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- WebKit.Object.Object(__builtin__.object, MiscUtils.NamedValueAccess.NamedValueAccess)
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- PlugIn
- exceptions.Exception
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- PlugInError
class PlugIn(WebKit.Object.Object) |
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Template for Webware Plug-ins.
A plug-in is a software component that is loaded by WebKit in order to
provide additional WebKit functionality without necessarily having to modify
WebKit's source. The most infamous plug-in is PSP (Python Server Pages)
which ships with Webware.
Plug-ins often provide additional servlet factories, servlet subclasses,
examples and documentation. Ultimately, it is the plug-in author's choice
as to what to provide and in what manner.
Instances of this class represent plug-ins which are ultimately Python
packages (see the Python Tutorial, 6.4: "Packages" at
http://www.python.org/doc/current/tut/node8.html#SECTION008400000000000000000).
A plug-in must also be a Webware component which at means that it will have
a Properties.py file advertising its name, version, requirements, etc.
You can ask a plug-in for its properties().
The plug-in/package must have an __init__.py while must contain a function:
def InstallInWebKit(appServer):
This function is invoked to take whatever actions are needed to plug the
new component into WebKit. See PSP for an example.
If you ask an AppServer for its plugIns(), you will get a list of instances
of this class.
The path of the plug-in is added to sys.path, if it's not already there.
This is convenient, but we may need a more sophisticated solution in the
future to avoid name collisions between plug-ins.
Note that this class is hardly ever subclassed. The software in the
plug-in package is what provides new functionality and there is currently
no way to tell AppServer to use custom subclasses of this class on a
case-by-case basis (and so far there is currently no need).
Instructions for invoking:
p = PlugIn(self, '../Foo') # 'self' is typically AppServer. It gets passed to InstallInWebKit()
willNotLoadReason = plugIn.load()
if willNotLoadReason:
print ' Plug-in %s cannot be loaded because:
%s' % (path, willNotLoadReason)
return None
p.install()
# Note that load() and install() could raise exceptions. You should expect this. |
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- Method resolution order:
- PlugIn
- WebKit.Object.Object
- __builtin__.object
- MiscUtils.NamedValueAccess.NamedValueAccess
Methods defined here:
- __init__(self, appServer, path)
- Initializes the plug-in with basic information.
This lightweight constructor does not access the file system.
- directory(self)
- Return the directory in which the plug-in resides. Example: '..'
- examplePages(self)
- examplePagesContext(self)
- hasExamplePages(self)
- install(self)
- Installs the plug-in by invoking it's required InstallInWebKit() function.
- load(self)
- Loads the plug-in into memory, but does not yet install it.
Will return None on success, otherwise a message (string) that says
why the plug-in could not be loaded.
- module(self)
- Return the Python module object of the plug-in.
- name(self)
- Return the name of the plug-in. Example: 'Foo'
- path(self)
- Return the full path of the plug-in. Example: '../Foo'
- properties(self)
- Return the properties.
This is a dictionary-like object, of the plug-in which comes
from its Properties.py file. See MiscUtils.PropertiesObject.py.
- serverSidePath(self, path=None)
- setUpExamplePages(self)
Methods inherited from WebKit.Object.Object:
- deprecated(self, method)
- Output a deprecation warning.
The implementation of WebKit sometimes invokes this method which prints
a warning that the method you are using has been deprecated.
This method expects that deprecated methods say so at the beginning of
their doc string and terminate that msg with @. For example:
DEPRECATED: Class.foo() on 01/24/01 in ver 0.5. Use Class.bar() instead. @
Putting this information in the doc string is important for accuracy
in the generated docs.
Example call:
deprecated(self.foo)
Data and other attributes inherited from WebKit.Object.Object:
- __dict__ = <dictproxy object>
- dictionary for instance variables (if defined)
- __weakref__ = <attribute '__weakref__' of 'Object' objects>
- list of weak references to the object (if defined)
Methods inherited from MiscUtils.NamedValueAccess.NamedValueAccess:
- hasValueForKey(self, key)
- Returns true if the key is available, although that does not
guarantee that there will not be errors caused by retrieving the key.
- hasValueForName(self, keysString)
- resetKeyBindings(self)
- setValueForKey(self, key, value)
- Suppose key is 'foo'. This method sets the value with the following precedence:
1. Public attributes before private attributes
2. Methods before non-methods
More specifically, this method then uses one of the following:
@@ 2000-03-04 ce: fill in
...or invokes handleUnknownSetKey().
- valueForKey(self, key, default=<class MiscUtils.NoDefault>)
- Suppose key is 'foo'. This method returns the value with the following precedence:
1. Methods before non-methods
2. Public attributes before private attributes
More specifically, this method then returns one of the following:
* foo()
* _foo()
* self.foo
* self._foo
...or default, if it was specified,
otherwise invokes and returns result of valueForUnknownKey().
Note that valueForUnknownKey(), normally returns an exception.
See valueForName() which is a more advanced version of this method that allows
multiple, qualified keys.
- valueForKeySequence(self, listOfKeys, default=None)
- valueForName(self, keysString, default=None)
- Returns the value for the given keysString. This is the more advanced version of
valueForKey(), which can only handle single names. This method can handle
'foo', 'foo1.foo2', 'a.b.c.d', etc. It will traverse dictionaries if needed.
- valueForUnknownKey(self, key, default)
- # Errors
- valuesForNames(self, keys, default=None, defaults=None, forgive=0, includeNames=0)
- Returns a list of values that match the given keys, each of which is passed
through valueForName() and so could be of the form 'a.b.c'.
keys is a sequence. default is any kind of object. defaults is a sequence.
forgive and includeNames is a flag.
If default is not None, then it is substituted when a key is not found.
Otherwise, if defaults is not None, then it's corresponding/parallel value
for the current key is substituted when a key is not found.
Otherwise, if forgive=1, then unknown keys simply don't produce any values.
Otherwise, if default and defaults are None, and forgive=0, then the unknown
keys will probably raise an exception through valueForUnknownKey() although
that method can always return a final, default value.
if keys is None, then None is returned. If keys is an empty list, then None
is returned.
Often these last four arguments are specified by key.
Examples:
names = ['origin.x', 'origin.y', 'size.width', 'size.height']
obj.valuesForNames(names)
obj.valuesForNames(names, default=0.0)
obj.valuesForNames(names, defaults=[0.0, 0.0, 100.0, 100.0])
obj.valuesForNames(names, forgive=0)
@@ 2000-03-04 ce: includeNames is only supported when forgive=1.
It should be supported for the other cases.
It should be documented.
It should be included in the test cases.
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