Parsing and data presentation in Django

Question

For some time now, I've been using a pattern which I think could be done more elegantly. I have a lot of XML files that need to be represented in a Django views. My current approach is like this:

I get a XML response from an API which gives me several documents.

First I define a mock class like this:

class MockDocument:
 pass

Then I write an XPath expression that gives me a list of the document nodes:

from lxml import etree 
with open("xmlapiresponse.xml", "r") as doc:
 xml_response = doc.read() 
tree = etree.fromstring(xml_response) 
document_nodes = tree.xpath("//documents/item") 

Now I iterate over the different documents and their fields using nested for-loops:

# list for storing the objects
document_objects = []
for document in document_nodes:
 # create a MockDocument for each item returned by the API
 document_object = MockDocument() 
 for field in document:
 # store the corresponding fields as object attributes
 if field.tag == "something":
 document.something = field.text
 document_objects.append(document) 

Now I can pass the list of mock objects to a Django view and represent them in the template in whichever way I want. Could this be done in a simpler fashion, though?

Answer 1

Using a generator function gives you some flexibility. You don't have to create a list.

def generate_documents( document_nodes ):
 for document in document_nodes:
 # create a MockDocument for each item returned by the API
 document_object = MockDocument() 
 for field in document:
 # store the corresponding fields as object attributes
 if field.tag == "something":
 document.something = field.text
 yield document_object 

You can do this of the list object is somehow important.

document_objects = list( generate_documents( document_nodes ) )

Or, more usefully, this

for d in generate_documents( document_nodes ):
 ... process the document ...

Which never actually creates a list object.