Mail::Cclient - Mailbox access via the c-client library API
use Mail::Cclient; $c = Mail::Cclient->new(MAILBOX [, OPTION ...]); ($envelope, $body) = $c->fetchstructure(MSGNO [, FLAG ...] ); $hdr = $c->fetchheader(MSGNO [, FLAG ...]); $text = $c->fetchtext(MSGNO [, FLAG ..i]); $text = $c->fetchbody(MSGNO, SECTION, [, FLAG ...]); $elt = $c->elt(MSGNO); $c->create(MAILBOX); $c->delete(MAILBOX); $c->rename(OLDNAME, NEWNAME); $c->open(MAILBOX); $nmsgs = $c->nmsgs; Mail::Cclient::set_callback KEY => CODE, ... $c->list(REF, PAT); # uses "list" callback $c->scan(REF, PAT, CONTENTS); $c->lsub(REF, PAT); $c->subscribe(MAILBOX); $c->unsubscribe(MAILBOX); $c->status(MAILBOX [, FLAG ...]); # uses "status" callback $c->copy(SEQUENCE, MAILBOX [, FLAG ...]); $c->move(SEQUENCE, MAILBOX [, FLAG ...]); $c->append(MAILBOX, MESSAGE [, DATE [, FLAGS]); $c->search(CRITERIA); # uses "search" callback $c->ping; $c->check; # uses "log" callback $c->expunge; # uses "expunge" callback $uid = $c->uid(MSGNO); $c->setflag(SEQUENCE, MAILFLAG [, FLAG ...]); $c->clearflag(SEQUENCE, MAILFLAG [, FLAG ...]); $c->fetchfast(SEQUENCE); $c->fetchflags(SEQUENCE); $c->gc( [FLAG, ...] ); $c->debug; $c->nodebug; $c->set_sequence(SEQUENCE); $c->uid_set_sequence(SEQUENCE); $result = $c->parameters(PARAM); $c->parameters(PARAM1 => NEWVALUE1 [, PARAM2 => NEWVALUE2 ...]); $text = Mail::Cclient::rfc822_base64(SOURCE); $text = Mail::Cclient::rfc822_qprint(SOURCE); $c->close;
Mail::Cclient gives access to mailboxes in many different formats (including remote IMAP folders) via the c-client API. The c-client library is the core library used by Pine and the University of Washington IMAP daemon (written by Mark Crispin).
The Perl API is mostly taken directly from the underlying c-client library with minor adjustments in places where Perl provides a more natural interface. The primary interface is an object oriented one via the
Mail::Cclient class but certain methods implicitly use callbacks set via the set_callback function.
The c-client library often provides a given piece of functionality by two different function names: one for simple usage under a name of the form
mail_foo and one with an additional flags arguments under a name of the form
mail_foo_full. The corresponding functionality is available from the Perl
Mail::Cclient class under the single name
Setting a flag bit such as
FT_UID in the c-client API is done in Perl by appending an extra argument
"uid" to the method call.
Arguments to c-client functions which are there only to pass or receive the length of a string argument or result are not present in the Perl API since Perl handles them automatically.
Some methods take arguments which refer to a message or messages in a mailbox. An argument denoted MSGNO is a number that refers to a single message. Message 1 refers to the first message in the mailbox, unless the "uid" option is passed as as additional argument in which case the number refers to the uid of the message. An argument denoted SEQUENCE refers to a list of messages and is a string such as '1,3,5-9,12'.
Mail::Cclient object and associating a mailstream with it is done with the
"new" constructor method (whereas the underlying c-client library uses the
The MAILBOX argument can be anything accepted by the underlying c-client library. This includes the following forms
This is the driver-dependent INBOX folder.
This specifies a mailbox in the default format (usually Berkeley format for most default library builds)
These refer to an IMAP folder held on host. The "folder" part can be "INBOX" to reference the distinguished INBOX folder that the IMAP protocol defines. The username and password required for logging in to the IMAP server are obtained by using the "login" callback (q.v.).
This refers to folder "/bar/baz" which is held in a non-default mailbox format handled by the c-client driver "foo" (e.g. "mbx").
The options which can be passed to the
new are as follows (taken almost verbatim from the c-client Internal.doc file):
Log IMAP protocol telemetry through "debug" callback (q.v.).
Open mailbox read-only.
Don't use or update a .newsrc file for news.
Don't cache envelopes or body structures.
Return the "prototype stream" for the driver associated with this mailbox instead of opening the stream.
For IMAP and NNTP names, open a connection to the server but don't open a mailbox.
Silently expunge the oldstream before recycling.
You can use the method
to get the mailstream object to open a different mailbox. The cclient library will try to reuse the same IMAP connection where possible in the case of IMAP mailboxes but the host part of the mailbox spec must be given exactly as in the original connection for this to work.
Read-only access to the fields of the underlying mailstream of a
Mail::Cclient object is supplied by the following methods:
Returns the number of messages in the mailbox.
Returns the mailbox name.
Stream is open read-only.
Stream is open with anonymous access.
Stream is half-open; it can be reopened or used for functions that don't need a open mailbox such as $c->create() but no message data can be fetched.
The relevant flag can be set permanently.
New user flags can be created by referencing them in setflag or clearflag method calls. This can change during a session (e.g. if there is a limit).
Returns a list of the user flags which can be set permanently.
Number of recent messages in current mailbox.
The UID validity value.
The highest currently assigned UID in the current mailbox.
The following methods are for creating/deleting/renaming folders.
The following methods provide access to messages themselves: their headers, structures and the text of their bodies (or parts thereof).
This returns the equivalent of what c-client calls an ENVELOPE structure for message MSGNO. If called in an array context then the equivalent of a BODY structure is passed as a second return value. The ENVELOPE structure is in the form of a Perl object of class
Mail::Cclient::Envelope. The BODY structure is in the form of a Perl object of class
Mail::Cclient::Body. See later on for the description of these objects. The FLAG "uid" can be passed which makes the MSGNO argument be interpreted as a message uid.
This returns the header text (as a single string) of message MSGNO (which is interpreted as a message uid if the flag "uid" is included). With no LINES argument, all headers are put into the string. If an array ref argument is passed then it is taken to be a reference to a list of header names. Those headers are the ones that are included in the result, unless the flag "not" is passed in which case all headers are included except those in the list. The flag "internal" can be passed to avoid canonicalising the header texts. The flag "prefetchtext" can be passed to pre-fetch the RFC822.TEXT part of the message at the same time.
This returns the body of message MSGNO (a message uid if the flag "uid" is included). The whole body is returned as a single string with no MIME processing done. Line endings are canonicalised to CRLF unless the "internal" flag is included. If the "peek" flag is included then the \Seen flag is not actively set (though it may already have been set previously, of course).
This returns a single (MIME) section of message MSGNO (a message uid if the flag "uid" is included). The SECTION argument determines which section is returned and is a string in the form of a dot-separated list of numbers. See the IMAP specification for details. As an example, a multipart/mixed MIME message has sections "1", "2", "3" and so on. If section "3" is multipart/mixed itself, then it has subsections "3.1", "3.2" and so on. The "peek" and "internal" flags may also be passed and have the same effect as in
fetchtext documented above.
This returns the MESSAGECACHE (commonly known as "elt") information associated with message MSGNO as an object in class Mail::Cclient::Elt. See below for what such an object contains. Important note: for this method to be valid, a previous
fetchflags must have been called on this message. Otherwise, you are into the realms of undefined behaviour and at the mercy of the underlying c-client library.
A message may be copied or moved into another mailbox with the methods
move. These methods only allow the destination mailbox to be of the same type as (and on the same host as) the mailstream object on which the methods are called.
This copies message MSGNO (a message uid if the "uid" flag is included) to mailbox MAILBOX. If the "move" flag is included then the message is actually moved instead (for compatibility with the CP_MOVE flag of the underlying c-client
This moved message MSGNO (a message uid if the "uid" flag is included) to mailbox MAILBOX.
Append a raw message (MESSAGE is an ordinary string) to MAILBOX, giving it an optional date and FLAGS (again, simply strings).
Search for messages satisfying CRITERIA. The "search" callback (q.v.) is called for each matching message. CRITERIA is a string containing a search specification as defined on pages 15-16 of RFC1176. Note that this is an IMAP2 search specification--this method does not support the more advanced IMAP4rev1 search specification.
The following methods provide access to information about mailboxes.
This method provides status information about MAILBOX. The information calculated is limited to those mentioned in FLAG arguments and is returned via the "status" callback (q.v.). The FLAG arguments possible are precisely those mentioned in the documentation below for the "status" callback.
The following are miscellaneous methods.
Checks where the mailstream is still alive: used as a keep-alive and to check for new mail.
Performs a (driver-dependent) checkpoint of the mailstream (not a check for new mail). Information about the checkpoint is passed to the "log" callback (q.v.).
Expunges all message marked as deleted in the mailbox. Calls the "expunged" callback (q.v.) on each such message and logging information is passed to the "log" callback. Decrementing message numbers happens after each and every message is expunged. As the example in the c-client documentation for mail_expunge says, if three consecutive messages starting at msgno 5 are expunged, the "expunged" callback will be called with a msgno of 5 three times.
Returns the uid associated with message MSGNO.
Sets flag MAILFLAG on each message in SEQUENCE (taken to be a sequence of message uids if the "uid" flag is passed). The "silent" flag causes the local cache not to be updated.
Clears flag MAILFLAG from each message in SEQUENCE (taken to be a sequence of message uids if the "uid" flag is passed). The "silent" flag causes the local cache not to be updated.
Garbage collects the cache for the mailstream. The FLAG arguments, "elt", "env", "texts", determine what is garbage collected.
Enables debugging for the mailstream, logged via the "dlog" callback (q.v.).
Disables debugging for the mailstream.
Sets the sequence bit for each message in SEQUENCE (and turns it off for all other messages). This has been renamed for Perl from the underlying c-client function
mail_sequence to avoid clashing with the sequence field member of the mailstream object.
Sets the sequence bit for each message referenced by uid in SEQUENCE (and turns it off for all other messages). This has been renamed for Perl from the underlying c-client function
mail_uid_sequence for consistency with
With a single argument, gets the current value of parameter PARAM. With one or more pairs of PARAM => VALUE arguments, sets those PARAM values to the given new values. PARAM can be one of the following strings: USERNAME, HOMEDIR, LOCALHOST, SYSINBOX, OPENTIMEOUT, READTIMEOUT, WRITETIMEOUT, CLOSETIMEOUT, RSHTIMEOUT, MAXLOGINTRIALS, LOOKAHEAD, IMAPPORT, PREFETCH, CLOSEONERROR, POP3PORT, UIDLOOKAHEAD, MBXPROTECTION, DIRPROTECTION, LOCKPROTECTION, FROMWIDGET, NEWSACTIVE, NEWSSPOOL, NEWSRC, DISABLEFCNTLLOCK, LOCKEACCESERROR, LISTMAXLEVEL, ANONYMOUSHOME.
The following are utility functions (not methods).
Certain methods mentioned above use callbacks to pass or receive extra information. Each callback has a particular name (e.g. "log", "dlog", "list", "login") and can be associated with a particular piece of Perl code via the
Mail::Cclient::set_callback function (available for export by the
Mail::Cclient class). The
set_callback function takes pairs of arguments NAME, CODE for setting callback NAME to be the given CODE, a subroutine reference. The only callback which is required to be set and the only callback whose return value matters is the "login" callback (only used when the "new" method constructs an IMAP mailstream). Apart from that case, callbacks which have not been set are ignored. A callback set to undef is also ignored.
This callback is invoked for each message number satifying the CRITERIA of the "search" method, defined above.
Attribute values passed can be "messages", "recent", "unseen", "uidvalidity", "uidnext".
The "login" callback is invoked when the c-client library is opening an IMAP mailstream and needs to find out the username and password required. This callback must return precisely two values in the form (USERNAME, PASSWORD). TRIAL is the number of the current login attempt (starting at 1). NETMBXINFO is a hash reference with the following keys:
The hostname of the IMAP server.
The username requested.
The mailbox name requested.
Set to 1 if anonymous access has been requested otherwise this key is not created at all.
Set to 1 if debugging access has been requested otherwise this key is not created at all.
The results of the
elt methods involve objects in the classes
Mail::Cclient::Elt. These will be referred to as Envelope, Body, Address and Elt objects respectively. These objects are all "read-only" and only have methods for picking out particular fields.
An Address object represents a single email address and has the following fields, available as methods or, if Perl 5.005 or later is being used, as pseudo-hash keys.
The personal phrase of the address (i.e. the part contained in parentheses or outside the angle brackets).
The at-domain-list or source route (not usually used).
The mailbox name (i.e. the part before the @ which is usually a username or suchlike).
The hostname (i.e. the part after the @).
Only set if the address has delivery errors when
smtp_mail is called. Since that function hasn't been implemented in the Perl module yet, this isn't any use.
An Envelope object represents a structured form of the header of a message. It has the following fields, available as methods or, if Perl 5.005 or later is being used, as pseudo-hash keys.
These are all strings.
These are all references to lists which contain one or more Address objects.
A Body object represents the structure of a message body (not its contents).It has the following fields, available as methods or, if Perl 5.005 or later is being used, as pseudo-hash keys.
The MIME type (as a string) of the message (currently in uppercase as returned from the c-client library). For example, "TEXT" or "MULTIPART".
The MIME encoding (as a string) of the message.
The MIME subtype (as a string) of the message. For example, "PLAIN", "HTML" or "MIXED".
A reference to a list of MIME parameter key/value pairs.
The message ID.
The MIME description of the body part.
If (and only if) the body is of MIME type multipart, then this field is a reference to a list of Body objects, each representing one of the sub parts of the message. If (and only if) the body is of MIME type message/rfc822, then this field is a reference to a list of the form (ENVELOPE, BODY) which are, respectively, the Body and Envelope objects referring to the encapsulated message. If the message is not of MIME type multipart or message/rfc822 then this field is undef.
The size in lines of the body.
The size in bytes of the body.
The MD5 checksum of the body.
The content disposition of the body: a reference to a list consisting of the disposition type followed by a (possibly empty) list of parameter key/value pairs.
These have fields containing flag information for a given message, along with internal date information and the RFC822 message size.
The message number.
This contains the internal date information (spread about a series of bitfields in the underlying c-client library C structure) in the form of a string:
yyyy-mm-dd hh:mm:ss [+-]hhmm
A reference to a list of flags associated with the message. The flags are in the forms of their RFC2060 names (e.g. \Deleted, \Seen) for official flags and the user-chosen name for user-defined flags.
The RFC822 size of the message.
This CAVEATS section was contributed by Bruce Gingery <firstname.lastname@example.org>.
The Mail::Cclient::mailbox method returns the actual full path opened, which may not give an accurate string comparison with the mailbox that was requested to be opened. This is especially true with remote mailboxes.
The C-Client library is VERY intolerant of logic errors, and does not automatically garbage collect. Use the
gc method as it makes sense for your application.
Some POP3 servers delete and expunge WITHOUT instruction to do so. This is not a malfunction in either the C-Client code nor the Mail::Cclient modules.
open method can be used to extend a
halfopen connection (e.g. use the same c-client instance to read a mailbox that was previously halfopened for a list of mailboxes. This may or may not be a good idea, depending upon your needs. It does, however, eliminate the problem of opening multiple connections, such as has been noted in Netscape 4.x mail handling, and which plagues some servers badly. It may be better, however, to
close the connection used for
list, and re-instantiate to process the mailbox.
C-Client may not support headers you need for send. Note that other modules can be used in place of sending with the c-client. These include Net::SMTP, local invocation of piped sendmail (or other E-mail insertion software), or sendto: URLs under libwww POST.
Elt information for remote mailboxes is server dependent, as well. You may or may not get rfc822_size in elt returns, for example.
Multiple c-client instances open simultaneously may not work as expected.
Malcolm Beattie, email@example.com.