Parse(List <KeyValuePair <string, string> > queryStringParts)
{
if (queryStringParts.Count == 0)
{
return(null);
}
if (queryStringParts.Count == 1)
{
string arg = queryStringParts[0].Value;
switch (queryStringParts[0].Key)
{
case "$skip":
return((IQDict qbl) => qbl.Skip(int.Parse(arg)));
case "$take":
return((IQDict qbl) => qbl.Take(int.Parse(arg)));
case "$filter":
var expParser = new ODataExpressionParser();
var cond = expParser.ParseToLambda(arg);
return((IQDict qbl) => qbl.Where(cond));
default:
return(null);
}
}
var partExpressions = queryStringParts
.Select(qsp => new { Key = qsp.Key, Value = Parse(new List <KeyValuePair <string, string> > {
qsp
}) })
.Where(pe => pe.Value != null)
.ToDictionary(pe => pe.Key, pe => pe.Value);
Expression <Func <IQDict, IQDict> > res = null;
partExpressions
.OrderBy(pe => pe.Key) // happens to work the right way
.Do(pe =>
{
if (res == null)
{
res = pe.Value;
}
else
{
res = Expression.Lambda <Func <IQDict, IQDict> >(Expression.Invoke(pe.Value, res.Body), res.Parameters);
}
});
return(res);
}
public Expression<Func<IQDict, IQDict>> Parse(List<KeyValuePair<string, string>> queryStringParts)
{
if (queryStringParts.Count == 0)
return null;
if (queryStringParts.Count == 1)
{
string arg = queryStringParts[0].Value;
switch (queryStringParts[0].Key)
{
case "$skip":
return (IQDict qbl) => qbl.Skip(int.Parse(arg));
case "$take":
return (IQDict qbl) => qbl.Take(int.Parse(arg));
case "$filter":
var expParser = new ODataExpressionParser();
var cond = expParser.ParseToLambda(arg);
return (IQDict qbl) => qbl.Where(cond);
default:
return null;
}
}
var partExpressions = queryStringParts
.Select(qsp => new { Key = qsp.Key, Value = Parse(new List<KeyValuePair<string, string>> { qsp }) })
.Where(pe => pe.Value != null)
.ToDictionary(pe => pe.Key, pe => pe.Value);
Expression<Func<IQDict, IQDict>> res = null;
partExpressions
.OrderBy(pe => pe.Key) // happens to work the right way
.Do(pe =>
{
if (res == null)
res = pe.Value;
else
{
res = Expression.Lambda<Func<IQDict, IQDict>>(Expression.Invoke(pe.Value, res.Body), res.Parameters);
}
});
return res;
}
