/// <summary>
/// Converts a normalized binary expression into the appropriate ParseQuery clause.
/// </summary>
private static ParseQuery <T> WhereBinaryExpression <T>(
this ParseQuery <T> source, Expression <Func <T, bool> > expression, BinaryExpression node)
where T : ParseObject
{
var leftTransformed = new ObjectNormalizer().Visit(node.Left) as MethodCallExpression;
if (!(IsParseObjectGet(leftTransformed) &&
leftTransformed.Object == expression.Parameters[0]))
{
throw new InvalidOperationException(
"Where expressions must have one side be a field operation on a ParseObject.");
}
var fieldPath = GetValue(leftTransformed.Arguments[0]) as string;
var filterValue = GetValue(node.Right);
if (filterValue != null && !ParseEncoder.IsValidType(filterValue))
{
throw new InvalidOperationException(
"Where clauses must use types compatible with ParseObjects.");
}
switch (node.NodeType)
{
case ExpressionType.GreaterThan:
return(source.WhereGreaterThan(fieldPath, filterValue));
case ExpressionType.GreaterThanOrEqual:
return(source.WhereGreaterThanOrEqualTo(fieldPath, filterValue));
case ExpressionType.LessThan:
return(source.WhereLessThan(fieldPath, filterValue));
case ExpressionType.LessThanOrEqual:
return(source.WhereLessThanOrEqualTo(fieldPath, filterValue));
case ExpressionType.Equal:
return(source.WhereEqualTo(fieldPath, filterValue));
case ExpressionType.NotEqual:
return(source.WhereNotEqualTo(fieldPath, filterValue));
default:
throw new InvalidOperationException(
"Where expressions do not support this operator.");
}
}
public async Task<IList<Site>> GetSites(string searchText, double latitude = 0, double longitude = 0)
{
var sitesQuery = new ParseQuery<ApParseSite>()
.OrderByDescending(x => x.UseCount)
.Limit(100);
if (!string.IsNullOrEmpty(searchText))
{
var lowerSearchText = searchText.ToLower();
sitesQuery = sitesQuery.Where(s => s.Search.Contains(lowerSearchText));
}
else
{
sitesQuery = sitesQuery.WhereGreaterThan("UseCount", 1000);
}
var allSites = (await sitesQuery.FindAsync())
.Select(s => ConvertToSite(s, new ParseGeoPoint(latitude, longitude)));
// Remove duplicates
var siteIds = new HashSet<long>();
var sites = new List<Site>();
foreach (var site in allSites)
{
if (site.SiteId.HasValue)
{
if (!siteIds.Contains(site.SiteId.Value))
{
siteIds.Add(site.SiteId.Value);
sites.Add(site);
}
}
}
return sites
.OrderByDescending(s => s.DistanceKm)
.ThenBy(s => s.UseCount)
.ToList();
}