[cpp-netlib-devel] Query parameters

[Matt T. <mat...@gm...>]

Hello folks,

How are query parameters meant to be set with cpp-netlib?

As a test I was trying to perform a GET to our Hudson
(https://hudson.dev.java.net/) build server.  The request looks
something like this:

    http::request
request("http://hudson_server/hudson/api/xml?xpath=//job[name='mainjob']/color/text()");
    http::client client;
    http::response response;
    response = client.get(request);
    cout << body(response) << endl;

The "/"'s in the xpath query cause problems.  The parser in
request.hpp (specifically, line 94) fails to match the "/" and
discards the query parameters.

[As an aside I appreciate that "/" is a reserved character in an URI
but haven't dug far enough into the RFC
(http://www.ietf.org/rfc/rfc3986.txt) to determine whether this usage
of it makes for a valid URI.  I *think* it is valid - even without
escaping - based on section 3.4 but I'm not 100%.]

I've worked around the issue with the following change:

    Index: boost/network/protocol/http/impl/request.hpp
    ===================================================================
    --- boost/network/protocol/http/impl/request.hpp	(revision 142)
    +++ boost/network/protocol/http/impl/request.hpp	(working copy)
    @@ -91,7 +91,7 @@
                             = construct_<typename
string_traits<tag>::type>(arg1, arg2)
                     ]
                     >> !(ch_p('?')
    -                    >> (+(alnum_p | '&' | '=' | '%' | '_' ))[
    +                    >> (+(anychar_p | '&' | '=' | '%' | '_' ))[
                             var(fusion::at_key<typename
tags::query>(uri_parts))
                                 = construct_<typename
string_traits<tag>::type>(arg1, arg2)
                         ]

But that's quite dirty!

I'm wondering if there's a better way to set queries for a request?  I
couldn't find anything in the code but I may well have missed
something.

I suppose I was looking for something like:

    http::request request("http://hudson_server/hudson/api/xml");
    request.addQuery("xpath", "//job[name='mainjob']/color/text()")

That way the parser could add the surrounding stuff (question marks,
amperstands etc) for me.  As it turns out this is similar to how
Pion's HTTPRequest class handles queries.

BTW I did notice there is a query() method to *return* the query
string.  I also noticed the "make_query_string" method but I wasn't
sure if I could (or should) try and use it since it was in an impl
file.  It also doesn't seem to be used internally either though...

Any comments?  Am I doing something obviously wrong?

Cheers,
Matt