Messages: Add ability to native save mail content to file

[jakubboucek]

PR is adding ability to store raw Message (or their parts) to file directly via native imap_savebody() function.

Direct handling I/O is much more effective than fetch Message Body as string and than save it. Some messages may have huge size, it may waste process memory.

Example how to simple store Message content file:

$filename = 'message-content.eml';
$message->saveRawMessage($filename);

Streams

The imap_savebody() function supports Streams too, this provides the ability to connect elements with pipes for effective manipulating with mail content.

Example how to simple store Message content to compressed file with single atomic operation:

$file = gzopen('message-content.eml.gz', 'wb');
$message->saveRawMessage($file);
gzclose($file);

• Add tests.

[codecov]

Codecov Report

Base: 94.76% // Head: 94.73% // Decreases project coverage by -0.04% ⚠️

Coverage data is based on head (ce12e39) compared to base (a238641).
Patch coverage: 92.30% of modified lines in pull request are covered.

Additional details and impacted files

@@             Coverage Diff              @@
##             master     #556      +/-   ##
============================================
- Coverage     94.76%   94.73%   -0.04%     
- Complexity      356      360       +4     
============================================
  Files            45       45              
  Lines           898      911      +13     
============================================
+ Hits            851      863      +12     
- Misses           47       48       +1     

Impacted Files	Coverage Δ
src/Message/AbstractPart.php	95.51% <88.88%> (-0.41%)	⬇️
src/Message.php	85.84% <100.00%> (+0.25%)	⬆️
src/Message/EmbeddedMessage.php	100.00% <100.00%> (ø)

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[jakubboucek]

Really IDK how to meaningfully test \Ddeboer\Imap\Message\EmbeddedMessage::saveRawMessage().

[Slamdunk]

Really IDK how to meaningfully test \Ddeboer\Imap\Message\EmbeddedMessage::saveRawMessage().

Just add few meaningful lines to \Ddeboer\Imap\Tests\EmbeddedMessageTest I'd say, and we are ready to merge 💪

[jakubboucek]

@Slamdunk Thanks to merge 👍