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Encoding of folder names, namespaces, and ids in Winery

Outdated Although the information about double-encoding is correct, the UI has been re-implemented using Angular, which introduces an additional layer of URLs.

Example to understand double encoding of URIs in Winery

In file systems, characters / and : are not allowed source. The design decision is that all files (node types, imports in CSARs, ...) are stored and structured using directories with human readable names. Therefore, the namespace URI must be used in a encoded form, otherwise the name would not be valid (http://www...). An example for such a directory name is http%3A%2F%2Fwww.w3.org%2F2001%2FXMLSchema. Since (1) namespaces are URIs and (2) percent-encoded URIs form valid directory names, URL encoding is used.

For a better understanding we distinguish two cases:

(1) calling a URL and (2) linking to the location of an tosca import in a tosca XML file contained in the CSAR.

First case: Calling a URL

When using the Winery UI to show a Node Type the following URL is used by the browser: http://localhost:8080/winery/nodetypes/http%253A%252F%252Fopentosca.org%252Fnodetypes/Java8/ The convention for URLs in the winery are: winery/type/namespace/id (see DevGuide).

  • winery: http://localhost:8080/winery/
  • type: nodetypes
  • namespace: http%253A%252F%252Fopentosca.org%252Fnodetypes
  • id: Java8

We have a closer look to the namespace part http%253A%252F%252Fopentosca.org%252Fnodetypes: The '/' and ':' of the URI are double percent-encoded, i.e., : is encoded --> %3A is encoded --> %253A (% is encoded --> %25).

If no double encoding whould be used http://localhost:8080/winery/nodetypes/http%3A%2F%2Fopentosca.org%252Fnodetypes/Java8/ whould be the used URL. Web servers such as Apache Tomcat [1, 2], Apache [3,4], nginx [5], and JBoss [6] forbit this due to security issues. See

Note that %2F and / are not the same in an URI: See Example 2 in W3C's URI recommendations.

Second Case: Encoding of directory names

As already mentioned, URLs used in directory names must be encoded. In XML files the location of an tosca:import is, for instance given as: ../imports/http%253A%252F%252Fwww.w3.org%252F2001%252FXMLSchema/http%253A%252F%252Fopentosca.org%252Fproperties/TopicProperties/TopicProperties.xsd, which represents the path of the file. The attribute location is of type anyURI, i.e., this part has to be decoded. If only single encouding is used like ../imports/http%3A%2F%2Fwww.w3.org... the decoding whould lead to ../imports/http://www.w3.org..., which is not a valid URI and also not a valid file name. Summary: Because the namespace is part of the used URIs and the ns itself is a URI too this double encoding is required.

License

Copyright (c) 2017 University of Stuttgart.

All rights reserved. This program and the accompanying materials are made available under the terms of the Eclipse Public License v1.0 and the Apache License v2.0 which both accompany this distribution.