hsemail-2: src/Text/Parsec/Rfc2822.hs
{-# LANGUAGE FlexibleContexts #-}
{- |
Module : Text.Parsec.Rfc2822
Copyright : (c) 2013 Peter Simons
License : BSD3
Maintainer : simons@cryp.to
Stability : provisional
Portability : portable
This module provides parsers for the grammar defined in
RFC2822, \"Internet Message Format\",
<http://www.faqs.org/rfcs/rfc2822.html>.
-}
module Text.Parsec.Rfc2822 where
import Text.Parsec.Rfc2234 hiding ( quoted_pair, quoted_string )
import Control.Monad ( replicateM )
import Data.Char ( ord )
import Data.List ( intercalate )
import Data.Maybe ( catMaybes )
import Data.Monoid ( Monoid, mempty )
import System.Time
import Text.Parsec hiding (crlf)
-- Customize hlint ...
{-# ANN module "HLint: ignore Use camelCase" #-}
-- * Useful parser combinators
-- |Return @Nothing@ if the given parser doesn't match. This
-- combinator is included in the latest parsec distribution as
-- @optionMaybe@, but ghc-6.6.1 apparently doesn't have it.
maybeOption :: Stream s m Char => ParsecT s u m a -> ParsecT s u m (Maybe a)
maybeOption p = option Nothing (fmap Just p)
-- |@unfold@ @=@ @between (optional cfws) (optional cfws)@
unfold :: Stream s m Char => ParsecT s u m a -> ParsecT s u m a
unfold = between (optional cfws) (optional cfws)
-- |Construct a parser for a message header line from the
-- header's name and a parser for the body.
header :: Stream s m Char => String -> ParsecT s u m a -> ParsecT s u m a
header n p = let nameString = caseString (n ++ ":")
in
between nameString crlf p <?> (n ++ " header line")
-- |Like 'header', but allows the obsolete white-space rules.
obs_header :: Stream s m Char => String -> ParsecT s u m a -> ParsecT s u m a
obs_header n p = let nameString = caseString n >> many wsp >> char ':'
in
between nameString crlf p <?> ("obsolete " ++ n ++ " header line")
-- ** Primitive Tokens (section 3.2.1)
-- |Match any US-ASCII non-whitespace control character.
no_ws_ctl :: Stream s m Char => ParsecT s u m Char
no_ws_ctl = satisfy (\c -> ord c `elem` ([1..8] ++ [11,12] ++ [14..31] ++ [127]))
<?> "US-ASCII non-whitespace control character"
-- |Match any US-ASCII character except for @\r@, @\n@.
text :: Stream s m Char => ParsecT s u m Char
text = satisfy (\c -> ord c `elem` ([1..9] ++ [11,12] ++ [14..127]))
<?> "US-ASCII character (excluding CR and LF)"
-- |Match any of the RFC's \"special\" characters: @()\<\>[]:;\@,.\\\"@.
specials :: Stream s m Char => ParsecT s u m Char
specials = oneOf "()<>[]:;@,.\\\"" <?> "one of ()<>[]:;@,.\\\""
-- ** Quoted characters (section 3.2.2)
-- |Match a \"quoted pair\". All characters matched by 'text' may be
-- quoted. Note that the parsers returns /both/ characters, the
-- backslash and the actual content.
quoted_pair :: Stream s m Char => ParsecT s u m String
quoted_pair = try obs_qp <|> do { _ <- char '\\'; r <- text; return ['\\',r] }
<?> "quoted pair"
-- ** Folding white space and comments (section 3.2.3)
-- |Match \"folding whitespace\". That is any combination of 'wsp' and
-- 'crlf' followed by 'wsp'.
fws :: Stream s m Char => ParsecT s u m String
fws = do r <- many1 $ choice [ blanks, linebreak]
return (concat r)
where
blanks = many1 wsp
linebreak = try $ do { r1 <- crlf; r2 <- blanks; return (r1 ++ r2) }
-- |Match any non-whitespace, non-control character except for \"@(@\",
-- \"@)@\", and \"@\\@\". This is used to describe the legal content of
-- 'comment's.
--
-- /Note/: This parser accepts 8-bit characters, even though this is
-- not legal according to the RFC. Unfortunately, 8-bit content in
-- comments has become fairly common in the real world, so we'll just
-- accept the fact.
ctext :: Stream s m Char => ParsecT s u m Char
ctext = no_ws_ctl <|> satisfy (\c -> ord c `elem` ([33..39] ++ [42..91] ++ [93..126] ++ [128..255]))
<?> "any regular character (excluding '(', ')', and '\\')"
-- |Match a \"comments\". That is any combination of 'ctext',
-- 'quoted_pair's, and 'fws' between brackets. Comments may nest.
comment :: Stream s m Char => ParsecT s u m String
comment = do _ <- char '('
r1 <- many ccontent
r2 <- option [] fws
_ <- char ')'
return ("(" ++ concat r1 ++ r2 ++ ")")
<?> "comment"
where
ccontent = try $ do r1 <- option [] fws
r2 <- choice [many1 ctext, quoted_pair, comment]
return (r1 ++ r2)
-- |Match any combination of 'fws' and 'comments'.
cfws :: Stream s m Char => ParsecT s u m String
cfws = do r <- many1 $ choice [ fws, comment ]
return (concat r)
-- ** Atom (section 3.2.4)
-- |Match any US-ASCII character except for control characters,
-- 'specials', or space. 'atom' and 'dot_atom' are made up of this.
atext :: Stream s m Char => ParsecT s u m Char
atext = alpha <|> digit <|> oneOf "!#$%&'*+-/=?^_`{|}~"
<?> "US-ASCII character (excluding controls, space, and specials)"
-- |Match one or more 'atext' characters and skip any preceeding or
-- trailing 'cfws'.
atom :: Stream s m Char => ParsecT s u m String
atom = unfold (many1 atext <?> "atom")
-- |Match 'dot_atom_text' and skip any preceeding or trailing 'cfws'.
dot_atom :: Stream s m Char => ParsecT s u m String
dot_atom = unfold (dot_atom_text <?> "dot atom")
-- |Match two or more 'atext's interspersed by dots.
dot_atom_text :: Stream s m Char => ParsecT s u m String
dot_atom_text = fmap (intercalate ".") (sepBy1 (many1 atext) (char '.'))
<?> "dot atom content"
-- ** Quoted strings (section 3.2.5)
-- |Match any non-whitespace, non-control US-ASCII character except
-- for \"@\\@\" and \"@\"@\".
qtext :: Stream s m Char => ParsecT s u m Char
qtext = no_ws_ctl <|> satisfy (\c -> ord c `elem` ([33] ++ [35..91] ++ [93..126]))
<?> "US-ASCII character (excluding '\\', and '\"')"
-- |Match either 'qtext' or 'quoted_pair'.
qcontent :: Stream s m Char => ParsecT s u m String
qcontent = many1 qtext <|> quoted_pair
<?> "quoted string content"
-- |Match any number of 'qcontent' between double quotes. Any 'cfws'
-- preceeding or following the \"atom\" is skipped automatically.
quoted_string :: Stream s m Char => ParsecT s u m String
quoted_string = unfold (do _ <- dquote
r1 <- many (do r1 <- option [] fws
r2 <- qcontent
return (r1 ++ r2))
r2 <- option [] fws
_ <- dquote
return ("\"" ++ concat r1 ++ r2 ++ "\""))
<?> "quoted string"
-- * Miscellaneous tokens (section 3.2.6)
-- |Match either 'atom' or 'quoted_string'.
word :: Stream s m Char => ParsecT s u m String
word = unfold (atom <|> quoted_string) <?> "word"
-- |Match either one or more 'word's or an 'obs_phrase'.
phrase :: Stream s m Char => ParsecT s u m [String]
phrase = {- many1 word <?> "phrase" <|> -} obs_phrase
-- |Match any non-whitespace, non-control US-ASCII character except
-- for \"@\\@\" and \"@\"@\".
utext :: Stream s m Char => ParsecT s u m Char
utext = no_ws_ctl <|> satisfy (\c -> ord c `elem` [33..126])
<?> "regular US-ASCII character (excluding '\\', and '\"')"
-- |Match any number of 'utext' tokens.
--
-- \"Unstructured text\" is used in free text fields such as 'subject'.
-- Please note that any comments or whitespace that prefaces or
-- follows the actual 'utext' is /included/ in the returned string.
unstructured :: Stream s m Char => ParsecT s u m String
unstructured = do r1 <- option [] fws
r2 <- many (do r3 <- utext
r4 <- option [] fws
return (r3 : r4))
return (r1 ++ concat r2)
<?> "unstructured text"
-- * Date and Time Specification (section 3.3)
-- |Parse a date and time specification of the form
--
-- > Thu, 19 Dec 2002 20:35:46 +0200
--
-- where the weekday specification \"@Thu,@\" is optional. The parser
-- returns a 'CalendarTime', which is set to the appropriate values.
-- Note, though, that not all fields of 'CalendarTime' will
-- necessarily be set correctly! Obviously, when no weekday has been
-- provided, the parser will set this field to 'Monday' - regardless
-- of whether the day actually is a monday or not. Similarly, the day
-- of the year will always be returned as @0@. The timezone name will
-- always be empty: @\"\"@.
--
-- Nor will the 'date_time' parser perform /any/ consistency checking.
-- It will accept
--
-- > 40 Apr 2002 13:12 +0100
--
-- as a perfectly valid date.
--
-- In order to get all fields set to meaningful values, and in order
-- to verify the date's consistency, you will have to feed it into any
-- of the conversion routines provided in "System.Time", such as
-- 'toClockTime'. (When doing this, keep in mind that most functions
-- return /local time/. This will not necessarily be the time you're
-- expecting.)
date_time :: Stream s m Char => ParsecT s u m CalendarTime
date_time = do wd <- option Monday (try (do wd <- day_of_week
_ <- char ','
return wd))
(y,m,d) <- date
_ <- fws
(td,z) <- time
optional cfws
return (CalendarTime y m d (tdHour td) (tdMin td) (tdSec td) 0 wd 0 "" z False)
<?> "date/time specification"
-- |This parser matches a 'day_name' or an 'obs_day_of_week' (optionally
-- wrapped in folding whitespace) and return its 'Day' value.
day_of_week :: Stream s m Char => ParsecT s u m Day
day_of_week = try (between (optional fws) (optional fws) day_name <?> "name of a day-of-the-week")
<|> obs_day_of_week
-- |This parser will the abbreviated weekday names (\"@Mon@\", \"@Tue@\", ...)
-- and return the appropriate 'Day' value.
day_name :: Stream s m Char => ParsecT s u m Day
day_name = do { caseString "Mon"; return Monday }
<|> do { try (caseString "Tue"); return Tuesday }
<|> do { caseString "Wed"; return Wednesday }
<|> do { caseString "Thu"; return Thursday }
<|> do { caseString "Fri"; return Friday }
<|> do { try (caseString "Sat"); return Saturday }
<|> do { caseString "Sun"; return Sunday }
<?> "name of a day-of-the-week"
-- |This parser will match a date of the form \"@dd:mm:yyyy@\" and return
-- a tripple of the form (Int,Month,Int) - corresponding to
-- (year,month,day).
date :: Stream s m Char => ParsecT s u m (Int, Month, Int)
date = do d <- day
m <- month
y <- year
return (y,m,d)
<?> "date specification"
-- |This parser will match a four digit number and return its integer
-- value. No range checking is performed.
year :: Stream s m Char => ParsecT s u m Int
year = do y <- manyN 4 digit
return (read y :: Int)
<?> "year"
-- |This parser will match a 'month_name', optionally wrapped in
-- folding whitespace, or an 'obs_month' and return its 'Month'
-- value.
month :: Stream s m Char => ParsecT s u m Month
month = try (between (optional fws) (optional fws) month_name <?> "month name")
<|> obs_month
-- |This parser will the abbreviated month names (\"@Jan@\", \"@Feb@\", ...)
-- and return the appropriate 'Month' value.
month_name :: Stream s m Char => ParsecT s u m Month
month_name = do { try (caseString "Jan"); return January }
<|> do { caseString "Feb"; return February }
<|> do { try (caseString "Mar"); return March }
<|> do { try (caseString "Apr"); return April }
<|> do { caseString "May"; return May }
<|> do { try (caseString "Jun"); return June }
<|> do { caseString "Jul"; return July }
<|> do { caseString "Aug"; return August }
<|> do { caseString "Sep"; return September }
<|> do { caseString "Oct"; return October }
<|> do { caseString "Nov"; return November }
<|> do { caseString "Dec"; return December }
<?> "month name"
-- Internal helper function: match a 1 or 2-digit number (day of month).
day_of_month :: Stream s m Char => ParsecT s u m Int
day_of_month = fmap read (manyNtoM 1 2 digit)
-- |Match a 1 or 2-digit number (day of month), recognizing both
-- standard and obsolete folding syntax.
day :: Stream s m Char => ParsecT s u m Int
day = try obs_day <|> day_of_month <?> "day"
-- |This parser will match a 'time_of_day' specification followed by a
-- 'zone'. It returns the tuple (TimeDiff,Int) corresponding to the
-- return values of either parser.
time :: Stream s m Char => ParsecT s u m (TimeDiff, Int)
time = do t <- time_of_day
_ <- fws
z <- zone
return (t,z)
<?> "time and zone specification"
-- |This parser will match a time-of-day specification of \"@hh:mm@\" or
-- \"@hh:mm:ss@\" and return the corrsponding time as a 'TimeDiff'.
time_of_day :: Stream s m Char => ParsecT s u m TimeDiff
time_of_day = do h <- hour
_ <- char ':'
m <- minute
s <- option 0 (do { _ <- char ':'; second } )
return (TimeDiff 0 0 0 h m s 0)
<?> "time specification"
-- |This parser will match a two-digit number and return its integer
-- value. No range checking is performed.
hour :: Stream s m Char => ParsecT s u m Int
hour = do r <- replicateM 2 digit
return (read r :: Int)
<?> "hour"
-- |This parser will match a two-digit number and return its integer
-- value. No range checking is performed.
minute :: Stream s m Char => ParsecT s u m Int
minute = do r <- replicateM 2 digit
return (read r :: Int)
<?> "minute"
-- |This parser will match a two-digit number and return its integer
-- value. No range checking takes place.
second :: Stream s m Char => ParsecT s u m Int
second = do r <- replicateM 2 digit
return (read r :: Int)
<?> "second"
-- |This parser will match a timezone specification of the form
-- \"@+hhmm@\" or \"@-hhmm@\" and return the zone's offset to UTC in
-- seconds as an integer. 'obs_zone' is matched as well.
zone :: Stream s m Char => ParsecT s u m Int
zone = ( do _ <- char '+'
h <- hour
m <- minute
return (((h*60)+m)*60)
<|> do _ <- char '-'
h <- hour
m <- minute
return (-((h*60)+m)*60)
<?> "time zone"
)
<|> obs_zone
-- * Address Specification (section 3.4)
-- |A NameAddr is composed of an optional realname a mandatory
-- e-mail 'address'.
data NameAddr = NameAddr { nameAddr_name :: Maybe String
, nameAddr_addr :: String
}
deriving (Show,Eq)
-- |Parse a single 'mailbox' or an address 'group' and return the
-- address(es).
address :: Stream s m Char => ParsecT s u m [NameAddr]
address = try (do { r <- mailbox; return [r] }) <|> group
<?> "address"
-- |Parse a 'name_addr' or an 'addr_spec' and return the
-- address.
mailbox :: Stream s m Char => ParsecT s u m NameAddr
mailbox = try name_addr <|> fmap (NameAddr Nothing) addr_spec
<?> "mailbox"
-- |Parse an 'angle_addr', optionally prefaced with a 'display_name',
-- and return the address.
name_addr :: Stream s m Char => ParsecT s u m NameAddr
name_addr = do name <- maybeOption display_name
addr <- angle_addr
return (NameAddr name addr)
<?> "name address"
-- |Parse an 'angle_addr' or an 'obs_angle_addr' and return the address.
angle_addr :: Stream s m Char => ParsecT s u m String
angle_addr = try (unfold (do _ <- char '<'
r <- addr_spec
_ <- char '>'
return r)
<?> "angle address"
)
<|> obs_angle_addr
-- |Parse a \"group\" of addresses. That is a 'display_name', followed
-- by a colon, optionally followed by a 'mailbox_list', followed by a
-- semicolon. The found address(es) are returned - what may be none.
-- Here is an example:
--
-- >>> parse group "" "my group: user1@example.org, user2@example.org;"
-- Right [NameAddr {nameAddr_name = Nothing, nameAddr_addr = "user1@example.org"},NameAddr {nameAddr_name = Nothing, nameAddr_addr = "user2@example.org"}]
group :: Stream s m Char => ParsecT s u m [NameAddr]
group = do _ <- display_name
_ <- char ':'
r <- option [] mailbox_list
_ <- unfold $ char ';'
return r
<?> "address group"
-- |Parse and return a 'phrase'.
display_name :: Stream s m Char => ParsecT s u m String
display_name = fmap unwords phrase
<?> "display name"
-- |Parse a list of 'mailbox' addresses, every two addresses being
-- separated by a comma, and return the list of found address(es).
mailbox_list :: Stream s m Char => ParsecT s u m [NameAddr]
mailbox_list = sepBy mailbox (char ',') <?> "mailbox list"
-- |Parse a list of 'address' addresses, every two addresses being
-- separated by a comma, and return the list of found address(es).
address_list :: Stream s m Char => ParsecT s u m [NameAddr]
address_list = do { r <-sepBy address (char ','); return (concat r) }
<?> "address list"
-- ** Addr-spec specification (section 3.4.1)
-- |Parse an \"address specification\". That is a 'local_part', followed
-- by an \"@\@@\" character, followed by a 'domain'. Return the complete
-- address as 'String', ignoring any whitespace or any comments.
addr_spec :: Stream s m Char => ParsecT s u m String
addr_spec = do r1 <- local_part
_ <- char '@'
r2 <- domain
return (r1 ++ "@" ++ r2)
<?> "address specification"
-- |Parse and return a \"local part\" of an 'addr_spec'. That is either
-- a 'dot_atom' or a 'quoted_string'.
local_part :: Stream s m Char => ParsecT s u m String
local_part = try obs_local_part <|> dot_atom <|> quoted_string
<?> "address' local part"
-- |Parse and return a \"domain part\" of an 'addr_spec'. That is either
-- a 'dot_atom' or a 'domain_literal'.
domain :: Stream s m Char => ParsecT s u m String
domain = try obs_domain <|> dot_atom <|> domain_literal
<?> "address' domain part"
-- |Parse a \"domain literal\". That is a \"@[@\" character, followed by
-- any amount of 'dcontent', followed by a terminating \"@]@\"
-- character. The complete string is returned verbatim.
domain_literal :: Stream s m Char => ParsecT s u m String
domain_literal = unfold (do _ <- char '['
r <- many (optional fws >> dcontent)
optional fws
_ <- char ']'
return ("[" ++ concat r ++ "]"))
<?> "domain literal"
-- |Parse and return any characters that are legal in a
-- 'domain_literal'. That is 'dtext' or a 'quoted_pair'.
dcontent :: Stream s m Char => ParsecT s u m String
dcontent = many1 dtext <|> quoted_pair
<?> "domain literal content"
-- |Parse and return any ASCII characters except \"@[@\", \"@]@\", and
-- \"@\\@\".
dtext :: Stream s m Char => ParsecT s u m Char
dtext = no_ws_ctl
<|> satisfy (\c -> ord c `elem` ([33..90] ++ [94..126]))
<?> "any ASCII character (excluding '[', ']', and '\\')"
-- * Overall message syntax (section 3.5)
-- |This data type repesents a parsed Internet Message as defined in
-- this RFC. It consists of an arbitrary number of header lines,
-- represented in the 'Field' data type, and a message body, which may
-- be empty.
data GenericMessage a = Message [Field] a deriving Show
-- |Parse a complete message as defined by this RFC and it broken down
-- into the separate header fields and the message body. Header lines,
-- which contain syntax errors, will not cause the parser to abort.
-- Rather, these headers will appear as 'OptionalField's (which are
-- unparsed) in the resulting 'Message'. A message must be really,
-- really badly broken for this parser to fail.
--
-- This behaviour was chosen because it is impossible to predict what
-- the user of this module considers to be a fatal error;
-- traditionally, parsers are very forgiving when it comes to Internet
-- messages.
--
-- If you want to implement a really strict parser, you'll have to put
-- the appropriate parser together yourself. You'll find that this is
-- rather easy to do. Refer to the 'fields' parser for further details.
message :: (Monoid s, Stream s m Char) => ParsecT s u m (GenericMessage s)
message = do f <- fields
b <- option mempty (do _ <- crlf; body)
return (Message f b)
-- |A message body is just an unstructured sequence of characters.
body :: (Monoid s, Monad m) => ParsecT s u m s
body = do v <- getInput
setInput mempty
return v
-- * Field definitions (section 3.6)
-- |This data type represents any of the header fields defined in this
-- RFC. Each of the various instances contains with the return value
-- of the corresponding parser.
data Field = OptionalField String String
| From [NameAddr]
| Sender NameAddr
| ReturnPath String
| ReplyTo [NameAddr]
| To [NameAddr]
| Cc [NameAddr]
| Bcc [NameAddr]
| MessageID String
| InReplyTo [String]
| References [String]
| Subject String
| Comments String
| Keywords [[String]]
| Date CalendarTime
| ResentDate CalendarTime
| ResentFrom [NameAddr]
| ResentSender NameAddr
| ResentTo [NameAddr]
| ResentCc [NameAddr]
| ResentBcc [NameAddr]
| ResentMessageID String
| ResentReplyTo [NameAddr]
| Received ([(String,String)], CalendarTime)
| ObsReceived [(String,String)]
deriving (Show)
-- |This parser will parse an arbitrary number of header fields as
-- defined in this RFC. For each field, an appropriate 'Field' value
-- is created, all of them making up the 'Field' list that this parser
-- returns.
--
-- If you look at the implementation of this parser, you will find
-- that it uses Parsec's 'try' modifier around /all/ of the fields.
-- The idea behind this is that fields, which contain syntax errors,
-- fall back to the catch-all 'optional_field'. Thus, this parser will
-- hardly ever return a syntax error -- what conforms with the idea
-- that any message that can possibly be accepted /should/ be.
fields :: Stream s m Char => ParsecT s u m [Field]
fields = many ( try (do { r <- from; return (From r) })
<|> try (do { r <- sender; return (Sender r) })
<|> try (do { r <- return_path; return (ReturnPath r) })
<|> try (do { r <- reply_to; return (ReplyTo r) })
<|> try (do { r <- to; return (To r) })
<|> try (do { r <- cc; return (Cc r) })
<|> try (do { r <- bcc; return (Bcc r) })
<|> try (do { r <- message_id; return (MessageID r) })
<|> try (do { r <- in_reply_to; return (InReplyTo r) })
<|> try (do { r <- references; return (References r) })
<|> try (do { r <- subject; return (Subject r) })
<|> try (do { r <- comments; return (Comments r) })
<|> try (do { r <- keywords; return (Keywords r) })
<|> try (do { r <- orig_date; return (Date r) })
<|> try (do { r <- resent_date; return (ResentDate r) })
<|> try (do { r <- resent_from; return (ResentFrom r) })
<|> try (do { r <- resent_sender; return (ResentSender r) })
<|> try (do { r <- resent_to; return (ResentTo r) })
<|> try (do { r <- resent_cc; return (ResentCc r) })
<|> try (do { r <- resent_bcc; return (ResentBcc r) })
<|> try (do { r <- resent_msg_id; return (ResentMessageID r) })
<|> try (do { r <- received; return (Received r) })
-- catch all
<|> (do { (name,cont) <- optional_field; return (OptionalField name cont) })
)
-- ** The origination date field (section 3.6.1)
-- |Parse a \"@Date:@\" header line and return the date it contains a
-- 'CalendarTime'.
orig_date :: Stream s m Char => ParsecT s u m CalendarTime
orig_date = header "Date" date_time
-- ** Originator fields (section 3.6.2)
-- |Parse a \"@From:@\" header line and return the 'mailbox_list'
-- address(es) contained in it.
from :: Stream s m Char => ParsecT s u m [NameAddr]
from = header "From" mailbox_list
-- |Parse a \"@Sender:@\" header line and return the 'mailbox' address
-- contained in it.
sender :: Stream s m Char => ParsecT s u m NameAddr
sender = header "Sender" mailbox
-- |Parse a \"@Reply-To:@\" header line and return the 'address_list'
-- address(es) contained in it.
reply_to :: Stream s m Char => ParsecT s u m [NameAddr]
reply_to = header "Reply-To" address_list
-- ** Destination address fields (section 3.6.3)
-- |Parse a \"@To:@\" header line and return the 'address_list'
-- address(es) contained in it.
to :: Stream s m Char => ParsecT s u m [NameAddr]
to = header "To" address_list
-- |Parse a \"@Cc:@\" header line and return the 'address_list'
-- address(es) contained in it.
cc :: Stream s m Char => ParsecT s u m [NameAddr]
cc = header "Cc" address_list
-- |Parse a \"@Bcc:@\" header line and return the 'address_list'
-- address(es) contained in it.
bcc :: Stream s m Char => ParsecT s u m [NameAddr]
bcc = header "Bcc" (try address_list <|> do { optional cfws; return [] })
-- ** Identification fields (section 3.6.4)
-- |Parse a \"@Message-Id:@\" header line and return the 'msg_id'
-- contained in it.
message_id :: Stream s m Char => ParsecT s u m String
message_id = header "Message-ID" msg_id
-- |Parse a \"@In-Reply-To:@\" header line and return the list of
-- 'msg_id's contained in it.
in_reply_to :: Stream s m Char => ParsecT s u m [String]
in_reply_to = header "In-Reply-To" (many1 msg_id)
-- |Parse a \"@References:@\" header line and return the list of
-- 'msg_id's contained in it.
references :: Stream s m Char => ParsecT s u m [String]
references = header "References" (many1 msg_id)
-- |Parse a \"@message ID:@\" and return it. A message ID is almost
-- identical to an 'angle_addr', but with stricter rules about folding
-- and whitespace.
msg_id :: Stream s m Char => ParsecT s u m String
msg_id = unfold (do _ <- char '<'
idl <- id_left
_ <- char '@'
idr <- id_right
_ <- char '>'
return ("<" ++ idl ++ "@" ++ idr ++ ">"))
<?> "message ID"
-- |Parse a \"left ID\" part of a 'msg_id'. This is almost identical to
-- the 'local_part' of an e-mail address, but with stricter rules
-- about folding and whitespace.
id_left :: Stream s m Char => ParsecT s u m String
id_left = dot_atom_text <|> no_fold_quote
<?> "left part of an message ID"
-- |Parse a \"right ID\" part of a 'msg_id'. This is almost identical to
-- the 'domain' of an e-mail address, but with stricter rules about
-- folding and whitespace.
id_right :: Stream s m Char => ParsecT s u m String
id_right = dot_atom_text <|> no_fold_literal
<?> "right part of an message ID"
-- |Parse one or more occurences of 'qtext' or 'quoted_pair' and
-- return the concatenated string. This makes up the 'id_left' of a
-- 'msg_id'.
no_fold_quote :: Stream s m Char => ParsecT s u m String
no_fold_quote = do _ <- dquote
r <- many (many1 qtext <|> quoted_pair)
_ <- dquote
return ("\"" ++ concat r ++ "\"")
<?> "non-folding quoted string"
-- |Parse one or more occurences of 'dtext' or 'quoted_pair' and
-- return the concatenated string. This makes up the 'id_right' of a
-- 'msg_id'.
no_fold_literal :: Stream s m Char => ParsecT s u m String
no_fold_literal = do _ <- char '['
r <- many (many1 dtext <|> quoted_pair)
_ <- char ']'
return ("[" ++ concat r ++ "]")
<?> "non-folding domain literal"
-- ** Informational fields (section 3.6.5)
-- |Parse a \"@Subject:@\" header line and return its contents verbatim.
-- Please note that all whitespace and/or comments are preserved, i.e.
-- the result of parsing @\"Subject: foo\"@ is @\" foo\"@, not @\"foo\"@.
subject :: Stream s m Char => ParsecT s u m String
subject = header "Subject" unstructured
-- |Parse a \"@Comments:@\" header line and return its contents verbatim.
-- Please note that all whitespace and/or comments are preserved, i.e.
-- the result of parsing @\"Comments: foo\"@ is @\" foo\"@, not @\"foo\"@.
comments :: Stream s m Char => ParsecT s u m String
comments = header "Comments" unstructured
-- |Parse a \"@Keywords:@\" header line and return the list of 'phrase's
-- found. Please not that each phrase is again a list of 'atom's, as
-- returned by the 'phrase' parser.
keywords :: Stream s m Char => ParsecT s u m [[String]]
keywords = header "Keywords" (do r1 <- phrase
r2 <- many (do _ <- char ','; phrase)
return (r1:r2))
-- ** Resent fields (section 3.6.6)
-- |Parse a \"@Resent-Date:@\" header line and return the date it
-- contains as 'CalendarTime'.
resent_date :: Stream s m Char => ParsecT s u m CalendarTime
resent_date = header "Resent-Date" date_time
-- |Parse a \"@Resent-From:@\" header line and return the 'mailbox_list'
-- address(es) contained in it.
resent_from :: Stream s m Char => ParsecT s u m [NameAddr]
resent_from = header "Resent-From" mailbox_list
-- |Parse a \"@Resent-Sender:@\" header line and return the 'mailbox_list'
-- address(es) contained in it.
resent_sender :: Stream s m Char => ParsecT s u m NameAddr
resent_sender = header "Resent-Sender" mailbox
-- |Parse a \"@Resent-To:@\" header line and return the 'mailbox'
-- address contained in it.
resent_to :: Stream s m Char => ParsecT s u m [NameAddr]
resent_to = header "Resent-To" address_list
-- |Parse a \"@Resent-Cc:@\" header line and return the 'address_list'
-- address(es) contained in it.
resent_cc :: Stream s m Char => ParsecT s u m [NameAddr]
resent_cc = header "Resent-Cc" address_list
-- |Parse a \"@Resent-Bcc:@\" header line and return the 'address_list'
-- address(es) contained in it. (This list may be empty.)
resent_bcc :: Stream s m Char => ParsecT s u m [NameAddr]
resent_bcc = header "Resent-Bcc" ( try address_list
<|> do optional cfws
return []
)
<?> "Resent-Bcc: header line"
-- |Parse a \"@Resent-Message-ID:@\" header line and return the 'msg_id'
-- contained in it.
resent_msg_id :: Stream s m Char => ParsecT s u m String
resent_msg_id = header "Resent-Message-ID" msg_id
-- ** Trace fields (section 3.6.7)
return_path :: Stream s m Char => ParsecT s u m String
return_path = header "Return-Path" path
path :: Stream s m Char => ParsecT s u m String
path = unfold ( try (do _ <- char '<'
r <- option "" addr_spec
_ <- char '>'
return ("<" ++ r ++ ">")
)
<|> obs_path
)
<?> "return path spec"
received :: Stream s m Char => ParsecT s u m ([(String,String)], CalendarTime)
received = header "Received" (do r1 <- name_val_list
_ <- char ';'
r2 <- date_time
return (r1,r2))
name_val_list :: Stream s m Char => ParsecT s u m [(String,String)]
name_val_list = do optional cfws
many1 name_val_pair
<?> "list of name/value pairs"
name_val_pair :: Stream s m Char => ParsecT s u m (String,String)
name_val_pair = do r1 <- item_name
_ <- cfws
r2 <- item_value
return (r1,r2)
<?> "a name/value pair"
item_name :: Stream s m Char => ParsecT s u m String
item_name = do r1 <- alpha
r2 <- many $ choice [ char '-', alpha, digit ]
return (r1 : r2)
<?> "name of a name/value pair"
item_value :: Stream s m Char => ParsecT s u m String
item_value = choice [ try (do { r <- many1 angle_addr; return (concat r) })
, try addr_spec
, try domain
, msg_id
, try atom
]
<?> "value of a name/value pair"
-- ** Optional fields (section 3.6.8)
-- |Parse an arbitrary header field and return a tuple containing the
-- 'field_name' and 'unstructured' text of the header. The name will
-- /not/ contain the terminating colon.
optional_field :: Stream s m Char => ParsecT s u m (String,String)
optional_field = do n <- field_name
_ <- char ':'
b <- unstructured
_ <- crlf
return (n,b)
<?> "optional (unspecified) header line"
-- |Parse and return an arbitrary header field name. That is one or
-- more 'ftext' characters.
field_name :: Stream s m Char => ParsecT s u m String
field_name = many1 ftext <?> "header line name"
-- |Match and return any ASCII character except for control
-- characters, whitespace, and \"@:@\".
ftext :: Stream s m Char => ParsecT s u m Char
ftext = satisfy (\c -> ord c `elem` ([33..57] ++ [59..126]))
<?> "character (excluding controls, space, and ':')"
-- * Miscellaneous obsolete tokens (section 4.1)
-- |Match the obsolete \"quoted pair\" syntax, which - unlike
-- 'quoted_pair' - allowed /any/ ASCII character to be specified when
-- quoted. The parser will return both, the backslash and the actual
-- character.
obs_qp :: Stream s m Char => ParsecT s u m String
obs_qp = do _ <- char '\\'
c <- satisfy (\c -> ord c `elem` [0..127])
return ['\\',c]
<?> "any quoted US-ASCII character"
-- |Match the obsolete \"text\" syntax, which - unlike 'text' - allowed
-- \"carriage returns\" and \"linefeeds\". This is really weird; you
-- better consult the RFC for details. The parser will return the
-- complete string, including those special characters.
obs_text :: Stream s m Char => ParsecT s u m String
obs_text = do r1 <- many lf
r2 <- many cr
r3 <- many (do r4 <- obs_char
r5 <- many lf
r6 <- many cr
return (r4 : (r5 ++ r6)))
return (r1 ++ r2 ++ concat r3)
-- |Match and return the obsolete \"char\" syntax, which - unlike
-- 'character' - did not allow \"carriage return\" and \"linefeed\".
obs_char :: Stream s m Char => ParsecT s u m Char
obs_char = satisfy (\c -> ord c `elem` ([0..9] ++ [11,12] ++ [14..127]))
<?> "any ASCII character except CR and LF"
-- |Match and return the obsolete \"utext\" syntax, which is identical
-- to 'obs_text'.
obs_utext :: Stream s m Char => ParsecT s u m String
obs_utext = obs_text
-- |Match the obsolete \"phrase\" syntax, which - unlike 'phrase' -
-- allows dots between tokens.
obs_phrase :: Stream s m Char => ParsecT s u m [String]
obs_phrase = do r1 <- word
r2 <- many $ choice [ word
, string "."
, do { _ <- cfws; return [] }
]
return (r1 : filter (/=[]) r2)
-- |Match a \"phrase list\" syntax and return the list of 'String's
-- that make up the phrase. In contrast to a 'phrase', the
-- 'obs_phrase_list' separates the individual words by commas. This
-- syntax is - as you will have guessed - obsolete.
obs_phrase_list :: Stream s m Char => ParsecT s u m [String]
obs_phrase_list = do r1 <- many1 (do r <- option [] phrase
_ <- unfold $ char ','
return (filter (/=[]) r))
r2 <- option [] phrase
return (concat r1 ++ r2)
<|> phrase
-- * Obsolete folding white space (section 4.2)
-- |Parse and return an \"obsolete fws\" token. That is at least one
-- 'wsp' character, followed by an arbitrary number (including zero)
-- of 'crlf' followed by at least one more 'wsp' character.
obs_fws :: Stream s m Char => ParsecT s u m String
obs_fws = do r1 <- many1 wsp
r2 <- many (do r3 <- crlf
r4 <- many1 wsp
return (r3 ++ r4))
return (r1 ++ concat r2)
-- * Obsolete Date and Time (section 4.3)
-- |Parse a 'day_name' but allow for the obsolete folding syntax.
obs_day_of_week :: Stream s m Char => ParsecT s u m Day
obs_day_of_week = unfold day_name <?> "day-of-the-week name"
-- |Parse a 'year' but allow for a two-digit number (obsolete) and the
-- obsolete folding syntax.
obs_year :: Stream s m Char => ParsecT s u m Int
obs_year = unfold (do r <- manyN 2 digit
return (normalize (read r :: Int)))
<?> "year"
where
normalize n
| n <= 49 = 2000 + n
| n <= 999 = 1900 + n
| otherwise = n
-- |Parse a 'month_name' but allow for the obsolete folding syntax.
obs_month :: Stream s m Char => ParsecT s u m Month
obs_month = between cfws cfws month_name <?> "month name"
-- |Parse a 'day' but allow for the obsolete folding syntax.
obs_day :: Stream s m Char => ParsecT s u m Int
obs_day = unfold day_of_month <?> "day"
-- |Parse a 'hour' but allow for the obsolete folding syntax.
obs_hour :: Stream s m Char => ParsecT s u m Int
obs_hour = unfold hour <?> "hour"
-- |Parse a 'minute' but allow for the obsolete folding syntax.
obs_minute :: Stream s m Char => ParsecT s u m Int
obs_minute = unfold minute <?> "minute"
-- |Parse a 'second' but allow for the obsolete folding syntax.
obs_second :: Stream s m Char => ParsecT s u m Int
obs_second = unfold second <?> "second"
-- |Match the obsolete zone names and return the appropriate offset.
obs_zone :: Stream s m Char => ParsecT s u m Int
obs_zone = choice [ mkZone "UT" 0
, mkZone "GMT" 0
, mkZone "EST" (-5)
, mkZone "EDT" (-4)
, mkZone "CST" (-6)
, mkZone "CDT" (-5)
, mkZone "MST" (-7)
, mkZone "MDT" (-6)
, mkZone "PST" (-8)
, mkZone "PDT" (-7)
, do { r <- oneOf ['A'..'I']; return $ (ord r - 64) * 60*60 } <?> "military zone spec"
, do { r <- oneOf ['K'..'M']; return $ (ord r - 65) * 60*60 } <?> "military zone spec"
, do { r <- oneOf ['N'..'Y']; return $ -(ord r - 77) * 60*60 } <?> "military zone spec"
, do { _ <- char 'Z'; return 0 } <?> "military zone spec"
]
where mkZone n o = try $ do { _ <- string n; return (o*60*60) }
-- * Obsolete Addressing (section 4.4)
-- |This parser matches the \"obsolete angle address\" syntax, a construct that
-- used to be called \"route address\" in earlier RFCs. It differs from a
-- standard 'angle_addr' in two ways: (1) it allows far more
-- liberal insertion of folding whitespace and comments and (2) the address may
-- contain a \"route\" (which this parser ignores):
--
-- >>> parse obs_angle_addr "" "<@example1.org,@example2.org:joe@example.org>"
-- Right "<joe@example.org>"
obs_angle_addr :: Stream s m Char => ParsecT s u m String
obs_angle_addr = unfold (do _ <- char '<'
_ <- option [] obs_route
addr <- addr_spec
_ <- char '>'
return ("<" ++ addr ++ ">") -- TODO: route is lost here.
)
<?> "obsolete angle address"
-- |This parser parses the \"route\" part of 'obs_angle_addr' and
-- returns the list of 'String's that make up this route. Relies on
-- 'obs_domain_list' for the actual parsing.
obs_route :: Stream s m Char => ParsecT s u m [String]
obs_route = unfold (do { r <- obs_domain_list; _ <- char ':'; return r })
<?> "route of an obsolete angle address"
-- |This parser parses a list of domain names, each of them prefaced
-- with an \"at\". Multiple names are separated by a comma. The list of
-- 'domain's is returned - and may be empty.
obs_domain_list :: Stream s m Char => ParsecT s u m [String]
obs_domain_list = do _ <- char '@'
r1 <- domain
r2 <- many (do _ <- cfws <|> string ","
optional cfws
_ <- char '@'
domain)
return (r1 : r2)
<?> "route of an obsolete angle address"
-- |Parse the obsolete syntax of a 'local_part', which allowed for
-- more liberal insertion of folding whitespace and comments. The
-- actual string is returned.
obs_local_part :: Stream s m Char => ParsecT s u m String
obs_local_part = do r1 <- word
r2 <- many (do _ <- string "."
r <- word
return ('.' : r))
return (r1 ++ concat r2)
<?> "local part of an address"
-- |Parse the obsolete syntax of a 'domain', which allowed for more
-- liberal insertion of folding whitespace and comments. The actual
-- string is returned.
obs_domain :: Stream s m Char => ParsecT s u m String
obs_domain = do r1 <- atom
r2 <- many (do _ <- string "."
r <- atom
return ('.' : r))
return (r1 ++ concat r2)
<?> "domain part of an address"
-- |This parser will match the obsolete syntax for a 'mailbox_list'.
-- This one is quite weird: An 'obs_mbox_list' contains an arbitrary
-- number of 'mailbox'es - including none -, which are separated by
-- commas. But you may have multiple consecutive commas without giving
-- a 'mailbox'. You may also have a valid 'obs_mbox_list' that
-- contains /no/ 'mailbox' at all. On the other hand, you /must/ have
-- at least one comma. The following example is valid:
--
-- >>> parse obs_mbox_list "" ","
-- Right []
--
-- But this one is not:
--
-- >>> parse obs_mbox_list "" "joe@example.org"
-- Left (line 1, column 16):
-- unexpected end of input
-- expecting obsolete syntax for a list of mailboxes
obs_mbox_list :: Stream s m Char => ParsecT s u m [NameAddr]
obs_mbox_list = do r1 <- many1 (try (do r <- maybeOption mailbox
_ <- unfold $ char ','
return r))
r2 <- maybeOption mailbox
return (catMaybes (r1 ++ [r2]))
<?> "obsolete syntax for a list of mailboxes"
-- |This parser is identical to 'obs_mbox_list' but parses a list of
-- 'address'es rather than 'mailbox'es. The main difference is that an
-- 'address' may contain 'group's. Please note that as of now, the
-- parser will return a simple list of addresses; the grouping
-- information is lost.
obs_addr_list :: Stream s m Char => ParsecT s u m [NameAddr]
obs_addr_list = do r1 <- many1 (try (do r <- maybeOption address
optional cfws
_ <- char ','
optional cfws
return r))
r2 <- maybeOption address
return (concat (catMaybes (r1 ++ [r2])))
<?> "obsolete syntax for a list of addresses"
-- * Obsolete header fields (section 4.5)
obs_fields :: Stream s m Char => ParsecT s u m [Field]
obs_fields = many ( try (do { r <- obs_from; return (From r) })
<|> try (do { r <- obs_sender; return (Sender r) })
<|> try (do { r <- obs_return; return (ReturnPath r) })
<|> try (do { r <- obs_reply_to; return (ReplyTo r) })
<|> try (do { r <- obs_to; return (To r) })
<|> try (do { r <- obs_cc; return (Cc r) })
<|> try (do { r <- obs_bcc; return (Bcc r) })
<|> try (do { r <- obs_message_id; return (MessageID r) })
<|> try (do { r <- obs_in_reply_to; return (InReplyTo r) })
<|> try (do { r <- obs_references; return (References r) })
<|> try (do { r <- obs_subject; return (Subject r) })
<|> try (do { r <- obs_comments; return (Comments r) })
<|> try (do { r <- obs_keywords; return (Keywords [r]) })
<|> try (do { r <- obs_orig_date; return (Date r) })
<|> try (do { r <- obs_resent_date; return (ResentDate r) })
<|> try (do { r <- obs_resent_from; return (ResentFrom r) })
<|> try (do { r <- obs_resent_send; return (ResentSender r) })
<|> try (do { r <- obs_resent_to; return (ResentTo r) })
<|> try (do { r <- obs_resent_cc; return (ResentCc r) })
<|> try (do { r <- obs_resent_bcc; return (ResentBcc r) })
<|> try (do { r <- obs_resent_mid; return (ResentMessageID r) })
<|> try (do { r <- obs_resent_reply; return (ResentReplyTo r) })
<|> try (do { r <- obs_received; return (ObsReceived r) })
-- catch all
<|> (do { (name,cont) <- obs_optional; return (OptionalField name cont) })
)
-- ** Obsolete origination date field (section 4.5.1)
-- |Parse a 'date' header line but allow for the obsolete
-- folding syntax.
obs_orig_date :: Stream s m Char => ParsecT s u m CalendarTime
obs_orig_date = obs_header "Date" date_time
-- ** Obsolete originator fields (section 4.5.2)
-- |Parse a 'from' header line but allow for the obsolete
-- folding syntax.
obs_from :: Stream s m Char => ParsecT s u m [NameAddr]
obs_from = obs_header "From" mailbox_list
-- |Parse a 'sender' header line but allow for the obsolete
-- folding syntax.
obs_sender :: Stream s m Char => ParsecT s u m NameAddr
obs_sender = obs_header "Sender" mailbox
-- |Parse a 'reply_to' header line but allow for the obsolete
-- folding syntax.
obs_reply_to :: Stream s m Char => ParsecT s u m [NameAddr]
obs_reply_to = obs_header "Reply-To" mailbox_list
-- ** Obsolete destination address fields (section 4.5.3)
-- |Parse a 'to' header line but allow for the obsolete
-- folding syntax.
obs_to :: Stream s m Char => ParsecT s u m [NameAddr]
obs_to = obs_header "To" address_list
-- |Parse a 'cc' header line but allow for the obsolete
-- folding syntax.
obs_cc :: Stream s m Char => ParsecT s u m [NameAddr]
obs_cc = obs_header "Cc" address_list
-- |Parse a 'bcc' header line but allow for the obsolete
-- folding syntax.
obs_bcc :: Stream s m Char => ParsecT s u m [NameAddr]
obs_bcc = header "Bcc" ( try address_list
<|> do { optional cfws; return [] }
)
-- ** Obsolete identification fields (section 4.5.4)
-- |Parse a 'message_id' header line but allow for the obsolete
-- folding syntax.
obs_message_id :: Stream s m Char => ParsecT s u m String
obs_message_id = obs_header "Message-ID" msg_id
-- |Parse an 'in_reply_to' header line but allow for the obsolete
-- folding and the obsolete phrase syntax.
obs_in_reply_to :: Stream s m Char => ParsecT s u m [String]
obs_in_reply_to = obs_header "In-Reply-To" (do r <- many ( do {_ <- phrase; return [] }
<|> msg_id
)
return (filter (/=[]) r))
-- |Parse a 'references' header line but allow for the obsolete
-- folding and the obsolete phrase syntax.
obs_references :: Stream s m Char => ParsecT s u m [String]
obs_references = obs_header "References" (do r <- many ( do { _ <- phrase; return [] }
<|> msg_id
)
return (filter (/=[]) r))
-- |Parses the \"left part\" of a message ID, but allows the obsolete
-- syntax, which is identical to a 'local_part'.
obs_id_left :: Stream s m Char => ParsecT s u m String
obs_id_left = local_part <?> "left part of an message ID"
-- |Parses the \"right part\" of a message ID, but allows the obsolete
-- syntax, which is identical to a 'domain'.
obs_id_right :: Stream s m Char => ParsecT s u m String
obs_id_right = domain <?> "right part of an message ID"
-- ** Obsolete informational fields (section 4.5.5)
-- |Parse a 'subject' header line but allow for the obsolete
-- folding syntax.
obs_subject :: Stream s m Char => ParsecT s u m String
obs_subject = obs_header "Subject" unstructured
-- |Parse a 'comments' header line but allow for the obsolete
-- folding syntax.
obs_comments :: Stream s m Char => ParsecT s u m String
obs_comments = obs_header "Comments" unstructured
-- |Parse a 'keywords' header line but allow for the obsolete
-- folding syntax. Also, this parser accepts 'obs_phrase_list'.
obs_keywords :: Stream s m Char => ParsecT s u m [String]
obs_keywords = obs_header "Keywords" obs_phrase_list
-- ** Obsolete resent fields (section 4.5.6)
-- |Parse a 'resent_from' header line but allow for the obsolete
-- folding syntax.
obs_resent_from :: Stream s m Char => ParsecT s u m [NameAddr]
obs_resent_from = obs_header "Resent-From" mailbox_list
-- |Parse a 'resent_sender' header line but allow for the obsolete
-- folding syntax.
obs_resent_send :: Stream s m Char => ParsecT s u m NameAddr
obs_resent_send = obs_header "Resent-Sender" mailbox
-- |Parse a 'resent_date' header line but allow for the obsolete
-- folding syntax.
obs_resent_date :: Stream s m Char => ParsecT s u m CalendarTime
obs_resent_date = obs_header "Resent-Date" date_time
-- |Parse a 'resent_to' header line but allow for the obsolete
-- folding syntax.
obs_resent_to :: Stream s m Char => ParsecT s u m [NameAddr]
obs_resent_to = obs_header "Resent-To" mailbox_list
-- |Parse a 'resent_cc' header line but allow for the obsolete
-- folding syntax.
obs_resent_cc :: Stream s m Char => ParsecT s u m [NameAddr]
obs_resent_cc = obs_header "Resent-Cc" mailbox_list
-- |Parse a 'resent_bcc' header line but allow for the obsolete
-- folding syntax.
obs_resent_bcc :: Stream s m Char => ParsecT s u m [NameAddr]
obs_resent_bcc = obs_header "Bcc" ( try address_list
<|> do { optional cfws; return [] }
)
-- |Parse a 'resent_msg_id' header line but allow for the obsolete
-- folding syntax.
obs_resent_mid :: Stream s m Char => ParsecT s u m String
obs_resent_mid = obs_header "Resent-Message-ID" msg_id
-- |Parse a @Resent-Reply-To@ header line but allow for the
-- obsolete folding syntax.
obs_resent_reply :: Stream s m Char => ParsecT s u m [NameAddr]
obs_resent_reply = obs_header "Resent-Reply-To" address_list
-- ** Obsolete trace fields (section 4.5.7)
obs_return :: Stream s m Char => ParsecT s u m String
obs_return = obs_header "Return-Path" path
obs_received :: Stream s m Char => ParsecT s u m [(String, String)]
obs_received = obs_header "Received" name_val_list
-- |Match 'obs_angle_addr'.
obs_path :: Stream s m Char => ParsecT s u m String
obs_path = obs_angle_addr
-- |This parser is identical to 'optional_field' but allows the more
-- liberal line-folding syntax between the \"field_name\" and the \"field
-- text\".
obs_optional :: Stream s m Char => ParsecT s u m (String,String)
obs_optional = do n <- field_name
_ <- many wsp
_ <- char ':'
b <- unstructured
_ <- crlf
return (n,b)
<?> "optional (unspecified) header line"