Colons in the XML

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George Harris

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Apr 22, 2016, 4:28:31 AM4/22/16

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Hey all,

This is probably a simple problem to fix but I've been frantically googling and can't find anything to fix the problem I've been having.

I'm currently using Python to receive the feed from the Darwin push ports and while I can easily get python to print certain elements of the XML I'm struggling to access the any that have a colon for example from the below "ns3:Location".

I have been using xmltodict,

I'm fairly new to XML never really touched it so any help would be greatly appreciated any links for further reading :D.

The code I am using:

p = xmltodict.parse(XML)

uid = p['Pport']['uR']['TS']['@uid']
ssd = p['Pport']['uR']['TS']['@ssd']

print uid, ssd

If I try using the above to access the tiploc

locationA = p['Pport']['uR']['TS']['ns3:Location']['@tpl']

print uid, ssd, locationA

This sometimes prints out the tipoc but other times I receive the error message "typeError: list indices must be integers, not str"

<?xml version="1.0" encoding="UTF-8"?>
<Pport
xmlns="http://www.thalesgroup.com/rtti/PushPort/v12"
xmlns:ns3="http://www.thalesgroup.com/rtti/PushPort/Forecasts/v2" ts="2016-04-22T08:23:41.1016956+01:00" version="12.0">
<uR updateOrigin="TD">
<TS rid="201604221220927" ssd="2016-04-22" uid="W02997">
<ns3:Location pta="08:28" tpl="CANONST" wta="08:26">
<ns3:arr at="08:24" src="TD"/>
</ns3:Location>
</TS>
</uR>
</Pport>

petermount

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Apr 22, 2016, 4:44:14 AM4/22/16

to A gathering place for the Open Rail Data community

The colon's separate the name space from the local name. In xml an element and it's attributes are defined within a namespace. In this case ns3. However ns3 is an alias as it's defined in the root. For example:

so in Pport ns3 is defined by xmlns:ns3="http://www.thalesgroup.com/rtti/PushPort/Forecasts/v2" and that points to the relevant schema which defines what is valid. In this case it's "http://www.thalesgroup.com/rtti/PushPort/Forecasts/v2" (note: not a URL can be almost anything).

Be aware, it's called ns3 here but it could change. The key is ns3:xxx needs an xmlns:ns3 higher up (not necessarily in the root). The best way is to use a proper xml parser rather than writing your own, as parsing xml isn't as easy as it looks (been there :-S )