Lua

Find XML Element where Attribute = Value

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Finds an XML element at a particular location where an attribute has a specified value. Lua

local chilkat = require("chilkat")

local success = false

-- We have the following XML and wish to find the value of the time attribute where msg = "alert-from".

-- <cdr id="4e5d3e7f41bf6201ad81000c29703270" e164="6207">
--     <user>
--         <grp name="wfln" mode="active"/>
--     </user>
--     <event msg="setup-to" time="287069" e164="5034"/>
--     <event msg="alert-from" time="287069" e164="5034"/>
--     <event msg="rel-to" time="287079" e164="5034"/>
-- </cdr>

-- First, build the above XML:

local xml = chilkat.Xml.new()
xml.tag = "cdr"
xml:add_attribute("id", "4e5d3e7f41bf6201ad81000c29703270")
xml:add_attribute("e164", "6207")
xml:update_attr_at("user|grp", true, "name", "wfln")
xml:update_attr_at("user|grp", true, "mode", "active")
xml:update_attr_at("event", true, "msg", "setup-to")
xml:update_attr_at("event", true, "time", "287069")
xml:update_attr_at("event", true, "e164", "5034")
xml:update_attr_at("event[1]", true, "msg", "alert-from")
xml:update_attr_at("event[1]", true, "time", "287069")
xml:update_attr_at("event[1]", true, "e164", "5034")
xml:update_attr_at("event[2]", true, "msg", "rel-to")
xml:update_attr_at("event[2]", true, "time", "287079")
xml:update_attr_at("event[2]", true, "e164", "5034")

-- Show that we have the above XML
print(xml:get_xml())

-- Find the element where msg = "alert-from"
-- This updates the xml object's reference to the found element (if successful).
local notUsed = xml:chilkat_path("/A/event,msg,alert-from|$")
if not xml.last_method_success then
    print("Not found.")
    return
end

-- Get the value of the "time" attribute.
print("time = " .. xml:get_attr_value("time"))

-- Restore the xml object's internal reference to the root of the XML document
xml:get_root2()