gridftp

Hello,

We are trying to use a small subset of CMIP6 data from ESGF server.
They expose their NetCDF files in different ways

from pyesgf.search import SearchConnection
server='https://esgf-data.dkrz.de/esg-search'
conn = SearchConnection(server, distrib=True)
source_id='CMCC-CM2-HR4'
activity_id='OMIP'
experiment_id='omip2'
variable_id='vmo'
ctx = conn.new_context(
    project='CMIP6',
    source_id=source_id,
    experiment_id=experiment_id,
    variable=variable_id,
    frequency='mon',
)
result = ctx.search()[0]
files = result.file_context().search()
files[35].urls

Which gives

defaultdict(list,
            {'HTTPServer': [('http://esgf-node2.cmcc.it/thredds/fileServer/esg_dataroot/CMIP6/OMIP/CMCC/CMCC-CM2-HR4/omip2/r1i1p1f1/Omon/vmo/gn/v20200226/vmo_Omon_CMCC-CM2-HR4_omip2_r1i1p1f1_gn_200801-201812.nc',
               'application/netcdf')],
             'GridFTP': [('gsiftp://esgf-node2.cmcc.it:2811//esg_dataroot/CMIP6/OMIP/CMCC/CMCC-CM2-HR4/omip2/r1i1p1f1/Omon/vmo/gn/v20200226/vmo_Omon_CMCC-CM2-HR4_omip2_r1i1p1f1_gn_200801-201812.nc',
               'application/gridftp')],
             'OPENDAP': [('http://esgf-node2.cmcc.it/thredds/dodsC/esg_dataroot/CMIP6/OMIP/CMCC/CMCC-CM2-HR4/omip2/r1i1p1f1/Omon/vmo/gn/v20200226/vmo_Omon_CMCC-CM2-HR4_omip2_r1i1p1f1_gn_200801-201812.nc.html',
               'application/opendap-html')],
             'Globus': [('globus:4101e3a0-b7df-11eb-a16a-5fad80e6400b/esg_dataroot/CMIP6/OMIP/CMCC/CMCC-CM2-HR4/omip2/r1i1p1f1/Omon/vmo/gn/v20200226/vmo_Omon_CMCC-CM2-HR4_omip2_r1i1p1f1_gn_200801-201812.nc',
               'Globus')]})

We just need small subset of netcdf file, and I would like to make kerchunk catalogue of it. I can use the HTTPServer link to transform it to kerchunk catalogue, but just out of curiosity, can it also handle 'ftp' or 'open dap' or 'gridftp' ?

Start with the pyesgf SearchConnection example in the issue and reproduce the result.file_context().search() output, including the HTTPServer, OPENDAP, GridFTP, and Globus URLs. Review kerchunk's existing URL and protocol handling to determine which forms are supported and what work would be needed for the others; done means a confirmed support status with tests or documented limitations.