[Haskell-cafe] Contributing to http-conduit

[Aristid Breitkreuz]

Is it possible to have both an Expires and a Max-age? If not, maybe
you should make a type like

data Expiry = NeverExpires | ExpiresAt UTCTime | ExpiresIn DiffTime


2012/2/4 Myles C. Maxfield <myles.maxfield at gmail.com>:
> Here is the patch to Web.Cookie. I didn't modify the tests at all because
> they were already broken - they looked like they hadn't been updated since
> SetCookie only had 5 parameters. I did verify by hand that the patch works,
> though.
>
> Thanks,
> Myles
>
>
> On Thu, Feb 2, 2012 at 11:26 PM, Myles C. Maxfield
> <myles.maxfield at gmail.com> wrote:
>>
>> Alright, I'll make a small patch that adds 2 fields to SetCookie:
>> setCookieMaxAge :: Maybe DiffTime
>> setCookieSecureOnly :: Bool
>>
>> I've also gotten started on those cookie functions. I'm currently writing
>> tests for them.
>>
>> @Chris: The best advice I can give is that Chrome (what I'm using as a
>> source on all this) has the data baked into a .cc file. However, they have
>> directions in a README and a script which will parse the list and generate
>> that source file. I recommend doing this. That way, the Haskell module would
>> have 2 source files: one file that reads the list and generates the second
>> file, which is a very large source file that contains each element in the
>> list. The list should export `elem`-type queries. I'm not quite sure how to
>> handle wildcards that appear in the list - that part is up to you. Thanks
>> for helping out with this :]
>>
>> --Myles
>>
>>
>> On Thu, Feb 2, 2012 at 10:53 PM, Michael Snoyman <michael at snoyman.com>
>> wrote:
>>>
>>> Looks good to me too. I agree with Aristid: let's make the change to
>>> cookie itself. Do you want to send a pull request? I'm also
>>> considering making the SetCookie constructor hidden like we have for
>>> Request, so that if in the future we realize we need to add some other
>>> settings, it doesn't break the API.
>>>
>>> Chris: I would recommend compiling it into the module. Best bet would
>>> likely being converting the source file to Haskell source.
>>>
>>> Michael
>>>
>>> On Fri, Feb 3, 2012 at 6:32 AM, Myles C. Maxfield
>>> <myles.maxfield at gmail.com> wrote:
>>> > Alright. After reading the spec, I have these questions / concerns:
>>> >
>>> > The spec supports the "Max-Age" cookie attribute, which Web.Cookies
>>> > doesn't.
>>> >
>>> > I see two possible solutions to this. The first is to have
>>> > parseSetCookie
>>> > take a UTCTime as an argument which will represent the current time so
>>> > it
>>> > can populate the setCookieExpires field by adding the Max-Age attribute
>>> > to
>>> > the current time. Alternatively, that function can return an IO
>>> > SetCookie so
>>> > it can ask for the current time by itself (which I think is inferior to
>>> > taking the current time as an argument). Note that the spec says to
>>> > prefer
>>> > Max-Age over Expires.
>>> > Add a field to SetCookie of type Maybe DiffTime which represents the
>>> > Max-Age
>>> > attribute
>>> >
>>> > Cookie code should be aware of the Public Suffix List as a part of its
>>> > domain verification. The cookie code only needs to be able to tell if a
>>> > specific string is in the list (W.Ascii -> Bool)
>>> >
>>> > I propose making an entirely unrelated package, public-suffix-list,
>>> > with a
>>> > module Network.PublicSuffixList, which will expose this function, as
>>> > well as
>>> > functions about parsing the list itself. Thoughts?
>>> >
>>> > Web.Cookie doesn't have a "secure-only" attribute. Adding one in is
>>> > straightforward enough.
>>> > The spec describes cookies as a property of HTTP, not of the World Wide
>>> > Web.
>>> > Perhaps "Web.Cookie" should be renamed? Just a thought; it doesn't
>>> > really
>>> > matter to me.
>>> >
>>> > As for Network.HTTP.Conduit.Cookie, the spec describes in section 5.3
>>> > "Storage Model" what fields a Cookie has. Here is my proposal for the
>>> > functions it will expose:
>>> >
>>> > receiveSetCookie :: SetCookie -> Req.Request m -> UTCTime -> Bool ->
>>> > CookieJar -> CookieJar
>>> >
>>> > Runs the algorithm described in section 5.3 "Storage Model"
>>> > The UTCTime is the current-time, the Bool is whether or not the caller
>>> > is an
>>> > HTTP-based API (as opposed to JavaScript or anything else)
>>> >
>>> > updateCookieJar :: Res.Response a -> Req.Request m -> UTCTime ->
>>> > CookieJar
>>> > -> (CookieJar, Res.Response a)
>>> >
>>> > Applies "receiveSetCookie" to a Response. The output CookieJar is
>>> > stripped
>>> > of any Set-Cookie headers.
>>> > Specifies "True" for the Bool in receiveSetCookie
>>> >
>>> > computeCookieString :: Req.Request m -> CookieJar -> UTCTime -> Bool ->
>>> > (W.Ascii, CookieJar)
>>> >
>>> > Runs the algorithm described in section 5.4 "The Cookie Header"
>>> > The UTCTime and Bool are the same as in receiveSetCookie
>>> >
>>> > insertCookiesIntoRequest :: Req.Request m -> CookieJar -> UTCTime ->
>>> > (Req.Request m, CookieJar)
>>> >
>>> > Applies "computeCookieString" to a Request. The output cookie jar has
>>> > updated last-accessed-times.
>>> > Specifies "True" for the Bool in computeCookieString
>>> >
>>> > evictExpiredCookies :: CookieJar -> UTCTime -> CookieJar
>>> >
>>> > Runs the algorithm described in the last part of section 5.3 "Storage
>>> > Model"
>>> >
>>> > This will make the relevant part of 'http' look like:
>>> >
>>> >     go count req'' cookie_jar'' = do
>>> >         now <- liftIO $ getCurrentTime
>>> >         let (req', cookie_jar') = insertCookiesIntoRequest req''
>>> > (evictExpiredCookies cookie_jar'' now) now
>>> >         res' <- httpRaw req' manager
>>> >         let (cookie_jar, res) = updateCookieJar res' req' now
>>> > cookie_jar'
>>> >         case getRedirectedRequest req' (responseHeaders res)
>>> > (W.statusCode
>>> > (statusCode res)) of
>>> >             Just req -> go (count - 1) req cookie_jar
>>> >             Nothing -> return res
>>> >
>>> > I plan to not allow for a user-supplied cookieFilter function. If they
>>> > want
>>> > that functionality, they can re-implement the redirection-following
>>> > logic.
>>> >
>>> > Any thoughts on any of this?
>>> >
>>> > Thanks,
>>> > Myles
>>> >
>>> > On Wed, Feb 1, 2012 at 5:19 PM, Myles C. Maxfield
>>> > <myles.maxfield at gmail.com>
>>> > wrote:
>>> >>
>>> >> Nope. I'm not. The RFC is very explicit about how to handle cookies.
>>> >> As
>>> >> soon as I'm finished making sense of it (in terms of Haskell) I'll
>>> >> send
>>> >> another proposal email.
>>> >>
>>> >> On Feb 1, 2012 3:25 AM, "Michael Snoyman" <michael at snoyman.com> wrote:
>>> >>>
>>> >>> You mean you're *not* making this proposal?
>>> >>>
>>> >>> On Wed, Feb 1, 2012 at 7:30 AM, Myles C. Maxfield
>>> >>> <myles.maxfield at gmail.com> wrote:
>>> >>> > Well, this is embarrassing. Please disregard my previous email. I
>>> >>> > should
>>> >>> > learn to read the RFC *before* submitting proposals.
>>> >>> >
>>> >>> > --Myles
>>> >>> >
>>> >>> >
>>> >>> > On Tue, Jan 31, 2012 at 6:37 PM, Myles C. Maxfield
>>> >>> > <myles.maxfield at gmail.com> wrote:
>>> >>> >>
>>> >>> >> Here are my initial ideas about supporting cookies. Note that I'm
>>> >>> >> using
>>> >>> >> Chrome for ideas since it's open source.
>>> >>> >>
>>> >>> >> Network/HTTP/Conduit/Cookies.hs file
>>> >>> >> Exporting the following symbols:
>>> >>> >>
>>> >>> >> type StuffedCookie = SetCookie
>>> >>> >>
>>> >>> >> A regular SetCookie can have Nothing for its Domain and Path
>>> >>> >> attributes. A
>>> >>> >> StuffedCookie has to have these fields set.
>>> >>> >>
>>> >>> >> type CookieJar = [StuffedCookie]
>>> >>> >>
>>> >>> >> Chrome's cookie jar is implemented as (the C++ equivalent of) Map
>>> >>> >> W.Ascii
>>> >>> >> StuffedCookie. The key is the "eTLD+1" of the domain, so lookups
>>> >>> >> for
>>> >>> >> all
>>> >>> >> cookies for a given domain are fast.
>>> >>> >> I think I'll stay with just a list of StuffedCookies just to keep
>>> >>> >> it
>>> >>> >> simple. Perhaps a later revision can implement the faster map.
>>> >>> >>
>>> >>> >> getRelevantCookies :: Request m -> CookieJar -> UTCTime ->
>>> >>> >> (CookieJar,
>>> >>> >> Cookies)
>>> >>> >>
>>> >>> >> Gets all the cookies from the cookie jar that should be set for
>>> >>> >> the
>>> >>> >> given
>>> >>> >> Request.
>>> >>> >> The time argument is whatever "now" is (it's pulled out of the
>>> >>> >> function so
>>> >>> >> the function can remain pure and easily testable)
>>> >>> >> The function will also remove expired cookies from the cookie jar
>>> >>> >> (given
>>> >>> >> what "now" is) and return the filtered cookie jar
>>> >>> >>
>>> >>> >> putRelevantCookies :: Request m -> CookieJar -> [StuffedCookie] ->
>>> >>> >> CookieJar
>>> >>> >>
>>> >>> >> Insert cookies from a server response into the cookie jar.
>>> >>> >> The first argument is only used for checking to see which cookies
>>> >>> >> are
>>> >>> >> valid (which cookies match the requested domain, etc, so site1.com
>>> >>> >> can't set
>>> >>> >> a cookie for site2.com)
>>> >>> >>
>>> >>> >> stuffCookie :: Request m -> SetCookie -> StuffedCookie
>>> >>> >>
>>> >>> >> If the SetCookie's fields are Nothing, fill them in given the
>>> >>> >> Request
>>> >>> >> from
>>> >>> >> which it originated
>>> >>> >>
>>> >>> >> getCookies :: Response a -> ([SetCookie], Response a)
>>> >>> >>
>>> >>> >> Pull cookies out of a server response. Return the response with
>>> >>> >> the
>>> >>> >> Set-Cookie headers filtered out
>>> >>> >>
>>> >>> >> putCookies :: Request a -> Cookies -> Request a
>>> >>> >>
>>> >>> >> A wrapper around renderCookies. Inserts some cookies into a
>>> >>> >> request.
>>> >>> >> Doesn't overwrite cookies that are already set in the request
>>> >>> >>
>>> >>> >> These functions will be exported from Network.HTTP.Conduit as
>>> >>> >> well, so
>>> >>> >> callers can use them to re-implement redirection chains
>>> >>> >> I won't implement a cookie filtering function (like what
>>> >>> >> Network.Browser
>>> >>> >> has)
>>> >>> >>
>>> >>> >> If you want to have arbitrary handling of cookies, re-implement
>>> >>> >> redirection following. It's not very difficult if you use the API
>>> >>> >> provided,
>>> >>> >> and the 'http' function is open source so you can use that as a
>>> >>> >> reference.
>>> >>> >>
>>> >>> >> I will implement the functions according to RFC 6265
>>> >>> >> I will also need to write the following functions. Should they
>>> >>> >> also be
>>> >>> >> exported?
>>> >>> >>
>>> >>> >> canonicalizeDomain :: W.Ascii -> W.Ascii
>>> >>> >>
>>> >>> >> turns "..a.b.c..d.com..." to "a.b.c.d.com"
>>> >>> >> Technically necessary for domain matching (Chrome does it)
>>> >>> >> Perhaps unnecessary for a first pass? Perhaps we can trust users
>>> >>> >> for
>>> >>> >> now?
>>> >>> >>
>>> >>> >> domainMatches :: W.Ascii -> W.Ascii -> Maybe W.Ascii
>>> >>> >>
>>> >>> >> Does the first domain match against the second domain?
>>> >>> >> If so, return the prefix of the first that isn't in the second
>>> >>> >>
>>> >>> >> pathMatches :: W.Ascii -> W.Ascii -> Bool
>>> >>> >>
>>> >>> >> Do the paths match?
>>> >>> >>
>>> >>> >> In order to implement domain matching, I have to have knowledge of
>>> >>> >> the Public Suffix List so I know that sub1.sub2.pvt.k12.wy.us can
>>> >>> >> set
>>> >>> >> a
>>> >>> >> cookie for sub2.pvt.k12.wy.us but not for k12.wy.us (because
>>> >>> >> pvt.k12.wy.us
>>> >>> >> is a "suffix"). There are a variety of ways to implement this.
>>> >>> >>
>>> >>> >> As far as I can tell, Chrome does it by using a script (which a
>>> >>> >> human
>>> >>> >> periodically runs) which parses the list at creates a .cc file
>>> >>> >> that is
>>> >>> >> included in the build.
>>> >>> >>
>>> >>> >> I might be wrong about the execution of the script; it might be a
>>> >>> >> build
>>> >>> >> step. If it is a build step, however, it is suspicious that a
>>> >>> >> build
>>> >>> >> target
>>> >>> >> would try to download a file...
>>> >>> >>
>>> >>> >> Any more elegant ideas?
>>> >>> >>
>>> >>> >> Feedback on any/all of the above would be very helpful before I go
>>> >>> >> off
>>> >>> >> into the weeds on this project.
>>> >>> >>
>>> >>> >> Thanks,
>>> >>> >> Myles C. Maxfield
>>> >>> >>
>>> >>> >> On Sat, Jan 28, 2012 at 8:17 PM, Michael Snoyman
>>> >>> >> <michael at snoyman.com>
>>> >>> >> wrote:
>>> >>> >>>
>>> >>> >>> Thanks, looks great! I've merged it into the Github tree.
>>> >>> >>>
>>> >>> >>> On Sat, Jan 28, 2012 at 8:36 PM, Myles C. Maxfield
>>> >>> >>> <myles.maxfield at gmail.com> wrote:
>>> >>> >>> > Ah, yes, you're completely right. I completely agree that
>>> >>> >>> > moving
>>> >>> >>> > the
>>> >>> >>> > function into the Maybe monad increases readability. This kind
>>> >>> >>> > of
>>> >>> >>> > function
>>> >>> >>> > is what the Maybe monad was designed for.
>>> >>> >>> >
>>> >>> >>> > Here is a revised patch.
>>> >>> >>> >
>>> >>> >>> >
>>> >>> >>> > On Sat, Jan 28, 2012 at 8:28 AM, Michael Snoyman
>>> >>> >>> > <michael at snoyman.com>
>>> >>> >>> > wrote:
>>> >>> >>> >>
>>> >>> >>> >> On Sat, Jan 28, 2012 at 1:20 AM, Myles C. Maxfield
>>> >>> >>> >> <myles.maxfield at gmail.com> wrote:
>>> >>> >>> >> > the fromJust should never fail, beceause of the guard
>>> >>> >>> >> > statement:
>>> >>> >>> >> >
>>> >>> >>> >> >     | 300 <= code && code < 400 && isJust l'' && isJust l' =
>>> >>> >>> >> > Just $
>>> >>> >>> >> > req
>>> >>> >>> >> >
>>> >>> >>> >> > Because of the order of the && operators, it will only
>>> >>> >>> >> > evaluate
>>> >>> >>> >> > fromJust
>>> >>> >>> >> > after it makes sure that the argument isJust. That function
>>> >>> >>> >> > in
>>> >>> >>> >> > particular
>>> >>> >>> >> > shouldn't throw any exceptions - it should only return
>>> >>> >>> >> > Nothing.
>>> >>> >>> >> >
>>> >>> >>> >> > Knowing that, I don't quite think I understand what your
>>> >>> >>> >> > concern
>>> >>> >>> >> > is.
>>> >>> >>> >> > Can
>>> >>> >>> >> > you
>>> >>> >>> >> > elaborate?
>>> >>> >>> >>
>>> >>> >>> >> You're right, but I had to squint really hard to prove to
>>> >>> >>> >> myself
>>> >>> >>> >> that
>>> >>> >>> >> you're right. That's the kind of code that could easily be
>>> >>> >>> >> broken
>>> >>> >>> >> in
>>> >>> >>> >> future updates by an unwitting maintainer (e.g., me). To
>>> >>> >>> >> protect
>>> >>> >>> >> the
>>> >>> >>> >> world from me, I'd prefer if the code didn't have the
>>> >>> >>> >> fromJust.
>>> >>> >>> >> This
>>> >>> >>> >> might be a good place to leverage the Monad instance of Maybe.
>>> >>> >>> >>
>>> >>> >>> >> Michael
>>> >>> >>> >
>>> >>> >>> >
>>> >>> >>
>>> >>> >>
>>> >>> >
>>> >
>>> >
>>
>>
>
>
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