add rio_tiler.io.MultiBandReader bands dependencies (#226)

CHANGES.md

@@ -10,6 +10,7 @@
 * deleted `titiler.models.mosaics` because the models are not used anymore (https://github.com/developmentseed/titiler/pull/221)
 * update rio-tiler and cogeo-mosaic minimal versions (https://github.com/developmentseed/titiler/pull/220, https://github.com/developmentseed/titiler/pull/213)
 * move STAC related dependencies to `titiler.dependencies (https://github.com/developmentseed/titiler/pull/225)
+* add `rio_tiler.io.MultiBandReader` bands dependencies (https://github.com/developmentseed/titiler/pull/226)
 
 ## 0.1.0a14 (2021-01-05)
 

titiler/dependencies.py

@@ -176,6 +176,41 @@ def __post_init__(self):
             )
 
 
+# Dependencies for  MultiBandReader
+@dataclass
+class BandsParams(DefaultDependency):
+    """Band names parameters."""
+
+    bands: str = Query(
+        ..., title="bands names", description="comma (',') delimited bands names.",
+    )
+
+    def __post_init__(self):
+        """Post Init."""
+        self.kwargs["bands"] = self.bands.split(",")
+
+
+@dataclass
+class BandsExprParams(DefaultDependency):
+    """Band names and Expression parameters."""
+
+    bands: Optional[str] = Query(
+        None, title="bands names", description="comma (',') delimited bands names.",
+    )
+    expression: Optional[str] = Query(
+        None,
+        title="Band Math expression",
+        description="rio-tiler's band math expression.",
+    )
+
+    def __post_init__(self):
+        """Post Init."""
+        if self.bands is not None:
+            self.kwargs["bands"] = self.bands.split(",")
+        if self.expression is not None:
+            self.kwargs["expression"] = self.expression
+
+
 @dataclass
 class MetadataParams(DefaultDependency):
     """Common Metadada parameters."""