1 #!/bin/bash

     2 

     3 getXML() {

     4 	# Just read a file:

     5 	cat "/etc/dbus-1/system.d/org.freedesktop.NetworkManager.conf"

     6 	# Or we can wget or curl it from the network

     7 	# or generate on-the-fly using some other command.

     8 }

     9 

    10 parseXML() {

    11 	# Convert the XML tree structure into multiple relations.

    12 	# Use XPath expressions to find record nodes

    13 	# and to find attributes inside them.

    14 	relpipe-in-xmltable \

    15 		--relation 'policy' \

    16 			--records '/busconfig/policy/allow|/busconfig/policy/deny' \

    17 			--attribute 'policy'           string 'name()' \

    18 			--attribute 'user'             string '../@user' \

    19 			--attribute 'context'          string '../@context' \

    20 			--attribute 'own'              string '@own' \

    21 			--attribute 'send_destination' string '@send_destination' \

    22 			--attribute 'send_interface'   string '@send_interface' \

    23 			--attribute 'send_member'      string '@send_member' \

    24 		--relation 'limit' \

    25 			--records '/busconfig/limit' \

    26 			--attribute 'name'             string '@name' \

    27 			--attribute 'value'            integer '.'

    28 }

    29 

    30 filterRecords() {

    31 	# Use native AWK command (called from relpipe-tr-awk)

    32 	# with all its power to filter the records.

    33 	# Work with named fields instead of numbered columns.

    34 	relpipe-tr-awk \

    35 		--relation "policy" \

    36 		--where 'policy == "allow" && user != "root"'

    37 

    38 	# Of course, we can do the same using SQL:

    39 	# relpipe-tr-sql \

    40 	#	--relation "policy" \

    41 	#		"SELECT * FROM policy WHERE policy = 'allow' AND user <> 'root'"

    42 	#	--copy 'limit'

    43 

    44 	# Or using Guile (Scheme):

    45 	# relpipe-tr-guile \

    46 	#	--relation policy \

    47 	#	--where '(and (string= $policy "allow") (not (string= $user "root")) )'

    48 }

    49 

    50 formatOutput() {

    51 	relpipe-out-tabular

    52 	# Or generate some other format:

    53 	# relpipe-out-ods       # spreadsheet for e.g. LibreOffice

    54 	# relpipe-out-xml       # XML e.g. for further XSLT or XQuery processing

    55 	# relpipe-out-recfile   # recfile for further GNU Recutils processing

    56 	# relpipe-out-asn1      # ASN.1 BER for the telco guys

    57 	# relpipe-out-gui       # display data in a GUI window

    58 	# etc.

    59 }

    60 

    61 # put the whole pipeline together:

    62 getXML | parseXML | filterRecords | formatOutput