/// <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;
}
/// <summary>
/// Builds the uri for purpose of probing the empty feed based on the base uri string.
/// </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)
{
int safetyTopping = 20;
Uri result = null;
// find out how many entries in the base feed
Uri uriFeedCount = new Uri(context.DestinationBasePath + "/$count");
var resp = WebHelper.Get(uriFeedCount, Constants.AcceptHeaderAtom, RuleEngineSetting.Instance().DefaultMaximumPayloadSize, context.RequestHeaders);
if (resp.StatusCode.HasValue && resp.StatusCode.Value == System.Net.HttpStatusCode.OK && !string.IsNullOrEmpty(resp.ResponsePayload))
{
string payload = resp.ResponsePayload.Trim();
int count = 0;
if (Int32.TryParse(payload, out count) && count >= 0)
{
int countToSkip = count + safetyTopping;
Uri uriBaseFeed = new Uri(context.DestinationBasePath);
ResourcePathHelper pathHelper = new ResourcePathHelper(uriBaseFeed);
pathHelper.AddQueryOption("$skip", countToSkip.ToString(CultureInfo.InvariantCulture));
result = new Uri(pathHelper.Product);
}
}
return result;
}