/// <summary>
/// Deserializes given HTTP payload as a json error payload or returns false
/// </summary>
/// <param name="serialized">The payload that was sent over HTTP</param>
/// <param name="encodingName">Optional name of an encoding to use if it is relevant to the current format. May be null if no character-set information was known.</param>
/// <param name="errorPayload">Error payload that is found</param>
/// <returns>True if it finds and error, false if not</returns>
public bool TryDeserializeErrorPayload(byte[] serialized, string encodingName, out ODataPayloadElement errorPayload)
{
ExceptionUtilities.CheckArgumentNotNull(serialized, "serialized");
errorPayload = null;
Encoding encoding = HttpUtilities.GetEncodingOrDefault(encodingName);
string payload = encoding.GetString(serialized, 0, serialized.Length);
// sample json error
// {
// “error”: {
// “code”: <string>
// “message”: {
// “lang”: <string>,
// “value“: <string>
// },
// “innererror”: {
// “message”: <string>,
// “type”: <string>,
// “stacktrace”: <string>,
// “internalexception”: {
// … another inner error structure …
// }
// }
// }
// }
string errorName = "\"" + ODataConstants.ErrorElementName + "\":";
int errorElementPos = payload.IndexOf(errorName, StringComparison.Ordinal);
// Look in the payload and see if an error exists
if (errorElementPos > -1)
{
ODataErrorPayload topLevelError = new ODataErrorPayload();
errorPayload = topLevelError;
ODataInternalExceptionPayload innerError = null;
bool inTopLevelMessage = false;
bool inError = false;
using (StringReader reader = new StringReader(payload.Substring(errorElementPos)))
{
JsonTokenizer tokenizer = new JsonTokenizer(reader);
while (tokenizer.HasMoreTokens())
{
if (tokenizer.TokenType == JsonTokenType.String)
{
string tokenValue = null;
if (tokenizer != null)
{
tokenValue = tokenizer.Value.ToString();
}
// don't start processing other properties until we're definitely inside the error itself
if (!inError)
{
inError = tokenValue == ODataConstants.ErrorElementName;
}
else
{
if (tokenValue == ODataConstants.InnerErrorElementName)
{
this.Assert.IsNull(innerError, "Should not find 'innererror' property on inner errors");
topLevelError.InnerError = innerError = new ODataInternalExceptionPayload();
}
else if (tokenValue == ODataConstants.InternalExceptionElementName)
{
this.Assert.IsNotNull(innerError, "Should not find 'internalexception' property on top-level errors");
ExceptionUtilities.Assert(innerError.InternalException == null, "Inner error should have been null");
innerError.InternalException = new ODataInternalExceptionPayload();
innerError = innerError.InternalException;
}
else if (tokenValue == ODataConstants.MessageElementName)
{
if (innerError == null)
{
inTopLevelMessage = true;
}
else
{
innerError.Message = this.GetIdentifierValue(tokenizer);
}
}
else if (tokenValue == ODataConstants.ValueElementName)
{
this.Assert.IsTrue(inTopLevelMessage, "Should not find 'value' property outside top-level message");
this.Assert.IsNull(innerError, "Should not find 'value' property on inner errors");
topLevelError.Message = this.GetIdentifierValue(tokenizer);
}
else if (tokenValue == ODataConstants.CodeElementName)
{
this.Assert.IsNull(innerError, "Should not find 'code' property on inner errors");
topLevelError.Code = this.GetIdentifierValue(tokenizer);
}
else if (tokenValue == ODataConstants.TypeNameElementName)
{
this.Assert.IsNotNull(innerError, "Should not find 'type' on top-level errors");
innerError.TypeName = this.GetIdentifierValue(tokenizer);
}
else if (tokenValue == ODataConstants.StackTraceElementName)
{
this.Assert.IsNotNull(innerError, "Should not find 'stacktrace' on top-level errors");
innerError.StackTrace = this.GetIdentifierValue(tokenizer);
}
}
}
else if (tokenizer.TokenType == JsonTokenType.RightCurly)
{
inTopLevelMessage = false;
}
tokenizer.GetNextToken();
}
}
return true;
}
return false;
}
private string GetIdentifierValue(JsonTokenizer tokenizer)
{
tokenizer.GetNextToken();
ExceptionUtilities.Assert(tokenizer.TokenType == JsonTokenType.Colon, "Error parsing JSON Error: Expected colon token next");
tokenizer.GetNextToken();
ExceptionUtilities.Assert(tokenizer.TokenType == JsonTokenType.String, "Error parsing JSON Error: Expected string token next");
ExceptionUtilities.CheckObjectNotNull(tokenizer.Value, "Expected tokenizer to have a value and not be null");
return tokenizer.Value.ToString();
}
