Python - xml parsing with Minidom - How do I iterate through each <parent> and get a list of <child> for that <parent>?

Question

Apologies if this is a basic question, but I have been stuck on it for a while and haven't found the minidom documentation that understandable. I have this xml file:

<?xml version="1.0"?>
<targetConfiguration>




    <virtualMachine>
        <boxNameUppercase>CENTOS65</boxNameUppercase>
        <boxNameLowercase>centos65</boxNameLowercase>
        <memoryMegabytes>2048</memoryMegabytes>
        <numCPUs>2</numCPUs>

        <installLocation>/home/user/VM_deployer_vms/CENTOS65_Auto/</installLocation>
        <diskSpaceGigabytes>10</diskSpaceGigabytes>
        <Vagrantfile>/Vagrantfiles/Vagrantfile.centos65.overwritable</Vagrantfile> 


        <fileToBeSent>
            <source>yaml file on system</source>
            <destination>bamboo agent location</destination>
        </fileToBeSent>

        <fileToBeSent>
            <source>yaml file on system</source>
            <destination>bamboo agent location</destination>
        </fileToBeSent>

        <scriptToBeRanPython>
            <paramaters>-autodetectOS -noPrompt -name</paramaters>          
            <sourceName>......agent_install.py </sourceName>
            <destinationName>SOME LOCATION ON THE MACHINE</destinationName>
        </scriptToBeRanPython>

    </virtualMachine>



    <virtualMachine>
        <boxNameUppercase>CENTOS64</boxNameUppercase>
        <boxNameLowercase>centos64</boxNameLowercase>
        <memoryMegabytes>2048</memoryMegabytes>
        <numCPUs>2</numCPUs>

        <installLocation>/home/user/VM_deployer_vms/CENTOS64_Auto/</installLocation>
        <diskSpaceGigabytes>10</diskSpaceGigabytes>
        <Vagrantfile>/Vagrantfiles/Vagrantfile.centos65.overwritable</Vagrantfile> 

        <fileToBeSent>
            <source>yaml file on system</source>
            <destination>bamboo agent location</destination>
        </fileToBeSent>

        <fileToBeSent>
            <source>yaml file on system</source>
            <destination>bamboo agent location</destination>
        </fileToBeSent>

        <scriptToBeRanPython>
            <paramaters>-autodetectOS -noPrompt -name</paramaters>          
            <sourceName>......agent_install.py </sourceName>
            <destinationName>SOME LOCATION ON THE MACHINE</destinationName>
        </scriptToBeRanPython>

    </virtualMachine>

</targetConfiguration>

Any my problem is basically with the "fileToBeSent" and "scriptToBeRanPython" nodes . In my program, I iterate through each "virtualMachine" node and create a python object called TargetVM based on it. I want to basically create a list of "fileToBeSent" and "scriptToBeRanPython" objects / tuples, and make that an attribute of my TargetVM class.

This is a method that is called from the constructor of a TargetVM, that parses the rest of the xml:

def buildConfiguration(self, inputFile):
        doc = minidom.parse(inputFile)

        #virtualMachine
        vm_xml_elements = doc.getElementsByTagName("virtualMachine")
        for vm in vm_xml_elements:
            myTargetVM=TargetVM()   

            #mandatory xml nodes    
            try:
                myTargetVM.diskSpaceGigabytes = vm.getElementsByTagName("diskSpaceGigabytes")[0].firstChild.nodeValue     
                myTargetVM.installLocation = vm.getElementsByTagName("installLocation")[0].firstChild.nodeValue 
                myTargetVM.vagrantfile = vm.getElementsByTagName("Vagrantfile")[0].firstChild.nodeValue 
            except:
                addFailure("XML error for virtualMachine. You've left out some mandatory tags. ")           


            #optional xml nodes
            try:


                myTargetVM.boxNameUppercase = vm.getElementsByTagName("boxNameUppercase")[0].firstChild.nodeValue
                myTargetVM.boxNameLowercase= vm.getElementsByTagName("boxNameLowercase")[0].firstChild.nodeValue
                myTargetVM.memoryMegabytes = vm.getElementsByTagName("memoryMegabytes")[0].firstChild.nodeValue        
                myTargetVM.numCPUs = vm.getElementsByTagName("numCPUs")[0].firstChild.nodeValue 



            except:
                addWarning("You left out some optional XML tags when specifying a vagrantBox.")         
            self.TargetVMList.append(myTargetVM)

How do I modify this to get it to work with the above xml? I have tried adding something like:

                printDebug( "   Adding commands to "+ VM.getBoxName())              
                commandsTagList = vm.getElementsByTagName("virtualMachine")             
                for command in commandsTagList:
                    commandString = command.getElementsByTagName("scriptToBeRanPython")[0].firstChild.nodeValue
                    myTargetVM.commandList.append(commandString)        
                    printDebug( "      added command '" + commandString + "' to "+VM.getBoxName())  

but it returns an empty list. Can anyone help me? Thanks very much.

Answer 1

You have to get the values from the sourceName, paramaters tags. Look at the following example:

doc = minidom.parse('data.xml')
commandsTagList = doc.getElementsByTagName("virtualMachine")
for command in commandsTagList:
    scriptToBeRanPython = command.getElementsByTagName("scriptToBeRanPython")[0]
    parameter = scriptToBeRanPython.getElementsByTagName("paramaters")[0].firstChild.nodeValue
    source = scriptToBeRanPython.getElementsByTagName("sourceName")[0].firstChild.nodeValue
    destination = scriptToBeRanPython.getElementsByTagName("destinationName")[0].firstChild.nodeValue
    commandString = source + ' ' + parameter + ' ' + destination
    print commandString

Output:

......agent_install.py  -autodetectOS -noPrompt -name SOME LOCATION ON THE MACHINE
......agent_install.py  -autodetectOS -noPrompt -name SOME LOCATION ON THE MACHINE