Source code for envisage.resource.resource_manager

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# All rights reserved.
#
# This software is provided without warranty under the terms of the BSD
# license included in LICENSE.txt and may be redistributed only under
# the conditions described in the aforementioned license. The license
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#
# Thanks for using Enthought open source!
""" The default resource manager. """


# Enthought library imports.
from traits.api import Dict, HasTraits, provides, Str

# Local imports.
from .i_resource_manager import IResourceManager
from .i_resource_protocol import IResourceProtocol


@provides(IResourceManager)
class ResourceManager(HasTraits):
    """The default resource manager."""

    #### 'IResourceManager' interface #########################################

    # The protocols used by the manager to resolve resource URLs.
    resource_protocols = Dict(Str, IResourceProtocol)

    ###########################################################################
    # 'IResourceManager' interface.
    ###########################################################################

    #### Trait initializers ###################################################

    def _resource_protocols_default(self):
        """Trait initializer."""

        # We do the import(s) here in case somebody wants a resource manager
        # that doesn't use the default protocol(s).
        from .file_resource_protocol import FileResourceProtocol
        from .http_resource_protocol import HTTPResourceProtocol
        from .package_resource_protocol import PackageResourceProtocol

        resource_protocols = {
            "file": FileResourceProtocol(),
            "http": HTTPResourceProtocol(),
            "pkgfile": PackageResourceProtocol(),
        }

        return resource_protocols

    #### Methods ##############################################################

    def file(self, url):
        """Return a readable file-like object for the specified url."""

        protocol_name, address = url.split("://")

        protocol = self.resource_protocols.get(protocol_name)
        if protocol is None:
            raise ValueError("unknown protocol in URL %s" % url)

        return protocol.file(address)