public async Task <IHttpJsonResponseMessage <T> > GetJsonAsync <T>(
Uri requestUri,
TimeSpan?requestTimeout = null,
AuthenticationHeaderValue authenticationHeaderValue = null)
{
// SocialGist only accepts TLS 1.1 or higher. AzureFunctions (on Azure) default to SSL3 or TLS
// AzureFunctions runing locally use defaults that work with SocialGist but remote Azure Functions do not.
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12 | SecurityProtocolType.Tls11;
log.Verbose($"Retrieving URL using protocol: {ServicePointManager.SecurityProtocol}");
telemetryClient.TrackEvent(TelemetryNames.HTTP_Get, new Dictionary <string, string> {
{ "URL", requestUri.ToString() }
});
var handler = new HttpClientHandler()
{
AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate
};
using (var client = new System.Net.Http.HttpClient(handler))
{
if (requestTimeout.HasValue)
{
client.Timeout = requestTimeout.Value;
}
if (authenticationHeaderValue != null)
{
client.DefaultRequestHeaders.Authorization = authenticationHeaderValue;
}
string data = "";
HttpResponseMessage response = null;
int retryCount = 0;
while (retryCount < RETRY_COUNT)
{
try
{
telemetryClient.TrackEvent(TelemetryNames.HTTP_Try, new Dictionary <string, string> {
{ "URL", requestUri?.ToString() }, { "try number", retryCount.ToString() }
});
log.Verbose($"Retrieving URL {requestUri} on attempt {retryCount}");
// Track telemetry for each host query
using (var tracker = telemetryClient.StartTrackDependency(requestUri.Host, requestUri.AbsolutePath, "HTTP"))
{
tracker.Properties.Add("Request URL", requestUri?.ToString());
tracker.Properties.Add("Try attempt", retryCount.ToString());
try
{
response = await client.GetAsync(requestUri);
}
catch (TaskCanceledException)
{
tracker.IsSuccess = false;
tracker.ResultCode = "Task Canceled (HTTP Timeout)";
throw;
}
catch (HttpRequestException e)
{
tracker.IsSuccess = false;
tracker.ResultCode = $"HTTPException: {e.Message}";
throw;
}
tracker.IsSuccess = response.IsSuccessStatusCode;
tracker.ResultCode = response.StatusCode.ToString();
// Get data after setting telemetry status codes incase this errors out.
data = await response.Content.ReadAsStringAsync();
if (!response.IsSuccessStatusCode)
{
// Do not store this data unless the request failed. This data can get very large very fast.
tracker.Properties.Add("Server Response", data);
}
}
if (response.IsSuccessStatusCode)
{
this.objectLogger.Log(data, "HttpClient", requestUri.ToString());
// Successfully completed request
break;
}
else
{
telemetryClient.TrackEvent(TelemetryNames.HTTP_Error, new Dictionary <string, string> {
{ "URL", requestUri?.ToString() },
{ "StatusCode", response?.StatusCode.ToString() }
});
retryCount = HandleFailure(retryCount, requestUri, response);
}
}
catch (Exception e)
{
retryCount++;
telemetryClient.TrackEvent(TelemetryNames.HTTP_Error, new Dictionary <string, string> {
{ "URL", requestUri?.ToString() },
{ "StatusCode", response?.StatusCode.ToString() },
{ "Exception", e.ToString() }
});
if (retryCount < RETRY_COUNT)
{
log.Error($"Error executing web request for URL {requestUri} on attempt {retryCount}. Retrying.", e);
}
else
{
log.Error($"Error executing web request for URI {requestUri} on attempt {retryCount}. NOT retrying", e);
// Rethrow the exception to fail the current job
throw;
}
}
// Do not wait after the final try.
if (retryCount < RETRY_COUNT)
{
// Request failed. Wait a random time and try again. Random() uses a time-dependent seed.
int wait = new Random().Next((int)minWaitBeforeRetry.TotalMilliseconds, (int)maxWaitBeforeRetry.TotalMilliseconds);
log.Verbose($"Waiting {wait} milliseconds before retrying");
Thread.Sleep(wait);
}
}
log.Verbose($"URL {requestUri} retrieved.");
var metric = new MetricTelemetry();
metric.Name = TelemetryNames.HTTP_RetryCount;
metric.Sum = retryCount;
metric.Timestamp = DateTime.Now;
metric.Properties.Add("Domain", requestUri.Host);
telemetryClient.TrackMetric(metric);
try
{
var obj = JsonConvert.DeserializeObject <T>(data);
log.Verbose($"Result deserialized from URL {requestUri}");
return(new HttpJsonResponseMessage <T>
{
Object = obj,
ResponseMessage = response
});
}
catch (Exception e)
{
telemetryClient.TrackEvent(TelemetryNames.HTTP_JSON_Error, new Dictionary <string, string>
{
{ "URL", requestUri?.ToString() },
{ "StatusCode", response?.StatusCode.ToString() },
{ "Exception", e.ToString() },
{ "Response", data }
});
// Log and rethrow the exception
log.Error($"Error deserializing result from URL {requestUri}", e);
// Rethrow the exception to fail the current job
throw;
}
}
}