fix(vMix): fragmented message handling SOFIE-2932

[ianshade]

About the Contributor

This PR is being opened on behalf of TV 2 Norge.

Type of Contribution

This is a:

Bug fix / Code improvement

Current Behavior

It could happen that incomplete XML message would be attempted to be processed by the 'data' event handler, causing an error to be thrown. As a result the old, incomplete data got indefinitely stuck in the _unprocessedLines of the BaseConnection.

New Behavior

The logic for processing incoming data is extracted, refactored and covered by unit tests.
Handling of messages that may be fragmented over multiple TCP packets is fixed.
Errors thrown during the message handler are no longer interrupting the processing.
When reconnecting, previous and possibly incomplete data is discarded.

Testing Instructions

Other Information

An assumption about the XML message being always terminated by a newline was made. This is not explicitly specified in the documentation, but the documentation says the following:

All messages are UTF8 encoded and \r\n terminated unless specified otherwise.

Optional binary data is the exact length specified in <status/length> including additional terminating characters such as \r\n
which are always appended to the end of multiline text such as from XMLTEXT.

(source: https://www.vmix.com/help25/index.htm?TCPAPI.html)

Status

• PR is ready to be reviewed.
• The functionality has been tested by the author.
• Relevant unit tests has been added / updated.
• Relevant documentation (code comments, system documentation) has been added / updated.

[codecov-commenter]

Codecov Report

Attention: 2 lines in your changes are missing coverage. Please review.

Comparison is base (d7caf7d) 37.19% compared to head (aa65001) 37.60%.

Files	Patch %	Lines
...state-resolver/src/integrations/vmix/connection.ts	83.33%	1 Missing ⚠️
...line-state-resolver/src/integrations/vmix/index.ts	0.00%	1 Missing ⚠️

Additional details and impacted files

@@              Coverage Diff              @@
##           release50     #320      +/-   ##
=============================================
+ Coverage      37.19%   37.60%   +0.41%     
=============================================
  Files            105      106       +1     
  Lines          10220    10234      +14     
  Branches        2493     2496       +3     
=============================================
+ Hits            3801     3849      +48     
+ Misses          5868     5837      -31     
+ Partials         551      548       -3     

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[Julusian]

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