3.2.5.3 DISCOVERY-REQUEST

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The server MUST query BITS Peer-Caching: Peer Authentication for the presence of certificate as specified in BITS Peer-Caching: Peer Authentication section 3.1.6.1. If BITS Peer-Caching: Peer Authentication reports that client's certificate is not present in the table of peer certificates, the server MUST return a DISCOVERY-RESPONSE with the value of the SearchResults/Status element set to "CertificateNotFound".

If the URL of the message is not "/BITS-peer-caching", the server MUST reply with an HTTP error response, as specified in section 3.2.5.1, using an HTTP status code of 404.

The server validates the message in the following ways:

  • The request MUST contain a Content-Length header. If it does not, the server MUST reply with an HTTP error response, as specified in section 3.2.5.1, using an HTTP status code of 411.

  • The value of the Content-Length header MUST be greater than zero and even. If it is not, the server MUST reply with an HTTP error response, as specified in section 3.2.5.1, using an HTTP status code of 400.

The server SHOULD impose a limit on the size of the HTTP headers and the XML body.<22> The limit on the XML body MUST be at least 16 kilobytes.

The server then checks the XML body for syntactic correctness. A parsing error causes the server to return a DISCOVERY-RESPONSE containing only the <SearchResults> and <SearchResults>/<Status> elements, with the <Status> element describing the error category. For the allowable values of <Status>, see section 2.2.1.3.

After the message is validated, the server searches the table of content records for records that match all the provided criteria. Such records are placed in an unordered list; the list is truncated (if necessary) to conform to the provided <MaxRecords> value.

If the list is empty, the server sends a DISCOVERY-RESPONSE message with the <SearchResults>/<Status> element set to "ContentNotFound". Otherwise, the server sends a DISCOVERY-RESPONSE message with the <SearchResults>/<Status> element set to "Success"; the message contains one <SearchResults>/<CacheRecord> element for each record in the truncated list.<23>