versions.py

当rest api请求是版本号时候，调用该模块中的类Versions进行处理。
绑定也是在api-paste.ini文件中。

  1. /: neutronversions
  2. [app:neutronversions]
  3. paste.app_factory = neutron.api.versions:Versions.factory

调用的是Versions类中的factory()方法，该方法返回一个类的实体。该类是一个callable对象，主要函数就是__call__()方法。

  1. @webob.dec.wsgify(RequestClass=wsgi.Request)
  2.     def __call__(self, req):
  3.         """Respond to a request for all Neutron API versions."""
  4.         version_objs = [
  5.             {
  6.                 "id": "v2.0",
  7.                 "status": "CURRENT",
  8.             },
  9.         ]
  11.         if req.path != '/':
  12.             language = req.best_match_language()
  13.             msg = _('Unknown API version specified')
  14.             msg = gettextutils.translate(msg, language)
  15.             return webob.exc.HTTPNotFound(explanation=msg)
  17.         builder = versions_view.get_view_builder(req)
  18.         versions = [builder.build(version) for version in version_objs]
  19.         response = dict(versions=versions)
  20.         metadata = {
  21.             "application/xml": {
  22.                 "attributes": {
  23.                     "version": ["status", "id"],
  24.                     "link": ["rel", "href"],
  25.                 }
  26.             }
  27.         }
  29.         content_type = req.best_match_content_type()
  30.         body = (wsgi.Serializer(metadata=metadata).
  31.                 serialize(response, content_type))
  33.         response = webob.Response()
  34.         response.content_type = content_type
  35.         response.body = body
  37.         return response