Mirror API

The Mirror API is responsible for mapping file requests to a URL, local filename, file-like object, or something that can construct a NetCDF Dataset. These are usually constructred using argopandas.url_mirror() and/or argopandas.file_mirror().

class Mirror

The Mirror class is the abstract base class for other mirror types. You can define your own subclass and use it in the main API if you have a non-standard mapping of files and would like to use features of the package-level API.

Parameters

path – A path to a file on the GDAC (e.g., /dac/csio/1234/1234_meta.nc)

filename(path) → str

Get a filename for this path. The filename is not guaranteed to exist unless prepare() is called first.

netcdf_dataset_src(path)

Return the best available input to argopandas.netcdf.NetCDFWrapper.

open(path) → BinaryIO

Get a file-like object for this path.

prepare(path_iter)

Prepare the mirror for loading all the paths in path_iter (e.g., by downloading them).

Parameters

path_iter – An iterable of path s.

url(path)

Return the URL to path without checking if it exists.

class CachedUrlMirror(root, cache_dir=None)

This is the most common mirror, which uses a cache to avoid unnecessarily downloading the same file more than once. By default the cache will reset when the session is restarted; however, you can set a persistent cache using cache_dir.

__init__(root, cache_dir=None)
Parameters

  • root – The URL of the base directory. This can be anything supported by urllib.request.urlopen.

  • cache_dir – The path to the local persistent cache or None to use a temporary directory.

class FileMirror(root)

The FileMirror maps a root directory on a filesystem. This is useful if you have a local copy of Argo downloaded via rsync or via a stable DOI version of the GDAC. This can also be a partial copy if you have a few files you need to access frequently.

__init__(root)
Parameters

root – The root directory containing the files.

class UrlMirror(root)

The UrlMirror is a cache-less mirror that only uses URL connections. You probably want the CachedUrlMirror unless you are doing real-time work that might be affected by an out-of-date cache. Note that filename() is not supported by the UrlMirror (use open() instead).

__init__(root)
Parameters

root – The URL of the base directory. This can be anything supported by urllib.request.urlopen.