According to CGI/1.1 RFC 3875:
The server MUST set this variable; if the Script-URI does not include a
query component, the QUERY_STRING MUST be defined as an empty string ("").
Python's PEP 333(3) allows omitting it in WSGI interface; PHP docs force no
requirements; PSGI and Rack specifications require it even if empty.
When nginx proxies requests over FastCGI, it always provides QUERY_STRING.
and some PHP apps have been observed to fail if it is missing (see issue
#201 on GitHub).
A drawback of this change (besides a small overhead) is that there will be
no easy way to tell a missing query string from an empty one (i.e. requests
with or without the "?" character); yet, it's negligible compared to the
possible benefits of wider application compatibility.
This closes#226 issue on GitHub.
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