urllib2 and exceptions

[robean]

Hi everyone,

I have a question about using urllib2.

I like urllib2 better than urllib at least in part because it has more
elaborate support for handling errors: there is built in support for
URLError (for faulty urls) and HTTPError (for http errors that might
originate from, say, passing an invalid stock-ticker in the program
below). However I can get neither to work. I'm attaching below the
(very short) code: can anyone point out what I'm doing wrong?

Now, if I replace the URLError and HTTPError with IOError (the class
from which both URLError and HTTPError inherit), the program works
fine. Why is it that I can call the generic IOError class, but none of
the Error classes derived from that? These are clearly defined in the
urllib2 manual. Very confused...

Here's the code:


import urllib2

# read stock information from yahoo finance for Traget (TGT)
goodTicker = 'TGT' # program works with this
badTicker = 'TGTttttttt' # python doesn't understand either HTTPError
or URLError with this

url = "http://ichart.finance. yahoo.com/table.csv?s=" + badTicker

try:
handle = urllib2.urlopen (url)

# this does not work
except HTTPError, e:
print "There was an http error"
print e

# this also does not work
except URLError, e:
print "There is a problem with the URL"
print e
exit(1)

#this works
except IOError, e:
print "You have an IOError"
print e

text = handle.readline s()[:20]
for line in text:
print line

[Chris Rebert]

Re: urllib2 and exceptions

On Sun, Sep 28, 2008 at 11:03 AM, robean <st1999@gmail.c omwrote:

Hi everyone,
>
I have a question about using urllib2.
>
I like urllib2 better than urllib at least in part because it has more
elaborate support for handling errors: there is built in support for
URLError (for faulty urls) and HTTPError (for http errors that might
originate from, say, passing an invalid stock-ticker in the program
below). However I can get neither to work. I'm attaching below the
(very short) code: can anyone point out what I'm doing wrong?
>
Now, if I replace the URLError and HTTPError with IOError (the class
from which both URLError and HTTPError inherit), the program works
fine. Why is it that I can call the generic IOError class, but none of
the Error classes derived from that? These are clearly defined in the
urllib2 manual. Very confused...
>
Here's the code:
>
>
import urllib2
>
# read stock information from yahoo finance for Traget (TGT)
goodTicker = 'TGT' # program works with this
badTicker = 'TGTttttttt' # python doesn't understand either HTTPError
or URLError with this
>
url = "http://ichart.finance. yahoo.com/table.csv?s=" + badTicker
>
try:
handle = urllib2.urlopen (url)
>
# this does not work
except HTTPError, e:
print "There was an http error"
print e
>
# this also does not work
except URLError, e:
print "There is a problem with the URL"
print e
exit(1)
>
#this works
except IOError, e:
print "You have an IOError"
print e
>
text = handle.readline s()[:20]
for line in text:
print line
>
--

http://mail.python.org/mailman/listinfo/python-list

>

My Python begs to differ:

#tmp.py
import urllib2

badTicker = 'TGTttttttt'
url = "http://ichart.finance. yahoo.com/table.csv?s=" + badTicker

try:
handle = urllib2.urlopen (url)

except urllib2.HTTPErr or, e:
print "There was an http error"
print e

except urllib2.URLErro r, e:
print "There is a problem with the URL"
print e

except urllib2.IOError , e:
print "You have an IOError"
print e

#in the shell
$ python -V
Python 2.5.1
$ python Desktop/tmp.py
There was an http error
HTTP Error 404: Not Found

Are you using an outdated version of Python perhaps?

Regards,
Chris

--
Follow the path of the Iguana...

http://rebertia.com

[robean]

Re: urllib2 and exceptions

On Sep 28, 12:11 pm, "Chris Rebert" <c...@rebertia. comwrote:

On Sun, Sep 28, 2008 at 11:03 AM, robean <st1...@gmail.c omwrote:

Hi everyone,

>

I have a question about using urllib2.

>

I like urllib2 better than urllib at least in part because it has more
elaborate support for handling errors: there is built in support for
URLError (for faulty urls) and HTTPError (for http errors that might
originate from, say, passing an invalid stock-ticker in the program
below).  However I can get neither to work.  I'm attaching below the
(very short) code: can anyone point out what I'm doing wrong?

>

Now, if I replace the URLError and HTTPError with IOError (the class
from which both URLError and HTTPError inherit), the program works
fine. Why is it that I can call the generic IOError class, but none of
the Error classes derived from that? These are clearly defined in the
urllib2 manual. Very confused...

>

Here's the code:

>

import urllib2

>

# read stock information from yahoo finance for Traget (TGT)
goodTicker = 'TGT' # program works with this
badTicker = 'TGTttttttt' # python doesn't understand either HTTPError
or URLError with this

>

url = "http://ichart.finance. yahoo.com/table.csv?s=" + badTicker

>

try:
       handle = urllib2.urlopen (url)

>

# this does not work
except HTTPError, e:
       print "There was an http error"
       print e

>

# this also does not work
except URLError, e:
       print "There is a problem with the URL"
       print e
       exit(1)

>

#this works
except IOError, e:
       print "You have an IOError"
       print e

>

text = handle.readline s()[:20]
for line in text:
       print line

>

--
http://mail.python.org/mailman/listinfo/python-list

>
My Python begs to differ:
>
#tmp.py
import urllib2
>
badTicker = 'TGTttttttt'
url = "http://ichart.finance. yahoo.com/table.csv?s=" + badTicker
>
try:
    handle = urllib2.urlopen (url)
>
except urllib2.HTTPErr or, e:
    print "There was an http error"
    print e
>
except urllib2.URLErro r, e:
    print "There is a problem with the URL"
    print e
>
except urllib2.IOError , e:
    print "You have an IOError"
    print e
>
#in the shell
$ python -V
Python 2.5.1
$ python Desktop/tmp.py
There was an http error
HTTP Error 404: Not Found
>
Are you using an outdated version of Python perhaps?
>
Regards,
Chris
>
--
Follow the path of the Iguana...http://rebertia.com

Then I expect that it is most likely my version of python that is
causing the problem. I'm using 2.5.2.

[robean]

Re: urllib2 and exceptions

On Sep 28, 12:27 pm, robean <st1...@gmail.c omwrote:

On Sep 28, 12:11 pm, "Chris Rebert" <c...@rebertia. comwrote:
>
>
>

On Sun, Sep 28, 2008 at 11:03 AM, robean <st1...@gmail.c omwrote:

Hi everyone,

>

I have a question about using urllib2.

>

I like urllib2 better than urllib at least in part because it has more
elaborate support for handling errors: there is built in support for
URLError (for faulty urls) and HTTPError (for http errors that might
originate from, say, passing an invalid stock-ticker in the program
below).  However I can get neither to work.  I'm attaching below the
(very short) code: can anyone point out what I'm doing wrong?

>

Now, if I replace the URLError and HTTPError with IOError (the class
from which both URLError and HTTPError inherit), the program works
fine. Why is it that I can call the generic IOError class, but none of
the Error classes derived from that? These are clearly defined in the
urllib2 manual. Very confused...

>

Here's the code:

>

import urllib2

>

# read stock information from yahoo finance for Traget (TGT)
goodTicker = 'TGT' # program works with this
badTicker = 'TGTttttttt' # python doesn't understand either HTTPError
or URLError with this

>

url = "http://ichart.finance. yahoo.com/table.csv?s=" + badTicker

>

try:
       handle = urllib2.urlopen (url)

>

# this does not work
except HTTPError, e:
       print "There was an http error"
       print e

>

# this also does not work
except URLError, e:
       print "There is a problem with the URL"
       print e
       exit(1)

>

#this works
except IOError, e:
       print "You have an IOError"
       print e

>

text = handle.readline s()[:20]
for line in text:
       print line

>

--
>http://mail.python.org/mailman/listinfo/python-list

>

My Python begs to differ:

>

#tmp.py
import urllib2

>

badTicker = 'TGTttttttt'
url = "http://ichart.finance. yahoo.com/table.csv?s=" + badTicker

>

try:
    handle = urllib2.urlopen (url)

>

except urllib2.HTTPErr or, e:
    print "There was an http error"
    print e

>

except urllib2.URLErro r, e:
    print "There is a problem with the URL"
    print e

>

except urllib2.IOError , e:
    print "You have an IOError"
    print e

>

#in the shell
$ python -V
Python 2.5.1
$ python Desktop/tmp.py
There was an http error
HTTP Error 404: Not Found

>

Are you using an outdated version of Python perhaps?

>

Regards,
Chris

>

--
Follow the path of the Iguana...http://rebertia.com

>
Then I expect that it is most likely my version of python that is
causing the problem. I'm using 2.5.2.

Actually, the problem seems to be that IOError is in my namespace, but
the other error classes are not. So,

except HTTPError, etc.

fails, but

except urllib2.HttpErr or, etc.

works fine. Now, I still don't understand why these classes shouldn't
automatically work....

[alex23]

Re: urllib2 and exceptions

On Sep 29, 5:52 am, robean <st1...@gmail.c omwrote:

Actually, the problem seems to be that IOError is in my namespace, but
the other error classes are not. So,
>
   except HTTPError, etc.
>
fails, but
>
   except urllib2.HttpErr or, etc.
>
works fine. Now, I still don't understand why these classes shouldn't
automatically work....

IOError is a standard Python exception. HTTPError & URLError are
exceptions provided by the urllib2 module. They need to be imported
from or referenced through urllib2 to be used.

[robean]

Re: urllib2 and exceptions

On Sep 28, 5:33 pm, alex23 <wuwe...@gmail. comwrote:

On Sep 29, 5:52 am, robean <st1...@gmail.c omwrote:
>

Actually, the problem seems to be that IOError is in my namespace, but
the other error classes are not. So,

>

   except HTTPError, etc.

>

fails, but

>

   except urllib2.HttpErr or, etc.

>

works fine. Now, I still don't understand why these classes shouldn't
automatically work....

>
IOError is a standard Python exception. HTTPError & URLError are
exceptions provided by the urllib2 module. They need to be imported
from or referenced through urllib2 to be used.

Many thanks for your reply. I was simply under the impression that
'import urllib2' would take care of the namespace issue and simply
import everything in urlib2, making it unnecessary to have to
reference HTTPError and URLError. Sorry for being dense about this
(I'm very new to Python).. Again, thanks for your help.

[Gabriel Genellina]

Re: urllib2 and exceptions

En Sun, 28 Sep 2008 22:44:20 -0300, robean <st1999@gmail.c omescribió:

Many thanks for your reply. I was simply under the impression that
'import urllib2' would take care of the namespace issue and simply
import everything in urlib2, making it unnecessary to have to
reference HTTPError and URLError. Sorry for being dense about this
(I'm very new to Python).. Again, thanks for your help.

That's a common misconception - see this article:

http://effbot.org/zone/import-confusion.htm

--
Gabriel Genellina