(Ruby) Find and Update an XML Attribute Value

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Demonstrates how to find an element in XML with a specified attribute name and then update the attribute value.

Chilkat Ruby Downloads install from rubygems.org gem install chilkat or download... Ruby Library for Windows, MacOS, Linux, Alpine Linux

require 'chilkat'

# Let's say you have 2 XML files with identical structures as shown directly below,
# and you wish to update the values in the 1st XML file with those in the 2nd XML file.

# <global>
#     <phrase id="2FADisabled" value="2factor authentication disabled"/>
#     <phrase id="2FAEnabled" value="2factor authentication enabled"/>
#     <phrase id="2FAResetFailed" value="Failed to disable two factor authentication"/>
# </global>

# <global>
#     <phrase id="2FAResetFailed" value="Failed to reset two factor authentication"/>
#     <phrase id="2FADisabled" value="2FA authentication disabled"/>
#     <phrase id="2FAEnabled" value="2FA authentication enabled"/>
# </global>

# First, initialize each of the Chilkat XML objects.
# These could be loaded from files, but we'll just create them manually for this example..

xml1 = Chilkat::CkXml.new()
xml1.put_Tag("global")
xml1.UpdateAttrAt("phrase",true,"id","2FADisabled")
xml1.UpdateAttrAt("phrase",true,"value","2factor authentication disabled")
xml1.UpdateAttrAt("phrase[1]",true,"id","2FAEnabled")
xml1.UpdateAttrAt("phrase[1]",true,"value","2factor authentication enabled")
xml1.UpdateAttrAt("phrase[2]",true,"id","2FAResetFailed")
xml1.UpdateAttrAt("phrase[2]",true,"value","Failed to disable two factor authentication")

xml2 = Chilkat::CkXml.new()
xml2.put_Tag("global")
xml2.UpdateAttrAt("phrase",true,"id","2FAResetFailed")
xml2.UpdateAttrAt("phrase",true,"value","Failed to reset two factor authentication")
xml2.UpdateAttrAt("phrase[1]",true,"id","2FADisabled")
xml2.UpdateAttrAt("phrase[1]",true,"value","2FA authentication disabled")
xml2.UpdateAttrAt("phrase[2]",true,"id","2FAEnabled")
xml2.UpdateAttrAt("phrase[2]",true,"value","2FA authentication enabled")

# Iterate over attribute values in xml2 and update the same in xml1.

sbPath = Chilkat::CkStringBuilder.new()

i = 0
count_i = xml2.NumChildrenHavingTag("phrase")
while i < count_i
    xml2.put_I(i)
    phrase_id = xml2.chilkatPath("phrase[i]|(id)")
    phrase_value = xml2.chilkatPath("phrase[i]|(value)")

    # Notice how the UpdateAttrAt method's 1st argument is a Chilkat path -- which is an expression
    # to find the location of the XML element to be updated.
    # Here we create a path of the form "/A/tagName,attributeName,attributeValuePattern", which means
    # find the direct descendent of xml2 having tag=tagName, with an attribute=attributeName where the attribute value
    # matches the attributeValuePattern.  If attributeValuePattern does not contain a "*", then it must match directly.
    # We'll build a Chilkat path such as "/A/phrase,id,2FADisabled"
    sbPath.SetString("/A/phrase,id,")
    sbPath.Append(phrase_id)

    # This assumes the corresponding element exists in xml1.
    xml1.UpdateAttrAt(sbPath.getAsString(),true,"value",phrase_value)

    i = i + 1
end

# Now see how xml1 has been updated..
print xml1.getXml() + "\n";