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version 1344, Sun Aug 17 03:48:31 2003 UTC version 2029, Sun Apr 3 16:01:31 2005 UTC
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 Fixes and Enhancements since Version 0.5 alpha 2  Fixes and Enhancements since Version 0.5 alpha 3
   
  Changed, Enhanced, or Newly Deprecated Features   - Changed 'running.lookupCommand()' to use the command's 'getCommandParent()'
      method, so that commands using the '--config' option will utilize the
      specified configuration(s) to lookup subcommands.
   
    - Added a '-c/--config' option to PEAK bootstrap commands to load an .ini
      configuration file in a new service area before executing any subcommands.
   
      This allows you to do things like::
   
           peak launch -c bulletins ref:sitemap@sitemap.xml
   
      which loads the 'bulletins' configuration file before launching the sitemap.
      Note that if you are subclassing 'commands.Bootstrap' you can suppress this
      option using 'options.reject_inheritance("-c","--config")' in the body of
      your subclass' class definition.  You may wish to do this if your
      application's subcommands must run in the same service area as the parent
      command.  (E.g. if the parent command expects the subcommand to partake in
      a transaction controlled by the parent command.)
   
    - Added a 'value' property to 'model.Enumeration', so that you can access
      an enumeration instance's value (i.e., the value it hashes and compares
      equal to)
   
    - Added a 'binding.hasParent(component,parent)' API function, which is
      specially optimized for use with generic functions, so that you can
      define generic function methods that apply only within some part of a
      component hierarchy.
   
    - PEAK no longer supports Python 2.2; Python 2.3.4 or better is required.
   
    - The kjbuckets extension module is no longer built and installed by default;
      you must explicitly enable it with a '--with-kjbuckets' flag passed to
      'setup.py'.  Please port your code as soon as practical, this option will
      go away soon.
   
    - Use of the included 'kjbuckets' module is now DEPRECATED, due to increasing
      bitrot.  Aaron Watters originally wrote this extension for Python 1.2, and
      it has not been well-maintained for newer versions of the Python/C API.
      Instead of 'kjSet' objects, use the Python 2.3 'Set' type, and instead of
      the 'kjGraph' type, use the new 'Graph' type in 'peak.util.Graph'.  Some
      porting effort may be required, as these types are not precisely the same
      in signature as the originals.
   
    - The '_setNS()' method of the 'peak.util.SOX.ISOXNode_NS' interface has
      changed signature, due to a lack of use of the second argument in the code
      base, and its dependency on 'kjbuckets'.
   
    - The old 'peak.security' implementation has been removed, and replaced with
      a simpler, more flexible implementation based on generic functions (using
      less than half the code and seven fewer interfaces).  Complete documentation
      and API tests for the new implementation can be found in 'rules.txt' in the
      'peak.security' package directory.
   
      Also, the new implemetation does not require redundant
      'security.allow(security.Anybody)' declarations just because you've declared
      other permissions for a class, so these declarations have been removed from
      ``peak.web``.  They don't do any harm, however, so you can leave them in
      your own code as long as you change them to use 'binding.metadata()' instead
      of the deprecated 'security.allow()'.
   
    - 'security.allow()' is now DEPRECATED; please use 'binding.metadata()'
      instead.  (There is no change to the calling signature, but
      'binding.metadata' accepts any metadata, not just permissions.)
   
    - Added 'peak.running.options', a new option-parsing framework that extends
      'optparse' to support the PEAK 'commands' framework.  Command instances
      can now refer to 'self.parsed_args' to find their non-option arguments,
      and to trigger setting of their attributes (or calling of methods) based on
      their raw arguments from 'self.argv'.  See 'options.txt' in the
      'peak.running' package directory for a complete tutorial.
   
    - There is now a 'binding.initAttrs()' function that can be used to initialize
      an object's attributes from e.g. constructor keyword arguments, similar to
      how 'binding.Component' and 'binding.Attribute' constructors work.
   
    - Security permissions can now be declared as attribute metadata.
   
      That is, instead of doing declarations like this::
   
           class Foo:
               bar = binding.Require("Something", permissionNeeded=SomePerm)
   
           class AnElement(model.Element):
               class someFeature(model.Attribute):
                   permissionNeeded = SomePerm
   
      you can (and should) now do them like this::
   
           class Foo:
               bar = binding.Require("Something", [SomePerm])
   
           class AnElement(model.Element):
               class someFeature(model.Attribute):
                   metadata = [SomePerm]
   
      or this::
   
           class Foo:
               binding.metadata(bar = [SomePerm])
   
           class AnElement(model.Element):
   
               binding.metadata(someFeature = [SomePerm])
   
               class someFeature(model.Attribute):
                   # ...
   
      It isn't necessary to enclose metadata in brackets, but it helps to
      emphasize its annotational nature.  Also note that e.g. 'web.bindResource()'
      needs 'metadata' to be a keyword argument.
   
    - The 'permissionNeeded' attribute of 'model.Feature' and 'binding.Attribute'
      objects is now DEPRECATED.  See examples above for how to upgrade, and please
      switch to using metadata as soon as practical.  In addition the
      'security.IGuardedDescriptor' interface has been removed, because it was
      only used in connection with the 'permissionNeeded' attribute mechanism.
   
    - Added a new "attribute metadata" mini-framework to 'peak.binding'.  This
      framework makes it possible to declare arbitrary metadata about attributes,
      using either a class advisor ('binding.metadata()', similar in form and
      function to the existing 'security.allow()') or using a 'metadata' attribute
      of attribute bindings (which is the second positional parameter in all
      the standard bindings like 'Make', 'Obtain', etc.).  Over time, existing
      metadata mechanisms will be refactored to use this new mini-framework,
      instead of the various integrated ad-hoc mechanisms that exist now (like
      the 'permissionNeeded' attribute).  For more information on how the new
      metadata hooks work, including doctest examples, see the 'attributes.txt'
      file in the 'peak.binding' package, under the heading "Attribute Metadata".
   
    - Added a new function, 'binding.activateClass()', that can be used to
      activate any bindings in the class.  This can now be used in place of
      subclassing a PEAK base class or using a PEAK metaclass.  In future, this
      will be integrated into PEAK attribute descriptors such that defining a
      descriptor within a class' body is sufficient to cause this function to be
      invoked.
   
    - 'binding.IBindingNode' was REMOVED, consolidated into 'binding.IComponent',
      as its various individual methods have been replaced with generic functions
      in the existing 'binding' API.  For example, 'binding.getParentComponent(x)'
      should be used in preference to 'x.getParentComponent()' unless it is
      a requirement that 'x' implement the full 'binding.IComponent' interface.
      This makes it easier to define what 'binding.getParentComponent()' and
      'binding.getComponentName()' will mean for non-component types, as you do
      not have to define an adapter class with all of the 'IBindingNode' methods.
      Also, this makes PEAK itself cleaner, as we often weren't bothering to
      properly implement the full 'IBindingNode' interface anyway.
   
      In addition, 'binding.suggestParentComponent()' is now also a generic
      function, dispatching on the target (i.e. child) object.
   
    - 'naming.IReferenceable' was REMOVED, as it is not in use anywhere in PEAK.
      This will be replaced with a generic function when we do actually need this
      functionality.
   
    - There is a new 'config.getStreamFactory' generic function, to make it easy
      to accept URLs, filenames, or 'naming.IStreamFactory' objects as the source
      of a "file".
   
      Its typical usage is just::
   
          factory = config.getStreamFactory(self,source)
          stream = factory.open('t')  # open for reading in text mode
   
      where 'source' is a string or a 'naming.IStreamFactory', and 'self' is a
      component to be used as lookup context.  The returned 'factory' is a
      'naming.IStreamFactory' that can then be '.open()'-ed for reading, or used
      in other ways as needed.
   
      If you have special objects that you'd like to be able to treat as stream
      sources, you can register them by defining an extension, e.g.::
   
       [config.getStreamFactory.when(MyType)]
       def getStreamFactory(context,source):
           """Return a naming.IStreamFactory for 'source' (a 'MyType' instance)"""
   
      Wherever practical, as we encounter them, we'll be changing PEAK API's that
      take filenames to also accept stream sources.
   
    - Added an optional 'base' argument to 'naming.parseURL()', to allow parsing
      URLs relative to a base URL.  For a URL scheme to support this, it must
      implement the new 'naming.IBaseURL' interface.  See the
      'peak.naming.factories.openable' module for example implementations.
   
    - Added a 'data:' URL scheme, implementing RFC 2397 (although it's not as
      strict in its parsing of the content type and parameters as the RFC calls
      for).  This is a semi-convenient way to provide configuration data in-line,
      since a 'data:' URL can be a 'config.getStreamFactory()' source.
   
    - Added 'config.processXML()', a function that provides a high-level,
      configuration-driven interface to 'peak.util.SOX.NegotiatingParser'.  This
      simple front-end lets you supply as little as a configuration context and
      a stream source, to do XML processing of arbitrary complexity, controlled by
      the configuration of the context.
   
    - Added 'config.XMLKey()', an 'IConfigKey' type that can be used to register
      configuration values for XML attribute and element names under specified
      XML namespace URI's.  Also, there are now '[XML Attributes for nsuri]' and
      '[XML Elements for nsuri]' section types available for use in .ini files.
      (Replace 'nsuri' with the appropriate XML namespace URI, or use '*' for a
      wildcard.)
   
    - 'web.IResource' is gone, replaced by 'web.IPlace'.  The notion of a place is
      broader than the notion of a resource, and we will soon need to have
      other "location" objects that implement 'IPlace'.
   
    - In order to support obtaining the line and column locations of problems in
      XML files, we are now using Python 2.4's version of the 'pyexpat' module,
      built as 'peak.util.pyexpat'.
   
    - There's a new class, 'config.IniLoader', that can be used to lazily load
      .ini files as configuration.  'IniLoader' instances have an 'iniFiles'
      attribute that lists the configuration sources (filenames/URLs/factories)
      to be used, and automatically load the .ini files as soon as you try to get
      any configuration data for them.  Previously, similar functionality was only
      available via 'config.makeRoot()'.
   
      Also, there's now an 'ini' reference type that instantiates an 'IniLoader'
      for one or more addresses.  You can use it like this::
   
        [Named Services]
   
        some.example = naming.Reference('ini',
            ['pkgfile:peak/peak.ini', '/etc/something.ini']
         )
   
        another.example = naming.LinkRef(
            'ref:ini@pkgfile:peak/peak.ini||/etc/something.ini'
         )
   
      The two examples above will each load the same pair of specified .ini files.
      You can also directly instantiate an 'IniLoader', as in::
   
        cfg = config.IniLoader(self, iniFiles=['pkgfile:peak/peak.ini'])
   
      Attempting to look up any configuration properties via the 'cfg' object
      will cause it to load the specified .ini file.
   
    - 'config.fileNearModule()' is DEPRECATED, in favor of 'config.packageFile()'.
      The latter returns a 'naming.IStreamFactory', which is more suitable for
      working with e.g. module data files compressed in a zipfile.  Uses of
      'fileNearModule()' that were being passed to 'config.loadConfigFile()' can
      be safely changed to 'config.packageFile()' without needing any other code
      changes, but if you were directly using 'fileNearModule()' as a filename,
      you will need to rewrite appropriately.
   
    - 'config.loadConfigFile()' and 'config.loadConfigFiles()' now accept URLs,
      'naming.IStreamFactory' objects, and other 'config.getStreamFactory()'
      targets as well as filenames.  This was primarily added to support use of
      'config.packageFile()' or 'pkgfile:' URLs, in place of using
      'config.fileNearModule()'.
   
    - The 'naming.IStreamFactory' interface now has an 'address' attribute, which
      is the string form of the canonical URL of the target stream.  This was
      added to make it easier to e.g. report errors in a stream that's being
      parsed, since the parser only needs the factory in order to report the
      location of an error.  (Note: if you implement 'naming.IStreamFactory', be
      sure to add this attribute to your implementations.)
   
    - The 'peak.util.WSGIServer' module has been moved to the
      'wsgiref.simple_server' module.  The 'wsgiref' reference library for WSGI
      (aka PEP 333) is now distributed with PEAK.
   
    - Added a 'WSGI' command to the 'peak' script, to allow you to run "foreign"
      (i.e. non-PEAK) PEP 333 applications in PEAK's various servers and
      launchers.  Basically, by prefixing 'WSGI' before the import specifier, you
      can now run such foreign apps.
   
      For example::
   
          peak launch WSGI import:some_app.application
   
      will run 'some_app.application' in the local web browser, and::
   
          peak CGI WSGI import:some_app.application
   
      will run it under the CGI/FastCGI runner.  Similarly, you can use this in
      the "Command" spec for the "peak supervise" pre-forking FastCGI supervisor
      subsystem.
   
    - There is a new 'running.IWSGIApplication' interface, for PEP 333-compliant
      "application" objects, and all of PEAK's provided applications now implement
      it instead of 'running.IRerunnableCGI'.  If you write your apps to the newer
      interface, they'll be portable to any PEP 333-compliant web server, not just
      the PEAK CGI, FastCGI, and "supervisor" containers.  There is a simple
      adapter that allows 'IWSGIApplication' objects to run in the CGI-based
      containers, but not the other way around, so using 'IRerunnableCGI' directly
      now limits your portability.  (For example, the "peak launch" and "peak
      serve" commands will soon require 'IWSGIApplication', and will not support
      'IRerunnableCGI' any more.)
   
      Of course, if you use the 'peak.web' framework, you don't need to worry
      about any of this; your apps will automatically be wrapped as
      'IWSGIApplication', and run in any PEAK server or gateway.
   
    - Most 'peak.web' interfaces have changed significantly.  If you implemented
      anything based on the older interfaces, and it still works, it's sheer
      bloody luck.  In particular, note that every method in 'web.IWebTraversable'
      now has different inputs and/or outputs than before.  Please read the new
      interface docs and update your code!  The changed interfaces offer much
      more flexibility and functionality than before, but they will require you to
      update your code.
   
    - 'web.ContainerAsTraversable' has been removed.  It was redundant, since the
      new default traversal mechanism used by 'Traversable' and 'Decorator' now
      handles getitem, getattr, and views.
   
    - Added Zope 3-like "namespaces" to 'peak.web'.  Path segments in a URL
      may be prefixed with '"++some_id++"' in order to invoke a corresponding
      namespace handler registered under '"peak.web.namespaces.some_id"'.
      Namespace handlers must implement 'web.INamespaceHandler', and they are
      supplied with the original path segment as well as the separated namespace
      and name.  Also, as in Zope 3, '"@@foo"' is a shortcut for '"++view++foo"'.
      Builtin namespaces at this time include 'view', 'item', 'attr', 'skin', and
      'resources'.  'skin' treats the rest of its path segment as a skin name,
      and sets the current skin, while 'resources' begins traversal to resources
      found in the current skin.  The other namespaces are as described at:
   
      "Resources and traversal in peak.web":http://www.eby-sarna.com/pipermail/peak/2004-August/001712.html
   
    - Fixed several 'peak.events' bugs, as reported by Vladimir Iliev, Yaroslav
      Samchuk, and Alexander Smishlajev:
   
      * 'events.AnyOf' could hold multiple references to a single event source,
        and nesting 'AnyOf()' calls could leak references to the nested events.
   
      * 'events.subscribe()' had a potential race condition wherein a callback
        could be invoked after its weak reference was garbage collected, leading
        to bizarre error messages about 'self' being 'None'.
   
      * 'select()' could be called on select event objects even if there were
        no current subscribers to the event, potentially leading to calling
        'select()' on a closed socket.
   
      * Non-default signal handlers were remaining installed even when there
        were no current subscribers to the applicable event, as long as a
        reference to the event object existed.
   
      As a result of these changes, certain I/O event types (esp. signals and
      stream readable/writeable events) are now longer-lived.  For example,
      signal event objects are now immortal, and the read/write event for a
      particular 'fileno()' will be reused for as long as its supplying
      'Selector' or 'EventLoop' instance exists.  (Previously, weak references
      were used so that these objects would be recycled when not in use.)
   
    - Added 'config.registeredProtocol()' API, that supports defining named and
      local protocols.  This allows easy emulation of Zope 3's "named" and "local"
      adapters and views.
   
    - 'binding.Component' objects no longer support instance configuration at
      runtime (i.e., they no longer implement 'config.IConfigurable').  If you
      need a component to be configurable at runtime, you must now derive from
      (or mix in) 'binding.Configurable' instead.  If you get errors about
      a missing 'registerProvider' attribute, or about being unable to adapt to
      'IConfigurable', try changing your base class from 'binding.Component'
      to 'binding.Configurable', or add it as a mixin if you're deriving from
      a class that uses 'binding.Component' as its base.
   
    - 'binding.IComponent' no longer derives from 'config.IConfigurable' or
      'config.IConfigMap', only 'config.IConfigSource'.  This means that
      'IComponent' no longer guarantees or requires the presence of the
      'registerProvider()' method: now only 'config.IConfigurable' does that.
   
    - The 'config.IConfigMap' interface is now DEPRECATED.  Use
      'config.IConfigurable' instead.  The '_configKeysMatching()' method
      of 'IConfigMap' was moved to 'config.IConfigSource', so if you've
      implemented a custom 'IConfigSource', be sure to add this method.
   
    - 'web.ISkinService' and 'web.ILayerService' were consolidated into
      'web.IInteractionPolicy', because the need to have configurable
      implementations of these services is negligible.  That is, the
      corresponding property namespaces ('peak.web.skins' and 'peak.web.layers')
      are more than adequate as registries.
   
    - Removed 'peak.running.timers' and 'peak.util.dispatch'.  Neither was in
      active use, and both are being replaced by the new generic functions
      package in PyProtocols.
   
    - The 'config.iterParents' API is now moved to 'binding.iterParents', and all
      'binding' functions that walk the component hierarchy use it.  It has also
      been changed to avoid infinite loops in the case of a pathological
      component structure.
   
    - The 'persistence' package has been moved to 'peak.persistence' to avoid
      conflicts with ZODB3 and the latest version of Zope 3.  It will eventually
      be phased out, but for now this move is the simplest way to get it out of
      the way.
   
    - The 'peak.util.SOX' module now uses only one parser, based directly on
      'expat', instead of using SAX.  The new parser expects a new node interface,
      'IXMLBuilder', but adapters from the previous interfaces ('ISOXNode' and
      'ISOXNode_NS') are supplied for backward compatibility.  All of PEAK's
      direct XML handling (currently just 'peak.storage.xmi' and
      'peak.web.templates') have been refactored to use the new interface.  Some
      parsing classes (such as 'ObjectMakingHandler', 'NSHandler', and
      'DOMletParser') are no longer available.
   
    - 'peak.web' no longer uses Zope X3 for HTTP publishing support; it has been
      refactored to use a "simpler, more uniform architecture":http://www.eby-sarna.com/pipermail/peak/2004-May/001462.html
      See also "more on the architecture":http://www.eby-sarna.com/pipermail/peak/2004-June/001482.html
      and subsequent posts in that thread.
   
      As a consequence, "various features have been removed":http://www.eby-sarna.com/pipermail/peak/2004-June/001500.html
      from 'peak.web', for possible return at a future date.  Here is a rough
      outline of the changes made so far:
   
       * The 'pageProtocol', 'pathProtocol', and 'errorProtocol' machinery are
         gone.  They will be replaced in the future with an explicit "controller"
         wrapping mechanism to allow application-specific renderings of the same
         underlying components.
   
       * The Zope 'request' and 'response' objects are gone, along with all of
         their special handling for cookies, character sets, form variables,
         automatically marshalling parameters to functions, etc.  These items of
         functionality will be gradually replaced by functions in 'peak.web.api'.
   
         As a result of this, arbitrary functions and methods can no longer be
         used as web pages; instead, functions and methods to be published must
         use the same inputs and outputs as the 'IHTTPHandler.handle_http()'
         method.
   
       * The 'IWebPage', 'IWebInteraction', 'ITraversalContext', 'Traversal',
         'TraversalContext', and 'Interaction' interfaces and classes no longer
         exist, as they are unneeded in the new architecture.  Instead of
         having a central 'IWebInteraction' that's referenced by numerous
         'ITraversalContext' objects, the new approach uses an 'environ' mapping
         for most functions.  For access control, a 'security.IInteraction' is
         now used, whose function is limited to security checks.  Most
         functions previously performed by 'IWebInteraction' have moved to
         'IInteractionPolicy' or to 'peak.web.api' functions operating on
         'environ' mappings.
   
       * Web exceptions can define a 'levelName' attribute that determines the
         severity level with which the exception will be logged.  This allows
         one to e.g. avoid logging tracebacks for 'NotFound' errors.
   
       * Various interface calling signatures have changed slightly.  For example,
         'IAuthService.getUser()' now accepts an 'environ' mapping instead of
         an interaction.  'IInteractionPolicy.newInteraction()' now takes keyword
         arguments, but not a 'request'.  The 'IWebTraversable' interface no longer
         has a 'getObject()' method, and the 'IWebException.handleException()'
         method signature has changed as well.  Finally, all methods that
         previously accepted 'ITraversalContext' (such as
         'IDOMletState.renderFor()') now expect 'environ' mappings.
   
       * 'web.TestInteraction' was replaced with 'web.TestPolicy', and
         'web.Interaction' was removed, since 'IWebInteraction' is no longer part
         of the architecture.
   
    - The 'log()' method of PEAK loggers ('logs.ILogger') now accepts a level name
      *or* a number, for convenient invocation.
   
    - SQL transaction semantics have changed.  Now, issuing an SQL statement
      *always* causes the connection to join the active PEAK transaction, even if
      you request that the SQL be issued "outside" a transaction.  Such SQL will
      be issued outside of the *database* transaction, but not outside of the
      PEAK transaction.  This simplifies the overall processing model for dealing
      with "untransacted" SQL such as Sybase DDL or read-only Oracle transactions.
      (In particular, the requirement that triggered this change was to allow
      Oracle read-only transactions to be released at the end of the current PEAK
      transaction.)  Also, got rid of the now-meaningless 'begin' command in n2.
   
    - The 'events.IEventSource' interface now returns a 'canceller' function from
      the 'addCallback()' method, allowing you to cancel a previously-scheduled
      callback.  This fixes a memory leak and performance problem with
      'events.AnyOf()', which previously could accumulate unneeded callbacks on
      the sources it was monitoring.  Note that if you have developed any custom
      event sources with 'addCallback()' methods, you must make sure that they
      return a canceller from now on.
   
    - Added 'ref:factory@addr1||addr2' URL scheme that maps to a corresponding
      'naming.Reference("factory",["addr1","addr2"])'.  'factory' can be either a
      dotted import string referencing a 'naming.IObjectFactory', or you can
      define a factory in the 'peak.naming.factories' property space.
   
    - Added a 'zconfig.schema' factory, so that 'ref:zconfig.schema@streamURL'
      will load a schema loader.  Schema loaders are themselves object factories,
      so you can do something like::
   
        [Named Services]
        peak.naming.factories.myschema = \
            naming.LinkRef('ref:zconfig.schema@pkgfile:mypkg/Schema.xml')
   
      in order to make URLs like 'ref:myschema@filename' work.  Note, by the way,
      that the above could also read::
   
        [Named Services]
        peak.naming.factories.myschema = \
            naming.Reference('zconfig.schema',['pkgfile:mypkg/Schema.xml'])
   
      which runs somewhat faster at lookup time.  Similarly, one can also use
      'naming.Reference("myschema",["somefile"])' in place of a
      'naming.LinkRef("ref:myschema@filename")'.  As well as being faster, for
      some use cases it's easier to 'Reference' directly than to glue together
      a 'ref:' URL string.
   
  - There's a new 'peak.storage.files' module, with handy classes like  
    'EditableFile'.  'EditableFile' is a class that lets you edit the contents  
    of a file "in place", with atomic replacement of the original at transaction  
    commit.  If the transaction is aborted, the original file is left unchanged.  
   
  - 'peak.running.scheduler.UntwistedReactor' now supports a configuration  
    property ('peak.running.reactor.checkInterval') to determine how long it  
    should run 'select()' calls for, when there are no scheduled tasks.  
   
  - 'peak.running.scheduler.UntwistedReactor' now supports using a "signal  
    manager" component (via the 'peak.running.signalManager' property) to  
    process signals while a 'run()' loop is in progress.  Signal managers can  
    also be added or removed at any time via the new 'peak.util.signal_stack'  
    module.  
   
  - 'peak.running.commands.AbstractCommand' now offers a '_run()' method that  
    can be overridden in subclasses, instead of 'run()'.  If you override the  
    new '_run()' method instead, you get the advantage of automatic handling  
    for invocation errors and 'SystemExit' exceptions, provided for you by the  
    'run()' method.  
   
  - There is now a 'storage.DMFor(class)' function that returns a configuration  
    key for registering or looking up data managers by class.  You can use the  
    returned key in a binding's 'offerAs' list, or as the target of a 'bindTo()'  
    or 'lookupComponent()'.  The key is constructed using  
    'config.ProviderOf(storage.IDataManager,class)'.  
   
  - You can now register utilities that are keyed by the combination of an  
    interface and one or more classes, using 'config.ProviderOf(iface,*classes)'  
    as a configuration key.  Providers are registered under an '(iface,klass)'  
    tuple for each specified class, and looked up using the MRO order of the  
    class specified for lookup.  In other words, searching for a provider will  
    find a provider for the requested class, or one of its base classes, with  
    precedence given to the more-specific provider.  This is primarily intended  
    for services like data managers and Specialists.  
   
  - It's now possible to extend .ini file parsing with custom section types,  
    and PEAK defines its own built-in section types using this extension  
    mechanism.  Custom section types must include at least one space, (e.g.  
    '[My Section]') or they will be treated as a plain property name.  
    See the 'peak.config.iniFile.sectionParsers' section in 'peak.ini' for  
    more details, along with the 'config.ISettingParser' and 'config.IIniParser'  
    interfaces.  
   
  - When creating a 'PropertyName()', it's now possible to force conversion of  
    invalid characters to '_', using the 'PropertyName.fromString()'  
    constructor.  (Note that the input must be a plain-ASCII string.)  Unless  
    you request that wildcards ('?' and '*') be kept, they will also be  
    converted to '_' characters.  This can be convenient for converting things  
    like filenames or text that might contain spaces, to property names.  
   
  - It's now possible to declare an attribute as offering a wildcard property;  
    such lookups now follow the same rules as other wildcard property lookups.  
    The 'config.IConfigKey' interface has been changed to cleanly support  
    implied keys at both registration and lookup time, so you can implement  
    your own key types that work the way interfaces or property names do for  
    configuration lookups.  
   
  - The 'EigenRegistry' class has been moved from 'peak.util.EigenData' to  
    'peak.config.registries', as it hasn't really been useful outside PEAK for  
    a while now.  
   
  - .ini files now support "smart property" objects ('config.ISmartProperty').  
    If a property rule defined in an .ini file evaluates at runtime to an object  
    that implements 'ISmartProperty', the object will be given a chance to  
    compute a value for the property, in place of being used itself.  This helps  
    to simplify definition of complex property rules in .ini files, by allowing  
    the use of helper classes.  Also, 'naming.LinkRef' and 'naming.Reference'  
    (indirectly) support this interface, so you can now use them in .ini files  
    to refer to an object via the naming system.  (Previously, 'naming.LinkRef'  
    wouldn't do the right thing unless the property was looked up via a  
    'config:' URL, and 'naming.Reference' didn't exist.)  
   
  - 'peak.util.imports.whenImported()' can now be used even when the specified  
    module has already been loaded.  
   
  - The naming system no longer has 'objectFactories' and 'stateFactories' as  
    utilities; they have been replaced with new mechanisms involving adaptation.  
    Previously, addresses had a 'retrieve()' method that could be used to  
    retrieve the object defined by the address.  Now, to retrieve an object for  
    an address, you must either define a context that processes the address, or  
    the address must have a 'defaultFactory' attribute, which provides a name  
    to be imported to get an 'IObjectFactory' that can construct the referenced  
    object.  (This is simpler than it sounds; for URLs that reference  
    ManagedConnections, for example, all you need to do is provide the fully  
    qualified name of the connection class.)  
   
    Meanwhile, writable naming contexts must have a 'serializationProtocol'  
    attribute, specifying what interface an object should be adapted to before  
    attempting to store it in that context.  
   
    The naming system no longer processes the 'creationName' keyword argument;  
    this is now considered the sole responsibility of 'peak.binding'.  The  
    'IComponent.lookupComponent()' method still accepts the keyword argument,  
    and attribute bindings still handle the creation name transparently.  It is  
    just not available via naming system APIs, and naming contexts no longer  
    have to deal with it.  
   
    The naming system base classes no longer use 'attrs' as an input parameter  
    or return value.  If you've subclassed anything from 'peak.naming.contexts',  
    note that your '_get()' methods should now just return the lookup value,  
    rather than a 'state,attrs' tuple.  For most naming contexts, this just  
    means you should change 'return foo, None' statements to just 'return foo'.  
   
  - Property definition rules in an .ini file can now refer to 'rulePrefix' and  
    'ruleSuffix' variables.  'rulePrefix' is a '.'-terminated string,  
    representing the name the rule was defined with.  For example, if the  
    rule was defined for '"foo.bar.*"', then 'rulePrefix' will be '"foo.bar."'.  
    The 'ruleSuffix' will be the portion of the 'propertyName' that follows  
    'rulePrefix'.  So, if looking up property '"foo.bar.baz"', then the  
    '"foo.bar.*"' rule will execute with a 'ruleSuffix' of '"baz"'.  This should  
    make it easier to work with hierarchical property namespaces.  
   
  - Added simple example scripts and small applications in the 'examples'  
    directory.  
   
  - There is a new command-line namespace introspection tool, 'n2', which  
    can be accessed by running 'peak n2'.  Type 'peak n2 -h' for help.  
   
  - The PEAK_CONFIG environment variable can now list multiple files, separated  
    by the platform's 'os.pathsep' (e.g. ':' on Unix, ';' on Windows).  
   
  - It's no longer necessary to provide a '_defaultState()' implementation  
    for an EntityDM: a default implementation is now supplied.  
   
  - Added automatic installation of 'datetime' package for Python < 2.3.  
   
  - CGI support has been moved from 'peak.running.zpublish' into  
    'peak.running.commands' (for "raw" CGI/FastCGI) and 'peak.web' (for the  
    PEAK high-level publishing framework).  You can use 'peak CGI someName' to  
    adapt 'someName' to a 'running.IRerunnableCGI' and run it as a CGI/FastCGI.  
   
  - There is now a 'peak.security' package, available from 'peak.api' as  
    'security'.  It provides permission management functions: you can define  
    abstract permissions by subclassing 'security.Permission', then create  
    permission checking rules by subclassing 'security.RuleSet', and declare  
    the permissions needed to access attributes of a class with  
    'security.allow()'.  The test suite demonstrates a complex application  
    ruleset with dynamic, data-driven permissions.  
   
  - There is now an interface for "Active Descriptors":  
    'binding.IActiveDescriptor'.  'peak.binding' now uses this interface to  
    identify active descriptors, so you can now create your own.  (Previously,  
    'peak.binding' used 'isinstance()' to detect active descriptors.)  
   
  - REMOVED 'naming.ParsedURL'; it was deprecated as of 0.5 alpha 2.  
   
  - The 'provides' keyword argument to various 'peak.binding' APIs has been  
    renamed to 'offerAs', and it must be a sequence of configuration keys.  
    (Previously, it accepted either a single key or a tuple of keys.)  
    The signature of 'binding.Constant()' was changed as well; the first  
    positional argument is now the constant value, and 'offerAs' is now a  
    keyword argument.  (Previously, 'provides' was the first positional argument  
    of 'binding.Constant()'.)  The 'registerProvider()' method of  
    'config.IConfigurable()' also now accepts only a single configuration key,  
    as does 'EigenRegistry.register()'.  
   
    Also, all 'peak.binding' APIs now only accept positional parameters for  
    items unique to that API.  Items common to multiple APIs (such as 'offerAs',  
    'doc', 'attrName', etc.) should now be supplied as keyword arguments.  
   
    Bindings also now automatically "suggest" the containing object as a parent  
    component for the contained object, whenever a value is assigned to them or  
    computed.  If a non-None 'adaptTo' is set on the binding, the value assigned  
    or computed will be adapted to the specified protocol before the parent  
    component is suggested.  'binding.New()' no longer relies on the  
    'IComponentFactory' interface, but instead uses the new adapt/suggest  
    mechanisms.  
   
    Previously, parent components were only "suggested" when a binding was set  
    via component constructor keyword arguments.  Now, this is done at any time  
    bindings are set, but *not* for non-binding keyword arguments.  In other  
    words, ordinary attributes of a component do not receive "suggested parent"  
    notices, even when set via constructor keyword arguments.  If you want an  
    attribute to do this, you must define the attribute with the binding API;  
    e.g. via 'requireBinding()' or 'binding.Constant()'.  If you do *not* want  
    a binding to suggest a parent component, use 'suggestParent=False' in the  
    binding definition.  
   
  Corrected Problems  
   
   - There was a typo in peak.naming.arithmetic that caused homogeneous non-URL  
     name subtraction to fail.  
   
   - The default reactor supplied in 'peak.running.scheduler' would consume  
     CPU continuously if it was waiting for I/O and no tasks were scheduled.  
   
   - The 'peak.util.imports.whenImported' function didn't work.  
   
   
   
   
 Fixes and Enhancements since Version 0.5 alpha 1  
   
  Changed, Enhanced, or Newly Deprecated Features  
   
  - Added a 'shellcmd:'  URL scheme that returns a function that calls  
    'os.system()' on the body of the URL.  It's intended for use as a command  
    factory, as is needed by the 'URLChecker' periodic task.  
   
  - You can now define adapters from arbitrary types to 'binding.IBindingNode',  
    and thus be able to use them as part of a component hierarchy - without  
    needing to directly add 'getParentComponent()' or 'getComponentName()'  
    methods to them.  
   
  - Added experimental 'invoke.c' script for POSIX-ish platforms with funky  
    '#!' support, or lack thereof.  
   
    'invoke' is designed to be used like this::  
   
      #!/usr/local/bin/invoke peak somearg otherarg...  
   
    This should work on most sane platforms with a long-enough commandline.  
    (See "this page":http://homepages.cwi.nl/~aeb/std/hashexclam-1.html for  
    details on the insanely incompatible ways different Unixes interpret '#!'  
    lines.)  
   
    The script is not currently built or installed by setup.py.  On the  
    platforms it's targeted at, you should be able to build it with::  
   
      gcc -o invoke invoke.c  
   
    (Yes, it really is that simple of a script.)  
   
  - Added a ZConfig schema for 'running.commands.EventDriven' applications,  
    a ZConfig component definition for adaptive tasks, and a running shortcut  
    called 'EventDriven'.  
   
    It should now be possible to do this::  
   
      #!/usr/bin/env peak EventDriven  
   
    at the top of a ZConfig file formatted according to the new schema, and  
    have it run.  There are two periodic tasks that can be configured and  
    run from such a file: 'CleanupFiles' and 'URLChecker'.  'CleanupFiles' will  
    delete files matching a pattern that are older than a certain age, while  
    'URLChecker' will check to see if the target of a naming system URL is  
    up/available/working, and if not, runs a command to restart it.  As an  
    amusing demo, try specifying a 'file:' URL with a 'shellcmd:touch theFile'  
    to recreate the file, then add a 'CleanupFiles' that deletes the file the  
    checker looks for.  This can be hours (well, minutes) of exciting fun as you  
    watch the dueling daemons undoing each others' work.  
   
  - Added 'zconfig.schema' URL scheme that loads an enhanced ZConfig schema  
    object that can act as a command line interpreter using the 'peak' script.  
   
    To use it, run 'peak zconfig.schema:urlToSchema urlOfConfig'.  Or, add  
    a line like this::  
   
      #!/usr/bin/env peak zconfig.schema:pkgfile:some.package/schema.xml  
   
    to the top of a configuration file, and make the configuration file  
    executable.  Note that the schema specified must convert to an object  
    that's usable with the commands bootstrap framework.  Also note that  
    if you have a local PEAK_CONFIG file, you can add a 'peak.running.shortcuts'  
    entry to shorten the URL reference in your #! line.  E.g.::  
   
      #!/usr/bin/env peak mySchema  
   
    will suffice if you have defined 'peak.running.shortcuts.mySchema' as  
    'naming.LinkRef("zconfig.schema:pkgfile:some.package/schema.xml")'.  
   
    There is also a 'peak ZConfig urlOfSchema urlOfConfig' variant, that was  
    added to support putting '#!/usr/bin/env peak ZConfig' at the top of  
    schema files, but unfortunately that's not valid XML.  
   
  - Standardized file-based URL syntaxes (e.g logfiles and lockfiles) to  
    follow RFC 1738/2396, and Python 'urllib'.  This shouldn't affect much  
    besides the canonical forms of the URLs.  Added 'pkgfile:some.pkg/filepath'  
    URL syntax for ease of referring to files near modules.  (A convenience  
    intended mainly for referencing ZConfig schemas.)  
   
  - Added the UML 1.4 metamodel, and thus the ability to load UML 1.4  
    models encoded in XMI 1.1.  
   
  - Added support in the mof2py code generator for "unprefixing" enumerated  
    values, so that UML and other metamodels' enumerations work correctly  
    when loading from XMI.  Also, mof2py no longer emits 'config.setupModule()'  
    calls in generated code, as in practice they are not needed.  
   
  - Running 'peak test' from the command line is roughly equivalent to running  
    'unittest.py', except that the test suite defaults to the PEAK test suite.  
    You can, however run any test suite from the command line with a dotted  
    module/attribute path, e.g 'peak test foo.bar.test_suite'.  
   
  - 'binding.Acquire()' now accepts a 'default' value argument, and  
    'binding.New()' no longer accepts the 'bindToOwner' flag.  
   
  - There is a new 'binding.IComponentKey' interface that is used to implement  
    'IComponent.lookupComponent()'.  Now you can implement this interface,  
    or create an adapter for it, in order to make an object usable as an  
    argument to 'binding.lookupComponent()' - and therefore usable as a key  
    for 'binding.bindTo()' or 'binding.bindToSequence()'.  Not that it's  
    necessarily very useful to do so; you're probably better off simply  
    creating a naming scheme.  But it might be useful for lookups done  
    in the context of classes, since naming schemes aren't usable there.  
    (It was actually added in order to factor out all the type testing that  
    'lookupComponent' used to do, so it doesn't matter if it's useful for  
    much else.)  
   
  - PEAK has been refactored to avoid the use of 'isImplementedBy()' and  
    similar introspection, in favor of 'adapt()'.  As a result, some  
    'peak.naming' interfaces have changed.  This should not affect you  
    if you are only subclassing PEAK-provided naming components and not  
    implementing these interfaces "from scratch".  However, the various  
    'isAddress', 'isAddressClass', 'isResolver', and 'isName' APIs have  
    also been removed, as they were based on 'isImplementedBy()'.  
   
  - REMOVED ability to use '__implements__' and '__class_implements__' to  
    declare support for interfaces.  Use 'protocols.advise()' or a related  
    API to do this now.  The 'protocols' package is available automatically  
    from 'peak.api'.  
   
    Similarly, the ability  to use 'isImplementedBy()' with interfaces declared  
    by PEAK is REMOVED.  You can still use 'isImplementedBy()' with Zope  
    interfaces, of course, but we recommend you switch to 'adapt()', which  
    should work with both PEAK and Zope interfaces.  
   
  - Replaced all use of 'zope.interface' with 'protocols' package because  
    the 'protocols' package:  
   
    * is considerably smaller and simpler than 'zope.interface'  
   
    * produces Interface objects that can be inspected with the Python  
      'pydoc' and 'help()' tools  
   
    * supports and implements the PEP 246 'adapt()' protocol  
   
    * transparently supports transitive adaptation - i.e. if adapter AB  
      adapts from A to B, and adapter BC adapts from B to C, then an adapt(x,C)  
      where 'x' is an 'A', will be implemented as BC(AB(x)).  
   
    * Supports "open protocols" that allow you to "superclass" a protocol  
      to create a subset protocol; objects that support the first protocol  
      will automatically support the subset protocol.  For example, if one  
      person defines a "dictionary" protocol, someone else can create a  
      "read-only dictionary" protocol, and all objects supporting the  
      "dictionary protocol" will be considered to implement the "read-only  
      dictionary" protocol.  
   
    * can interoperate with other interface packages, including Zope's, but  
      does not require them  
   
    * works with module inheritance (for everything but moduleProvides(), and  
      we should get to that by 0.5a2)  
   
    * lets you use Interfaces as abstract base classes (i.e., you can  
      inherit from an interface and turn it into an implementation, and  
      you can define default attribute values or method implementations in  
      your interfaces  
   
    * Lets you mix interface declarations from any number of frameworks and  
      any number of interface types, in a single 'implements()' or  
      'classProvides()'  
   
    * uses adaptation as the fundamental approach to dealing with interfaces,  
      and avoids the use of 'isImplementedBy()'.  In the *rare* case that you  
      need to introspect rather than adapt, you can always call adapt() and  
      check the result.  (But introspection usually means that you're using  
      interfaces as a form of metadata; it's better to create an explicit  
      interface that provides the metadata you seek, and adapt to that  
      interface, than to use interfaces as data.)  
   
    Most of these features are unavailable in 'zope.interface', and some have  
    been declared by the Zope Pope to be unacceptable or undesirable features  
    for Zope interfaces.  (Others may be available in some form in future  
    versions of Zope X3.)  So, we no longer require or distribute  
    'zope.interface'.  
   
  - The signatures of the 'getObjectInstance()', 'getStateToBind()', and  
    'getURLContext()' methods in the 'peak.naming' package have changed, to  
    place the context or parent component as the first, non-optional argument.  
    (If you don't know what these methods are for, you don't need to do anything  
    about this, as they are part of the naming package's extensibility  
    framework.)  
   
  - 'binding.bindTo()' now accepts a 'default=' argument, whose value will be  
    used in case of a 'NameNotFound' error.  
   
  - DEPRECATED 'naming.ParsedURL'.  It will disappear in 0.5 alpha 3 or beta.  
    It is replaced by the new 'naming.URL.Base'.  The 'naming.URL' package  
    provides a new URL parsing framework based on 'peak.model'.  Upgrading from  
    'ParsedURL' to 'URL.Base' is trivial for ParsedURL subclasses that used  
    only the 'scheme' and 'body' fields, and in fact may not require any  
    changes except for the choice of base class.  Also, the 'retrieve()' method  
    of URLs is deprecated; please begin defining the 'getObjectInstance()'  
    method instead.  This is to cut down a bit on the number of ways that the  
    naming package spells the idea of retrieving something!  
   
    For more complex URL classes, the '__init__' methods go away, 'parse'  
    methods change slightly, and explicit field definitions (using  
    'model.structField' or similar) are required.  See PEAK's 'URL.Base'  
    subclasses for examples.  There is also a sophisticated parsing and  
    formatting framework (see the 'peak.naming.URL' and 'peak.util.fmtparse'  
    modules) that can be used in place of the old regex-based approach.  
   
  - Added 'peak.util.fmtparse', a parsing and formatting framework, and  
    integrated it with 'peak.model' so that any element type can have a  
    syntax for parsing from, or formatting to, a string.  
   
  - Added 'binding.whenAssembled(...)' as syntax sugar for  
    'binding.Once(...,activateUponAssembly=True)'.  
   
  - Removed 'LOG_XYZ' convenience functions from 'peak.api', and refactored  
    'peak.running.logs' to use a PEP 282-like interface, 'running.ILogger'.  
    Under the new scheme, messages must be sent to a specific entry point  
    (e.g. 'self.logger.warning("foo")').  Components can bind an attribute  
    directly to a logger object, or via configuration properties or utilities.  
    PEAK components that do logging all define a 'logger' attribute, bound  
    to a configuration property in the 'peak.logs' property namespace.  By  
    a default in 'peak.ini', 'peak.logs.*' is configured to output messages  
    of 'WARNING' priority or higher to 'sys.stderr'.  
   
    For compatibility with the PEP 282 logging package, a 'logging.logger:'  
    URL scheme has been added; looking up the URL '"logging.logger:foo.bar"'  
    is equivalent to 'logging.getLogger("foo.bar")', unless the 'logging'  
    package is not available, in which case the configuration property  
    'peak.logs.foo.bar' will be looked up in the target context of the  
    lookup.  Optionally, you can configure the 'logging.logger' URL scheme so  
    that it only uses PEAK loggers, and never uses the PEP 282 loggers.  
   
  - Added 'binding.metamethod()' wrapper for metaclass methods that might  
    not be accessible from their instances if the instances (classes) also  
    defined the method for *their* instances.  You must now use this wrapper  
    on any such metaclass-defined methods, as PEAK no longer works around  
    this via the 'x.__class__.foo(x,...)' trick that was used previously.  
    In particular, if you have metaclass definitions of 'getParentComponent',  
    '_getConfigData', 'getComponentName', or 'notifyUponAssembly', you need  
    to wrap them with 'binding.metamethod' now.  
   
  - Made 'NOT_GIVEN' and 'NOT_FOUND' recognizable by humans (they 'repr'  
    and 'str' to their names) and by Python (they can be pickled, and  
    when restored they come back as the same object).  
   
   
  Corrected Problems  
   
  - Fixed a problem in ZConfig 'schema.dtd'; I used 'PCDATA' where I should've  
    used 'CDATA'.  
   
  - Fixed a problem with 'binding.supertype()' not working correctly if the MRO  
    it was searching contained a "classic" class.  Now 'supertype()' skips any  
    classic classes it finds.  (It probably should be rewritten entirely.)  
   
  - Fixed misc. problems with 'fromZConfig()' component constructor  
   
  - Fixed source distributions missing essential setup files  
   
  - Fixed a problem with assembly events, where a parent component that didn't  
    need assembly notification, wouldn't ever notify its children of assembly  
    if they requested the notification after the parent had already received  
    it.  
   
  - Fixed a bug in automatic metaclass generation that caused extra unneeded  
    metaclasses to be generated.  
   
  - Fixed 'naming.lookup()' and related APIs not setting the parent component  
    of created objects without an explicitly supplied 'creationParent' keyword  
    argument.  This used to "sort of work" when we had implicit configuration  
    parents, but was broken when we went "all explicit" for 0.5 alpha 1.  
   
  - Fixed a problem where initializing single-valued immutable fields of  
   'peak.model' types did not perform type/value normalization.  
   
  - Fixed a problem where bindTo would use the attribute name as the  
    default value for a lookup, if the requested name/property/utility  
    was not found.  
   
  - Fixed 'mof2py' generator script not working  
   
  - Fixed model.Element not getting parent component set when passed as a  
    constructor argument.  
   
  - Fixed property/utility lookups not working correctly on model.*  
    objects.  
   
  - Fixed IndentedStream generating all-whitespace lines  
   


Generate output suitable for use with a patch program
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  Added in v.2029

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