Adam Loving’s BlogSeattle Facebook, OpenSocial, and Web Development

My earlier (rather lame) post on Ruby Regex’s (Regular Expressions) is getting some Google love, so I thought I would supplement it with some more useful information.

If you are searching for Ruby Regex help, my guess is you are looking for…

Validating an email address with a Ruby Regex

Something simple like this next one will get you started.

irb(main):023:0> “me@adamloving.com”.match /^([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})$/i

For a much more complete email address ruby regex, try:

#
# RFC822 Email Address Regex
# --------------------------
#
# Originally written by Cal Henderson
# c.f. http://iamcal.com/publish/articles/php/parsing_email/
#
# Translated to Ruby by Tim Fletcher, with changes suggested by Dan Kubb.
#
# Licensed under a Creative Commons Attribution-ShareAlike 2.5 License
# http://creativecommons.org/licenses/by-sa/2.5/
#
module RFC822
  EmailAddress = begin
    qtext = '[^\\x0d\\x22\\x5c\\x80-\\xff]'
    dtext = '[^\\x0d\\x5b-\\x5d\\x80-\\xff]'
    atom = '[^\\x00-\\x20\\x22\\x28\\x29\\x2c\\x2e\\x3a-' +
      '\\x3c\\x3e\\x40\\x5b-\\x5d\\x7f-\\xff]+'
    quoted_pair = '\\x5c[\\x00-\\x7f]'
    domain_literal = "\\x5b(?:#{dtext}|#{quoted_pair})*\\x5d"
    quoted_string = "\\x22(?:#{qtext}|#{quoted_pair})*\\x22"
    domain_ref = atom
    sub_domain = "(?:#{domain_ref}|#{domain_literal})"
    word = "(?:#{atom}|#{quoted_string})"
    domain = "#{sub_domain}(?:\\x2e#{sub_domain})*"
    local_part = "#{word}(?:\\x2e#{word})*"
    addr_spec = "#{local_part}\\x40#{domain}"
    pattern = /\A#{addr_spec}\z/
  end
end

Find URLs using a Regular Expression in Ruby

Here is a simple URL matching regular expression.

irb(main):028:0> "http://www.adamloving.com/".match /^(http|https):\/\/[a-z0-9]+([\-\.]{1}[a-z0-9]+)*\.[a-z]{2,5}(([0-9]{1,5})?\/.*)?$/ix

UPDATE: you should definitely go with Benjamin Golub’s Python FriendFeed library for App Engine (fftogo). It is cleaner than mine and includes some undocumented API calls (like fetch_entry).

I had to make some minor modifications to the FriendFeed python library to get it to work with Google App Engine. App Engine does not support out urllib2, and has its own urlfetch library.

Here is the cut and paste-able code (see also pastie, I’m having trouble with code formatting in Wordpress)

# original (FriendFeed.py 0.9)
def _fetch(self, uri, post_args, **url_args):
    url_args["format"] = "json"
    args = urllib.urlencode(url_args)
    url = "http://friendfeed.com" + uri + "?" + args
    if post_args is not None:
        request = urllib2.Request(url, urllib.urlencode(post_args))
    else:
        request = urllib2.Request(url)
    if self.auth_nickname and self.auth_key:
        pair = "%s:%s" % (self.auth_nickname, self.auth_key)
        token = base64.b64encode(pair)
        request.add_header("Authorization", "Basic %s" % token)
    stream = urllib2.urlopen(request)
    data = stream.read()
    stream.close()
    return parse_json(data)

# modified
def _fetch(self, uri, post_args, **url_args):
    url_args["format"] = "json"
    args = urllib.urlencode(url_args)
    url = "http://friendfeed.com" + uri + "?" + args
    headers = {}
    if post_args is not None:
        post_data = urllib.urlencode(post_args)
        method = "POST"
        headers={'Content-Type': 'application/x-www-form-urlencoded'}
    else:
        post_data = None
        method = "GET"

    if self.auth_nickname and self.auth_key:
        pair = "%s:%s" % (self.auth_nickname, self.auth_key)
        token = base64.b64encode(pair)
        headers["Authorization"] = "Basic %s" % token

    result = urlfetch.fetch(url=url, payload=post_data, method=method, headers=headers)
    data = result.content

    self.result = result
    self.feed_json = data

    return parse_json(data)

This has bitten me a couple times in the last few days. The Ruby “or” (or equals) operator appears to have a bug where, when used in an assignment, the first value is assigned rather than the results of the entire expression.

irb(main):001:0> x = false || true
=> true
irb(main):002:0> x
=> true
irb(main):003:0> z = false or true
=> true
irb(main):004:0> z
=> false

ruby version: ruby 1.8.6 (2007-03-13 patchlevel 0) [i686-darwin8.10.1]

I would expect z to be true in that last example.

I created a Google spreadsheet to help me learn common phrases in Ruby and Python. This is an overly-ambitious project that I’ll probably never finish (I’ll have the function names learned faster than I update the spreadsheet). Anyone out there want to help? Add a comment below and I’ll ad you as a contributor to the spreadsheet.

I upgraded Python 2.3 to Python 2.5 on my Macbook, and changed some symbolic links so that 2.5 is the default version when run from the command line. In backwards order, here is what I did.

Python is pre-installed on Mac OS X Tiger, but what version am I running and where is it?

Open a terminal window (bash command shell) and type “python”

$ python

Python 2.5.2 (r252:60911, Jun  1 2008, 16:53:35)

[GCC 4.0.1 (Apple Computer, Inc. build 5367)] on darwin

I’m running 2.5 now, but I wasn’t earlier. Ok, where is Python installed?

$ which python

/usr/bin/python

Is that the real location? No, it is a symbolic link.

$ ls -l /usr/bin/python*
lrwxr-xr-x   1 root  wheel      9 Jun 19 13:13 /usr/bin/python -> python2.5

lrwxr-xr-x   1 root  wheel     72 Oct 14  2006 /usr/bin/python2.3 -> ../../System/Library/Frameworks/Python.framework/Versions/2.3/bin/python

lrwxr-xr-x   1 root  wheel     82 Jun 19 13:15 /usr/bin/python2.5 -> /opt/local/var/macports/software/python25/2.5.2_2+darwin_8/opt/local/bin/python2.5

As you can see, I changed “python” to point to python2.5. Previously it pointed to python2.3.

Where can I get Python 2.5 for Mac OS X Tiger? I used macports.

$ port install python25

this will put it in /opt/local/var/macports

$ port location python25

Port python25 2.5.2_2+darwin_8 is installed as an image in:

/opt/local/var/macports/software/python25/2.5.2_2+darwin_8

$ python

['', '/opt/local/var/macports/software/python25/2.5.2_2+darwin_8/opt/local/lib/python25.zip', '/opt/local/var/macports/software/python25/2.5.2_2+darwin_8/opt/local/lib/python2.5', '/opt/local/var/macports/software/python25/2.5.2_2+darwin_8/opt/local/lib/python2.5/plat-darwin', '/opt/local/var/macports/software/python25/2.5.2_2+darwin_8/opt/local/lib/python2.5/plat-mac', '/opt/local/var/macports/software/python25/2.5.2_2+darwin_8/opt/local/lib/python2.5/plat-mac/lib-scriptpackages', '/opt/local/var/macports/software/python25/2.5.2_2+darwin_8/opt/local/lib/python2.5/lib-tk', '/opt/local/var/macports/software/python25/2.5.2_2+darwin_8/opt/local/lib/python2.5/lib-dynload', '/opt/local/var/macports/software/python25/2.5.2_2+darwin_8/opt/local/lib/python2.5/site-packages']

Python 2.5.2 (r252:60911, Jun  1 2008, 16:53:35)

[GCC 4.0.1 (Apple Computer, Inc. build 5367)] on darwin

Type "help", "copyright", "credits" or "license" for more information.

>>> import sys

>>> sys.path

>>> exit()

from google.appengine.ext.bulkload import constants

EXTRA_PATHS = [

DIR_PATH,

os.path.join(GOOGLE_PATH, 'lib', 'django'),

os.path.join(GOOGLE_PATH, 'lib', 'webob'),

os.path.join(GOOGLE_PATH, 'lib', 'yaml', 'lib'),

]

if __name__ == '__main__':

sys.path = EXTRA_PATHS + sys.path

script_path = os.path.join(DIR_PATH, BULKLOAD_CLIENT_PATH)

execfile(script_path, globals())

$ PYTHONPATH=$PYTHONPATH:/include/this:/and/this

export $PYTHONPATH

response = HttpClient.default.request(url)

mugshot = Mugshot.new

temp_file_name = mugshot.write_to_temp_file(response.body)

mugshot.temp_path = temp_file_name

mugshot.content_type = "image/#{content_type}"

mugshot.filename = "imported_photo.#{content_type}"

if person.mugshot

# remove existing database records of files for this person

thumbnail = Mugshot.find_by_parent_id(person.mugshot.id)

thumbnail.destroy

person.mugshot.destroy

end

mugshot.person = person

UPDATE updatefrom p, updateto pp

SET pp.last_name = p.last_name

WHERE pp.visid = p.id