[Haskell-cafe] Contributing to http-conduit

[Michael Snoyman]

On Wed, Feb 8, 2012 at 6:28 AM, Myles C. Maxfield
<myles.maxfield at gmail.com> wrote:
> I have been looking around at possibly making a Browser module for
> Network.HTTP.Conduit on top of Control.Monad.State. I came across this
> roadbump:
>
> In order to implement redirection following, client code must call 'http'
> with a redirection count of 0. If there is a redirect, 'http' will throw an
> exception. In order to catch this exception and continue on with the

Actually, this is just a setting: you can override with checkStatus[1].

[1] http://hackage.haskell.org/packages/archive/http-conduit/1.2.4/doc/html/Network-HTTP-Conduit.html#v:checkStatus

> redirection chain, the 'catch' function must be called. The problem is that
> the 'catch' function has a type of (catch :: Exception e => IO a -> (e -> IO
> a) -> IO a) which means that it can only be used in the IO monad. A call to
> 'http' inside the first argument of 'catch' must be wrapped in a
> 'runResourceT'
>
> This has a couple implications:
>
> The catch function cannot yield a Source, because any connections which
> 'http' opened will have to be immediately closed as soon as control reaches
> the 'catch' function (because of the runResourceT). The only way around this
> is to put the bind inside the catch block with some default sink, but this
> loses all of the constant-memory benefits of using a conduit in the first
> place.
> The function that will be calling 'catch' operates as a State monad. Cookie
> state must be updated both before and after making the request (both inside
> the 'catch' block and outside). I could pass around an updated cookie jar
> out of the IO monad as an extra entry in a tuple, but this defeats the
> purpose of using a State monad in the first place. This kind of programming
> is very ugly.
>
> I see two solutions to these problems:
>
> Make 'http' not throw a StatusCodeException if the _original_ redirection
> count = 0
> Make my internal module call the un-exported 'httpRaw' function. This has
> the problem that it doen't solve the problem for anyone else trying to use
> http-conduit; it only solves the problem for me. Perhaps this could be
> alleviated by exporting httpRaw.
>
> What do you think?
> --Myles
>
> On Tue, Feb 7, 2012 at 12:35 AM, Myles C. Maxfield
> <myles.maxfield at gmail.com> wrote:
>>
>> Alright. I'll issue another pull request to you when it's done (expect in
>> a couple weeks).
>>
>> Thanks for your input so far, Aristid and Michael.
>>
>> @Chris Wong: Do you want to talk about the Suffix List stuff some time?
>>
>> --Myles
>>
>>
>> On Mon, Feb 6, 2012 at 10:14 PM, Michael Snoyman <michael at snoyman.com>
>> wrote:
>>>
>>> +1
>>>
>>> On Mon, Feb 6, 2012 at 11:16 PM, Aristid Breitkreuz
>>> <aristidb at googlemail.com> wrote:
>>> > 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
>>> >>> >> >>> >>> >>> >
>>> >>> >> >>> >>> >>> >
>>> >>> >> >>> >>> >>
>>> >>> >> >>> >>> >>
>>> >>> >> >>> >>> >
>>> >>> >> >>> >
>>> >>> >> >>> >
>>> >>> >> >>
>>> >>> >> >>
>>> >>> >> >
>>> >>> >
>>> >>> >
>>> >>
>>> >>
>>> >>
>>> >> _______________________________________________
>>> >> Haskell-Cafe mailing list
>>> >> Haskell-Cafe at haskell.org
>>> >> http://www.haskell.org/mailman/listinfo/haskell-cafe
>>> >>
>>> >
>>
>>
>