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Fix Issue5419 - explaining bytes return value of urlopen, use of .decode() to convert to str.

This commit is contained in:
Senthil Kumaran 2010-04-15 17:18:22 +00:00
parent 7337a5432b
commit b213ee33c0
1 changed files with 25 additions and 9 deletions
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34
Doc/library/urllib.request.rst
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@ -1073,23 +1073,39 @@ Examples
--------
This example gets the python.org main page and displays the first 100 bytes of
it::
it.::
>>> import urllib.request
>>> f = urllib.request.urlopen('http://www.python.org/')
>>> print(f.read(100))
b'<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<?xml-stylesheet href="./css/ht2html'
Note that in Python 3, urlopen returns a bytes object by default. In many
circumstances, you might expect the output of urlopen to be a string. This
might be a carried over expectation from Python 2, where urlopen returned
string or it might even the common usecase. In those cases, you should
explicitly decode the bytes to string.
In the examples below, we have chosen *utf-8* encoding for demonstration, you
might choose the encoding which is suitable for the webpage you are
requesting::
>>> import urllib.request
>>> f = urllib.request.urlopen('http://www.python.org/')
>>> print(f.read(100).decode('utf-8')
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<?xml-stylesheet href="./css/ht2html
Here we are sending a data-stream to the stdin of a CGI and reading the data it
returns to us. Note that this example will only work when the Python
installation supports SSL. ::
In the following example, we are sending a data-stream to the stdin of a CGI
and reading the data it returns to us. Note that this example will only work
when the Python installation supports SSL. ::
>>> import urllib.request
>>> req = urllib.request.Request(url='https://localhost/cgi-bin/test.cgi',
... data='This data is passed to stdin of the CGI')
>>> f = urllib.request.urlopen(req)
>>> print(f.read())
>>> print(f.read().decode('utf-8'))
Got Data: "This data is passed to stdin of the CGI"
The code for the sample CGI used in the above example is::
@ -1161,7 +1177,7 @@ containing parameters::
>>> import urllib.parse
>>> params = urllib.parse.urlencode({'spam': 1, 'eggs': 2, 'bacon': 0})
>>> f = urllib.request.urlopen("http://www.musi-cal.com/cgi-bin/query?%s" % params)
>>> print(f.read())
>>> print(f.read().decode('utf-8'))
The following example uses the ``POST`` method instead::
@ -1169,7 +1185,7 @@ The following example uses the ``POST`` method instead::
>>> import urllib.parse
>>> params = urllib.parse.urlencode({'spam': 1, 'eggs': 2, 'bacon': 0})
>>> f = urllib.request.urlopen("http://www.musi-cal.com/cgi-bin/query", params)
>>> print(f.read())
>>> print(f.read().decode('utf-8'))
The following example uses an explicitly specified HTTP proxy, overriding
environment settings::
@ -1178,14 +1194,14 @@ environment settings::
>>> proxies = {'http': 'http://proxy.example.com:8080/'}
>>> opener = urllib.request.FancyURLopener(proxies)
>>> f = opener.open("http://www.python.org")
>>> f.read()
>>> f.read().decode('utf-8')
The following example uses no proxies at all, overriding environment settings::
>>> import urllib.request
>>> opener = urllib.request.FancyURLopener({})
>>> f = opener.open("http://www.python.org/")
>>> f.read()
>>> f.read().decode('utf-8')
:mod:`urllib.request` Restrictions