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Publicaciones sobre programming (publicaciones antiguas, página 38)

Pickling can be expensive

When try­ing to se­ri­al­ize python data, of­ten the first thing we look at is pick­le. Well, some­times pick­le can be very ex­pen­sive!

Here Post is an elixir class, which means it's an ob­ject mapped to a re­la­tion­al database, and com­par­ing its prop­er­ties to some­thing is pret­ty much a piece of a SQL WHERE state­men­t.

>>> print Post.important==True
posts.important = ?

What hap­pens when we pick­le it?

>>> print len(pickle.dumps(Post.important==True))
>>> print pickle.loads(s)
posts.important = :important_1

Yikes. What's a bet­ter so­lu­tion?

>>> print eval('Post.important==True')
posts.important = ?

As long as we are sure no weird da­ta will get in­to the eval...

uRSSus: first post 0.2.10 features (has screenie)

It's run­ning pre­ty sta­ble (at least for me) so I de­cid­ed to fix some is­sues and add some fea­tures. First a screen­shot:


And now tex­t:

  • A new fea­­ture that al­­so fix­es an is­­sue:

    vgar­­vardt asked about sort­ing by feed,­­for ex­am­­ple when read­­ing a fold­er. Im­­ple­­men­t­ed it us­ing a "feed" col­umn that you can en­able/dis­­able. Since your choice is per­­sis­ten­t, there's no need to add a con­­fig­u­ra­­tion op­­tion to the di­a­log.

  • Im­­por­­tant is now Starred. I rel­­ly like google's idea of us­ing stars at hand to mark things im­­por­­tan­t. So, there they are. The star icon I did my­­self, in Inkscape, try­ing to re­spect the Rein­hardt style. I think it looks nice.

  • Google News feed­s! Yes, I know I could just go to http://news.­­google.­­com, make a search and sub­­scribe to the re­­sults page. Can my mom? Nope. So, when adding new feed, just choose "Cre­ate google news feed" en­ter some key­­word­s, and it's ready.

    I need to add "cus­­tom field­­s" to the feed con­­fig di­alog, though, since once it's cret­ed it's just a reg­u­lar feed with a long URL.

  • Al­­so did some per­­for­­mance and re­li­a­­bil­i­­ty work, and cur­rent SVN (r476) is ac­­tu­al­­ly quite a bit nicer than 0.2.10 al­ready. So there may be an­oth­er re­lease soon­ish.

uRSSus 0.2.10 is out!

Yes friend­s, my desk­top feed agre­ga­tor uRSSus has a brand new re­lease.

You can get it at http://urssus.­google­code.­com or http://pyp­ or via easy_in­stal­l.

There is a rather large bug in that the con­fig­u­ra­tion di­a­log may or may not work for you. Don't wor­ry, there is no life-or-death op­tion there, just ig­nore it.

As al­ways, I am look­ing for a hand mak­ing it work well on Win­dows and Mac.

Let me know if you like it (or if you don't).

uRSSus: now with configuration dialog goodness!

I felt that a "user-friend­ly" con­fig­u­ra­tion di­a­log for uRSSus was not a good way to spend ef­fort, be­cause I ex­pect op­tions to change of­ten for a while, and I did­n't want an out­dat­ed di­alog, ei­ther. The so­lu­tion? Au­to­gen­er­ate a medi­ocre con­fig­u­ra­tion di­alog!

First, de­fine what op­tions uRSSus sup­ports (Up­date: sug­ges­tion by Ale­jan­dro Cu­ra, us­ing tu­ples works much bet­ter!):

options = (
      ('alwaysShowFeed',  ('bool', False, "Always show a link to the post's feed when diplaying a post")),
      ('hideOnTrayClick', ('bool', True, "Hide the main window when clicking on the tray icon")),
      ('defaultRefresh'      ,  ('int', 1800, "How often feeds should be refreshed by default (in seconds).", 300, None )),
      ('maxPostsDisplayed'   ,  ('int', 1000, "Limit the display to this many posts. If set too high, opening 'All Feeds' may take forever", 0, None)),
      ('defaultExpiration'   ,  ('int',    7, "How long should articles be kept by default. (In days)", 0, 9999)),
      ('username',  ('string', None, 'Your Twitter user name.' )),
      ('password',  ('password', None, 'Your Twitter password.' )),

Then a lit­tle mag­ic, and this comes out:


How mag­ic? This mag­ic:

class ConfigDialog(QtGui.QDialog):
  def __init__(self, parent):
    QtGui.QDialog.__init__(self, parent)
    # Set up the UI from designer

    for sectionName, options in config.options:
      # Create a page widget/layout for this section:
      for optionName, definition in options:
        if definition[0]=='bool':
          cb.setChecked(config.getValue(sectionName, optionName, definition[1]))
          layout.addWidget(cb, row, 0, 1, 2)
          self.values[sectionName+'/'+optionName]=[cb, lambda(cb): cb.isChecked()]

        elif definition[0]=='int':
          if definition[3] is not None:
          if definition[4] is not None:
          spin.setValue(config.getValue(sectionName, optionName, definition[1]))
          layout.addWidget(label, row, 0, 1, 1)
          layout.addWidget(spin, row, 1, 1, 1)
          self.values[sectionName+'/'+optionName]=[spin, lambda(spin): spin.value()]

        elif definition[0]=='string':
          text.setText(config.getValue(sectionName, optionName, definition[1]))
          layout.addWidget(label, row, 0, 1, 1)
          layout.addWidget(text, row, 1, 1, 1)
          self.values[sectionName+'/'+optionName]=[text, lambda(text): unicode(text.text())]

        elif definition[0]=='password':
          text.setText(config.getValue(sectionName, optionName, definition[1]))
          layout.addWidget(label, row, 0, 1, 1)
          layout.addWidget(text, row, 1, 1, 1)
          self.values[sectionName+'/'+optionName]=[text, lambda(text): unicode(text.text())]

        layout.addWidget(help, row, 2, 1, 1)
        layout.addWidget(separator, row+1, 0, 1, 3)

    for page, name in zip(pages,sections) :
      # Make a tab out of it
      self.ui.tabs.addTab(page, name)

My first ev­er thing that I just don't see how it would work with­out a lamb­da ;-)

Urssus: Sorry about 0.2.9

Tru­ly a pa­perbag re­lease. But there's still hope!

While 0.2.9 had a num­ber of bugs and aw­ful per­for­mance, I have to say that the cur­rent svn re­vi­sions are much, much, bet­ter.

  • Snap­py per­­for­­mance (ok, not quite snap­py, but snap­pi­er than 0.2.0)

  • Fi­­nal­­ly a co­her­ent nex/pre­vi­ous/what­ev­er mech­a­nis­m. The on­­ly bro­ken piece is that posts may van­ish from view when the feed is up­­­dat­ed (and I can fix that, too).

  • Fixed is­­sues 16,14 and 22

So, 0.2.10, com­ing tonight, should be a pret­ty good one.

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