.iter('ITEM'):
        if item.attrib['layout'] == 'true':
            return True # found a layout
    return False # no layouts found
    
def editLayout(xml):  # edit the layout to delete print queue entries after printing
    xmlRoot = ET.fromstring(xml) # parse the XML retured by SoftRIP
    xmlRoot.find('LAYOUT').append(ET.Element('DELETEAFTERPRINT'))
    return ET.tostring(xmlRoot, encoding='Utf-8', method='xml').decode("utf-8")
 
#
# Now loop endlessly, testing the print queue with the nesting method
#
while True:
    xml, height = getLayout(printUnit)
    if height > printWhenThisHeightIsExceeded:
        if not layoutAlreadyInQueue(printUnit):
            xml = editLayout(xml)
            printLayout(xml)
        else:
            print("Layout already in process in Print Queue")
    time.sleep(frequency)