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Sieve implementation for Dovecot (1.2)
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!! WARNING !!
This sieve implementation is highly experimental. In addition to the usual GPL
disclaimer you are advised not to use this for any important mail just yet!
The current status of this project is outlined in the TODO file.
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Compiling and Configuring
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Stephan Bosch
committed
Refer to INSTALL file.
Using
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The main purpose of this package is to replace the existing cmusieve plugin that
is currently available for Dovecot's deliver. With this respect it is currently
not very different from the cmusieve plugin implementation.
Unlike cmusieve, this sieve module logs runtime errors to <scriptfile>.log if it
can and not '<scriptfile>.err'. It appends new timestamped log entries to the
end of the logfile. I currently didn't bother to implement log rotation, so keep
this in mind. Some development-related debug output is sent to stderr/stdout at
all times, this will be removed when this project matures.
The cmusieve plugin compiled the script into a file with an appended c, e.g.
'test.sievec'. This new implementation recognizes scripts to have the .sieve
extension. The binary is (by default) written to a file with extension .svbin.
This means that the default .dovecot.sieve is compiled into .dovecot.svbin.
Included scripts are currently always compiled into the main binary, meaning
that no other files are written and no permission to do so is necessary for the
global script directories.
To test the sieve engine outside deliver it is useful to execute the binaries
that exist in the src/sieve-bin/ directory of this package. After installation,
these scripts are available in the dovecot lib directory. The following commands
are available:
Compiles the script and produces a sieve binary. However, when the -d option is
provided, a code dump is written to the output file. When the output file is '-'
the dump output is written to stdout (only if -d is specified).
--
sieved <bin-file> [<dump-file>]
Reads a sieve binary and produces a code dump. The optional dump-file parameter
provides the means to specify a file to which the dump is to be written.
Otherwise, the dump is printed to stdout.
sieve-test [-r <recipient address>][-s <envelope sender>]
[-m <mailbox>][-d <dump filename>][-c] <scriptfile> <mailfile>
Reads mail message from the specified mailfile and executes the specified sieve
script to produce a verdict. This prints an execution dump with the instructions
encountered during execution and finally it prints a list of actions that would
have been performed on this message.
-r envelope recipient address
-s envelope sender
-m the mailbox where the keep action should store
-d causes a dump of the generated code to be written to the specified
file. Using - as filename causes the dump to be written to stdout
-c force compilation (ignore any existing binary)
--
sieve-exec
Currently undocumented (will be merged with sieve-test).
Various example scripts are bundled in the directory 'sieve'.
Authors
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Refer to AUTHORS file.
* Well-structured 3-stage compiler: uses dovecot framework and avoids using
lex/yucc. Compiler doesn't bail on first error, but tries to find more.
* Highly extendable with new sieve capabilities: This keeps the possibility of
plugins in mind. It should eventually provide the necessary infrastructure for
at least all currently known (proposed) extensions. The goal is to keep the
extension interface provided by sieve engine as generic as possible, i.e.
without explicit support for specific extensions. New similar extensions can
then use the same interface methods without changes to the sieve engine code.
* Scripts can be parsed, the grammar is fully supported.
* Script code generation works for all core commands. Comparators, match-types
and address-part modifiers work as required.
* Interpreter runs core commands and tests. Comparators, match-types and
address-part modifiers have the desired effect.
* The interpreter produces a result containing a set of actions to execute.
Duplicate actions can be avoided and conflicts can be detected. Multiple
scripts could be executed in succession on the result object although no
support to do so is currently available. Runtime errors are a bit obscure
though; these should provide line numbers.
* Execution of the result is supported for all core action commands and all
fully implemented extensions (see list below).
* Compiled binary code can be saved to and loaded back from disk. The binary
is structured as a set of data blocks, which can contain extension-dependent
extra data. For example, the include extension uses this to store the
compiled included scripts (no external inclusion of binaries supported yet).
* This sieve implementation is available as an alternative plugin to
dovecot's deliver. It is not completely useful yet, but hopefully this will
soon be able to replace the current cmusieve implementation.
false, true: trivial, full
address: full
header: full
exists: full
size: full
not, anyof, allof: full
Base commands and their implementation status:
require: full
if,elsif,else: full
discard: full
keep: full
redirect: full
stop: trivial, full
Extensions and their implementation status:
Base specification (RFC5228):
Other RFCs/drafts:
Stephan Bosch
committed
subaddress: mostly full; not configurable
Stephan Bosch
committed
comparator-i;ascii-numeric: full
Stephan Bosch
committed
regex: mostly full; but suboptimal and no UTF-8
body: full, but text body-transform implementation is simple
Stephan Bosch
committed
include: mostly full; needs some more work (no external binaries)
vacation: mostly full; no support for required References header
imapflags: full
variables: mostly full; currently no support for future namespaces
Next in order of descending priority:
environment: planned
editheader: planned, needs additional support from Dovecot though.
mimeloop: planned
All implemented extensions are like the engine itself currently very much
experimental. A status of 'full' does not mean that the extension is bug-free
or even fully RFC-compliant. Other extensions will be added as soon as the
necessary infrastructure is available. Extensions already supported by cmusieve
have priority.
Contact Info
------------
Stephan Bosch <stephan at rename-it dot nl>
IRC: Freenode, #dovecot, S[r]us
Please use the Dovecot mailing list <dovecot at dovecot.org> for questions about
this package. You can post to the list without subscribing, the mail then waits
in a moderator queue for a while. See http://dovecot.org/mailinglists.html