IMAPFILTER_CONFIG(5)

NAME
imapfilter_config - imapfilter configuration file

SYNOPSIS
$HOME/.imapfilter/config.lua

DESCRIPTION
imapfilter(1) uses the Lua programming language (http://www.lua.org) as a configuration and extension language, therefore the configuration file is a Lua script.

Although knowledge of Lua is not required to use imapfilter(1), it is nonetheless recommended, especially if one wants to extend imapfilter(1). The user is advised to have a look at the available Lua documentation at:

    http://www.lua.org/docs.html

CONVENTIONS

A brief description of the Lua values and types mentioned hereafter in the manual page follows:

The nil is the type of the value ``nil'' , whose main property is to be different from any other value; usually it represents the absence of a useful value.

The boolean is the type of the values ``true'' and ``false''. Both ``nil'' and ``false'' make a condition false; any other value makes it true.

The type number represents real numbers.

The type string represents a sequence of characters and can be defined using single quotes, double quotes or double square brackets.

The type table implements associative arrays, that is, arrays that can be indexed not only with numbers, but with any value.

A function is a first-class value; it can be stored in variables, passed as argument to other functions, and returned as a result.

OPTIONS
Program's options are set using an already initialised table named ``options'' , in the following manner:

    options.timeout = 120
    options.namespace = false

Available options are:

create
    According to the IMAP specification, when trying to write a message to a non-existent mailbox, the server must send a hint to the client, whether it should create the mailbox and try again or not. However some broken IMAP servers don't follow the specification and don't send the correct response code to the client. By enabling this option the client tries to create the mailbox, despite of the server's response. This variable takes a boolean as a value. Default is ``false''.

close
    This option controls whether the currently selected mailbox is implicitly closed at the end of each performed operation, thus removing all messages that are marked deleted. This variable takes a boolean as a value. Default is ``false''.

crammd5
    When this option is enabled and the server supports the Challenge-Response Authentication Mechanism (specifically CRAM-MD5), this method will be used for user authentication instead of a plaintext password LOGIN. This variable takes a boolean as a value. Default is ``true''.

expunge
    Normally, messages are marked for deletion and are actually deleted when the mailbox is closed. When this option is enabled, messages are expunged immediately after being marked deleted. This variable takes a boolean as a value. Default is ``true''.

info
    When this options is enabled, a summary of the program's actions is printed, while processing mailboxes. This variable takes a boolean as a value. Default is ``true''.

namespace
    When enabled, the program gets the namespace of the user's personal mailboxes, and applies automatically the prefix and hierarchy delimiter to any mailboxes residing on the mail server; the user must use the `/' character as the delimiter and ``'' (ie. nothing) as the prefix, regardless of the folder format of the mail server. This must be disabled, if the user wants to manually specify mailbox names (eg. because they are not part of the user's personal namespace mailboxes). This variable takes boolean as a value. Default is ``true''.

starttls
    When this option is enabled and the server supports the IMAP STARTTLS extension, a TLS connection will be negotiated with the mail server in the beginning of the session. This variable takes a boolean as value. Default is ``true''.

subscribe
    By enabling this option new mailboxes that were automatically created, get also subscribed; they are set active in order for IMAP clients to recognize them. This variable takes a boolean as a value. Default is ``false''.

timeout
    The time in seconds for the program to wait for a mail server's response. If not set, the client will block indefinitely. This variable takes a number as a value.

ACCOUNT
Accounts are initialized using the IMAP() function, and the details of the connection are defined using an account table:

    myaccount = IMAP {
        server = 'imap.mail.server',
        username = 'me',
        password = 'secret',
        ssl = 'ssl3'
    }

An account table must have the following elements:

server
    The hostname of the IMAP server to connect to. It takes a string as a value.

username
    User's name. It takes a string as a value.

An account table can also have the following optional elements:

password
    User's secret keyword. If a password wasn't supplied the user will be asked to enter one interactively the first time it will be needed. It takes a string as a value.

port
    The port to connect to. It takes a number as a value. Default is ``143'' for imap and ``993'' for imaps.

ssl Forces an imaps connection and specifies the SSL/TLS protocol to be used. It takes a string as a value, specifically one of: ``ssl2'' , ``ssl3'' , ``tls1''.

  LISTING
The following methods can be used on an account to list mailboxes in a folder of an account:

list_all(folder)
    Lists all the available mailboxes in the folder (string), and returns a table that contains strings, the available mailboxes, and a table that contains strings, the available folders.

list_subscribed(folder)
    Lists all the subscribed mailboxes in the folder (string), and returns a table that contains strings, the subscribed mailboxes, and a table that contains strings, the subscribed folders.

The following methods can be used on an account to list mailboxes, using wildcards, in a folder of an account. The `*' wildcard, matches any character and the `%' matches any character except the folder delimiter, ie. non-recursively:

list_all(folder, mailbox)
    Lists all the available mailboxes in the folder (string) with the name mailbox (string), and returns a table that contains strings, the available mailboxes, and a table that contains strings, the available folders. Wildcards may only be used in the mailbox argument.

list_subscribed(folder, mailbox)
    Lists all the subscribed mailboxes in the folder (string) with the name mailbox (string), and returns a table that contains strings, the subscribed mailboxes, and a table that contains strings, the subscribed folders. Wildcards may only be used in the mailbox argument.

Examples:

    mailboxes, folders = myaccount:list_subscribed('myfolder')
    mailboxes, folders = myaccount:list_all('myfolder/mysubfolder', '*')

  MANIPULATING
The following methods can be used to manipulate mailboxes in an account:

create_mailbox(name)
    Creates the name (string) mailbox.

delete_mailbox(name)
    Deletes the name (string) mailbox.

rename_mailbox(oldname, newname)
    Renames the oldname (string) mailbox to newname (string).

subscribe_mailbox(name)
    Subscribes the name (string) mailbox.

unsubscribe_mailbox(name)
    Unsubscribes the name (string) mailbox.

Examples:

    myaccount:create_mailbox('mymailbox')
    myaccount:subscribe_mailbox('mymailbox')
    myaccount:unsubscribe_mailbox('myfolder/mymailbox')
    myaccount:delete_mailbox('myfolder/mymailbox')

MAILBOX
After an IMAP account has been initialized, mailboxes residing in that account can be accessed simply as elements of the account table:

    myaccount.mymailbox

If mailbox names don't only include letters, digits and underscores, or begin with a digit, an alternative form must be used:

    myaccount['mymailbox']

A mailbox inside a folder can be only accessed by using the alternative form:

    myaccount['myfolder/mymailbox']

The methods that are available for an account (eg. list_all(), create_mailbox(), etc.) , are considered keywords and must not be used as mailbox names, and the same also applies for any string starting with an underscore, as they are considered reserved.

  CHECKING
The following methods can be used to check the status of a mailbox:

check_status()

    The check_status() method gets the current status of a mailbox, and returns three values of number type: the total number of messages, the number of recent messages and the number of unseen messages in the mailbox.

        exist, unread, unseen = myaccount.mymailbox:check_status()

  SEARCHING

All the searching methods in this subsection return a special form of table. This table can be combined with other tables using logic theory. There are three available operations, that implement logical ``or'', logical ``and'' and logical ``not''.

The logical ``or'' is implemented using the `+' operator:

    messages = myaccount.mymailbox:is_unseen() +
               myaccount.mymailbox:is_larger(100000)

The logical ``and'' is implemented using the `*' operator:

    messages = myaccount.mymailbox:is_unseen() *
               myaccount.mymailbox:is_larger(100000)

The logical ``not'' is implemented using the `-' operator:

    messages = myaccount.mymailbox:is_unseen() -
               myaccount.mymailbox:is_larger(100000)

The three logical operators can be combined in the same expression. The logical ``and'' has higher precedence than the logical ``or'' and the logical ``not'', with the latter two having the same precedence, and parentheses may be used to change this behaviour:

    messages = myaccount.mymailbox:is_unseen() +
               myaccount.mymailbox:is_larger(100000) *
               myaccount.mymailbox:contain_subject('test')
    messages = ( myaccount.mymailbox:is_unseen() +
                 myaccount.mymailbox:is_larger(100000) ) *
               myaccount.mymailbox:contain_subject('test')

The returned tables of the searching methods can also be stored in variables and then further processed:

    unseen = myaccount.myaccount:is_unseen()
    larger = myaccount.mymailbox:is_larger(100000)
    subject = myaccount.mymailbox:contain_subject('test')
    messages = unseen + larger * subject

A composite filter that includes one or more simple rules can be defined:

    myfilter = function ()
    	       return myaccount.mymailbox:is_unseen() +
    	              myaccount.mymailbox:is_larger(100000) *
                          myaccount.mymailbox:contain_subject('test')
               end
    messages = myfilter()

Composite filters can may be more dynamic by adding arguments:

    myfilter = function (mailbox, size, subject)
    	       return mailbox:is_unseen() +
                          mailbox:is_larger(size) *
                          mailbox:contain_subject(subject)
               end
    messages = myfilter(myaccount.mailbox, 100000, 'test')

The following methods can be used to search for messages that are in a specific state:

is_answered()
    Messages that have been answered.

is_deleted()
    Messages that are marked for later removal.

is_draft()
    Messages that have not completed composition.

is_flagged()
    Messages that are flagged for urgent/special attention.

is_new()
    Messages that are recently arrived (this session is the first to have been notified about these messages) and have not been read.

is_old()
    Messages that are not recently arrived (this session is not the first to have been notified about these messages) and have not been read.

is_recent()
    Messages that are recently arrived (this session is not the first to have been notified about these messages).

is_seen()
    Messages that have been read.

is_unanswered()
    Messages that have not been answered.

is_undeleted()
    Messages that are not marked for later removal.

is_undraft()
    Messages that have completed composition.

is_unflagged()
    Messages that are not flagged for urgent/special attention.

is_unseen()
    Messages that have not been read.

The following method can be used to search for messages that have a specific flag set:

has_flag(keyword)
    Messages with the specified keyword flag (string) set.

The following methods can be used to search for messages based on their size:

is_larger(size)
    Messages that are larger than the size (number) in octets (bytes).

is_smaller(size)
    Messages that are smaller than the size (number) in octets (bytes).

The following methods can be used to search for messages based on their age:

is_newer(age)
    Messages that are newer than the age (number) in days.

is_older(age)
    Messages that are older than the age (number) in days.

The following methods can be used to search for messages based on their arrival or sent date, in the ``day-month-year'' form, where day is the day of the month as a decimal number (01-31), month is the abbreviated month (``Jan'', ``Feb'', ``Mar'', ``Apr'', ``May'', ``Jun'', ``Jul'', ``Aug'', ``Sep'', ``Oct'', ``Nov'', ``Dec'') and year is the year as decimal number including the century (eg. 2007):

arrived_before(date)
    messages that have arrived before the date (string), where date is in the ``day-month-year'' form.

arrived_on(date)
    Messages that have arrived on the date (string), where date is in the ``day-month-year'' form.

arrived_since(date)
    Messages that have arrived after the date (string), where date is in the ``day-month-year'' form.

sent_before(date)
    Messages that have been sent before the date (string), where date is in the ``day-month-year'' form.

sent_on(date)
    Messages that have been sent on the date (string), where date is in the ``day-month-year'' form.

sent_since(date)
    Messages that have been sent after the date (string), where date is in the ``day-month-year'' form.

The following methods can be used to search for messages that contain a specific word or phrase:

contain_bcc(string)
    Messages that contain the string (string) in the ``Bcc'' header field.

contain_cc(string)
    Messages that contain the string (string) in the ``Cc'' header field.

contain_from(string)
    Messages that contain the string (string) in the ``From'' header field.

contain_subject(string)
    Messages that contain the string (string) in the ``Subject'' header field.

contain_to(string)
    Messages that contain the string (string) in the ``To'' header field.

contain_field(field, string)
    Messages that contain the string (string) in the field (string) header field.

contain_header(string)
    Messages that contain the string (string) in the message header, but not in the message body. Note that due to an IMAP limitation there is no way to search for a string only in the message header, and this oddly behaving method is included only for consistency.

contain_body(string)
    Messages that contain the string (string) in the message body.

contain_message(string)
    Messages that contain the string (string) in the message.

The following methods can be used to search for messages that match a specific regular expression pattern. Note that due to Lua using backslash `\' as an escape character for its strings, one has to double backslashes in order to insert a single backslash inside a regular expression pattern:

match_bcc(pattern)
    Messages that match the regular expression pattern (string) in the ``Bcc'' header field.

match_cc(pattern)
    Messages that match the regular expression pattern (string) in the ``Cc'' header field.

match_from(pattern)
    Messages that match the regular expression pattern (string) in the ``From'' header field.

match_subject(pattern)
    Messages that match the regular expression pattern (string) in the ``Subject'' header field.

match_to(pattern)
    Messages that match the regular expression pattern (string) in the ``To'' header field.

match_field(field, pattern)
    Messages that match the regular expression pattern (string) in the field (string) header field.

match_header(pattern)
    Messages that match the regular expression pattern (string) in the message header.

match_body(pattern)
    Messages that match the regular expression pattern (string) in the message body.

match_message(pattern)
    Messages that match the regular expression pattern (string) in the message.

The following method can be used to get all messages in a mailbox:

select_all()
    All messages.

The following method can be used to search for messages using user queries based on the IMAP specification (RFC 3501 Section 6.4.4):

send_query(criteria)
    Searches messages by sending an IMAP search query as described in the search criteria (string).

send_query(criteria, charset)
    Searches messages by sending an IMAP search query as described in the search criteria (string). while charset (string) indicates to the server the character set of the strings that appear in the query. Character sets are defined in RFC 2978 and must be supported by the server.

Examples:

    messages = myaccount.mymailbox:is_new()
    messages = myaccount.mymailbox:is_recent()
    messages = myaccount.mymailbox:is_larger(100000)
    messages = myaccount.mymailbox:is_older(10)
    messages = myaccount.mymailbox:has_flag('MyFlag')
    messages = myaccount.mymailbox:arrived_before('01-Jan-2007')
    messages = myaccount.mymailbox:sent_since('01-Jan-2007')
    messages = myaccount.mymailbox:contain_subject('test')
    messages = myaccount.mymailbox:contain_field('Sender', 'user@host')
    messages = myaccount.mymailbox:contain_body('hello world')
    messages = myaccount.mymailbox:match_from('.*(user1|user2)@host')
    messages = myaccount.mymailbox:match_message('^[Hh]ello world!?$')
    messages = myaccount.mymailbox:select_all()
    messages = myaccount.mymailbox:send_query('ALL', 'ISO-8859-1')
    messages = myaccount['mymailbox']:is_new()
    messages = myaccount['myfolder/mymailbox']:is_recent()

  PROCESSING
The following method can be used to delete messages in a mailbox:

delete_messages(messages)
    Deletes the messages (table).

The following methods can be used to copy and move messages in a mailbox at the same or different accounts. If the destination mailbox is in a different account than the source mailbox, then the messages are downloaded and then uploaded to the destination:

copy_messages(destination, messages)
    Copies the messages contained in messages (table), to the destination, which is a mailbox at an account.

move_messages(destination, messages)
    Moves the messages contained in messages (table), to the destination, which is a mailbox at an account.

The following methods can be used to mark messages in a mailbox:

mark_answered(messages)
    Marks messages (table) as answered.

mark_deleted(messages)
    Marks messages (table) for later removal.

mark_draft(messages)
    Marks messages (table) as draft.

mark_flagged(messages)
    Marks messages (table) for urgent/special attention.

mark_seen(messages)
    Marks messages (table) as read.

unmark_answered(messages)
    Unmarks messages (table) that have been marked as answered.

unmark_deleted(messages)
    Unmarks messages (table) that have been marked for later removal.

unmark_draft(messages)
    Unmarks messages (table) that have been marked as draft.

unmark_flagged(messages)
    Unmarks messages (table) that have been marked for urgent/special attention.

unmark_seen(messages)
    Unmarks messages (table) that have been marked as read.

The following methods can be used to flag messages in a mailbox. The standard system flags are ``\Answered'', ``\Deleted'', ``\Draft'', ``\Flagged'', ``\Seen'', while if the server supports it, new user keywords may be defined:

add_flags(flags, messages)
    Adds the flags (table that contains strings) to the messages (table).

remove_flags(flags, messages)
    Removes the flags (table that contains strings) from the messages (table).

replace_flags(flags, messages)
    Replaces the flags (table that contains strings) of the messages (table).

Examples:

    myaccount.mymailbox:delete_messages(messages)
    myaccount.mymailbox:copy_messages(myaccount.othermailbox, messages)
    myaccount.mymailbox:move_messages(otheraccount.mymailbox, messages)
    myaccount.mymailbox:mark_seen(messages)
    myaccount.mymailbox:unmark_flagged(messages)
    myaccount.mymailbox:add_flags({ 'MyFlag', '\\Seen' }, messages)
    myaccount.mymailbox:remove_flags({ '\\Seen' }, messages)
    myaccount['mymailbox']:delete_messages(messages)
    myaccount['myfolder/mymailbox']:copy_messages(myaccount.othermailbox,
                                                  messages)
    myaccount.mymailbox:move_messages(otheraccount['myfolder/mymailbox'],
                                      messages)

  FETCHING

The following methods can be used to fetch parts of messages. The methods return a table, which for each message contains a string, the part that has been fetched. The downloaded messages are cached locally, so they can be reused inside the same program session:

fetch_message(messages)
    Fetches the header and body of the messages (table).

fetch_header(messages)
    Fetches the header of the messages (table).

fetch_body(messages)
    Fetches the body of the messages (table).

fetch_fields(fields, messages)
    Fetches the header fields of the messages (table).

The following methods can be used to fetch details about the state of messages:

fetch_flags(messages)
    Fetches the flags of the messages (table). Returns a table, which for each message contains a table of strings.

fetch_date(messages)
    Fetches the internal date of the messages (table). Returns a table which for each message contains a string.

fetch_size(messages)
    Fetches the size of the messages (table). Returns a table which for each message contains a number.

Examples:

    myaccount.mymailbox:fetch_message(messages)
    myaccount.mymailbox:fetch_fields({ 'from', 'subject' }, messages)
    myaccount['mymailbox']:fetch_message(messages)
    myaccount['myfolder/mymailbox']:fetch_message(messages)

FUNCTIONS
The following auxiliary functions are also available for convenience:

form_date(days)
    Forms a date in ``day-month-year'' format that the system had before the number of days (number), and returns it as a string.

get_password(prompt)
    Displays the specified prompt (string), and reads a password, while character echoing is turned off. Returns that password as a string.

become_daemon(interval, commands)
    Detaches the program from the controlling terminal and runs it in the background as system daemon. The program will then repeatedly poll at the specified interval (number) in seconds. Each time the program wakes up, the commands (function) are executed.

pipe_to(command, data)
    Executes the system's command (string) and sends the data (string) to the standard input channel of the subprocess. Returns a number, the exit status of the child process.

pipe_from(command)
    Executes the system's command (string) and retrieves the data from the standard output channel of the subprocess. Returns a number, the exit status of the child process, and a string, the output of the child process.

regex_search(pattern, string)
    Implements Perl-compatible regular expressions (http://www.pcre.org). The pattern (string) is a PCRE pattern. The string (string) is the subject string in which the pattern is matched against. Returns at least a boolean, that denotes if the match was successful, and any captures which are of string type. Note that due to Lua using backslash `\' as an escape character for its strings, one has to double backslashes in order to insert a single backslash inside a regular expression pattern:

Examples:

    date = form_date(14)
    password = get_password('Enter password: ')
    become_daemon(600, myfunction)
    status = pipe_to('mycommandline', 'mydata')
    status, data = pipe_from('mycommandline')
    success, capture = regex_search('^[PpCcRrEe]: (\\w)$', 'mystring')

EXAMPLES
See sample.config.lua and sample.extend.lua.

ENVIRONMENT

HOME
    User's home directory.

SEE ALSO
imapfilter(1)

AUTHORS
Lefteris Chatzimparmpas <lefcha@hellug.gr>