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Diffstat (limited to '')
| -rw-r--r-- | synapse/util/httpresourcetree.py | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/synapse/util/httpresourcetree.py b/synapse/util/httpresourcetree.py new file mode 100644 index 0000000000..45be47159a --- /dev/null +++ b/synapse/util/httpresourcetree.py @@ -0,0 +1,98 @@ +# Copyright 2016 OpenMarket Ltd +# +# Licensed under the Apache License, Version 2.0 (the "License"); +# you may not use this file except in compliance with the License. +# You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +# See the License for the specific language governing permissions and +# limitations under the License. + +from twisted.web.resource import Resource + +import logging + +logger = logging.getLogger(__name__) + + +def create_resource_tree(desired_tree, root_resource): + """Create the resource tree for this Home Server. + + This in unduly complicated because Twisted does not support putting + child resources more than 1 level deep at a time. + + Args: + web_client (bool): True to enable the web client. + root_resource (twisted.web.resource.Resource): The root + resource to add the tree to. + Returns: + twisted.web.resource.Resource: the ``root_resource`` with a tree of + child resources added to it. + """ + + # ideally we'd just use getChild and putChild but getChild doesn't work + # unless you give it a Request object IN ADDITION to the name :/ So + # instead, we'll store a copy of this mapping so we can actually add + # extra resources to existing nodes. See self._resource_id for the key. + resource_mappings = {} + for full_path, res in desired_tree.items(): + logger.info("Attaching %s to path %s", res, full_path) + last_resource = root_resource + for path_seg in full_path.split('/')[1:-1]: + if path_seg not in last_resource.listNames(): + # resource doesn't exist, so make a "dummy resource" + child_resource = Resource() + last_resource.putChild(path_seg, child_resource) + res_id = _resource_id(last_resource, path_seg) + resource_mappings[res_id] = child_resource + last_resource = child_resource + else: + # we have an existing Resource, use that instead. + res_id = _resource_id(last_resource, path_seg) + last_resource = resource_mappings[res_id] + + # =========================== + # now attach the actual desired resource + last_path_seg = full_path.split('/')[-1] + + # if there is already a resource here, thieve its children and + # replace it + res_id = _resource_id(last_resource, last_path_seg) + if res_id in resource_mappings: + # there is a dummy resource at this path already, which needs + # to be replaced with the desired resource. + existing_dummy_resource = resource_mappings[res_id] + for child_name in existing_dummy_resource.listNames(): + child_res_id = _resource_id( + existing_dummy_resource, child_name + ) + child_resource = resource_mappings[child_res_id] + # steal the children + res.putChild(child_name, child_resource) + + # finally, insert the desired resource in the right place + last_resource.putChild(last_path_seg, res) + res_id = _resource_id(last_resource, last_path_seg) + resource_mappings[res_id] = res + + return root_resource + + +def _resource_id(resource, path_seg): + """Construct an arbitrary resource ID so you can retrieve the mapping + later. + + If you want to represent resource A putChild resource B with path C, + the mapping should looks like _resource_id(A,C) = B. + + Args: + resource (Resource): The *parent* Resourceb + path_seg (str): The name of the child Resource to be attached. + Returns: + str: A unique string which can be a key to the child Resource. + """ + return "%s-%s" % (resource, path_seg) |