/// <summary/>
private static IEnumerable<KeyValuePair<string,T>> ApplyPath<T>(JToken root, string path)
{
// Children
var children = SelectChildren<T>(root, path);
foreach(var token in children)
{
// Token => T
var value = (T)JsonFunctions.ConvertToken(token, typeof(T));
// Tuple(path, value)
yield return new KeyValuePair<string,T>(token.Path, value);
}
}
/// <summary/>
internal static object ConvertToken(JToken token, Type type)
{
try
{
if(type == typeof(string))
{
return JsonFunctions.GetTokenString(token);
}
// We simply delegate to Json.Net for data conversions
return token.ToObject(type);
}
catch(Exception e)
{
// Make this easier to debug (with field and type context)
// Note: We don't expose the actual value to be converted in the error message (since it might be sensitive, information disclosure)
throw new JsonSerializationException(
string.Format(typeof(JsonToken).Namespace + " failed to deserialize '{0}' from '{1}' to '{2}'", token.Path, token.Type.ToString(), type.FullName),
e);
}
}
protected override void JObjectToRow(JObject o, IUpdatableRow row)
{
if (jsonPaths.Length == 0)
{
base.JObjectToRow(o, row);
}
else
{
for (int i = 0; i < jsonPaths.Length; i++)
{
var path = jsonPaths[i];
var jObj = findByPath(o, path);
object value = null;
if (jObj != default(JToken))
{
var schemaColumn = row.Schema[i];
value = JsonFunctions.ConvertToken(jObj, schemaColumn.Type) ?? schemaColumn.DefaultValue;
}
row.Set <object>(i, value);
}
}
}
/// <summary/>
protected virtual void JObjectToRow(JObject o, IUpdatableRow row)
{
foreach (var c in row.Schema)
{
JToken token = null;
object value = c.DefaultValue;
// All fields are represented as columns
// Note: Each JSON row/payload can contain more or less columns than those specified in the row schema
// We simply update the row for any column that matches (and in any order).
if (o.TryGetValue(c.Name, out token) && token != null)
{
// Note: We simply delegate to Json.Net for all data conversions
// For data conversions beyond what Json.Net supports, do an explicit projection:
// ie: SELECT DateTime.Parse(datetime) AS datetime, ...
// Note: Json.Net incorrectly returns null even for some non-nullable types (sbyte)
// We have to correct this by using the default(T) so it can fit into a row value
value = JsonFunctions.ConvertToken(token, c.Type) ?? c.DefaultValue;
}
// Update
row.Set <object>(c.Name, value);
}
}
/// <summary/>
internal static object ConvertToken(JToken token, Type type)
{
try
{
if (type == typeof(string))
{
return(JsonFunctions.GetTokenString(token));
}
if (type == typeof(byte[]))
{
var bytes = Encoding.UTF8.GetBytes(JsonFunctions.GetTokenString(token));
using (var msi = new MemoryStream(bytes))
using (var mso = new MemoryStream())
{
using (var gs = new GZipStream(mso, CompressionLevel.Optimal))
{
msi.CopyTo(gs);
}
return(mso.ToArray());
};
}
// We simply delegate to Json.Net for data conversions
return(token.ToObject(type));
}
catch (Exception e)
{
// Make this easier to debug (with field and type context)
// Note: We don't expose the actual value to be converted in the error message (since it might be sensitive, information disclosure)
throw new JsonSerializationException(
string.Format(typeof(JsonToken).Namespace + " failed to deserialize '{0}' from '{1}' to '{2}'", token.Path, token.Type.ToString(), type.FullName),
e);
}
}