added ncmeta process with opendap (#54)

emu/processes/__init__.py

@@ -13,6 +13,7 @@
 from .wps_esgf import ESGFDemo
 from .wps_output_formats import OutputFormats
 from .wps_poly_centroid import PolyCentroid
+from .wps_ncmeta import NCMeta
 
 processes = [
     UltimateQuestion(),
@@ -30,4 +31,5 @@
     ESGFDemo(),
     OutputFormats(),
     PolyCentroid(),
+    NCMeta(),
 ]

emu/processes/wps_ncmeta.py

@@ -0,0 +1,64 @@
+import os
+
+from pywps import Process
+from pywps import ComplexInput, ComplexOutput, FORMATS, Format
+from pywps.validator.mode import MODE
+from pywps.app.Common import Metadata
+
+import logging
+LOGGER = logging.getLogger("PYWPS")
+
+FORMAT_OPENDAP = Format('application/x-ogc-dods')
+
+
+class NCMeta(Process):
+    """
+    Notes
+    -----
+
+    Returns metadata of a NetCDF file or OpenDAP resource.
+    """
+    def __init__(self):
+        inputs = [
+            ComplexInput('dataset', 'Dataset',
+                         supported_formats=[FORMATS.NETCDF],
+                         min_occurs=0,
+                         mode=MODE.NONE),
+            ComplexInput('dataset_opendap', 'Dataset OpenDAP',
+                         supported_formats=[FORMAT_OPENDAP],
+                         min_occurs=0,
+                         mode=MODE.NONE),
+        ]
+        outputs = [
+            ComplexOutput('output', 'Metadata',
+                          as_reference=True,
+                          supported_formats=[FORMATS.TEXT]), ]
+
+        super(NCMeta, self).__init__(
+            self._handler,
+            identifier='ncmeta',
+            title='Show NetCDF Metadata',
+            version='4',
+            metadata=[
+                Metadata('User Guide', 'http://emu.readthedocs.io/en/latest/'),
+            ],
+            inputs=inputs,
+            outputs=outputs,
+            store_supported=True,
+            status_supported=True)
+
+    def _handler(self, request, response):
+        from netCDF4 import Dataset
+        if 'dataset_opendap' in request.inputs:
+            inpt = request.inputs['dataset_opendap'][0]
+            ds = Dataset(inpt.url)
+        else:
+            inpt = request.inputs['dataset'][0]
+            ds = Dataset(inpt.file)
+        with open(os.path.join(self.workdir, 'out.txt'), "w") as fp:
+            response.outputs['output'].file = fp.name
+            fp.write("URL: {}\n\n".format(inpt.url))
+            fp.write("MIME Type: {}\n\n".format(inpt.data_format.mime_type))
+            for attr in ds.ncattrs():
+                fp.write("{}: {}\n\n".format(attr, ds.getncattr(attr)))
+        return response

environment.yml

@@ -4,12 +4,14 @@ channels:
 - conda-forge
 - defaults
 dependencies:
-- pywps=4.1.6
+- pywps=4.1.7
 - jinja2
 - click
 - psutil
 - birdhouse-eggshell=0.3
 - libiconv
 - defusedxml
+# opendap support
+- netcdf4
 # tests
 - pytest-flake8

tests/test_wps_caps.py

@@ -21,11 +21,11 @@ def test_wps_caps():
         'inout',
         'multiple_outputs',
         'nap',
+        'ncmeta',
         'output_formats',
         'poly_centroid',
         'show_error',
         'sleep',
         'ultimate_question',
         'wordcounter',
-
     ]

tests/test_wps_ncmeta.py

@@ -0,0 +1,20 @@
+import pytest
+
+from pywps import Service
+from pywps.tests import assert_response_success
+
+from .common import client_for
+from emu.processes.wps_ncmeta import NCMeta
+
+OPENDAP_URL = 'http://www.esrl.noaa.gov/psd/thredds/dodsC/Datasets/ncep.reanalysis.derived/surface/air.mon.ltm.nc'
+
+
+@pytest.mark.online
+def test_wps_ncmeta_opendap():
+    client = client_for(Service(processes=[NCMeta()]))
+    datainputs = "dataset_opendap=@xlink:href={0}".format(OPENDAP_URL)
+    resp = client.get(
+        service='wps', request='execute', version='1.0.0',
+        identifier='ncmeta',
+        datainputs=datainputs)
+    assert_response_success(resp)