/// <summary>
/// Serializes an expression to a string
/// </summary>
/// <param name='context'>Data context used to generate type names for types.</param>
/// <param name="e">Expression to serialize</param>
/// <param name='inPath'>Whether or not the expression being written is part of the path of the URI.</param>
/// <param name="uriVersion">the request data service version for the uri</param>
/// <returns>serialized expression</returns>
internal static string ExpressionToString(DataServiceContext context, Expression e, bool inPath, ref Version uriVersion)
{
ExpressionWriter ew = new ExpressionWriter(context, inPath);
string serialized = ew.Translate(e);
WebUtil.RaiseVersion(ref uriVersion, ew.uriVersion);
if (ew.cantTranslateExpression)
{
throw new NotSupportedException(Strings.ALinq_CantTranslateExpression(e.ToString()));
}
return(serialized);
}
/// <summary>
/// Input resource set references are intentionally omitted from the URL string for the top level
/// references to input parameter (i.e. outside of any/all methods).
/// For parameter references to input (range variable for Where) inside any/all methods we write "$it".
/// </summary>
/// <param name="ire">The input reference</param>
/// <returns>The same input reference expression</returns>
internal override Expression VisitInputReferenceExpression(InputReferenceExpression ire)
{
// This method intentionally does not write anything to the URI for implicit references to the input parameter ($it).
// This is how 'Where(<input>.Id == 5)' becomes '$filter=Id eq 5'.
Debug.Assert(ire != null, "ire != null");
if (this.parent == null || (!this.InSubScope && this.parent.NodeType != ExpressionType.MemberAccess && this.parent.NodeType != ExpressionType.TypeAs && this.parent.NodeType != ExpressionType.Call))
{
// Ideally we refer to the parent expression as the un-translatable one,
// because we cannot reference 'this' as a standalone expression; however
// if the parent is null for any reason, we fall back to the expression itself.
string expressionText = (this.parent != null) ? this.parent.ToString() : ire.ToString();
throw new NotSupportedException(Strings.ALinq_CantTranslateExpression(expressionText));
}
// Write "$it" for input parameter reference inside any/all methods
if (this.InSubScope || this.parent.NodeType == ExpressionType.Call)
{
this.builder.Append(XmlConstants.ImplicitFilterParameter);
}
return(ire);
}
/// <summary>
/// MethodCallExpression visit method
/// </summary>
/// <param name="m">The MethodCallExpression expression to visit</param>
/// <returns>The visited MethodCallExpression expression </returns>
internal override Expression VisitMethodCall(MethodCallExpression m)
{
string methodName;
if (TypeSystem.TryGetQueryOptionMethod(m.Method, out methodName))
{
this.builder.Append(methodName);
this.builder.Append(UriHelper.LEFTPAREN);
// There is a single function, 'contains', which reorders its argument with
// respect to the CLR method. Thus handling it as a special case rather than
// using a more general argument reordering mechanism.
if (methodName == "contains")
{
Debug.Assert(m.Method.Name == "Contains", "m.Method.Name == 'Contains'");
Debug.Assert(m.Object != null, "m.Object != null");
Debug.Assert(m.Arguments.Count == 1, "m.Arguments.Count == 1");
this.Visit(m.Object);
this.builder.Append(UriHelper.COMMA);
this.Visit(m.Arguments[0]);
}
else
{
if (m.Object != null)
{
this.Visit(m.Object);
}
if (m.Arguments.Count > 0)
{
if (m.Object != null)
{
this.builder.Append(UriHelper.COMMA);
}
for (int ii = 0; ii < m.Arguments.Count; ii++)
{
this.Visit(m.Arguments[ii]);
if (ii < m.Arguments.Count - 1)
{
this.builder.Append(UriHelper.COMMA);
}
}
}
}
this.builder.Append(UriHelper.RIGHTPAREN);
}
else if (m.Method.Name == "HasFlag")
{
Debug.Assert(m.Method.Name == "HasFlag", "m.Method.Name == 'HasFlag'");
Debug.Assert(m.Object != null, "m.Object != null");
Debug.Assert(m.Arguments.Count == 1, "m.Arguments.Count == 1");
this.Visit(m.Object);
this.builder.Append(UriHelper.SPACE);
this.builder.Append(UriHelper.HAS);
this.builder.Append(UriHelper.SPACE);
this.Visit(m.Arguments[0]);
}
else
{
SequenceMethod sequenceMethod;
if (ReflectionUtil.TryIdentifySequenceMethod(m.Method, out sequenceMethod))
{
if (ReflectionUtil.IsAnyAllMethod(sequenceMethod))
{
// Raise the uriVersion each time we write any or all methods to the uri.
WebUtil.RaiseVersion(ref this.uriVersion, Util.ODataVersion4);
this.Visit(m.Arguments[0]);
this.builder.Append(UriHelper.FORWARDSLASH);
if (sequenceMethod == SequenceMethod.All)
{
this.builder.Append(XmlConstants.AllMethodName);
}
else
{
this.builder.Append(XmlConstants.AnyMethodName);
}
this.builder.Append(UriHelper.LEFTPAREN);
if (sequenceMethod != SequenceMethod.Any)
{
// SequenceMethod.Any represents Enumerable.Any(), which has only source argument
// AnyPredicate and All has a second parameter which is the predicate lambda.
Debug.Assert(m.Arguments.Count == 2, "m.Arguments.Count() == 2");
LambdaExpression le = (LambdaExpression)m.Arguments[1];
string rangeVariable = le.Parameters[0].Name;
this.builder.Append(rangeVariable);
this.builder.Append(UriHelper.COLON);
this.scopeCount++;
this.Visit(le.Body);
this.scopeCount--;
}
this.builder.Append(UriHelper.RIGHTPAREN);
return(m);
}
else if (sequenceMethod == SequenceMethod.OfType && this.parent != null)
{
// check to see if this is an OfType filter for Any or All.
// e.g. ctx.CreateQuery<Movie>("Movies").Where(m=>m.Actors.OfType<MegaStar>().Any())
// which translates to /Movies()?$filter=Actors/MegaStar/any()
MethodCallExpression mce = this.parent as MethodCallExpression;
if (mce != null && ReflectionUtil.TryIdentifySequenceMethod(mce.Method, out sequenceMethod) && ReflectionUtil.IsAnyAllMethod(sequenceMethod))
{
Type filteredType = mce.Method.GetGenericArguments().SingleOrDefault();
if (ClientTypeUtil.TypeOrElementTypeIsEntity(filteredType))
{
this.Visit(m.Arguments[0]);
this.builder.Append(UriHelper.FORWARDSLASH);
UriHelper.AppendTypeSegment(this.builder, filteredType, this.context, this.inPath, ref this.uriVersion);
return(m);
}
}
}
else if (sequenceMethod == SequenceMethod.Count && this.parent != null)
{
if (m.Arguments.Any() && m.Arguments[0] != null)
{
this.Visit(m.Arguments[0]);
}
this.builder.Append(UriHelper.FORWARDSLASH).Append(UriHelper.DOLLARSIGN).Append(UriHelper.COUNT);
return(m);
}
else if (sequenceMethod == SequenceMethod.Contains)
{
// First argument is the collection expression
// Second argument is the value expression
// Note that arguments must be reordered for the IN operator
// e.g. ctx.CreateQuery<Product>("Products").Where(p => (new [] { "Milk", "Cheese", "Donut"}).Contains(p.Name))
// which translates to /Products()?$filter=Name in ('Milk', 'Cheese', 'Donut')
this.Visit(m.Arguments[1]);
this.builder.Append(UriHelper.SPACE)
.Append(UriHelper.IN)
.Append(UriHelper.SPACE);
this.Visit(m.Arguments[0]);
return(m);
}
}
else
{
if (m.Object != null)
{
this.Visit(m.Object);
}
if (m.Method.Name != "GetValue" && m.Method.Name != "GetValueAsync")
{
this.builder.Append(UriHelper.FORWARDSLASH);
// writing functions in query options
writingFunctionsInQuery = true;
string declaringType = this.context.ResolveNameFromTypeInternal(m.Method.DeclaringType);
if (string.IsNullOrEmpty(declaringType))
{
throw new NotSupportedException(Strings.ALinq_CantTranslateExpression(m.ToString()));
}
int index = declaringType.LastIndexOf('.');
string fullNamespace = declaringType.Remove(index + 1);
string serverMethodName = ClientTypeUtil.GetServerDefinedName(m.Method);
this.builder.Append(fullNamespace + serverMethodName);
this.builder.Append(UriHelper.LEFTPAREN);
string[] argumentNames = m.Method.GetParameters().Select(p => p.Name).ToArray();
for (int i = 0; i < m.Arguments.Count; ++i)
{
this.builder.Append(argumentNames[i]);
this.builder.Append(UriHelper.EQUALSSIGN);
this.scopeCount++;
this.Visit(m.Arguments[i]);
this.scopeCount--;
this.builder.Append(UriHelper.COMMA);
}
if (m.Arguments.Any())
{
this.builder.Remove(this.builder.Length - 1, 1);
}
this.builder.Append(UriHelper.RIGHTPAREN);
writingFunctionsInQuery = false;
}
return(m);
}
this.cantTranslateExpression = true;
}
return(m);
}