SVGHMI: JsonTable now use intermediate variables again to address JSON data without duplicating code or referencing. Using intermediate variables also alows to check for availability of data and stop evaluating early if data is missing. Finally added complete roundtrip example to illustrate use of JSonTable to display "alarms" collected in python from changes on PLC boolean variables.
#!/usr/bin/env python
# -*- coding: utf-8 -*-
# See COPYING file for copyrights details.
from __future__ import absolute_import
import hashlib
class ConnectorBase(object):
chuncksize = 1024*1024
def BlobFromFile(self, filepath, seed):
s = hashlib.new('md5')
s.update(seed)
blobID = self.SeedBlob(seed)
with open(filepath, "rb") as f:
while blobID == s.digest():
chunk = f.read(self.chuncksize)
if len(chunk) == 0:
return blobID
blobID = self.AppendChunkToBlob(chunk, blobID)
s.update(chunk)
raise IOError("Data corrupted during transfer or connection lost")