Changeset 2564

Timestamp:

08/06/07 12:21:26 (12 years ago)

Author:

spascoe

Message:

Moved OWS parameter handling into the @operation decorator. Missing operation parameters are now trapped automatically.

Location:

TI05-delivery/ows_framework/trunk/ows_server/ows_server

Files:

• controllers/csml_wms.py (modified) (3 diffs)
• lib/base.py (modified) (2 diffs)
• lib/decorators.py (modified) (4 diffs)

TI05-delivery/ows_framework/trunk/ows_server/ows_server/controllers/csml_wms.py

@@ -26 +26 @@
         'ExceptionFormat': make_domain(['text/xml']),
         }
-
-    _ows_versions = ['1.1.0']
 
     #_ows_constraints = {
@@ -58 +56 @@
     @operation
     @parameter('Format', possibleValues=['text/xml'])
-    @parameter('Service', possibleValues=['WMS'])
+    @parameter('Service', possibleValues=['WMS'], required=True)
+    @parameter('Version', possibleValues=['1.1.0'])
     def GetCapabilities(self, file, service=None, version=None):
         """
@@ -65 +64 @@
 
         """
-
-        #!TODO: This error checking could be done automatically based on the method
-        #       decorators.
-        if service is None:
-            raise OWS_E.MissingParameterValue('SERVICE parameter not specified',
-                                              'SERVICE')
-        if service != 'WMS':
-            raise OWS_E.InvalidParameterValue('SERVICE parameter must be "WMS"',
-                                              'SERVICE')
-
-        #!TODO: Version negotiation could be done automatically
-        if version not in self._ows_versions:
-            raise OWS_E.InvalidParameterValue('VERSION parameter must be one of %s'
-                                              % ','.join(self._ows_versions),
-                                              'VERSION')
         
         c.dataset = get_csml_doc(file)

TI05-delivery/ows_framework/trunk/ows_server/ows_server/lib/base.py

@@ -32 +32 @@
         try:
             self._fix_ows_action(environ)
-            return WSGIController.__call__(self, environ, start_response)  
+            return super(OwsController, self).__call__(environ, start_response)
         except OWS_E.OwsError, e:
             return render_response('exception_report', report=e.report,
@@ -53 +53 @@
         del self.ows_params['request']
 
-    def _get_method_args(self):
-        """Extends Controller._get_method_args to retrieve arguments
-        from the query string.
+### This should be handled by the decorators now.
+##     def _get_method_args(self):
+##         """Extends Controller._get_method_args to retrieve arguments
+##         from the query string.
+    
+##         See the docstring for Controller._get_method_args for details.
 
-        See the docstring for Controller._get_method_args for details.
+##         """
 
-        """
+##         # Get the method arguments and add the query string arguments
+##         kargs = WSGIController._get_method_args(self)
+##         kargs.update(self.ows_params)
 
-        # Get the method arguments and add the query string arguments
-        kargs = WSGIController._get_method_args(self)
-        kargs.update(self.ows_params)
-
-        return kargs
+##         return kargs
 
     def _load_capabilities(self):

TI05-delivery/ows_framework/trunk/ows_server/ows_server/lib/decorators.py

@@ -11 +11 @@
 
 from ows_common.util import make_domain
+from ows_common.exceptions import * 
+import inspect
 
 def operation(method):
     """
-    A decorator which tags a method as a OWS operation.
-
-    """
-    method._ows_name = method.__name__
-
-    return method
+    A decorator which defines a method as a OWS operation.
+
+    The decorator assumes it is used in the context of an OwsController object with the
+    attribute self.ows_params available.
+
+
+    The method is wrapped in function that performs various OWS compatible checks:
+     1. Parameters from the request are checked against the methods _ows_parameters attribute
+        to ensure they conform to possibleValues.  Valid parameters are passed to the method
+        as arguments, invalid parameters trigger an exception.
+
+    @note: It would seem natural to implement this as a decorator class
+        but I can't make it work.
+
+    """
+
+    argspec = inspect.getargspec(method)
+
+    def wrapper(self, **kw):
+        """
+        This wrapper assumes invocation via GET with KVP encoding.  Future implementations
+        could detect POST and support XML encoding.
+
+        @param mself: The object of the method being called.
+        @param kw: All other keyword arguments are passed to the method.
+        
+        """
+
+        # Remove unwanted arguments from kw
+        if not argspec[2]:
+            kw2 = {}
+            for k, v in kw.iteritems():
+                if k in argspec[0]:
+                    kw2[k] = v
+            kw = kw2
+                    
+
+        # Add arguments to kw according to self._ows_parameters
+        for param in wrapper._ows_parameters:
+            try:
+                pl = param.lower()
+                kw[pl] = self.ows_params[pl]
+            except KeyError:
+                if param in wrapper._ows_required_parameters:
+                    raise MissingParameterValue('%s parameter is not specified' % param,
+                                                param)
+        return method(self, **kw)
+
+    # Propergate the OWS protocol attributes up to the wrapper
+    wrapper._ows_name = method.__name__
+    wrapper._ows_parameters = getattr(method, '_ows_parameters', {})
+    wrapper._ows_constraints = getattr(method, '_ows_constraints', {})
+    wrapper._ows_required_parameters = getattr(method, '_ows_required_parameters', [])        
+
+    return wrapper
+
 
 def parameter(name, value=None, possibleValues=None,
-              meaning=None, dataType=None, valuesUnit=None):
+              meaning=None, dataType=None, valuesUnit=None, required=False):
     """
     A decorator to add a parameter to an operation.
@@ -30 +82 @@
     @param possibleValues: None or a list of allowed values or a
         PossibleValues instance.
+    @param required: A boolean that indicates whether to raise an exception if the parameter
+       is missing.
     
     """
@@ -39 +93 @@
                                                  dataType=dataType,
                                                  valuesUnit=valuesUnit)
+        method._ows_required_parameters = getattr(method, '_ows_required_parameters', [])
+        if required:
+            method._ows_required_parameters.append(name)
+            
         return method
 
     return d
+
 
 def constraint(name, value=None, possibleValues=None,
@@ -115 +174 @@
                domain.possibleValues.ALLOWED_VALUES
         assert domain.possibleValues.allowedValues == [1,2,3]
+
+
+class TestOperationDecorator(TestCase):
+    def setUp(self):
+        class Foo(object):
+            @operation
+            @parameter('Bar', required=True)
+            def MyOp(self, bar):
+                return bar+1
+
+        self.foo = Foo()
+
+    def testOwsProtocol(self):
+        # Check OWS protocol is adhered to
+        assert self.foo.MyOp._ows_name == 'MyOp'
+        assert self.foo.MyOp._ows_parameters.keys() == ['Bar']
+        assert self.foo.MyOp._ows_constraints == {}
+        assert self.foo.MyOp._ows_required_parameters == ['Bar']
+
+    def testCall(self):
+        self.foo.ows_params = {'bar': 2}
+        assert self.foo.MyOp() == 3
+
+    def testCallFail(self):
+        self.foo.ows_params = {'baz': 2}
+        self.assertRaises(MissingParameterValue, self.foo.MyOp)