External metadata guids were implemented for the new Plex Movie and Plex TV Series agent in this previous feature request.
Example:
<Guid id="imdb://tt5433138"/>
<Guid id="tmdb://385128"/>
<Guid id="tvdb://8856"/>
However, these external guids are only available when retrieving the metadata XML for a single item (i.e. /library/metadata/<ratingKey>). They are not available when retrieving the contents of a library (i.e. /library/sections/<librarySectionID>/all). Many 3rd party applications depend on these external guids, thus all these applications are making individual API calls for each item in the library. This is extremely taxing on the Plex server and network which can cause the Plex server to lock up and become unresponsive. For example, a library of 10k movies will require 10k individual API calls.
This feature request is to add a new includeGuids=1 URL parameter that is available for the /library/sections/<librarySectionID>/all API endpoint which will include the <Guid> tags in the response. With this new new include parameter only a single API call will be required to get the external guids for the entire library, thus significantly reducing the load on the Plex server from 3rd party applications. This new parameter would also be analogous to the currently existing parameters (e.g. includeBandwidth, includeExtras, includeReviews, etc.). Becuase this will be an optional parameter to return additional data, it will have zero impact on all existing Plex clients which do not use the guids anyways.
