surface `asset_expression` in MultiBaseTilerFactory (STAC)

[vincentsarago]

https://github.com/cogeotiff/rio-tiler/blob/master/rio_tiler/io/base.py#L458-L460

For this we'll need to update

titiler/src/titiler/core/titiler/core/dependencies.py

Lines 128 to 180 in d1f4f41

	# Dependencies for MultiBaseReader (e.g STACReader)
	@dataclass
	class AssetsBidxParams(DefaultDependency):
	"""Asset and Band indexes parameters."""
	assets: Optional[str] = Query(
	..., title="Asset indexes", description="comma (',') delimited asset names.",
	)
	bidx: Optional[str] = Query(
	None, title="Band indexes", description="comma (',') delimited band indexes",
	)
	def __post_init__(self):
	"""Post Init."""
	if self.assets is not None:
	self.kwargs["assets"] = self.assets.split(",")
	if self.bidx is not None:
	self.kwargs["indexes"] = tuple(
	int(s) for s in re.findall(r"\d+", self.bidx)
	)
	@dataclass
	class AssetsBidxExprParams(DefaultDependency):
	"""Assets, Band Indexes and Expression parameters."""
	assets: Optional[str] = Query(
	None, title="Asset indexes", description="comma (',') delimited asset names.",
	)
	expression: Optional[str] = Query(
	None,
	title="Band Math expression",
	description="rio-tiler's band math expression (e.g B1/B2)",
	)
	bidx: Optional[str] = Query(
	None, title="Band indexes", description="comma (',') delimited band indexes",
	)
	def __post_init__(self):
	"""Post Init."""
	if not self.assets and not self.expression:
	raise MissingAssets(
	"assets must be defined either via expression or assets options."
	)
	if self.assets is not None:
	self.kwargs["assets"] = self.assets.split(",")
	if self.expression is not None:
	self.kwargs["expression"] = self.expression
	if self.bidx is not None:
	self.kwargs["indexes"] = tuple(
	int(s) for s in re.findall(r"\d+", self.bidx)
	)