Ruby nokogiri attribute selector in XML file - ruby

Question

this is the xml file:
<?xml version="1.0" encoding="UTF-8"?>
<SOAP-ENV:Envelope SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"
xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/">
<SOAP-ENV:Body>
<ns1:putResponse
xmlns:ns1="urn:DmsManagerClient">
<result xsi:type="xsd:string">
<?xml version="1.0" encoding="ISO-8859-1"?>
<MESSAGE ID="11c73b9e-687c-4300-baba-b743c26f7c83" TYPE="CUSDMS">
<DELIVERY>
<FROM>
<SENDER>0072000</SENDER>
<SERVICE>eService</SERVICE>
<DATE>2019-03-08T12:27:25</DATE>
</FROM>
<TO>
<DEALER DEALERCODE="0072000" MARKETCODE="1000"/>
</TO>
</DELIVERY>
<CONTENT>
<dms:ComplexResponse ErrorCode="430" ErrorDescription="null : PrivacyUE Mancante" Return="false"
xmlns:dms="http://dmsmanagerservice">
<dms:Element Name="DMSVERSION">2.7</dms:Element>
</dms:ComplexResponse>
</CONTENT>
</MESSAGE>
</result>
</ns1:putResponse>
</SOAP-ENV:Body>
</SOAP-ENV:Envelope>
I am coding with Ruby and I used Nokogiri and the method xpath to extrapole the "CONTENT" of the file
this is the code:
def extrapolate_error(xml)
doc = Nokogiri::XML(File.open(xml))
doc.xpath('//CONTENT')
end
and this is the result:
[#<Nokogiri::XML::Element:0x1c5ba78 name="CONTENT" children=[
#<Nokogiri::XML::Text:0x1c5b940 "\n">,
#<Nokogiri::XML::Element:0x1c5b8bc name="ComplexResponse" namespace=#<Nokogiri::XML::Namespace:0x1c5b88c prefix="dms" href="http://dmsmanagerservice">
attributes=[
#<Nokogiri::XML::Attr:0x1c5b874 name="ErrorCode" value="430">,
#<Nokogiri::XML::Attr:0x1c5b868 name="ErrorDescription" value="null : PrivacyUE Mancante">,
#<Nokogiri::XML::Attr:0x1c5b85c name="Return" value="false">]
children=[#<Nokogiri::XML::Text:0x1c5b118 "\n">,
#<Nokogiri::XML::Element:0x1c5b094 name="Element" namespace=#<Nokogiri::XML::Namespace:0x1c5b88c prefix="dms" href="http://dmsmanagerservice">
attributes=[#<Nokogiri::XML::Attr:0x1c5b058 name="Name" value="DMSVERSION">]
children=[#<Nokogiri::XML::Text:0x1c5abe4 "2.7">]>,
#<Nokogiri::XML::Text:0x1c5aaac "\n">]>,
#<Nokogiri::XML::Text:0x1c5a974 "\n">]>]
Now I need to enter in it and select some attributes.
In the specific I need this:
name="ErrorCode" value="430"
name="ErrorDescription" value="null : PrivacyUE Mancante"
I do not know how to procceed. Can you help me?

Answer 1

The following should work for you assuming the dms namespace is always the same
doc.xpath('//CONTENT/dms:ComplexResponse', dms: 'http://dmsmanagerservice')
.xpath('#ErrorCode | #ErrorDescription')
.each_with_object({}) do |e,obj|
obj[e.name] = e.text
end
#=> {"ErrorCode"=>"430", "ErrorDescription"=>"null : PrivacyUE Mancante"}
You already understand how you got to //CONTENT so from there we use dms:ComplexResponse to navigate deeper but since this is namespaced we have to provide the namespace reference e.g. dms: 'http://dmsmanagerservice'.
Then we select the attributes we are interested in #ErrorCode and #ErrorDescription.
In XPath the pipe | means UNION (think AND) so we want to select both.
Then we are just building a Hash using the name as the key and the text as the value.
XPath Cheatsheet - Useful resource if you need additional reference
Update
You asked about conditionals so this is what I would propose
ndoc = Nokogiri::XML(doc)
namespaces = ndoc.collect_namespaces
response = ndoc.xpath("//CONTENT/dms:ComplexResponse", namespaces)
if response.xpath("self::node()[#ErrorCode != '' and #ErrorDescription != '']").any?
response.xpath("#ErrorCode | #ErrorDescription")
.each_with_object({}) do |e,obj|
obj[e.name] = e.text
end
else
response.xpath('dms:Element/#Name | dms:Element/text()',namespaces)
.each_slice(2)
.map {|s| s.map(&:text)}.to_h
end
This checks to see if there is an ErrorCode and and ErrorDescription if so then Hash as originally proposed. If Not then it returns all the dms:Elements as a Hash so {"DMSVERSION"=>"2.7"} in this case Functional Example