Download excel file from web?

patf at well.com patf at well.com
Tue Jul 29 00:43:20 CEST 2008


On Jul 28, 3:33 pm, "p... at well.com" <p... at well.com> wrote:
> On Jul 28, 3:29 pm, "Diez B. Roggisch" <de... at nospam.web.de> wrote:
>
>
>
> > p... at well.com schrieb:
>
> > > On Jul 28, 3:00 pm, "p... at well.com" <p... at well.com> wrote:
> > >> Hi - experienced programmer but this is my first Python program.
>
> > >> This URL will retrieve an excel spreadsheet containing (that day's)
> > >> msci stock index returns.
>
> > >>http://www.mscibarra.com/webapp/indexperf/excel?priceLevel=0&scope=0&...
>
> > >> Want to write python to download and save the file.
>
> > >> So far I've arrived at this:
>
> > >> [quote]
> > >> # import pdb
> > >> import urllib2
> > >> from win32com.client import Dispatch
>
> > >> xlApp = Dispatch("Excel.Application")
>
> > >> # test 1
> > >> # xlApp.Workbooks.Add()
> > >> # xlApp.ActiveSheet.Cells(1,1).Value = 'A'
> > >> # xlApp.ActiveWorkbook.ActiveSheet.Cells(2,1).Value = 'B'
> > >> # xlBook = xlApp.ActiveWorkbook
> > >> # xlBook.SaveAs(Filename='C:\\test.xls')
>
> > >> # pdb.set_trace()
> > >> response = urllib2.urlopen('http://www.mscibarra.com/webapp/indexperf/
> > >> excel?
> > >> priceLevel=0&scope=0&currency=15&style=C&size=36&market=1897&asOf=Jul
> > >> +25%2C+2008&export=Excel_IEIPerfRegional')
> > >> # test 2 - returns check = False
> > >> check_for_data = urllib2.Request('http://www.mscibarra.com/webapp/
> > >> indexperf/excel?
> > >> priceLevel=0&scope=0&currency=15&style=C&size=36&market=1897&asOf=Jul
> > >> +25%2C+2008&export=Excel_IEIPerfRegional').has_data()
>
> > >> xlApp = response.fp
> > >> print(response.fp.name)
> > >> print(xlApp.name)
> > >> xlApp.write
> > >> xlApp.Close
> > >> [/quote]
>
> > > Woops hit Send when I wanted Preview.  Looks like the html [quote] tag
> > > doesn't work from groups.google.com (nice).
>
> > > Anway, in test 1 above, I determined how to instantiate an excel
> > > object; put some stuff in it; then save to disk.
>
> > > So, in theory, I'm retrieving my excel spreadsheet with
>
> > > response = urllib2.urlopen()
>
> > > Except what then do I do with this?
>
> > > Well for one read some of the urllib2 documentation and found the
> > > Request class with the method has_data() on it.  It returns False.
> > > Hmm that's not encouraging.
>
> > > I supposed the trick to understand what urllib2.urlopen is returning
> > > to me; rummage around in there; and hopefully find my excel file.
>
> > > I use pdb to debug.  This is interesting:
>
> > > (Pdb) dir(response)
> > > ['__doc__', '__init__', '__iter__', '__module__', '__repr__', 'close',
> > > 'code', '
> > > fileno', 'fp', 'geturl', 'headers', 'info', 'msg', 'next', 'read',
> > > 'readline', '
> > > readlines', 'url']
> > > (Pdb)
>
> > > I suppose the members with __*_ are methods; and the names without the
> > > underbars are attributes (variables) (?).
>
> > No, these are the names of all attributes and methods. read is a method,
> > for example.
>
> right - I got it backwards.
>
>
>
>
>
> > > Or maybe this isn't at all the right direction to take (maybe there
> > > are much better modules to do this stuff).  Would be happy to learn if
> > > that's the case (and if that gets the job done for me).
>
> > The docs (http://docs.python.org/lib/module-urllib2.html) are pretty
> > clear on this:
>
> > """
> > This function returns a file-like object with two additional methods:
> > """
>
> > And then for file-like objects:
>
> >http://docs.python.org/lib/bltin-file-objects.html
>
> > """
> > read(   [size])
> >      Read at most size bytes from the file (less if the read hits EOF
> > before obtaining size bytes). If the size argument is negative or
> > omitted, read all data until EOF is reached. The bytes are returned as a
> > string object. An empty string is returned when EOF is encountered
> > immediately. (For certain files, like ttys, it makes sense to continue
> > reading after an EOF is hit.) Note that this method may call the
> > underlying C function fread() more than once in an effort to acquire as
> > close to size bytes as possible. Also note that when in non-blocking
> > mode, less data than what was requested may be returned, even if no size
> > parameter was given.
> > """
>
> > Diez
>
> Just stumbled upon .read:
>
> response = urllib2.urlopen('http://www.mscibarra.com/webapp/indexperf/
> excel?
> priceLevel=0&scope=0&currency=15&style=C&size=36&market=1897&asOf=Jul
> +25%2C+2008&export=Excel_IEIPerfRegional').read
>
> Now the question is: what to do with this?  I'll look at the
> documentation that you point to.
>
> thanx - pat

Or rather (next iteration):

response = urllib2.urlopen('http://www.mscibarra.com/webapp/indexperf/
excel?
priceLevel=0&scope=0&currency=15&style=C&size=36&market=1897&asOf=Jul
+25%2C+2008&export=Excel_IEIPerfRegional').read(1000000)

The file is generally something like 26 KB so specifying 1,000,000
seems like a good idea (first approximation).

And then when I do:

print(response)

I get a whole lot of garbage (and some non-garbage), so I know I'm
onto something.

When I read the .read documentation further, it says that read() has
returned the data as a string object.  Now - how do I convince Python
that the string object is in fact an excel file - and save it to disk?

pat



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