[Haskell-cafe] Contributing to http-conduit

Aristid Breitkreuz aristidb at googlemail.com
Mon Feb 6 22:16:17 CET 2012


I would say: if it adds no package dependencies, put it right in.

Aristid
Am 06.02.2012 22:09 schrieb "Myles C. Maxfield" <myles.maxfield at gmail.com>:

> After all these commits have been flying around, I have yet another
> question:
>
> the 'HTTP' package defines Network.Browser which is a State monad which
> keeps state about a "browser" (i.e. a cookie jar, a proxy, redirection
> parameters, etc.) It would be pretty straightforward to implement this kind
> of functionality on top of http-conduit.
>
> I was originally going to do it and release it as its own package, but it
> may be beneficial to add such a module to the existing http-conduit
> package. Should I add it in to the existing package, or release it as its
> own package?
>
> --Myles
>
> On Mon, Feb 6, 2012 at 12:15 AM, Michael Snoyman <michael at snoyman.com>wrote:
>
>> Just an FYI for everyone: Myles sent an (incredibly thorough) pull
>> request to handle cookies:
>>
>> https://github.com/snoyberg/http-conduit/pull/13
>>
>> Thanks!
>>
>> On Sun, Feb 5, 2012 at 8:20 AM, Myles C. Maxfield
>> <myles.maxfield at gmail.com> wrote:
>> > 1. The spec defines a grammar for the attributes. They're in uppercase.
>> > 2. Yes - 1.3 is the first version that lists DiffTime as an instance of
>> > RealFrac (so I can use the 'floor' function to pull out the number of
>> > seconds to render it)
>> > 3. I'll see what I can do.
>> >
>> > --Myles
>> >
>> >
>> > On Sat, Feb 4, 2012 at 9:06 PM, Michael Snoyman <michael at snoyman.com>
>> wrote:
>> >>
>> >> Looks good, a few questions/requests:
>> >>
>> >> 1. Is there a reason to upper-case all the attributes?
>> >> 2. Is the time >= 1.3 a requirements? Because that can cause a lot of
>> >> trouble for people.
>> >> 3. Can you send the patch as a Github pull request? It's easier to
>> >> track that way.
>> >>
>> >> Michael
>> >>
>> >> On Sat, Feb 4, 2012 at 1:21 AM, Myles C. Maxfield
>> >> <myles.maxfield at gmail.com> wrote:
>> >> > 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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