Trivia: What is the difference between the encoded query string parameter “a+b” and “a%20b” ?
Answer: Nothing! They are both encoded representations for “a b”.
Isn’t a “+” supposed to remain a “+”? Well, the URL and the query strings are not encoded following the same rules. In the URL, the “+” remains a “+” indeed, but in the query string it’s actually encoded and becomes a “%2B”. This can be misleading.
So basically, the choice is left to the encoder. In Python we get
In [1]: from urllib import urlencode
In [2]: urlencode({"a" : "a b+c"})
Out[2]: 'a=a+b%2Bc'
And in JavaScript
"a=" + encodeURIComponent("a b+c");
"a=a%20b%2Bc"
So both converted the “+” as a “%2B” and Python encoded the white space as “+” while JavaScript encoded it as “%20”.
Remember, the encoding differs between the URL and the query strings so the functions called do too. In python, to encode a URL you do
In [1]: from urllib import quote
In [2]: quote('test.com/a b+c')
Out[2]: 'test.com/a%20b%2Bc'
And in JavaScript you do
encodeURI('test.com/a b+c')
"test.com/a%20b+c"
Again, the results differ but are both valid. Python and JavaScript both encoded the white space as “%20” while the “+” remained the same in JavaScript but was converted to “%2B” in Python.
Mind blown.
References
https://en.wikipedia.org/wiki/Percent-encoding https://stackoverflow.com/questions/1005676/urls-and-plus-signs http://bugs.python.org/issue13866