def resolve_data_element(self, uri):
"""
Given the URI to some data, resolve it down to a DataElement instance.
:raises ValueError: Issue with the given URI regarding either URI source
resolution or data resolution.
:param uri: URI to data
:type uri: str
:return: DataElement instance wrapping given URI to data.
:rtype: smqtk.data_rep.DataElement
"""
# Resolve URI into appropriate DataElement instance
if uri[:7] == "file://":
self.log.debug("Given local disk filepath")
filepath = uri[7:]
if not os.path.isfile(filepath):
raise ValueError("File URI did not point to an existing file "
"on disk.")
else:
de = DataFileElement(filepath)
elif uri[:9] == "base64://":
self.log.debug("Given base64 string")
content_type = flask.request.args.get('content_type', None)
self.log.debug("Content type: %s", content_type)
if not content_type:
raise ValueError("No content-type with given base64 data")
else:
b64str = uri[9:]
de = DataMemoryElement.from_base64(b64str, content_type)
else:
self.log.debug("Given URL")
try:
de = DataUrlElement(uri)
except requests.HTTPError, ex:
raise ValueError("Failed to initialize URL element due to "
"HTTPError: %s" % str(ex))
def compute_descriptor(descriptor_label, uri):
"""
# Data modes for upload/use
- local filepath
- base64
- http/s URL
The following sub-sections detail how different URI's can be used.
## Local Filepath
The URI string must be prefixed with ``file://``, followed by the
full path to the data file to describe.
## Base 64 data
The URI string must be prefixed with "base64://", followed by the
base64 encoded string. This mode also requires an additional
``?content_type=`` to provide data content type information. This
mode saves the encoded data to temporary file for processing.
## HTTP/S address
This is the default mode when the URI prefix is none of the above.
This uses the requests module to locally download a data file
for processing.
"""
success = True
message = "Nothing has happened yet"
# Data element to compute a descriptor for
de = None
# Resolve URI into DataElement instance
if uri[:7] == "file://":
self.log.debug("Given local disk filepath")
filepath = uri[7:]
if not os.path.isfile(filepath):
success = False
message = "File URI did not point to an existing file on " \
"disk."
else:
de = DataFileElement(filepath)
elif uri[:9] == "base64://":
self.log.debug("Given base64 string")
content_type = flask.request.args.get('content_type', None)
self.log.debug("Content type: %s", content_type)
if not content_type:
self.log.warning("No content-type with given base64 data")
success = False
message = "No content-type with given base64 content."
else:
b64str = uri[9:]
de = DataMemoryElement.from_base64(b64str, content_type)
else:
self.log.debug("Given URL")
de = DataUrlElement(uri)
descriptor = None
if success: # so far...
# Get the descriptor instance for the given label, creating it
# if necessary.
if descriptor_label not in descriptor_cache:
self.log.debug("Creating descriptor '%s'", descriptor_label)
with descriptor_cache_lock:
descriptor_cache[descriptor_label] = \
ContentDescriptorConfiguration\
.new_inst(descriptor_label)
with descriptor_cache_lock:
#: :type: smqtk.content_description.ContentDescriptor
d = descriptor_cache[descriptor_label]
with SimpleTimer("Computing descriptor...", self.log.debug):
try:
descriptor = d.compute_descriptor(de).tolist()
message = "Descriptor computed of type '%s'" \
% descriptor_label
except ValueError, ex:
success = False
message = "Descriptor '%s' had an issue with the input " \
"data: %s" \
% (descriptor_label, str(ex))
