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What is to replace Perl then?What is to replace Perl then?Posted Dec 3, 2008 21:59 UTC (Wed) by jwb (guest, #15467)In reply to: What is to replace Perl then? by drag Parent article: On the future of Perl 5
You can do anything you want in python, except the incredibly simple things like parsing URLs. And the last time I tried to use the python postgresql interface, it was popen()ing psql behind the scenes. I would say that python's standard library has about 50% of the coverage of CPAN and roughly 10% of the maturity. If you want to get something done you can get it done quickly and easily in perl. If you want to gaze at the beauty of your code, python is a far better choice.
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What is to replace Perl then? Posted Dec 3, 2008 23:00 UTC (Wed) by sbergman27 (subscriber, #10767) [Link]
"""
You can do anything you want in python, except the incredibly simple things like parsing URLs. """
Ummm... import urlparse and/or urllib? Which have been in the standard library for, oh... years and years? Unless you think those should be builtins?
"""
Please show me where this was ever true, if it was ever true, and when. IIRC, historically, there have been pgSQL, psycopg, and psycopg2 modules. Giving you the benefit of the doubt for the time being, *maybe* one of the early ones did that sometime back in the 90s or something. I've certainly never heard of it.
But based upon the level of disinformation I see in your post, it just looks to me like a Perl programmer feeling threatened.
What is to replace Perl then? Posted Dec 4, 2008 11:42 UTC (Thu) by niner (subscriber, #26151) [Link]
> Ummm... import urlparse and/or urllib?
> there have been pgSQL, psycopg, and psycopg2 modules
And they say that Perl is bad for there being more than one way to do something.
What is to replace Perl then? Posted Dec 4, 2008 17:58 UTC (Thu) by dlang (✭ supporter ✭, #313) [Link]
to be fair there are sometimes alternate database packages for perl, the DBI/DBM arrangement works well for many things, but it's a 'least common denominator' type of interface.
for postgres there is the Pg.pm module as well as the DBI interface.
What is to replace Perl then? Posted Dec 4, 2008 23:07 UTC (Thu) by niner (subscriber, #26151) [Link]
Fair? The last version of Pg.pm is from April 2000, 8 1/2 years ago.
Honestly, who would be tempted by this ancient module?
What is to replace Perl then? Posted Dec 3, 2008 23:06 UTC (Wed) by drag (subscriber, #31333) [Link]
You could be right. I don't know about the relative maturity of either language's libraries of modules.
For parsing urls though it's simple. From within ipython shell:
In [1]: from urlparse import urlparse
In [2]: url = urlparse('http://lwn.net/Articles/309375/')
In [3]: print url.hostname
In [4]: print url.path
If specified in the string it'll do port, username, and passwords and whatnot.
What is to replace Perl then? Posted Dec 3, 2008 23:38 UTC (Wed) by jwb (guest, #15467) [Link] That wasn't exactly what I was referring to:Python 2.5.2 (r252:60911, Oct 5 2008, 19:24:49)
[GCC 4.3.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from urllib2 import urlopen
>>> urlopen('http://user:password@google.com/')
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/lib/python2.5/urllib2.py", line 124, in urlopen
return _opener.open(url, data)
File "/usr/lib/python2.5/urllib2.py", line 381, in open
response = self._open(req, data)
File "/usr/lib/python2.5/urllib2.py", line 399, in _open
'_open', req)
File "/usr/lib/python2.5/urllib2.py", line 360, in _call_chain
result = func(*args)
File "/usr/lib/python2.5/urllib2.py", line 1107, in http_open
return self.do_open(httplib.HTTPConnection, req)
File "/usr/lib/python2.5/urllib2.py", line 1064, in do_open
h = http_class(host) # will parse host:port
File "/usr/lib/python2.5/httplib.py", line 639, in __init__
self._set_hostport(host, port)
File "/usr/lib/python2.5/httplib.py", line 651, in _set_hostport
raise InvalidURL("nonnumeric port: '%s'" % host[i+1:])
httplib.InvalidURL: nonnumeric port: 'password@google.com'
urllib2 can't understand a URL when the authority contains a colon. The fact that there exists, quite separately, urlparse module actually reinforces my point. The tuple returned by urlparse is completely useless anywhere else in the standard library. urlopen won't accept it. urlopen takes either a string or an instance of urllib2.Request object.
In Perl the situation is quite satisfactory. The URI module exists and works, and work harmoniously with HTTP::Message and its descendants, which in turn work harmoniously with LWP and WWW::Mechanize and so forth. Considering python's age and the fact that it has developed coincidentally with the web, you would think that python's web support would be quite mature by now, but it isn't. python's support for basic web operations in quite bad.
What is to replace Perl then? Posted Dec 4, 2008 0:15 UTC (Thu) by sbergman27 (subscriber, #10767) [Link]
"""
That wasn't exactly what I was referring to """
You mean when you said: "You can do anything you want in python, except the incredibly simple things like parsing URLs."? Yeah, I can see where you might really have meant you have a trivial quibble with the syntax.
Python URL parsing 101, in case anyone is interested:
---
> o = urlparse('http://user:password@google.com:8080/')
> o.netloc
> o.path
> o.username
> o.password
> o.hostname
> o.port
What is to replace Perl then? Posted Dec 4, 2008 0:17 UTC (Thu) by jwb (guest, #15467) [Link]
That's great, now what are you going to do with that tuple? You can't feed it to urllib2. urllib2 wants the URL as a string, but it can't parse all the ones that urlparse can parse. See the problem?
What is to replace Perl then? Posted Dec 4, 2008 2:40 UTC (Thu) by drag (subscriber, #31333) [Link]
Ya. I would consider that a bug.
What is to replace Perl then? Posted Dec 4, 2008 3:42 UTC (Thu) by sbergman27 (subscriber, #10767) [Link]
If so, it doesn't seem to be one that many Python users care about. I spend a lot of time in Python web development communities (Django, TurboGears) and its not something I hear complaints about.
urllib does support this directly:
---
There have, however, been a couple of request nibbles on the issue tracker over the last 4 years or so to add the functionality to urllib2 as well, and no actual opposition to it. Interestingly, there was activity today from a dev saying he was implementing it, noting that it would be trivial to do.
Personally, I think its probably a good idea, but since its just a few lines to handle this case, it doesn't really bother me.
Like I said, this seems something of a cherry-picked example to "prove" that Python's url handling is "not mature". I'm sure that Python and Ruby folks could pick more than a few cherries regarding Perl's problems if they wanted to.
What is to replace Perl then? Posted Dec 4, 2008 1:49 UTC (Thu) by jamesh (guest, #1159) [Link]
It probably isn't very helpful to you, but the RFC for HTTP URLs doesn't actually allow for putting passwords in the URL.
The urllib2 module can perform authentication though, as described in http://docs.python.org/library/urllib2.html#examples
What is to replace Perl then? Posted Dec 4, 2008 2:27 UTC (Thu) by jwb (guest, #15467) [Link]
That is interesting, I hadn't noticed before that HTTP RFC specifies 'host' instead of 'authority', but you're right it's of little use because the problem is that such URLs are found in the wild and when you're building a crawler you pretty much have to handle them.
What is to replace Perl then? Posted Dec 4, 2008 1:43 UTC (Thu) by jamesh (guest, #1159) [Link]
Having contributed to the more popular PostgreSQL database adapters for Python (psycopg and psycopg2), I can't say I ever ran into a case where it was spawning psql as a subprocess to perform queries.
Do you remember what module you were using?
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