All resources are visible to WK/C

[jannewmarch]

The draft-ietf-core-resource-directory-09 adds a Resource Directory (RD) to CoAP. It adds a number of resources such as rd.core-lookup which should be findable through WK/C but also a number of resources such as rd.core-lookup/res which probably should not. Remote resources added to the RD almost certainly should not be findable from WK/C. I suggest the following changes to resource.py to add another attribute to a resource. There should be no changes required to existing programs. This conforms to RFC 6690 Section 4 " It is, however, up to the application which links are included and how they are organized."

def add_resource(self, path, resource, dont_add_to_WKC=False):
    # Parameter dont_add_to_WKC is to make resource invisible to WKC
    # Default is visible
    self._resources[tuple(path)] = resource
    if dont_add_to_WKC:
        # set a new attribute on the resource
        resource.dont_add_to_WKC = True

and

def get_resources_as_linkheader(self):
    import link_header

    links = []
    for path, resource in self._resources.items():
        # skip resources with dont_add_to_WKC set
        if hasattr(resource, 'dont_add_to_WKC'):
            continue
        if hasattr(resource, "get_link_description"):
            details = resource.get_link_description()
        else:
            details = {}
        lh = link_header.Link('/' + '/'.join(path), **details)

        links.append(lh)
    return link_header.LinkHeader(links)

Called by

# visible to WK/C, standard use
root.add_resource(('rd-lookup',),
                  ResourceDirectoryLookup(resource_directory))
# not visible to WKC
root.add_resource(('rd-lookup','res'),
                  ResourceDirectoryLookupResources(resource_directory),
                  True)

[chrysn]

good point, i'll add something. (probably it'll be called .hidden or similar, and come with a more explicit interface in terms of inheritance). if you are working on rd, be sure to check out the recent ``rd`` branch, which contains an implementation of the resource directory. (my rd-lookup/* resources are actually still visible, but it did not occur to me to hide them since most whoever is looking for a compact lookup would ?rt=core.rd* anyway, and their presence makes the rd easier to use with rd-agnostic gui tools like copper).