archie/tcl-dp/doc/email.html
2024-05-27 16:13:40 +02:00

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<h3>Email Channel</h3>
<p><b>Syntax</b></p>
<p><tt>dp_connect email -address </tt><em><tt>email_adress</tt></em><tt>
-identifier </tt><em><tt>unique_id</tt></em></p>
<p><b>Comments</b></p>
<p><i>email_address</i> is the address to which outgoing messages
will be sent, and from which they will be received&nbsp;</p>
<p><i>unique_id</i> must be a unique identifier that will be used
to generate the files associated with the email channels (see
below). It is mandatory when opening the first email channel, and
optional when opening subsequent ones. If given, the value of the
parameter has to be the same for all opened email channels.
Different identifiers can be used to open email channels in
independent processes that run dp. The value of the identifier
can also be used to recover information from the email files
after a crash of dpsh (this feature is not implemented).&nbsp;</p>
<p>Incoming email messages will be filtered and the relevant ones
will be directed toward the files associated with the email
channels. All incoming messages will be also forwarded to the
address(es) given in the original ~/.forward file or, if this did
not exist, to the user's mailbox. The messages sent through email
channels will always have &quot;email channel&quot; in their
subject line.&nbsp;</p>
<p>Opening several email channels associated with the same
address is possible, but an incoming message will be delivered
only to one of them.&nbsp;</p>
<p>An email channel is always writable, and will never block. The
channel specific options are the following:&nbsp;</p>
<ul>
<li>peek (boolean) - usual interpretation&nbsp;</li>
<li>sequence (boolean) - if set, a line of the form
&quot;Sequence: &lt;sequence_number&gt;&quot; will be
inserted after the subject line of outgoing
messages.&nbsp;</li>
</ul>
<p><b>Temporary Files&nbsp;</b></p>
<p>When the first email channel is opened file ~/.forward is
created (or extended, if it exists already) to include dpfilter.
Dpfilter is an utility that selectes incoming email messages for
which an email channel was opened. These will be stored in files
~/.emailSpool&lt;unique_id&gt;. File
~/.emailSeek&lt;unique_id&gt; serves as an index for
~/.emailSpool&lt;unique_id&gt; ~/.emailChannel&lt;unique_id&gt;
stores the addresses corresponding to the opened email channel.
To synchronize the activity of dpsh and dpfilter, a symbolic link
~/.emailLock&lt;unique_id&gt; is sometimes created.&nbsp;</p>
<p>If dpsh crashes with at least one open email channel, one
should delete files ~/.email*, and restore the initial state or
delete the ~/.forward file.&nbsp;</p>
<p><b>Examples&nbsp;</b></p>
<dl>
<dt><tt>set first [dp_connect email -address root -identifier
100]&nbsp;</tt></dt>
<dt><tt>set second [dp_connect email -address
foobar@cs.foo.edu]&nbsp;</tt></dt>
<dt><tt>fconfigure $first -peek yes -sequence yes&nbsp;</tt></dt>
</dl>
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