[issue24460] urlencode() of dictionary not as expected

[David Rueter]

New submission from David Rueter:

In Python 3.4 I would like to serialize a dictionary into a URL-encoded string.

Given a dictionary like this: 

>>> thisDict = {'SomeVar1': [b'abc'], 'SomeVar2': [b'def'], 'SomeVar3': [b'ghi']}

I would like to be able to return this string:

	SomeVar1=abc&SomeVar2=def&SomeVar3=ghi

I thought that urllib.parse.urlencode would work for me, but it does not:

>>> print(urllib.parse.urlencode(thisDict))
	SomeVar1=%5Bb%27abc%27%5D&SomeVar2=%5Bb%27def%27%5D&SomeVar3=%5Bb%27ghi%27%5D

In other words, urlencode on the dictionary is performing a URL encode on the string that is returned when the dictionary is cast to a string...and is including the square brackets (escaped) and the byte literal "b" indicator.

{'SomeVar1': [b'abc'], 'SomeVar2': [b'def'], 'SomeVar3': [b'ghi']}

I can obtain the desired string with this:

>>> '&'.join("{!s}={!s}".format(key,urllib.parse.quote_plus(str(val[0],'utf-8'))) for (key,val) in thisDict.items())

Is the behavior of urllib.parse.urlencode() on a dictionary intentional?  When would the current behavior ever be useful?

Would it make sense to change the behavior of urllib.parse.urlencode such that it works as described above?

----------
components: Library (Lib)
messages: 245431
nosy: drueter at assyst.com
priority: normal
severity: normal
status: open
title: urlencode() of dictionary not as expected
type: behavior
versions: Python 3.4

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue24460>
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