private static string ComputeNewObject(Expression predicate, RequestBuilderConfiguration configuration)
{
var newPredicate = (predicate as NewExpression);
var properties = newPredicate.Arguments.Select(a => ComputeMemberAccess(a, configuration));
return(string.Join(",", properties));
}
/// <summary>
/// Converts fields case depending on configuration provided
/// </summary>
/// <param name="fieldName"></param>
/// <param name="configuration"></param>
/// <returns></returns>
public static string Run(string fieldName, RequestBuilderConfiguration configuration)
{
return(configuration.CaseContract switch
{
CaseContract.SnakeCase => fieldName.ToSnakeCase(),
CaseContract.PascalCase => fieldName.ToPascalCase(),
CaseContract.CamelCase => fieldName.ToCamelCase(),
_ => fieldName
});
/// <summary>
/// Interprets a list of fields and add to each of them a "desc" sort modificator
/// </summary>
/// <param name="predicate"></param>
/// <param name="configuration"></param>
/// <returns></returns>
public static string Run(Expression predicate, RequestBuilderConfiguration configuration)
{
if (predicate is null)
{
throw new ArgumentNullException(nameof(predicate));
}
return(string.Join(",", MemberPredicateInterpreter.Run(predicate, configuration)
.Split(',').Select(s => s + " desc")));
}
private static string UnrollMemberPath(MemberExpression predicate, RequestBuilderConfiguration configuration)
{
var path = "";
if (predicate.Expression != null && predicate.Expression is MemberExpression)
{
path = UnrollMemberPath(predicate.Expression as MemberExpression, configuration) + ".";
}
return(path + FieldInterpreter.Run(predicate.Member.Name, configuration));
}
public void Setup()
{
snakeCaseConfiguration = new RequestBuilderConfiguration {
CaseContract = CaseContract.SnakeCase
};
camelCaseConfiguration = new RequestBuilderConfiguration {
CaseContract = CaseContract.CamelCase
};
pascalCaseConfiguration = new RequestBuilderConfiguration {
CaseContract = CaseContract.PascalCase
};
}
/// <summary>
/// Interprets the public properties of the generic type to generate a list of selects
/// </summary>
/// <typeparam name="T"></typeparam>
/// <returns></returns>
public static string Run <T>(RequestBuilderConfiguration configuration)
{
var properties = typeof(T)
.GetProperties();
var fields = new List <string>();
foreach (var p in properties)
{
fields.Add(GetFields(p, configuration));
}
return(string.Join(",", fields.Where(f => !string.IsNullOrEmpty(f))));
}
/// <summary>
/// Assembles a request from the statements
/// </summary>
/// <param name="selects"></param>
/// <param name="filters"></param>
/// <param name="excludes"></param>
/// <param name="orders"></param>
/// <param name="search"></param>
/// <param name="take"></param>
/// <param name="skip"></param>
/// <param name="configuration"></param>
/// <returns></returns>
public static string Run(
string selects,
string filters,
string excludes,
string orders,
string search,
int take,
int skip,
RequestBuilderConfiguration configuration
)
{
if (string.IsNullOrEmpty(selects))
{
throw new ArgumentNullException(nameof(selects));
}
string body = $"fields {selects};";
if (!string.IsNullOrEmpty(filters))
{
body += $"\nwhere {filters};";
}
if (!string.IsNullOrEmpty(excludes))
{
body += $"\nexclude {excludes};";
}
if (!string.IsNullOrEmpty(orders))
{
body += $"\nsort {orders};";
}
if (!string.IsNullOrEmpty(search))
{
body += $"\nsearch {search};";
}
if (take != default)
{
body += $"\nlimit {take.ToString(CultureInfo.InvariantCulture)};";
}
if (skip != default)
{
body += $"\noffset {skip.ToString(CultureInfo.InvariantCulture)};";
}
return(body);
}
private static string ComputeMemberAccess(Expression predicate, RequestBuilderConfiguration configuration)
{
var memberExpression = (predicate as MemberExpression);
switch (memberExpression.Member.MemberType)
{
case System.Reflection.MemberTypes.Property:
var path = UnrollMemberPath(memberExpression, configuration);
return(path);
default:
throw new NotImplementedException($"Works only with properties of the Generic object");
}
}
/// <summary>
/// Returns a member or list of members as a string from a predicate
/// </summary>
/// <param name="predicate"></param>
/// <param name="configuration"></param>
/// <returns></returns>
public static string Run(Expression predicate, RequestBuilderConfiguration configuration)
{
if (predicate is null)
{
throw new ArgumentNullException(nameof(predicate));
}
switch (predicate.NodeType)
{
case ExpressionType.MemberAccess:
return(ComputeMemberAccess(predicate, configuration));
case ExpressionType.New:
return(ComputeNewObject(predicate, configuration));
default:
throw new Exception("Invalid predicate provided");
}
}
private static string GetFields(PropertyInfo property, RequestBuilderConfiguration configuration, string parentPath = "")
{
var fields = new List <string>();
var path = parentPath + FieldInterpreter.Run(property.Name, configuration);
if (property.GetCustomAttribute <IncludeAttribute>() != null)
{
foreach (var p in property.PropertyType.GetProperties())
{
fields.Add(GetFields(p, configuration, path + "."));
}
}
else if (property.GetCustomAttribute <ExcludeAttribute>() == null)
{
fields.Add(path);
}
return(string.Join(",", fields));
}
private static string ComputeConstant(Expression constant, RequestBuilderConfiguration configuration)
{
var value = (constant as ConstantExpression).Value;
if (value is string)
{
return($"\"{(value as string).Replace("\"", "\\\"")}\"");
}
if (value is bool boolean)
{
return(boolean ? "true" : "false");
}
if (value is null)
{
return("null");
}
if (value is IConvertible)
{
return((value as IConvertible).ToString(CultureInfo.InvariantCulture));
}
return(value.ToString());
}
private static string ComputeMemberAccess(Expression predicate, RequestBuilderConfiguration configuration)
{
return(MemberPredicateInterpreter.Run(predicate, configuration));
}
/// <summary>
/// Interpretes a predicate to convert it to a string usable by IGDB API
/// </summary>
/// <param name="predicate"></param>
/// <returns></returns>
public static string Run(Expression predicate, RequestBuilderConfiguration configuration, bool invert = false, ArrayPostfixMode arrayPostfixMode = ArrayPostfixMode.ContainsAny)
{
if (predicate is null)
{
throw new ArgumentNullException(nameof(predicate));
}
var binaryPredicate = predicate as BinaryExpression;
switch (predicate.NodeType)
{
/*
* First part of switch : binary operators
* -------
* if Node type referes to a binary operators we set the operator
* and let the method continue after the switch to create the
* expression.
* binary operators are either logical operators (&& or ||),
* relational operators (>, >=, <, <=) or equality operators (==, !=)
*/
case ExpressionType.AndAlso:
return(ComputeBinaryOperator(binaryPredicate.Left, binaryPredicate.Right, "&", configuration));
case ExpressionType.OrElse:
return(ComputeBinaryOperator(binaryPredicate.Left, binaryPredicate.Right, "|", configuration));
case ExpressionType.GreaterThan:
return(ComputeBinaryOperator(binaryPredicate.Left, binaryPredicate.Right, ">", configuration));
case ExpressionType.GreaterThanOrEqual:
return(ComputeBinaryOperator(binaryPredicate.Left, binaryPredicate.Right, ">=", configuration));
case ExpressionType.LessThan:
return(ComputeBinaryOperator(binaryPredicate.Left, binaryPredicate.Right, "<", configuration));
case ExpressionType.LessThanOrEqual:
return(ComputeBinaryOperator(binaryPredicate.Left, binaryPredicate.Right, "<=", configuration));
case ExpressionType.NotEqual:
return(ComputeBinaryOperator(binaryPredicate.Left, binaryPredicate.Right, "!=", configuration));
case ExpressionType.Equal:
return(ComputeBinaryOperator(binaryPredicate.Left, binaryPredicate.Right, "=", configuration));
/*
* Second part of switch : members
* -------
* If node type refers to a member, a constant or an array then
* then return an interpretation.
*/
case ExpressionType.MemberAccess:
return(ComputeMemberAccess(predicate, configuration));
case ExpressionType.Constant:
return(ComputeConstant(predicate, configuration));
case ExpressionType.NewArrayInit:
return(ComputeArray(predicate, arrayPostfixMode, configuration));
/*
* Third part of switch : methods
* -------
* if node type referes to a method corresponding to
*/
case ExpressionType.Not:
return(ComputeNotCall(predicate, configuration));
case ExpressionType.Call:
return(ComputeMethodCall(predicate, configuration, invert));
default:
throw new InvalidPredicateException(predicate);
}
}
private static string ComputeArray(Expression array, ArrayPostfixMode arrayPostfixMode, RequestBuilderConfiguration configuration)
{
var list = string.Join(
",",
(array as NewArrayExpression).Expressions.Select(e => Run(e as ConstantExpression, configuration))
);
return(arrayPostfixMode switch
{
ArrayPostfixMode.ContainsAny => $"({list})",
ArrayPostfixMode.ContainsAll => $"[{list}]",
ArrayPostfixMode.ExactMatch => $"{{{list}}}",
_ => throw new Exception("Unknown array postfix mode"),
});
public void Setup()
{
configuration = new RequestBuilderConfiguration {
CaseContract = CaseContract.SnakeCase
};
}
private static string ComputeBinaryOperator(Expression left, Expression right, string binaryOperator, RequestBuilderConfiguration configuration)
{
var leftMember = Run(left, configuration);
var rightMember = Run(right, configuration);
return($"{leftMember} {binaryOperator} {rightMember}");
}
/// <summary>
/// Constructor.
/// </summary>
public RequestBuilder(RequestBuilderConfiguration configuration)
{
selects = "*";
orders = "";
this.configuration = configuration;
}