Common MIME types are not recognized

[clnsmth]

EMLassemblyline assign a value to /element(*,PhysicalType)/dataFormat/externallyDefinedFormat/formatName based on mime::guess_type() (see code). This function maps the data entity's file extension to a MIME type. However, this map is missing several common file extensions (e.g. .bz2 = application/x-bzip2) thus returning a value of "Unknown".

A potential solution here is to extend the list of MIME types recognized by mime::guess_type() using the mime_extra parameter, which can reference a curated list of other MIME types.

However, do note:

• EDI best practices for EML recommends use of DataONE's object format list when assigning values to the formatName element.
• EDI best practices for EML also recommends the use of MIME type for values of the entityType element.
• After a quick browse through the EML schema and associated documentation, it is unclear where a MIME type value should go, if at all.