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95 e Hyperlink URLs may include example operation requests
f Hyperlink URL that is a complete KVP-encoded basic GetCapabilities operation request, included in a manner that allows a CSW catalogue to find it.
NOTE 1 A CSW catalogue can then use this GetCapabilities operation request to harvest server
metadata. One possible approach is to record this basic GetCapabilities operation request in an anchor A element with the ―type‖ attribute value of ―GetCapabilities‖.
EDITOR’S QUESTIONS The goal is to allow a CSW catalogue to automatically harvest all the servers andor services referenced on a HTML web page. How should the basic GetCapabilities
operation request be encoded on such a HTML web page, to make it easy for a CSW catalogue to easily find it? How else could these HTML web pages reference XML documents that a CSW
catalog might harvest to obtain server metadata?
NOTE 2 An added benefit to this approach is that web indexing tools based on web crawlers or other
information discovery and indexing mechanisms will eventually contain references to this data and thus serve to locate and advertise OWS-compliant services.
EDITOR’S QUESTION How should this subclause be modified to support SOAP encoding
of operation requests and responses?
12.6 Valid URLs in operation requests and responses
Most URLs included in operation requests and responses should be links to actual and correct documents, or to other web resources. These recommendations apply to responses
from and requests to all operations implemented. However, these recommendations are most important in GetCapabilities operation responses.
NOTE 1 This subclause applies when URLs are used where URIs are permitted.
More specifically, all URLs included in operation responses and requests should be links to actual resources that will be retrieved if this URL is used in a HTTP GET. In some
cases, the nature of the resource at that URL is not specified. However in other cases, the subject andor format of the resource at that URL is specified by the specific OWS. When
the subject andor format of the resource at that URL are specified, the resource available there should be as specified. If XML document contents and format are specified by a
XML Schema, the available document should be a valid instance of the specified XML Schema, and should reference that XML Schema.
One exception to URLs being links to actual documents are the URLs that are HTTP connect point URLs, as specified in Subclause 7.4.5 and in the ows:RequestMethodType
in owsOperationsMetadata.xsd. Those URLs serve the functions specified in Subclauses 7.4.5, 11.2, and 11.4.
Another common exception to URLs being links to actual documents are URLs that are used to identify XML Schema namespaces. However, URLs used to identify XML
Schema namespaces can reference a resource that describes that namespace, and that is recommended. In particular, when a URL beginning with ―
http:www.opengis.net ‖ is
used to identify a XML Schema namespace, that URL should reference a HTML Web page that describes that namespace.
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EDITOR’S QUESTION: Should the URL for a namespace reference a RDDL Resource Directory Description Language document like the one found at
http:www.opengis.netgml ?
For operation responses, it is the responsibility of the server provider to try to ensure that these URLs link to actual and correct resources. For operation requests, it is the
responsibility of the organization operating each client to try to ensure that these URLs link to actual and correct resources. The word try is used because there are multiple
ways for resources to be available at most times, but not at other times.
By nature, the Internet can make remote references sometimes unreachable. When this occurs for URLs in operation requests, and the server is able to detect this occurrence and
to respond to it, the server should return a valid Exception Message, or at least an applicable HTTP status code. Other types of server outputs, such as HTML text or an
image, should be avoided, to simplify software management of the problem.
NOTE 2 If the document at a URL is not as specified or is not reachable, then how a client reacts is
undefined. This is undefined because there are several possible client reactions, depending upon the nature of the client software. Some possible reactions are to show an error message to the user, retry at a later
time, fail silently, log the situation, or connect to another similar service.
EDITOR’S QUESTION How should this subclause be modified to support SOAP encoding of operation requests and responses?
12.7 Can define more XML global names
