/// <summary>
/// Fetches the metadata for a specified 'service'. This method is automatically called
/// internally by an EntityManager before its first query against a new service.
/// </summary>
/// <param name="dataService"></param>
/// <returns></returns>
public async Task <DataService> FetchMetadata(DataService dataService)
{
String serviceName;
serviceName = dataService.ServiceName;
var ds = GetDataService(serviceName);
if (ds != null)
{
return(dataService);
}
await _asyncSemaphore.WaitAsync();
String metadata;
try {
ds = GetDataService(serviceName);
if (ds != null)
{
return(dataService);
}
metadata = await dataService.GetAsync("Metadata");
} catch (Exception e) {
throw new Exception("Unable to locate metadata resource for: " + dataService.ServiceName, e);
} finally {
_asyncSemaphore.Release();
}
metadata = metadata.Trim();
if (metadata.Substring(0, 1) == "\"" && metadata.Substring(metadata.Length - 1, 1) == "\"")
{
metadata = Regex.Unescape(metadata.Substring(1, metadata.Length - 2));
}
var metadataProcessor = new CsdlMetadataProcessor();
metadataProcessor.ProcessMetadata(this, metadata);
dataService.ServerMetadata = metadata;
AddDataService(dataService);
return(dataService);
}
/// <summary>
/// Fetches the metadata for a specified 'service'. This method is automatically called
/// internally by an EntityManager before its first query against a new service.
/// </summary>
/// <param name="dataService"></param>
/// <param name="cancellationToken"></param>
/// <returns></returns>
public async Task <DataService> FetchMetadata(DataService dataService, CancellationToken cancellationToken)
{
String serviceName;
serviceName = dataService.ServiceName;
var ds = GetDataService(serviceName);
if (ds != null)
{
return(dataService);
}
await _asyncSemaphore.WaitAsync();
cancellationToken.ThrowIfCancellationRequested();
String metadata;
try {
ds = GetDataService(serviceName);
if (ds != null)
{
return(dataService);
}
metadata = await dataService.GetAsync("Metadata", cancellationToken);
cancellationToken.ThrowIfCancellationRequested();
metadata = metadata.Trim();
// this section is needed if metadata is returned as an escaped string - ( not common but does happen ... ).
if (metadata.Substring(0, 1) == "\"" && metadata.Substring(metadata.Length - 1, 1) == "\"")
{
metadata = Regex.Unescape(metadata.Substring(1, metadata.Length - 2));
}
metadata = regExGeneric.Replace(metadata, string.Empty);
var json = (JObject)JsonConvert.DeserializeObject(metadata);
var schema = json["schema"];
if (schema != null)
{
// metadata returned in CSDL format
var metadataProcessor = new CsdlMetadataProcessor();
metadataProcessor.ProcessMetadata(this, json);
}
else
{
// metadata returned in breeze native format
this.ImportMetadata(metadata, true);
}
var errorMessages = GetMessages(MessageType.Error).ToList();
if (errorMessages.Any())
{
throw new DomainException("Metadata errors encountered: \n" + errorMessages.ToAggregateString("\n"));
}
dataService.ServerMetadata = metadata;
AddDataService(dataService);
return(dataService);
} catch (Exception e) {
if (!(e is DomainException))
{
throw new Exception("Unable to locate metadata resource for: " + dataService.ServiceName, e);
}
throw;
} finally {
_asyncSemaphore.Release();
}
}
