/// <summary>
/// Loads the most recent Device telemetry.
/// </summary>
/// <param name="deviceId">
/// The ID of the Device for which telemetry should be returned.
/// </param>
/// <param name="minTime">
/// The minimum time of record of the telemetry that should be returned.
/// </param>
/// <returns>
/// Telemetry for the Device specified by deviceId, inclusively since
/// minTime.
/// </returns>
public async Task<IEnumerable<DeviceTelemetryModel>> LoadLatestDeviceTelemetryAsync(
string deviceId,
IList<DeviceTelemetryFieldModel> telemetryFields,
DateTime minTime)
{
IEnumerable<DeviceTelemetryModel> result = new DeviceTelemetryModel[0];
IEnumerable<DeviceTelemetryModel> blobModels;
var telemetryBlobReader = await _blobStorageManager.GetReader(_telemetryDataPrefix, minTime);
foreach (var telemetryStream in telemetryBlobReader)
{
try
{
blobModels = LoadBlobTelemetryModels(telemetryStream.Data, telemetryFields);
}
catch
{
continue;
}
if (blobModels == null)
{
break;
}
int preFilterCount = blobModels.Count();
blobModels =
blobModels.Where(
t =>
(t != null) &&
t.Timestamp.HasValue &&
t.Timestamp.Value >= minTime);
if (preFilterCount == 0)
{
break;
}
result = result.Concat(blobModels);
}
if (!string.IsNullOrEmpty(deviceId))
{
result = result.Where(t => t.DeviceId == deviceId);
}
return result;
}
/// <summary>
/// Loads the most recent Device telemetry.
/// </summary>
/// <param name="deviceId">
/// The ID of the Device for which telemetry should be returned.
/// </param>
/// <param name="minTime">
/// The minimum time of record of the telemetry that should be returned.
/// </param>
/// <returns>
/// Telemetry for the Device specified by deviceId, inclusively since
/// minTime.
/// </returns>
public async Task<IEnumerable<DeviceTelemetryModel>> LoadLatestDeviceTelemetryAsync(
string deviceId,
DateTime minTime)
{
IEnumerable<DeviceTelemetryModel> blobModels;
IEnumerable<IListBlobItem> blobs;
CloudBlockBlob blockBlob;
CloudBlobContainer container;
int preFilterCount;
IEnumerable<DeviceTelemetryModel> result;
minTime = minTime.ToUniversalTime();
result = new DeviceTelemetryModel[0];
container =
await BlobStorageHelper.BuildBlobContainerAsync(
this._telemetryStoreConnectionString,
_telemetryContainerName);
blobs =
await BlobStorageHelper.LoadBlobItemsAsync(
async (token) =>
{
return await container.ListBlobsSegmentedAsync(
_telemetryDataPrefix,
true,
BlobListingDetails.None,
null,
token,
null,
null);
});
blobs =
blobs.OrderByDescending(
t => BlobStorageHelper.ExtractBlobItemDate(t));
foreach (IListBlobItem blob in blobs)
{
if ((blockBlob = blob as CloudBlockBlob) == null)
{
continue;
}
try
{
blobModels = await LoadBlobTelemetryModelsAsync(blockBlob);
}
catch
{
continue;
}
if (blobModels == null)
{
break;
}
preFilterCount = blobModels.Count();
blobModels =
blobModels.Where(
t =>
(t != null) &&
t.Timestamp.HasValue &&
t.Timestamp.Value.ToUniversalTime() >= minTime);
if (preFilterCount == 0)
{
break;
}
result = result.Concat(blobModels);
if (preFilterCount != blobModels.Count())
{
break;
}
}
if (!string.IsNullOrEmpty(deviceId))
{
result = result.Where(t => t.DeviceId == deviceId);
}
return result;
}
private static List<DeviceTelemetryModel> LoadBlobTelemetryModels(Stream stream, IList<DeviceTelemetryFieldModel> telemetryFields)
{
Debug.Assert(stream != null, "stream is a null reference.");
List<DeviceTelemetryModel> models = new List<DeviceTelemetryModel>();
TextReader reader = null;
try
{
stream.Position = 0;
reader = new StreamReader(stream);
IEnumerable<StrDict> strdicts = ParsingHelper.ParseCsv(reader).ToDictionaries();
DeviceTelemetryModel model;
string str;
foreach (StrDict strdict in strdicts)
{
model = new DeviceTelemetryModel();
if (strdict.TryGetValue("deviceid", out str))
{
model.DeviceId = str;
}
model.Timestamp = DateTime.Parse(
strdict["eventenqueuedutctime"],
CultureInfo.InvariantCulture,
DateTimeStyles.AllowWhiteSpaces);
IEnumerable<DeviceTelemetryFieldModel> fields;
if (telemetryFields != null && telemetryFields.Count > 0)
{
fields = telemetryFields;
}
else
{
List<string> reservedColumns = new List<string>
{
"DeviceId",
"EventEnqueuedUtcTime",
"EventProcessedUtcTime",
"IoTHub",
"PartitionId"
};
fields = strdict.Keys
.Where((key) => !reservedColumns.Contains(key))
.Select((name) => new DeviceTelemetryFieldModel
{
Name = name,
Type = "double"
});
}
foreach (var field in fields)
{
if (strdict.TryGetValue(field.Name, out str))
{
switch (field.Type.ToLowerInvariant())
{
case "int":
case "int16":
case "int32":
case "int64":
case "sbyte":
case "byte":
int intValue;
if (
int.TryParse(
str,
NumberStyles.Integer,
CultureInfo.InvariantCulture,
out intValue) &&
!model.Values.ContainsKey(field.Name))
{
model.Values.Add(field.Name, intValue);
}
break;
case "double":
case "decimal":
case "single":
double dblValue;
if (
double.TryParse(
str,
NumberStyles.Float,
CultureInfo.InvariantCulture,
out dblValue) &&
!model.Values.ContainsKey(field.Name))
{
model.Values.Add(field.Name, dblValue);
}
break;
}
}
}
models.Add(model);
}
}
finally
{
IDisposable disp;
if ((disp = stream) != null)
{
disp.Dispose();
}
if ((disp = reader) != null)
{
disp.Dispose();
}
}
return models;
}
private async static Task<List<DeviceTelemetryModel>> LoadBlobTelemetryModelsAsync(
CloudBlockBlob blob)
{
DateTime date;
IDisposable disp;
DeviceTelemetryModel model;
List<DeviceTelemetryModel> models;
double number;
TextReader reader;
string str;
IEnumerable<StrDict> strdicts;
MemoryStream stream;
Debug.Assert(blob != null, "blob is a null reference.");
models = new List<DeviceTelemetryModel>();
reader = null;
stream = null;
try
{
stream = new MemoryStream();
await blob.DownloadToStreamAsync(stream);
stream.Position = 0;
reader = new StreamReader(stream);
strdicts = ParsingHelper.ParseCsv(reader).ToDictionaries();
foreach (StrDict strdict in strdicts)
{
model = new DeviceTelemetryModel();
if (strdict.TryGetValue("DeviceId", out str))
{
model.DeviceId = str;
}
if (strdict.TryGetValue("ExternalTemperature", out str) &&
double.TryParse(str, out number))
{
model.ExternalTemperature = number;
}
if (strdict.TryGetValue("Humidity", out str) &&
double.TryParse(str, out number))
{
model.Humidity = number;
}
if (strdict.TryGetValue("Temperature", out str) &&
double.TryParse(str, out number))
{
model.Temperature = number;
}
if (strdict.TryGetValue("EventEnqueuedUtcTime", out str) &&
DateTime.TryParse(str, out date))
{
model.Timestamp = date;
}
models.Add(model);
}
}
finally
{
if ((disp = stream) != null)
{
disp.Dispose();
}
if ((disp = reader) != null)
{
disp.Dispose();
}
}
return models;
}
