datasette.urls.table(..., format="json") argument

[simonw]

That datasette.urls.table("db", "table") + ".json" example is bad because if the table name contains a . it should be ?_format=json instead.

Maybe .table() should have a format="json" option that knows how to do this.

Originally posted by @simonw in #1026 (comment)

[simonw]

Relevant code:

datasette/datasette/utils/__init__.py

Lines 681 to 696 in 091441a

	def path_with_format(request, format, extra_qs=None):
	qs = extra_qs or {}
	path = request.path
	if "." in request.path:
	qs["_format"] = format
	else:
	path = "{}.{}".format(path, format)
	if qs:
	extra = urllib.parse.urlencode(sorted(qs.items()))
	if request.query_string:
	path = "{}?{}&{}".format(path, request.query_string, extra)
	else:
	path = "{}?{}".format(path, extra)
	elif request.query_string:
	path = "{}?{}".format(path, request.query_string)
	return path

Only used here:

datasette/datasette/views/base.py

Lines 498 to 502 in 091441a

	it_can_render = await await_me_maybe(it_can_render)
	if it_can_render:
	renderers[key] = path_with_format(
	request, key, {**url_labels_extra}
	)

[simonw]

That renderers[key] = path_with_format( is in a base class which can be used for both arbitrary queries, canned queries and the table view. I think that's OK, but it means that the format="json" argument on datasette.urls.table() won't be used by Datasette internally, it will just be available for plugins.

[simonw]

Makes me question if datasette.urls should grow functionality equivalent to the other path and querystring manipulation methods in datasette.utils:

datasette/datasette/utils/__init__.py

Lines 216 to 279 in 66120a7

	def append_querystring(url, querystring):
	op = "&" if ("?" in url) else "?"
	return "{}{}{}".format(url, op, querystring)
	def path_with_added_args(request, args, path=None):
	path = path or request.path
	if isinstance(args, dict):
	args = args.items()
	args_to_remove = {k for k, v in args if v is None}
	current = []
	for key, value in urllib.parse.parse_qsl(request.query_string):
	if key not in args_to_remove:
	current.append((key, value))
	current.extend([(key, value) for key, value in args if value is not None])
	query_string = urllib.parse.urlencode(current)
	if query_string:
	query_string = "?{}".format(query_string)
	return path + query_string
	def path_with_removed_args(request, args, path=None):
	query_string = request.query_string
	if path is None:
	path = request.path
	else:
	if "?" in path:
	bits = path.split("?", 1)
	path, query_string = bits
	# args can be a dict or a set
	current = []
	if isinstance(args, set):
	def should_remove(key, value):
	return key in args
	elif isinstance(args, dict):
	# Must match key AND value
	def should_remove(key, value):
	return args.get(key) == value
	for key, value in urllib.parse.parse_qsl(query_string):
	if not should_remove(key, value):
	current.append((key, value))
	query_string = urllib.parse.urlencode(current)
	if query_string:
	query_string = "?{}".format(query_string)
	return path + query_string
	def path_with_replaced_args(request, args, path=None):
	path = path or request.path
	if isinstance(args, dict):
	args = args.items()
	keys_to_replace = {p[0] for p in args}
	current = []
	for key, value in urllib.parse.parse_qsl(request.query_string):
	if key not in keys_to_replace:
	current.append((key, value))
	current.extend([p for p in args if p[1] is not None])
	query_string = urllib.parse.urlencode(current)
	if query_string:
	query_string = "?{}".format(query_string)
	return path + query_string