51Degrees Device Detection .NET  4.4

Device detection services for 51Degrees Pipeline


The cloud service exposes meta data that can provide additional information about the various properties that might be returned.This example shows how to access this data and display the values available.

A list of the properties will be displayed, along with some additional information about each property. Note that this is the list of properties used by the supplied resource key, rather than all properties that can be returned by the cloud service.

In addition, the evidence keys that are accepted by the service are listed. These are the keys that, when added to the evidence collection in flow data, could have some impact on the result that is returned.

Bear in mind that this is a list of ALL evidence keys accepted by all products offered by the cloud. If you are only using a single product (for example - device detection) then not all of these keys will be relevant.

This example is available in full on GitHub.

To run this example, you will need to create a resource key. The resource key is used as shorthand to store the particular set of properties you are interested in as well as any associated license keys that entitle you to increased request limits and/or paid-for properties.

You can create a resource key using the 51Degrees Configurator.

Required NuGet Dependencies:

/* *********************************************************************
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* Copyright 2022 51 Degrees Mobile Experts Limited, Davidson House,
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* amended by the European Commission) shall be deemed incompatible for
* the purposes of the Work and the provisions of the compatibility
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using FiftyOne.Pipeline.CloudRequestEngine.FlowElements;
using FiftyOne.Pipeline.Core.Data;
using Microsoft.Extensions.Logging;
using System;
using System.IO;
public class Program
public class Example : ExampleBase
public void Run(string resourceKey, ILoggerFactory loggerFactory, TextWriter output)
using (var pipeline = new DeviceDetectionPipelineBuilder(loggerFactory)
OutputProperties(pipeline.GetElement<DeviceDetectionCloudEngine>(), output);
// We use the CloudRequestEngine to get evidence key details, rather than the
// DeviceDetectionCloudEngine.
// This is because the DeviceDetectionCloudEngine doesn't actually make use
// of any evidence values. It simply processes the JSON that is returned
// by the call to the cloud service that is made by the CloudRequestEngine.
// The CloudRequestEngine is actually taking the evidence values and passing
// them to the cloud, so that's the engine we want the keys from.
OutputEvidenceKeyDetails(pipeline.GetElement<CloudRequestEngine>(), output);
private void OutputEvidenceKeyDetails(CloudRequestEngine engine, TextWriter output)
if (typeof(EvidenceKeyFilterWhitelist).IsAssignableFrom(engine.EvidenceKeyFilter.GetType()))
// If the evidence key filter extends EvidenceKeyFilterWhitelist then we can
// display a list of accepted keys.
var filter = engine.EvidenceKeyFilter as EvidenceKeyFilterWhitelist;
output.WriteLine($"Accepted evidence keys:");
foreach (var entry in filter.Whitelist)
output.WriteLine($"The evidence key filter has type " +
$"{engine.EvidenceKeyFilter.GetType().Name}. As this does not extend " +
$"EvidenceKeyFilterWhitelist, a list of accepted values cannot be " +
$"displayed. As an alternative, you can pass evidence keys to " +
$"filter.Include(string) to see if a particular key will be included " +
$"or not.");
output.WriteLine($"For example, header.user-agent is " +
(engine.EvidenceKeyFilter.Include("header.user-agent") ? "" : "not ") +
private void OutputProperties(DeviceDetectionCloudEngine engine, TextWriter output)
foreach (var property in engine.Properties)
// Output some details about the property.
// If we're outputting to console then we also add some formatting to make it
// more readable.
Console.ForegroundColor = ConsoleColor.White;
Console.BackgroundColor = ConsoleColor.DarkRed;
output.Write($"Property - {property.Name}");
var typeName = property.Type.IsGenericType ?
property.Type.GenericTypeArguments[0].Name : property.Type.Name;
output.WriteLine($"[Category: {property.Category}] ({typeName})");
static void Main(string[] args)
// Use the command line args to get the resource key if present.
// Otherwise, get it from the environment variable.
string resourceKey = args.Length > 0 ? args[0] :
// Configure a logger to output to the console.
var loggerFactory = new LoggerFactory();
var logger = loggerFactory.CreateLogger<Program>();
if (string.IsNullOrEmpty(resourceKey))
logger.LogError($"No resource key specified in the configuration file " +
$"'appsettings.json' or the environment variable " +
$"'{ExampleUtils.RESOURCE_KEY_ENV_VAR}'. The 51Degrees cloud service is " +
$"accessed using a 'ResourceKey'. For more information see " +
$"https://51degrees.com/documentation/_info__resource_keys.html. " +
$"A resource key with the properties required by this example can be " +
$"created for free at https://configure.51degrees.com/1QWJwHxl. " +
$"Once complete, supply the resource key as a command line argument or via " +
$"the environment variable mentioned at the start of this message.");
new Example().Run(resourceKey, loggerFactory, Console.Out);
// Dispose the logger to ensure any messages get flushed