py2store.my.grabbers

Grabbers: fetch an object from a key (a path or URL) and post-process it by kind.

A grabber is py2store.misc.get_obj with optional key and value transformations. The 'ipython' grabber turns image, WAV audio and HTML bytes into the matching IPython display objects, so that grabbing a file in a notebook shows it.

Main entry points:

• mk_grabber: build a grabber from key_trans and val_trans functions

• grabber_for: the ready-made grabbers by name ('ipython')

• ipython_display_val_trans: the value transformation behind the 'ipython' grabber

Functions

fullpath(path)	The absolute path of path, with a leading ~ expanded.
grabber_for(kind)	The ready-made grabber named kind: 'ipython' gives mk_grabber(val_trans=ipython_display_val_trans).
ipython_display_val_trans(val[, key])	Wrap val (bytes) in an IPython display object by content: Image for image data, Audio for WAV data, HTML for HTML (by the key's extension when key is a string longer than 4 characters, else by a <!DOCTYPE html> start); anything else is returned unchanged.
mk_grabber(*[, key_trans, val_trans])	Make a function that fetches an object with get_obj, with optional pre- and post-processing.

py2store.my.grabbers.fullpath(path)

The absolute path of path, with a leading ~ expanded.

py2store.my.grabbers.grabber_for(kind)

The ready-made grabber named kind: 'ipython' gives mk_grabber(val_trans=ipython_display_val_trans).

Raises:

ValueError – If kind is not a known grabber name.

py2store.my.grabbers.ipython_display_val_trans(val, key=None)

Wrap val (bytes) in an IPython display object by content: Image for image data, Audio for WAV data, HTML for HTML (by the key’s extension when key is a string longer than 4 characters, else by a <!DOCTYPE html> start); anything else is returned unchanged.

Requires IPython, and uses the imghdr module to detect images.

py2store.my.grabbers.mk_grabber(*, key_trans=None, val_trans=None)

Make a function that fetches an object with get_obj, with optional pre- and post-processing.

Parameters:

• key_trans – Applied to the key before fetching (to strip whitespace or expand a path, say).

• val_trans – Applied as val_trans(value, key) to the fetched object before it is returned.

Returns:

A function grab(k, *args, **kwargs) that forwards *args and **kwargs to get_obj.

>>> import os, tempfile
>>> path = os.path.join(tempfile.mkdtemp(), 'hello.txt')
>>> _ = open(path, 'w').write('world')
>>> grab = mk_grabber(key_trans=str.strip, val_trans=lambda v, k: v.upper())
>>> grab(' ' + path + ' ')
'WORLD'