51Degrees Device Detection .NET  4.4

Device detection services for 51Degrees Pipeline


The example illustrates a "clock-time" benchmark for assessing detection speed.Using a YAML formatted evidence file - "20000 Evidence Records.yml" - supplied with the distribution or can be obtained from the data repository on Github.

It's important to understand the trade-offs between performance, memory usage and accuracy, that the 51Degrees pipeline configuration makes available, and this example shows a range of different configurations to illustrate the difference in performance.

Requesting properties from a single component reduces detection time compared with requesting properties from multiple components. If you don't specify any properties to detect, then all properties are detected.

Please review performance options and hash dataset options for more information about adjusting performance.

This example is available in full on GitHub.

This example requires a local data file. The free 'Lite' data file can be acquired by pulling the git submodules under this repository (run `git submodule update --recursive`) or from the device-detection-data GitHub repository.

The Lite data file is only used for illustration, and has limited accuracy and capabilities. Find out about the more capable data files that are available on our pricing page

Required NuGet Dependencies:

/* *********************************************************************
* This Original Work is copyright of 51 Degrees Mobile Experts Limited.
* Copyright 2022 51 Degrees Mobile Experts Limited, Davidson House,
* Forbury Square, Reading, Berkshire, United Kingdom RG1 3EU.
* This Original Work is licensed under the European Union Public Licence
* (EUPL) v.1.2 and is subject to its terms as set out below.
* If a copy of the EUPL was not distributed with this file, You can obtain
* one at https://opensource.org/licenses/EUPL-1.2.
* The 'Compatible Licences' set out in the Appendix to the EUPL (as may be
* amended by the European Commission) shall be deemed incompatible for
* the purposes of the Work and the provisions of the compatibility
* clause in Article 5 of the EUPL shall not apply.
* If using the Work as, or as part of, a network application, by
* including the attribution notice(s) required under Article 5 of the EUPL
* in the end user terms of the application under an appropriate heading,
* such notice(s) shall fulfill the requirements of that article.
* ********************************************************************* */
using FiftyOne.Pipeline.Core.FlowElements;
using FiftyOne.Pipeline.Engines;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
public class Program
private class BenchmarkResult
public long Count { get; set; }
public Stopwatch Timer { get; } = new Stopwatch();
public long MobileCount { get; set; }
public long NotMobileCount { get; set; }
private static readonly PerformanceConfiguration[] _configs = new PerformanceConfiguration[]
new PerformanceConfiguration(true, PerformanceProfiles.MaxPerformance, false, true, false),
new PerformanceConfiguration(true, PerformanceProfiles.MaxPerformance, true, true, false),
new PerformanceConfiguration(false, PerformanceProfiles.LowMemory, false, true, false),
new PerformanceConfiguration(false, PerformanceProfiles.LowMemory, true, true, false)
private const ushort DEFAULT_THREAD_COUNT = 4;
public class Example : ExampleBase
private IPipeline _pipeline;
public Example(IPipeline pipeline)
_pipeline = pipeline;
private void Run(
TextReader evidenceReader,
TextWriter output,
int threadCount)
var evidence = GetEvidence(evidenceReader).ToList();
// Make an initial run to warm up the system
output.WriteLine("Warming up");
var warmup = Benchmark(evidence, threadCount);
var warmupTime = warmup.Sum(r => r.Timer.ElapsedMilliseconds);
var execution = Benchmark(evidence, threadCount);
var executionTime = execution.Sum(r => r.Timer.ElapsedMilliseconds);
output.WriteLine($"Finished - Execution time was {executionTime} ms, " +
$"adjustment from warm-up {executionTime - warmupTime} ms");
Report(execution, threadCount, output);
private void Report(List<BenchmarkResult> results,
int threadCount,
TextWriter output)
var detections = results.Sum(r => r.Count);
var milliseconds = results.Sum(r => r.Timer.ElapsedMilliseconds);
// Calculate approx. real-time ms per detection.
var msPerDetection = (float)(milliseconds / threadCount) / detections;
var detectionsPerSecond = 1000 / msPerDetection;
output.WriteLine($"Overall: {detections} detections, Average millisecs per " +
$"detection: {msPerDetection}, Detections per second: {detectionsPerSecond}");
output.WriteLine($"Overall: Concurrent threads: {threadCount}");
private List<BenchmarkResult> Benchmark(
List<Dictionary<string, object>> allEvidence,
int threadCount)
CancellationTokenSource cancellationTokenSource = new CancellationTokenSource();
List<BenchmarkResult> results = new List<BenchmarkResult>();
// Start multiple threads to process a set of evidence.
var processing = Parallel.ForEach(allEvidence,
new ParallelOptions()
// Note - MaxDegreeOfParallelism does not actually guarantee anything
// about the number of threads involved.
// It just guarantees that there will be no more than x Tasks running
// concurrently.
MaxDegreeOfParallelism = threadCount,
CancellationToken = cancellationTokenSource.Token
// Create a benchmark result instance per parallel unit
// (not necessarily per thread!).
() => new BenchmarkResult(),
(evidence, loopState, result) =>
// A using block MUST be used for the FlowData instance. This ensures that
// native resources created by the device detection engine are freed in
// good time.
using (var data = _pipeline.CreateFlowData())
// Add the evidence to the flow data.
// Get the device from the engine.
var device = data.Get<IDeviceData>();
// Access a property to ensure compiler optimizer doesn't optimize
// out the very method that the benchmark is testing.
if(device.IsMobile.HasValue && device.IsMobile.Value)
return result;
// Add the results from this run to the overall results.
(result) =>
lock (results)
return results;
public static void Run(string dataFile, string evidenceFile,
PerformanceConfiguration config, TextWriter output, ushort threadCount)
// Initialize a service collection which will be used to create the services
// required by the Pipeline and manage their lifetimes.
using (var serviceProvider = new ServiceCollection()
// Make sure we're logging to the console.
.AddLogging(l => l.AddConsole())
// Add a factory to create the singleton DeviceDetectionHashEngine instance.
.AddSingleton((x) =>
var builder = x.GetRequiredService<DeviceDetectionHashEngineBuilder>()
// Disable any data file updates
// Set performance profile
// Configure detection graphs
// Hint for cache concurrency
// Performance is improved by selecting only the properties you intend to
// use. Requesting properties from a single component reduces detection
// time compared with requesting properties from multiple components.
// If you don't specify any properties to detect, then all properties are
// detected, here we choose "all properties" by specifying none, or just
// "isMobile".
// Specify "BrowserName" for just the browser component, "PlatformName"
// for just platform or "IsCrawler" for the crawler component.
if (config.AllProperties == false)
// The data file can be loaded directly from disk or from a byte array
// in memory.
// This latter option is useful for cloud-based environments with little
// or no hard drive space available. In this scenario, the 'LowMemory'
// performance profile is recommended, as the data is actually already
// in memory. Using MaxPerformance would just cause the native code to
// make another copy of the data in memory for little benefit.
DeviceDetectionHashEngine engine = null;
if (config.LoadFromDisk)
engine = builder.Build(dataFile, false);
using (MemoryStream stream = new MemoryStream(File.ReadAllBytes(dataFile)))
engine = builder.Build(stream);
return engine;
// Add a factory to create the singleton IPipeline instance
.AddSingleton((x) => {
return x.GetRequiredService<PipelineBuilder>()
using (var evidenceReader = new StreamReader(File.OpenRead(evidenceFile)))
// If we don't have a resource key then log an error.
if (string.IsNullOrWhiteSpace(dataFile))
"Failed to find a device detection data file. Make sure the " +
"device-detection-data submodule has been updated by running " +
"`git submodule update --recursive`.");
output.WriteLine($"Processing evidence from '{evidenceFile}'");
output.WriteLine($"Data loaded from '{(config.LoadFromDisk ? "disk" : "memory")}'");
output.WriteLine($"Benchmarking with profile '{config.Profile}', " +
$"AllProperties {config.AllProperties}, " +
$"PerformanceGraph {config.PerformanceGraph}, " +
$"PredictiveGraph {config.PredictiveGraph}");
serviceProvider.GetRequiredService<Example>().Run(evidenceReader, output, threadCount);
static void Main(string[] args)
// Use the supplied path for the data file or find the lite file that is included
// in the repository.
var dataFile = args.Length > 0 ? args[0] :
// In this example, by default, the 51degrees "Lite" file needs to be somewhere in the
// project space, or you may specify another file as a command line parameter.
// Note that the Lite data file is only used for illustration, and has limited accuracy
// and capabilities. Find out about the Enterprise data file on our pricing page:
// https://51degrees.com/pricing
// Do the same for the yaml evidence file.
var evidenceFile = args.Length > 1 ? args[1] :
// This file contains the 20,000 most commonly seen combinations of header values
// that are relevant to device detection. For example, User-Agent and UA-CH headers.
foreach (var config in _configs)
Example.Run(dataFile, evidenceFile, config, Console.Out, DEFAULT_THREAD_COUNT);