/// <summary>
/// Builds the uri for purpose of probing any remaining entries satisfying the request of service context
/// use the last entry's token in the feed as the marker of skiptoken;
/// and reduce the $top count if top was in context request URI.
/// </summary>
/// <param name="context">The service context object</param>
/// <returns>Uri object if a meaningful prober can be constructed; null otherwise </returns>
private static Uri ConstructProbeUri(ServiceContext context)
{
Uri result = null;
JObject response = JsonParserHelper.GetResponseObject(context);
if (response != null)
{
JArray entries = JsonParserHelper.GetEntries(response);
if (entries != null)
{
JObject lastEntry = JsonParserHelper.GetLastEntry(entries);
if (lastEntry != null)
{
string lastToken = JsonParserHelper.GetTokenOfEntry(lastEntry);
string lastTokenOfValues = ResourcePathHelper.GetValuesOfKey(lastToken);
var uri = context.Destination;
ResourcePathHelper pathHelper = new ResourcePathHelper(uri);
// replace top value with the reduced value, if $top was in context request
string topValue = pathHelper.GetQueryValue("$top");
if (!string.IsNullOrEmpty(topValue))
{
pathHelper.RemoveQueryOption("$top");
int entriesGot = entries.Count;
int entriesToGet;
if (Int32.TryParse(topValue, out entriesToGet) && entriesToGet > entriesGot)
{
int entriesLeft = entriesToGet - entriesGot;
pathHelper.AddQueryOption("$top", entriesLeft.ToString(CultureInfo.InvariantCulture));
}
}
// set up new skiptoken query
pathHelper.RemoveQueryOption("$skiptoken");
pathHelper.AddQueryOption("$skiptoken", lastTokenOfValues);
result = new Uri(pathHelper.Product);
}
}
}
return result;
}
