Assumes AffectedSOPClass is returned in C-ECHO-RSP

[gilbahat]

Hi,

pynetdicom assumes that AffectedSOPClass is returned in a C-ECHO-RSP. However, it seems that at least mirth does not return AffectedSOPClass in its response, making pynetdicom unable to properly ping mirth, throwing the following trace:

File "pinger.py", line 38, in
st = assoc.VerificationSOPClass.SCU(1)
File "/usr/local/lib/python2.7/site-packages/netdicom/SOPclass.py", line 60, in SCU
ans, id = self.DIMSE.Receive(Wait=True)
File "/usr/local/lib/python2.7/site-packages/netdicom/DIMSEprovider.py", line 75, in Receive
return tmp.ToParams(), tmp.ID
File "/usr/local/lib/python2.7/site-packages/netdicom/DIMSEmessages.py", line 248, in ToParams
tmp.AffectedSOPClassUID = self.CommandSet[(0x0000,0x0002)]
File "/usr/local/lib/python2.7/site-packages/pydicom-0.9.9-py2.7.egg/dicom/dataset.py", line 277, in getitem
data_elem = dict.getitem(self, tag)
KeyError: (0000, 0002)

the quick fix is to change AffectedSOPClassUID to optional, in DIMSEmessages.py line 247:

    if self.CommandSet.has_key((0x0000,0x0002)):
        tmp.AffectedSOPClassUID = self.CommandSet[(0x0000,0x0002)]

I will file a bug with Mirth in parallel, but I believe pynetdicom should be more lenient.

[gilbahat]

Looks like this is affecting more SOP classes and more keys like AffectedSOPInstanceUID. This had better be a more generic thing rather than just those classes.