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51Degrees API Documentation  4.4

Introduction

User-Agent Client Hints (UA-CH) values can be obtained using HTTP headers or a JavaScript API. This page explains how to use the JavaScript approach with our API.

The UA-CH headers page explains the alternative. The Overview page includes advice if you're unsure which approach to take.

Using the UA-CH JavaScript API is very simple if you are calling our cloud service directly. See details below.

Otherwise, if you are using one of our web integrations, you can use the 'Integrated' approach described below. If not, you'll need to use the 'non-integrated' approach instead.

#

Cloud

Firstly, ensure that the JavascriptGetHighEntropyValues property is selected when you create your Resource Key. This contains the JavaScript snippet to get the values from the UA-CH API on the client device.

If you are calling our cloud service directly from the client device, our solution will take care of the rest.

If you are calling our cloud service via our Pipeline API, hosted on your servers, then you'll also need to get this snippet to the client device. See the 'on-premise' section below for the two approaches to doing this.

#

On-Premise Pipeline API

If you are using our Pipeline API on your server (either cloud or on-premise) then you'll need a way to get the necessary JavaScript to run on the client and get the values back to your server.

In either case, you need to ensure the JavascriptGetHighEntropyValues property is included in the results (all properties are included by default for on-premise).

#

Integrated

If you are using our web integration with client-side evidence enabled, then this will take care of sending the snippet to the client device, getting the values back to the server and passing them into our API.

If you're using our cloud service, no other changes are needed. However, if you're using our on-premise solution, then you'll also need to modify your configuration to include a new engine called UachJsConversionEngine to convert the result from the JavaScript snippet to evidence values that can be used by the existing device detection engine.

For example:

"PipelineOptions": {
"Elements": [
{
"BuilderName": "UachJsConversionEngine"
},
{
"BuilderName": "DeviceDetectionHashEngineBuilder",
"BuildParameters": {
...
}
}
]
},

#

Non-integrated

If you don't want to, or can't, use the web integrations as described above, then you'll need to handle the steps of getting the values from the JavaScript API, transferring those to the server and adding them to the pipeline evidence values.

This will require a good knowledge of your production environment and how communication works between your client and server side code.

The following snippet demonstrates how to get the UA-CH values using JavaScript. The exact mechanism to get this value from the client device to your server will depend on your infrastructure. Once there, it will need to be added to the flow data evidence:

flowData.AddEvidence("cookie.51D_GetHighEntropyValues", b64Uach);
<script type="text/javascript">
if (navigator.userAgentData) {
    navigator.userAgentData.getHighEntropyValues(
        ["model",
        "platform",
        "platformVersion",
        "fullVersionList"])
    .then((ua) => { 
        // Convert to base64-encoded JSON
        // This string needs to be passed back to the server and added to evidence. E.g.
        // flowData.AddEvidence("cookie.51D_GetHighEntropyValues", b64Uach);
        var b64Uach = btoa(JSON.stringify(ua));        
    });
}
</script>

If you're using our cloud service, no other changes are needed. However, if you're using on-premise solution, then you'll also need to modify your configuration to include a new engine called UachJsConversionEngine to convert the base-64 json from the JavaScript snippet above to evidence values that can be used by the existing device detection engine.

For example:

"PipelineOptions": {
"Elements": [
{
"BuilderName": "UachJsConversionEngine"
},
{
"BuilderName": "DeviceDetectionHashEngineBuilder",
"BuildParameters": {
...
}
}
]
},