/// <summary>
/// We compile each entityQuery with EqlCompiler and build a Select call from the fields
/// </summary>
/// <param name="context"></param>
/// <returns></returns>
public override IGraphQLBaseNode VisitEntityQuery(EntityGraphQLParser.EntityQueryContext context)
{
string name;
string query;
if (context.alias != null)
{
name = context.alias.name.GetText();
query = context.entity.GetText();
}
else
{
query = context.entity.GetText();
name = query;
if (name.IndexOf(".") > -1)
{
name = name.Substring(0, name.IndexOf("."));
}
if (name.IndexOf("(") > -1)
{
name = name.Substring(0, name.IndexOf("("));
}
}
try
{
CompiledQueryResult result = null;
if (selectContext == null)
{
// top level are queries on the context
result = EqlCompiler.Compile(query, schemaProvider, methodProvider, variables);
}
else
{
result = EqlCompiler.CompileWith(query, selectContext, schemaProvider, methodProvider, variables);
}
var exp = result.ExpressionResult;
IGraphQLNode graphQLNode = null;
if (exp.Type.IsEnumerableOrArray())
{
graphQLNode = BuildDynamicSelectOnCollection(result, name, context);
}
else
{
// Could be a list.First() that we need to turn into a select, or
// other levels are object selection. e.g. from the top level people query I am selecting all their children { field1, etc. }
// Can we turn a list.First() into and list.Select().First()
var listExp = Compiler.Util.ExpressionUtil.FindIEnumerable(result.ExpressionResult);
if (listExp.Item1 != null)
{
// yes we can
// rebuild the ExpressionResult so we keep any ConstantParameters
var item1 = (ExpressionResult)listExp.Item1;
item1.AddConstantParameters(result.ExpressionResult.ConstantParameters);
graphQLNode = BuildDynamicSelectOnCollection(new CompiledQueryResult(item1, result.ContextParams), name, context);
graphQLNode.SetNodeExpression((ExpressionResult)Compiler.Util.ExpressionUtil.CombineExpressions(graphQLNode.GetNodeExpression(), listExp.Item2));
}
else
{
graphQLNode = BuildDynamicSelectForObjectGraph(query, name, context, result);
}
}
// the query result may be a mutation
if (result.IsMutation)
{
return(new GraphQLMutationNode(result, graphQLNode));
}
return(graphQLNode);
}
catch (EntityGraphQLCompilerException ex)
{
throw SchemaException.MakeFieldCompileError(query, ex.Message);
}
}
/// Given a syntax of someField { fields, to, selection, from, object }
/// it will build the correct select statement
private IGraphQLNode BuildDynamicSelectForObjectGraph(string query, string name, EntityGraphQLParser.EntityQueryContext context, CompiledQueryResult rootField)
{
var selectWasNull = false;
if (selectContext == null)
{
selectContext = Expression.Parameter(schemaProvider.ContextType);
selectWasNull = true;
}
if (schemaProvider.TypeHasField(selectContext.Type.Name, name, new string[0]))
{
name = schemaProvider.GetActualFieldName(selectContext.Type.Name, name);
}
try
{
var exp = (Expression)rootField.ExpressionResult;
var oldContext = selectContext;
var rootFieldParam = Expression.Parameter(exp.Type);
selectContext = rootField.IsMutation ? rootFieldParam : exp;
// visit child fields. Will be field or entityQueries again
var fieldExpressions = context.fields.children.Select(c => Visit(c)).Where(n => n != null).ToList();
var graphQLNode = new GraphQLNode(schemaProvider, fragments, name, null, (ExpressionResult)selectContext, (rootField.IsMutation ? new ParameterExpression[] { rootFieldParam } : rootField.ContextParams.ToArray()), fieldExpressions, null);
if (rootField != null && rootField.ConstantParameters != null)
{
graphQLNode.AddConstantParameters(rootField.ConstantParameters);
}
selectContext = oldContext;
if (selectWasNull)
{
selectContext = null;
}
return(graphQLNode);
}
catch (EntityGraphQLCompilerException ex)
{
throw SchemaException.MakeFieldCompileError(query, ex.Message);
}
}
/// Given a syntax of someField { fields, to, selection, from, object }
/// it will build the correct select statement
private IGraphQLNode BuildDynamicSelectForObjectGraph(string query, string name, EntityGraphQLParser.EntityQueryContext context, QueryResult rootField)
{
var selectWasNull = false;
if (selectContext == null)
{
selectContext = Expression.Parameter(schemaProvider.ContextType);
selectWasNull = true;
}
if (schemaProvider.TypeHasField(selectContext.Type.Name, name, new string[0]))
{
name = schemaProvider.GetActualFieldName(selectContext.Type.Name, name);
}
try
{
Expression exp = rootField.LambdaExpression.Body;
var oldContext = selectContext;
var rootFieldParam = Expression.Parameter(exp.Type);
selectContext = rootField.IsMutation ? rootFieldParam : exp;
// visit child fields. Will be field or entityQueries again
var fieldExpressions = context.fields.children.Select(c => Visit(c)).Where(n => n != null).ToList();
var newExp = ExpressionUtil.CreateNewExpression(selectContext, fieldExpressions, schemaProvider);
var anonType = newExp.Type;
// make a null check from this new expression
if (!rootField.IsMutation)
{
newExp = Expression.Condition(Expression.MakeBinary(ExpressionType.Equal, selectContext, Expression.Constant(null)), Expression.Constant(null, anonType), newExp, anonType);
}
selectContext = oldContext;
var t = MergeConstantParametersFromFields(rootField, fieldExpressions, rootFieldParam);
var parameters = t.Item1;
var constantParameterValues = t.Item2;
var graphQLNode = new GraphQLNode(name, new QueryResult((ExpressionResult)newExp, parameters, constantParameterValues), (ExpressionResult)exp);
if (selectWasNull)
{
selectContext = null;
}
return(graphQLNode);
}
catch (EntityGraphQLCompilerException ex)
{
throw SchemaException.MakeFieldCompileError(query, ex.Message);
}
}
/// Given a syntax of someCollection { fields, to, selection, from, object }
/// it will build a select assuming 'someCollection' is an IEnumerables
private IGraphQLNode BuildDynamicSelectOnCollection(CompiledQueryResult queryResult, string name, EntityGraphQLParser.EntityQueryContext context)
{
var elementType = queryResult.BodyType.GetEnumerableOrArrayType();
var contextParameter = Expression.Parameter(elementType, $"param_{elementType}");
var exp = queryResult.ExpressionResult;
var oldContext = selectContext;
selectContext = contextParameter;
// visit child fields. Will be field or entityQueries again
var fieldExpressions = context.fields.children.Select(c => Visit(c)).Where(n => n != null).ToList();
var gqlNode = new GraphQLNode(schemaProvider, fragments, name, null, exp, queryResult.ContextParams, fieldExpressions, contextParameter);
selectContext = oldContext;
return(gqlNode);
}
/// Given a syntax of someCollection { fields, to, selection, from, object }
/// it will build a select assuming 'someCollection' is an IEnumerables
private IGraphQLNode BuildDynamicSelectOnCollection(QueryResult queryResult, string name, EntityGraphQLParser.EntityQueryContext context, bool isRootSelect)
{
var elementType = queryResult.BodyType.GetEnumerableType();
var contextParameter = Expression.Parameter(elementType);
var exp = queryResult.LambdaExpression.Body;
var oldContext = selectContext;
selectContext = contextParameter;
// visit child fields. Will be field or entityQueries again
var fieldExpressions = context.fields.children.Select(c => Visit(c)).Where(n => n != null).ToList();
// Default we select out sub objects/relations. So Select(d => new {Field = d.Field, Relation = new { d.Relation.Field }})
var selectExpression = (ExpressionResult)ExpressionUtil.SelectDynamic(contextParameter, exp, fieldExpressions, schemaProvider);
selectContext = oldContext;
var t = MergeConstantParametersFromFields(queryResult, fieldExpressions, contextParameter);
var parameters = t.Item1;
var constantParameterValues = t.Item2;
var gqlNode = new GraphQLNode(name, new QueryResult(selectExpression, parameters, constantParameterValues), (ExpressionResult)exp);
return(gqlNode);
}
