Added a method to serialize a Url to a path with a query string

[gtolle]

Intended for use by HTTP clients. The Hyper client currently calls serialize_path() when constructing its GET requests, but this discards the query string. I'm suggesting this new rust-url method so that Hyper can use it.

[gtolle]

Also, this is my first bit of public/production Rust code, so feel free to suggest changes. I'm still learning.

[Manishearth]

Should this be Option<&'b str> instead?

[gtolle]

@Manishearth good suggestion. I updated the PathWithQueryFormatter to take a slice instead of a String, following the same conventions as the password field in UserInfoFormatter. But, I kept the named lifetime as 'a instead of 'b, and realized I don't know enough about Rust named lifetimes to understand how to make it work with 'b instead of 'a.

[Manishearth]

pub struct PathWithQueryFormatter<'a, 'b, T:'a> {
 pub path: &'a [T],
 pub query: Option<&'b str>,
}

should work? I'm not too clear on this either, but if the two lifetimes are the same we may get conflicting lifetime issues while using it (eg if we pass it a static string slice and a non-static array slice)

[Manishearth]

Aside from the lifetime thing (and perhaps the indentation for serialize_path_with_query could be improved), this looks good to me.

I'll wait for @SimonSapin to sign off on this though.

[gtolle]

OK, I just tried your change with separate lifetimes and it worked fine, as long as I also change:

impl<'a, 'b, T: Str + Show> Show for PathWithQueryFormatter<'a, 'b, T> {

Happy to push it, but before I do, I wonder why UserInfoFormatter used the same lifetime for both the username and password fields instead of splitting into 'a and 'b.

Also, I'm using emacs rust-mode for indentation, and that's what came out for serialize_path_with_query. If you don't mind, could you show me the indentation you'd prefer? I'll make the change.

[Manishearth]

Huh, you're right. I tested it with using strings of different lifetimes -- it seems to upcast to the smaller lifetime.

[gtolle]

Hmm, alright then. Thanks for testing this!

Looking forward to hearing from @SimonSapin.

[pyfisch]

Is this PR still relevant? Should I create a new PR with updated code for this function?

[SimonSapin]

With #176 this will be &url[Position::BeforePath..Postition::AfterQuery].