ENH: handler for hdf5 files that have variable frames per point

area_detector_handlers/handlers.py

@@ -21,6 +21,67 @@ class IntegrityError(Exception):
     pass
 
 
+class HDF5VariableFramesHandler(HandlerBase):
+    """
+    Handler for data stored in one Dataset of an HDF5 file.
+
+    Parameters
+    ----------
+    filename : string
+        path to HDF5 file
+    swmr : bool, optional
+        Open the hdf5 file in SWMR read mode. Only used when mode = 'r'.
+        Default is False.
+    """
+
+    specs = {"AD_HDF5_v1"} | HandlerBase.specs
+
+    def __init__(self, filename):
+        self._filename = filename
+        self._key = "/entry/data/data"
+        self._file = None
+        self._dataset = None
+        self._open()
+
+    def get_file_list(self, datum_kwarg_gen):
+        return [self._filename]
+
+    def __call__(self, offset, num_frames):
+        return self._dataset[offset: offset + num_frames]
+
+    def _open(self):
+        if self._file:
+            return
+
+        self._file = h5py.File(self._filename, "r")
+        self._dataset = self._file[self._key]
+
+    def close(self):
+        super().close()
+        self._dataset = None
+        self._file.close()
+        self._file = None
+
+
+class HDF5VariableFramesHandlerTS(HDF5VariableFramesHandler):
+    specs = {"AD_HDF5_TS_v1"} | HandlerBase.specs
+
+    def _open(self):
+        if self._file:
+            return
+
+        self._file = h5py.File(self._filename, "r")
+        self._dataset1 = self._file["/entry/instrument/NDAttributes/NDArrayEpicsTSSec"]
+        self._dataset2 = self._file["/entry/instrument/NDAttributes/NDArrayEpicsTSnSec"]
+
+    def __call__(self, offset, num_frames):
+        # Don't read out the dataset until it is requested for the first time.
+        start, stop = offset, offset + num_frames
+        rtn = self._dataset1[start:stop].squeeze()
+        rtn = rtn + (self._dataset2[start:stop].squeeze() * 1e-9)
+        return rtn
+
+
 class AreaDetectorSPEHandler(HandlerBase):
     specs = {"AD_SPE"} | HandlerBase.specs
 

setup.py

@@ -52,8 +52,10 @@
             "AD_EIGER2 = area_detector_handlers.eiger:EigerHandler",
             "AD_EIGER_SLICE = area_detector_handlers.eiger:EigerHandler",
             "AD_HDF5 = area_detector_handlers.handlers:AreaDetectorHDF5Handler",
+            "AD_HDF5_v1 = area_detector_handlers.handlers:HDF5VariableFramesHandler",
             "AD_HDF5_SWMR = area_detector_handlers.handlers:AreaDetectorHDF5SWMRHandler",
             "AD_HDF5_TS = area_detector_handlers.handlers:AreaDetectorHDF5TimestampHandler",
+            "AD_HDF5_TS_v1 = area_detector_handlers.handlers:HDF5VariableFramesHandlerTS",
             "AD_HDF5_SWMR_TS = area_detector_handlers.handlers:AreaDetectorHDF5SWMRTimestampHandler",
             "AD_HDF5_SINGLE = area_detector_handlers.handlers:AreaDetectorHDF5SingleHandler",
             "SPECS_HDF5_SINGLE_DATAFRAME = area_detector_handlers.handlers:SpecsHDF5SingleHandlerDataFrame",