/// <summary>
/// Get all GraphQL fields to query for given a Type. The Type needs to
/// have JsonPath attributes specified for its properties for them to
/// be included.
/// </summary>
/// <param name="inputType">Type of the class</param>
/// <param name="convert">Convert the fields to GraphQL</param>
/// <returns>List of (nested) GrapQL fields</returns>
private static string[] GetQueryFields(Type inputType, bool convert = true)
{
// the type could be an array for which we need to know the child
// types so we make a copy that we can overwrite.
Type type = inputType.IsArray && inputType.HasElementType
? inputType.GetElementType()
: inputType;
// Each property that we're querying in the GraphQL response needs
// to have a JsonPath attribute. This function will return the
// properties that have an attribute.
PropertyInfo[] properties = JsonPath.GetJsonPathProperties(type);
// The JsonPath attribute is a JSONP string, so we need to translate
// that into a GraphQL query list.
List <string> fields = new List <string>();
// we need to cleanup some of the JSONPath specific things from the string
// for which we use this regular expression.
Regex regex = new Regex("[^a-zA-Z.0-9]+");
foreach (PropertyInfo property in properties)
{
JsonPath attribute = JsonPath.GetJsonPathAttribute(property);
// this removes all characters that we don't want
string cleanName = regex.Replace(attribute.Path, "");
// depending on the property type we need to handle this
// differently.
Type propertyType = property.PropertyType;
if (propertyType.IsArray && propertyType.HasElementType)
{
propertyType = propertyType.GetElementType();
}
// we need to do this recursively, otherwise we can just work
// with primitives we don't recurse built-in classes.
if (IsBasicType(propertyType))
{
fields.Add(cleanName);
continue;
}
string[] childFields = GetQueryFields(property.PropertyType, false);
foreach (string childField in childFields)
{
fields.Add(string.Concat(cleanName, childField));
}
}
if (convert)
{
return(GraphQLFieldsFromJsonp(fields.ToArray()));
}
return(fields.ToArray());
}
/// <summary>
/// Converts a JObject to a .NET object as per the provided type name
/// </summary>
/// <param name="objectData">JObject data to convert</param>
/// <param name="type">Target type</param>
/// <returns>Populated object</returns>
public object ObjectFromJObject(JObject objectData, Type type)
{
if (objectData == null)
{
return(null);
}
// initialize empty result object
object result = Activator.CreateInstance(type);
// Each property that we're querying in the GraphQL response needs
// to have a JsonPath attribute. We will only convert the properties
// that have the JsonPath property set.
PropertyInfo[] properties = JsonPath.GetJsonPathProperties(type);
foreach (PropertyInfo property in properties)
{
try
{
// there should only be one of these attributes be specified
JsonPath attribute = JsonPath.GetJsonPathAttribute(property);
string jsonPath = attribute.Path;
// depending on the type, we need to handle the conversion
// differently.
Type propertyType = property.PropertyType;
if (!propertyType.IsArray)
{
JToken element = objectData.SelectToken(jsonPath, false);
if (element == null)
{
continue;
}
// numbers, booleans and strings can easily be handled
// by just moving over the value.
if (propertyType.IsValueType || propertyType == typeof(string))
{
property.SetValue(result, element.ToObject(property.PropertyType));
continue;
}
// objects (that we support) will be handled recursively
JObject elementData = element.Value <JObject>();
property.SetValue(result, ObjectFromJObject(elementData, property.PropertyType));
continue;
}
// for an array, we need to know the child type and
// instantiate every single element individually and we
// need to add "[*]" to the JSON path to the array is
// unfolded (if it is not properly set).
if (jsonPath.IndexOf("[*]") == -1)
{
jsonPath = string.Concat(jsonPath, @"[*]");
}
Type elementType = property.PropertyType.GetElementType();
List <object> tmp = new List <object>();
try
{
IEnumerable <JToken> elements = objectData.SelectTokens(jsonPath, false);
if (elements == null)
{
property.SetValue(result, Array.CreateInstance(elementType, 0));
continue;
}
foreach (var childElement in elements)
{
// numbers, booleans and strings can easily
// be handled by just moving over the value.
if (elementType.IsValueType || elementType.Equals(typeof(string)))
{
tmp.Add(childElement.ToObject(elementType));
continue;
}
JObject childData = childElement.Value <JObject>();
tmp.Add(ObjectFromJObject(childData, elementType));
}
}
catch (Exception err)
{
Logger.WriteDebug(err.Message);
}
Array test = Array.CreateInstance(elementType, tmp.Count);
for (int i = 0; i < test.Length; i++)
{
test.SetValue(tmp[i], i);
}
property.SetValue(result, test);
}
catch (Exception ex)
{
string errorMessage = string.Concat(
"Error converting property '",
property.Name,
"' of type '",
property.PropertyType.Name,
"': ",
ex.Message
);
Logger.WriteWarning(errorMessage);
}
}
return(result);
}
private static string FormatGraphQLValue(object value, int depth = 0)
{
// some types require recursion as they can't be directly
// converted. There is a maximum depth we're using to avoid stack
// overflow. For null values we just return an empty string.
if (value == null || depth > MAX_RECURSION_DEPTH)
{
return(@"");
}
// string is probably the most common one.
// for strings, we need to add " and escape quotes.
if (value is string)
{
string input = (string)value;
string output = string.Concat("\"", input.Replace("\"", "\\\""), "\"");
return(output);
}
// GUIDs are a special type of string
if (value is Guid)
{
Guid input = (Guid)value;
string output = string.Concat("\"", input.ToString(), "\"");
return(output);
}
// boolean are expected to be lower case.
if (value is bool?)
{
bool?input = (bool?)value;
if (input.HasValue)
{
string output = input.ToString().ToLowerInvariant();
return(output);
}
return("");
}
// boolean are expected to be lower case.
if (value is bool)
{
bool input = (bool)value;
string output = input.ToString().ToLowerInvariant();
return(output);
}
// DateTime values are expected to be in JSON format.
if (value is DateTime)
{
DateTime input = (DateTime)value;
string output = string.Concat("\"", input.ToString("yyyy-MM-ddTHH:MM:ss.sssZ"), "\"");
return(output);
}
// numbers can be directly converted using their internal to string.
if (value is ValueType)
{
if (value is byte ||
value is short ||
value is int ||
value is long ||
value is sbyte ||
value is ushort ||
value is uint ||
value is ulong ||
value is float ||
value is double ||
value is decimal)
{
string output = value.ToString();
return(output);
}
}
// enumerations can be directly converted. This only works if the
// enumeration in C# is named exactly as in the GraphQL API.
if (value is Enum)
{
string output = value.ToString();
return(output);
}
// for arrays we don't care about the array's child types as they
// will be handled by a recursive function
if (value is Array)
{
IEnumerable input = value as IEnumerable;
List <string> inputList = new List <string>();
foreach (object element in input)
{
string fValue = FormatGraphQLValue(element, depth + 1);
// exclude empty values (strings that are of length 0.
// note that if the parameter supplies an empty string,
// it will actually be '\"\"' that is returned by
// FormatGraphQLValue, so this still works
if (string.IsNullOrEmpty(fValue))
{
continue;
}
inputList.Add(fValue);
}
// create an output string. We don't need to handle the case
// where inputList length is 0 as string.Join does that for us.
string output = string.Concat(@"[", string.Join(@",", inputList), @"]");
return(output);
}
// for GraphQLParameters we also need to apply recursion. If the
// rest of the code is adhering to a standard, this should only be
// called once and the recursion is not needed.
if (value is GraphQLParameters)
{
GraphQLParameters input = (GraphQLParameters)value;
string output = string.Concat(@"{", input.ToString(), @"}");
return(output);
}
// here we format every remaining object type. We recursively
// include every property that has the JsonPath attribute defined.
PropertyInfo[] properties = JsonPath.GetJsonPathProperties(value);
if (properties.Length > 0)
{
List <string> inputList = new List <string>();
foreach (PropertyInfo property in properties)
{
// this will return the first attribute matching. We don't
// need to check for null as the properties list is already
// filtered for only properties with the JsonPath attribute.
JsonPath attr = JsonPath.GetJsonPathAttribute(property);
// try formatting the value. If it is null, we won't add it
// to the parameter list.
string fValue = FormatGraphQLValue(property.GetValue(value), depth + 1);
if (string.IsNullOrEmpty(fValue))
{
continue;
}
string element = string.Concat(attr.BasePath, @":", fValue);
inputList.Add(element);
}
// if there are no property values set, we consider this an
// empty parameter set and we return an empty string.
if (inputList.Count == 0)
{
return(@"");
}
string output = string.Concat(@"{", string.Join(@",", inputList), @"}");
return(output);
}
// Catch all. We should not reach this.
throw new NebException("unsupported object type supplied");
}
