Python & XML

Building the Profiles Access Class

In addition to the Profiles database is the CustomerProfile Python class. This object performs XML input and output against the database, and exposes methods for use by the XML Switch. The basic profile actions allow you to retrieve, insert, update, and delete profiles. Arguments to these methods are XML versions of profile data. By making the customer profile packets in XML, it’s easy for other applications to generate and consume the packets without any concern for the structure of the database, or even how to access it directly. In fact, a CustomerProfile can easily become the payload of a SOAP message. A profile packet appears as:

<CustomerProfile id="555-99JKK39">
  <firstname>John</firstname>
  <lastname>Doolittle</lastname>
  <address1>396 Evergreen Terrace</address1>
  <address2/>
  <city>Springfield</city>
  <state>WA</state>
  <zip>98072</zip>
</CustomerProfile>

Note that the address2 element exists, even though it is empty. The DTD for such a document appears as:

<!ELEMENT firstname (#PCDATA)>
<!ELEMENT lastname (#PCDATA)>
<!ELEMENT address1 (#PCDATA)>
<!ELEMENT address2 (#PCDATA)>
<!ELEMENT city (#PCDATA)>
<!ELEMENT state (#PCDATA)>
<!ELEMENT zip (#PCDATA)>
<!ATTLIST CustomerProfile 
   id CDATA #REQUIRED>
<!ELEMENT CustomerProfile
  (firstname, lastname,
   address1, address2,
   city, state, zip)>

An instance of the document using the DTD needs to have the declaration within the document as well:

<?xml version="1.0"?>
<!DOCTYPE CustomerProfile SYSTEM "CustomerProfile.dtd"> ...