XML 问题: 投票系统的实用 XML 数据设计和操作

<ballot election_date="2008-11-04" country="US" state="CA"
        county="Santa Clara County" precinct="2216">
  <contest ordered="No" coupled="Yes"
           allow_writein="Yes" name="Presidency">
    <selection party="Reform"
               name="President">Martin Luther King</selection>
    <selection party="Reform"
               name="Vice President">John Anderson</selection>
    <selection party="Workers"
               name="President">Helen Keller</selection>
    <selection party="Workers"
               name="Vice President">Amelia Earhart</selection>
    <selection party="Socialist"
               name="President">V. I. Lenin</selection>
    <selection party="Socialist"
               name="Vice President">Karl Marx</selection>
  </contest>
  <contest ordered="No" coupled="No"
           allow_writein="Yes" name="Senator">
    <selection party="Green">Frances E. Willard</selection>
    <selection party="Libertarian">Lucy Stone</selection>
    <selection party="Democrat">Karl Menninger</selection>
    <selection party="Labor">William Lloyd Garrison</selection>
  </contest>
  <contest ordered="No" coupled="No" allow_writein="No"
           name="Transportation Initiative">
    <summary>
      <scope>Constitutional Amendment Article X, Section 19</scope>
      <type>initiative</type>
      <title>California Transportation Initiative For Statewide Solar
        Powered Magnetic Levitation System</title>
    </summary>
    <description>
      To reduce traffic and increase travel alternatives, this amendment
      provides for development of a high-speed solar powered magnetic
      levitation system to run along Interstate 5.  Construction to begin
      November 1, 2004.
    </description>
    <selection>Yes</selection>
    <selection>No</selection>
  </contest>
  <contest ordered="Yes" coupled="No" allow_writein="Yes"
           name="County Commissioner">
    <selection>William Hewlett</selection>
    <selection>Steve Wozniak</selection>
    <selection>William Shockely</selection>
    <selection>Gordon Moore</selection>
    <selection>Philip Kahn</selection>
  </contest>
</ballot>

<cast_ballot election_date="2008-11-04" country="US" state="CA"
             county="Santa Clara County" precinct="2216"
             number="1274" serial="213" source="voting_machine">
  <contest ordered="No" coupled="Yes" name="Presidency">
    <selection writein="No" name="President">V. I. Lenin</selection>
    <selection writein="No" name="Vice President">Karl Marx</selection>
  </contest>
  <contest ordered="No" coupled="No" name="Senator">
    <selection writein="No">William Lloyd Garrison</selection>
  </contest>
  <contest ordered="No" coupled="No" name="Transportation Initiative">
    <selection writein="No">Yes</selection>
  </contest>
  <contest ordered="Yes" coupled="No" name="County Commissioner">
    <selection writein="Yes">David Packard</selection>
    <selection writein="No">Gordon Moore</selection>
    <selection writein="No">William Hewlett</selection>
  </contest>
</cast_ballot>

from gnosis.xml.objectify import make_instance
ballot = make_instance(xml_data)
contnames, cont = [], {}
for contest in ballot.contest:
    name = contest.name
    contnames.append(name)
    if contest.coupled=="No":
        cont[name] = [select.PCDATA for select in contest.selection]
        if contest.allow_writein=="Yes":
            cont[name].append("")
    else:
        cont[name] = []
        for n in range(0, len(contest.selection), 2):
            cont[name].append([s.PCDATA for s in contest.selection[n:n+2]])
        if contest.allow_writein=="Yes":
            cont[name].append(["",""])

"""Compare ballot XML files for equivalence
.
This file may be imported as a module or used as a command-line ballot
comparison tool. If imported, e.g.:
.
    >>> import evm2003.utils.equiv
    >>> from gnosis.xml.objectify import make_instance
    >>> a = make_instance('scanned.xml')
    >>> b = make_instance('stored.xml')
    >>> a == b
    1
.
At the command-line:
.
    % python equiv.py scanned.xml stored.xml
.
(lack of any output means success, in that ultra-terse UNIX-philosophy
way).
.
We implement custom .__eq__() and .__ne__() methods specific to cast
ballots.  Injecting such methods is the recommended technique for enhancing
gnosis.xml.objectify objects.
.
The files scanned.xml and stored.xml documents were used to test this.
They differ in several non-significant respects:
    (1) the top-level attributes occur in a different order;
    (2) non-ordered multi-select contests have selections in a different
        order;
    (3) Write-in votes have different PCDATA content (for example, nothing for
        scanned.xml).
"""
import gnosis.xml.objectify
import sys
class cast_ballot(gnosis.xml.objectify._XO_):
    def __eq__(self, other):
        metadata = '''election_date country state county
                      number precinct serial'''.split()
        for attr in metadata:
            if getattr(self, attr) != getattr(other, attr):
                return 0
        by_name = lambda a, b: cmp(a.name, b.name)
        self.contest.sort(by_name)
        other.contest.sort(by_name)
        for my, your in zip(self.contest, other.contest):
            if my.name != your.name or \
               my.ordered != your.ordered or \
               my.coupled != your.coupled:
                return 0
            if my.ordered == "No":
                # Compare non-writeins (but don't know if same num writeins)
                my_select = dict([(x.PCDATA,None) for x in my.selection
                                                  if x.writein=="No"])
                your_select = dict([(x.PCDATA,None) for x in your.selection
                                                    if x.writein=="No"])
                if my_select != your_select:
                    return 0
                continue
            for my_select, your_select in zip(my.selection, your.selection):
                if (my_select.writein, your_select.writein) == ("Yes","Yes"):
                    pass
                elif my_select.PCDATA != your_select.PCDATA:
                    return 0
        return 1
    def __ne__(self, other):
        return not self == other
#-- Namespace injection
gnosis.xml.objectify._XO_cast_ballot = cast_ballot
#-- Command-line operation
if __name__=='__main__':
    a, b = map(gnosis.xml.objectify.make_instance, sys.argv[1:3])
    if a != b:
        print sys.argv[1], "and", sys.argv[2], "are NOT equivalent ballots!"