PHP Error in loadExporterByCode() breaks download of object representations files in CA 2.0

[amergelCGI]

In CA 2.0 (dev/php8), a PHP error occurs when trying to download object representations media files.

Fatal error: Uncaught TypeError: ca_data_exporters::exportRecord(): Argument #1 ($exporter_code) must be of type string, array given, called in /var/www/html/collectiveaccess/app/helpers/mediaPluginHelpers.php on line 902 and defined in /var/www/html/collectiveaccess/app/models/ca_data_exporters.php:1148

Stack trace:
#0 /var/www/html/collectiveaccess/app/helpers/mediaPluginHelpers.php(902): ca_data_exporters::exportRecord()
#1 /var/www/html/collectiveaccess/app/helpers/mediaPluginHelpers.php(827): caExportMediaMetadataForRecord()
#2 /var/www/html/collectiveaccess/app/lib/BaseEditorController.php(2548): caEmbedMediaMetadataIntoFile()
#3 /var/www/html/collectiveaccess/app/lib/Controller/RequestDispatcher.php(289): BaseEditorController->DownloadMedia() #4 /var/www/html/collectiveaccess/app/lib/Controller/AppController.php(108): RequestDispatcher->dispatch()
#5 /var/www/html/collectiveaccess/index.php(128): AppController->dispatch()
#6 {main} thrown in /var/www/html/collectiveaccess/app/models/ca_data_exporters.php on line 1148

This is due to an array passed to $ps_exporter_code which is expected to be a string in function loadExporterByCode() in app/models/ca_data_exporters.php.
This caused only a warning in PHP 7 but it became an error since PHP 8.

Here is some debug info that might be helpful:

json representation of $ps_exporter_code:
{"XMP:Title":{"ca_objects.preferred_labels.name":[]},"XMP:Description":{"ca_objects.description":[]},"XMP:Rights":["static:(c) 2011"],"XMP:Creator":{"ca_entities.preferred_labels.displayname":{"delimiter":","}},"XMP:Subjects":{"ca_list_items.preferred_labels.name_plural":{"delimiter":","}}}

[amergelCGI]

Issue is still occuring with the latest code. I am not sure what exactly is supposed to be the exporter code. Can it be for example "XMP"?
Currently it seems like the whole mapping is being passed as the exporter code while it probably expects only the prefix of the mapping's keys?

[collectiveaccess]

What does your media_metadata.conf file look like?

[amergelCGI]

extract_embedded_exif_georeferencing_to = []
extract_embedded_exif_georeferencing_to_container = {
}

extract_embedded_exif_creation_date_to = [ca_object_representations.media_creation_date]
extract_embedded_exif_creation_date_to_container = {
}

import_mappings = {
	ca_object_representations = {
		__default__ = {
			EXIF:IPTC:CopyrightNotice = {
				ca_object_representations.media_copyright
			},
			EXIF:IPTC:By-line = {
				ca_object_representations.media_author
			},
			EXIF:IPTC:Source = {
				ca_object_representations.media_source
			},
			EXIF:IFD0:Model = {
				ca_object_representations.media_model
			},
			EXIF:ExifIFD:ColorSpace = {
				ca_object_representations.media_color_space
			},
			EXIF:System:FileName = {
				preferred_labels.name
			},
			EXIF:System:FileSize = {
				ca_object_representations.media_file_size
			},
			EXIF:File:ImageWidth = {
				ca_object_representations.media_image_width
			},
			EXIF:File:ImageHeight = {
				ca_object_representations.media_image_height
			},
		}
	}
}

export_mappings = {
	ca_objects = {
		__default__ = {
			XMP:Title = {
				ca_objects.preferred_labels.name = {}
			},
			XMP:Description = {
				ca_objects.description = {}
			},
			
			XMP:Rights = {
				static:(c) 2011
			},
			XMP:Creator = {
				ca_entities.preferred_labels.displayname = {
					delimiter = ", "
				}
			},
			XMP:Subjects = {
				ca_list_items.preferred_labels.name_plural = {
					delimiter = ", "
				}
			}
		}
	}
}

[amergelCGI]

Your latest commit fixed my issue,
Thank you for the support!