public Task <CoinTrend> GetTrend(string symbol)
{
var tcs = new TaskCompletionSource <CoinTrend>();
if (_trend == null)
{
_trend = new CoinTrend
{
Symbol = symbol,
CurrentValue = OriginalValue,
Trend = OriginalTrend
};
}
else
{
_trend.Symbol = symbol;
_trend.CurrentValue += 1000;
_trend.Trend =
_trend.Trend == 0 ? 1
: _trend.Trend == 1 ? -1
: 0;
}
tcs.SetResult(_trend);
return(tcs.Task);
}
public static async Task <HttpResponseMessage> Run(
[HttpTrigger(
AuthorizationLevel.Function,
"get",
Route = "get/symbol/{symbol}")]
HttpRequestMessage req,
string symbol,
TraceWriter log)
{
log.Info($"CoinTrendGetter executed at: {DateTime.Now} for {symbol}");
// Create account, client and table
var account = CloudStorageAccount.Parse(CoinValueSaver.ConnectionString);
var tableClient = account.CreateCloudTableClient();
var table = tableClient.GetTableReference(CoinValueSaver.TableName);
await table.CreateIfNotExistsAsync();
// Get the last 10 coin
var coinsQuery = table.CreateQuery <CoinEntity>()
.Where(c => c.Symbol == symbol)
.ToList();
var count = coinsQuery.Count;
var trend = new CoinTrend();
if (count == 0)
{
log.Info("No coins found");
}
else
{
var selectedCount = (count < StandardCount) ? count : StandardCount;
var coinValues = coinsQuery
.Skip(count - selectedCount)
.Select(c => c.PriceUsd)
.ToArray();
// Prepare the data for analysis
var currentIndex = 1;
var indexes = coinValues.Select(c => (double)currentIndex++).ToArray();
// Calculate the linear regression
double rSquared, yIntercept, slope;
Stats.CalculateLinearRegression(indexes, coinValues, 0, selectedCount, out rSquared, out yIntercept, out slope);
// Prepare the result
trend.Symbol = symbol;
trend.CurrentValue = coinValues.Last();
trend.Trend = (slope > 0.05) ? 1 // Positive trend
: (slope < -0.05) ? -1 // Negative trend
: 0; // Flat trend
}
return(req.CreateResponse(HttpStatusCode.OK, trend, "application/json"));
}
public static async Task <IActionResult> Run(
[HttpTrigger(AuthorizationLevel.Function, "get", Route = "symbol/{symbol}")] HttpRequest req,
[Table(CoinValueSaver.TableName, Connection = "AzureWebJobsStorage")] CloudTable table,
[FromRoute] string symbol,
ILogger log)
{
log.LogInformation("CoinTrendGetterSymbol executed at: {time} for {symbol}", DateTime.Now, symbol);
var coinsQuery = new TableQuery <CoinEntity>();
var coinsSegment = await table.ExecuteQuerySegmentedAsync(coinsQuery, null);
var coinsResult = coinsSegment.Results.Where(c => c.Symbol == symbol).ToList();
var trend = new CoinTrend();
var count = coinsResult.Count;
if (count == 0)
{
// This is a user-generated error
log.LogInformation("No coins for {symbol} found", symbol);
return(new StatusCodeResult(StatusCodes.Status404NotFound));
}
else
{
var selectedCount = (count < StandardCount) ? count : StandardCount;
var coinValues = coinsResult
.Skip(count - selectedCount)
.Select(c => c.PriceUsd)
.ToArray();
// Prepare the data for analysis
var currentIndex = 1;
var indexes = coinValues.Select(c => (double)currentIndex++).ToArray();
// Calculate the linear regression
double rSquared, yIntercept, slope;
Stats.CalculateLinearRegression(indexes, coinValues, 0, selectedCount, out rSquared, out yIntercept, out slope);
// Prepare the result
trend.Symbol = symbol;
trend.CurrentValue = coinValues.Last();
trend.Trend = (slope > 0.05) ? 1 // Positive trend
: (slope < -0.05) ? -1 // Negative trend
: 0; // Flat trend
}
return(new OkObjectResult(trend));
}
public CoinTrendViewModel(CoinTrend model)
{
Model = model;
}
