Converting OpenStruct/Hash to XML - ruby

Question

I have a collection of OpenStruct elements using which I need to build an XML with help of Nokogiri.
collection = [
OpenStruct.new(:catalogStoreNumber => '657758',
:catalogStoreId => 'CTH6536',
:catalogStoreLocation => 'UnitedStates',
:catalogOwnerId => 'TYCT11190',
:catalogOwner => 'McGrawHill Pub.',
:catalogList => OpenStruct.new(
:catalogProductInfo => OpenStruct.new(
:productType => 'Book',
:productName => 'The Client',
:productAuthorized => 'Y',
:productId => 'BKSUS113246A',
:productVerificationCode => '4546747',
:productPurcTransactionTime => '2012-05-21T13:36:38+05:30',
:productAuditDetails => OpenStruct.new(
:productAuditNo => '1',
:prodHandledByUser => 'StoreUserS14',
:productAuditTime => '2012-05-21T13:36:38+05:30',
:productAuditAdminId => 'McGr1132',
:productPurchaseRate => '50.14 Prcnt',
:productSystemLoggerId => 'UNX-NETW4536'
),
:productAuditDetails => OpenStruct.new(
:productAuditNo => '2',
:prodHandledByUser => 'OnlineUserOn008',
:productAuditTime => '2012-05-23T16:16:08+05:30',
:productAuditAdminId => 'McGr1132',
:productPurchaseRate => '84.86 Prcnt',
:productSystemLoggerId => 'UNX-NETW4536'
)
),
:catalogProductInfo => OpenStruct.new(
:productType => 'Pen',
:productName => 'Reynolds'
:productAuthorized => 'N',
:productId => 'PNSUS228886B',
:productVerificationCode => '2330076',
:productPurcTransactionTime => '2012-04-22T15:06:18+04:30',
:productAuditDetails => OpenStruct.new(
:productAuditNo => '1',
:prodHandledByUser => 'CCUserA14',
:productAuditTime => '2012-04-26T13:36:38+05:30',
:productAuditAdminId => 'ReyGr1132',
:productPurchaseRate => '20.19 Prcnt',
:productSystemLoggerId => 'WIN-NETW4536'
)
)
)
)]
I tried with below code .. as per your answer (handpick of elements)
builder = Nokogiri::XML::Builder.new do |xml|
xml.CatalogOrder do
collection.each do |ctlg|
xml.CatalogStoreNumber ctlg.catalogStoreNumber
xml CatalogStoreId ctlg.catalogStoreId
xml.CatalogOwnerId ctlg.catalogOwnerid
xml.CatalogOwner ctlg.catalogOwner
xml.CatalogList do
prod_count = 0
aud_list_count = 0
collection.each do |prod|
info = prod.catalogList[0].catalogProductInfo
xml.ProductInfo do
xml.ProductType info.productType
xml.ProductName info.productName
xml.ProductId info.productId
xml.ProductVerificationCode info.ProductVerificationCode
xml.ProductPurcTransactionTime info.productPurcTransactionTime
xml.ProductAuditDetails do
collection.each do |aud_dtl|
aud_info = aud_dtl.catalogList[0].catalogProductinfo[0].productAuditDetails
xml.ProductAuditNo aud_info.productAuditNo
xml.ProdHandledByUser aud_info.prodHandledByUser
xml.ProductAuditTime aud_info.productAuditTime
xml.ProductAuditAdminId aud_info.productAuditAdminId
xml.ProductPurchaseRate aud_info.productPurchaseRate
xml.ProductSystemLoggerId aud_info.productSystemLoggerId
# Do whatever you must above to concoct your ProductId
end
aud_list_count = aud_list_count + 1
end
prod_count = prod_count + 1
end
end
end
puts builder.to_xml
I need the Output as below...
<CatalogOrder>
<CatalogStoreNumber>657758</CatalogStoreNumber>
<CatalogStoreId>CTH6536</CatalogStoreId>
<CatalogStoreLocation>UnitedStates</CatalogStoreLocation>
<CatalogOwnerId>TYCT11190</CatalogOwnerId>
<CatalogOwner>McGrawHill Pub.</CatalogOwner>
<CatalogList>
<CatalogProductInfo>
<ProductType>Book</ProductType>
<ProductName>The Client</ProductName>
<ProductAuthorized>Y</ProductAuthorized>
<ProductId>BKSUS113246A</ProductId>
<ProductVerificationCode>4546747</ProductVerificationCode>
<ProductPurcTransactionTime>2012-05-21T13:36:38+05:30</ProductPurcTransactionTime>
<ProductAuditDetails>
<ProductAuditNo>1</ProductAuditNo>
<ProdHandledByUser>StoreUserS14</ProdHandledByUser>
<ProductAuditTime>2012-05-21T13:36:38+05:30</ProductAuditTime>
<ProductAuditAdminId>McGr1132</ProductAuditAdminId>
<ProductPurchaseRate>50.14 Prcnt</ProductPurchaseRate>
<ProductSystemLoggerId>WIN-NETW4536</ProductSystemLoggerId>
</ProductAuditDetails>
<ProductAuditDetails>
<ProductAuditNo>2</ProductAuditNo>
<ProdHandledByUser>OnlineUserOn008</ProdHandledByUser>
<ProductAuditTime>2012-05-23T16:16:08+05:30</ProductAuditTime>
<ProductAuditAdminId>McGr1132</ProductAuditAdminId>
<ProductPurchaseRate>84.86 Prcnt</ProductPurchaseRate>
<ProductSystemLoggerId>UNX-NETW4536</ProductSystemLoggerId>
</ProductAuditDetails>
</CatalogProductInfo>
<CatalogProductInfo>
<ProductType>Pen</ProductType>
<ProductName>Reynolds</ProductName>
<ProductAuthorized>N</ProductAuthorized>
<ProductId>PNSUS228886B</ProductId>
<ProductVerificationCode>2330076</ProductVerificationCode>
<ProductPurcTransactionTime>2012-04-22T15:06:18+04:30</ProductPurcTransactionTime>
<ProductAuditDetails>
<ProductAuditNo>1</ProductAuditNo>
<ProdHandledByUser>CCUserA14</ProdHandledByUser>
<ProductAuditTime>2012-04-26T13:36:38+05:30</ProductAuditTime>
<ProductAuditAdminId>ReyGr1132</ProductAuditAdminId>
<ProductPurchaseRate>20.19 Prcnt</ProductPurchaseRate>
<ProductSystemLoggerId>WIN-NETW4536</ProductSystemLoggerId>
</ProductAuditDetails>
</CatalogProductInfo>
</CatalogList>
</CatalogOrder>
I tried to loop in the nested Array of OpenStruct of elements, but couldn't land on right logic for that ..
Ref.. How to add child nodes in NodeSet using Nokogiri

Answer 1

Setup Code
require 'ostruct'
require 'nokogiri'
collection = [
OpenStruct.new(
:catalogStoreNumber => '657758',
:catalogStoreId => 'CTH6536',
:catalogStoreLocation => 'UnitedStates',
:catalogOwnerId => 'TYCT11190',
:catalogOwner => 'McGrawHill Pub.',
:catalogList => OpenStruct.new(
:catalogProductInfo => OpenStruct.new(
:productType => 'Book',
:productName => 'The Client'
)
)
)
]
If You Want To Hand-Pick Your Elements and Data
builder = Nokogiri::XML::Builder.new do |xml|
xml.CatalogOrder do
xml.CatalogList do
collection.each do |prod|
info = prod.catalogList.catalogProductInfo
xml.ProductInfo do
xml.ProductType info.productType
xml.ProductName info.productName
xml.ProductId "#{prod.catalogOwnerId}-#{prod.catalogStoreNumber}"
# Do whatever you must above to concoct your ProductId
end
end
end
end
end
puts builder.to_xml
Output
<?xml version="1.0"?>
<CatalogOrder>
<CatalogList>
<ProductInfo>
<ProductType>Book</ProductType>
<ProductName>The Client</ProductName>
<ProductId>TYCT11190-657758</ProductId>
</ProductInfo>
</CatalogList>
</CatalogOrder>
If you want a more generic conversion (an XML representation of your OpenStruct hierarchy) see either of the two solutions below:
One Way to Perform Generic Conversion
# Add all entries of an OpenStruct to an XML builder
# Recursively creates sub-nodes for OpenStruct instances
def ostruct_each(ostruct,xml)
ostruct.instance_variable_get(:#table).each do |field,value|
if value.is_a?(OpenStruct)
xml.send(field) do
ostruct_each(value,xml)
end
else
xml.send(field,value)
end
end
end
builder = Nokogiri::XML::Builder.new do |xml|
xml.CatalogOrder do
xml.CatalogList do
collection.each do |prod_info|
xml.ProductInfo do
ostruct_each(prod_info,xml)
end
end
end
end
end
puts builder.to_xml
Output
<?xml version="1.0"?>
<CatalogOrder>
<CatalogList>
<ProductInfo>
<catalogStoreNumber>657758</catalogStoreNumber>
<catalogStoreId>CTH6536</catalogStoreId>
<catalogStoreLocation>UnitedStates</catalogStoreLocation>
<catalogOwnerId>TYCT11190</catalogOwnerId>
<catalogOwner>McGrawHill Pub.</catalogOwner>
<catalogList>
<catalogProductInfo>
<productType>Book</productType>
<productName>The Client</productName>
</catalogProductInfo>
</catalogList>
</ProductInfo>
</CatalogList>
</CatalogOrder>
A Different Way to Generically Convert It
# Create a NodeSet of elements for all attributes in an OpenStruct
# Recursively creates child elements for any value that is an OpenStruct
def ostruct_to_elements(xml_doc,ostruct)
Nokogiri::XML::NodeSet.new(
xml_doc,
ostruct.instance_variable_get(:#table).map do |name,val|
xml_doc.create_element(name.to_s).tap do |el|
el << (val.is_a?(OpenStruct) ? ostruct_to_elements(xml_doc,val) : val)
end
end
)
end
builder = Nokogiri::XML::Builder.new do |xml|
xml.CatalogOrder do
xml.CatalogList do
collection.each do |prod_info|
xml.ProductInfo do
xml.parent << ostruct_to_elements(xml.doc,prod_info)
end
end
end
end
end
puts builder.to_xml

Answer 2

Answering your changed question and data.
Here's your source data, summarized:
collection = [
OpenStruct.new(
:foo => 'bar',
:list => OpenStruct.new(
:catalogProductInfo => OpenStruct.new(...)
:catalogProductInfo => OpenStruct.new(...)
)
)
]
The first thing we notice is that collection is an array, but it only has one item. That doesn't seem very useful.
The second—far more important—thing to notice is that you are attempting to use an OpenStruct (the inner one) as an array. This fails quite fully, as the second value completely overwrites the first:
require 'ostruct'
p OpenStruct.new( a:1, a:2 )
#=> #<OpenStruct a=2>
You can't have two values for the same key in a struct. Instead, you probably wanted an array value inside your object. For example:
root = OpenStruct.new(
:foo => 'bar',
:list => [ # this is an array of two distinct objects
OpenStruct.new( :catalogProductInfo => OpenStruct.new(...) ),
OpenStruct.new( :catalogProductInfo => OpenStruct.new(...) )
]
)
Thirdly, as I noted earlier, I see no good reason for you to be using an OpenStruct here. Instead, just use Hash literals. Combined with the code I provided in my other answer, this is what your data (simplified) and a working solution looks like:
Source Data
MyOrder = {
catalogStoreNumber: '657758', # Ruby 1.9 Hash syntax;
catalogStoreId: 'CTH6536', # same as :catalogStoreId => 'CTH536'
catalogList: {
catalogProductInfo: [
{
productType: 'Book',
productName: 'The Client',
productAuditDetails: [
{ productAuditNo: '1', prodHandledByUser: 'StoreUserS14' },
{ productAuditNo: '2', prodHandledByUser: 'OnlineUserOn008' }
]
},
{
productType: 'Pen',
productName: 'Reynolds',
productAuditDetails: [
{ productAuditNo: '1', prodHandledByUser: 'CCUserA14' }
]
}
]
}
}
Generic Conversion
# Adds key/value pairs from a Hash to a Nokogiri::XML::Builder
def hash2xml(hash,xml)
hash.each do |field,value|
name = field.to_s.sub(/^./,&:upcase) # convert "fooBar" to "FooBar"
case value
when Hash then xml.send(name){ hash2xml(value,xml) }
when Array then value.each{ |o| xml.send(name){ hash2xml(o,xml) } }
else xml.send(name,value)
end
end
end
Working Code
builder = Nokogiri::XML::Builder.new do |xml|
xml.CatalogOrder do
hash2xml(MyOrder,xml)
end
end
puts builder.to_xml
Output
<?xml version="1.0"?>
<CatalogOrder>
<CatalogStoreNumber>657758</CatalogStoreNumber>
<CatalogStoreId>CTH6536</CatalogStoreId>
<CatalogList>
<CatalogProductInfo>
<ProductType>Book</ProductType>
<ProductName>The Client</ProductName>
<ProductAuditDetails>
<ProductAuditNo>1</ProductAuditNo>
<ProdHandledByUser>StoreUserS14</ProdHandledByUser>
</ProductAuditDetails>
<ProductAuditDetails>
<ProductAuditNo>2</ProductAuditNo>
<ProdHandledByUser>OnlineUserOn008</ProdHandledByUser>
</ProductAuditDetails>
</CatalogProductInfo>
<CatalogProductInfo>
<ProductType>Pen</ProductType>
<ProductName>Reynolds</ProductName>
<ProductAuditDetails>
<ProductAuditNo>1</ProductAuditNo>
<ProdHandledByUser>CCUserA14</ProdHandledByUser>
</ProductAuditDetails>
</CatalogProductInfo>
</CatalogList>
</CatalogOrder>