Use key-value pairs in a function

You can use key-value pairs from a key value store in a function.

Note

You must use JavaScript runtime 2.0 for the following code sample.

The example shows a function that uses the content of the URL in the HTTP request to look up a custom path in the key value store. CloudFront then uses that custom path to make the request. This function helps manage the multiple paths that are part of a website.

import cf from 'cloudfront';
​
// Declare the ID of the key value store that you have associated with this function
// The import fails at runtime if the specified key value store is not associated with the function

const kvsId = "a1b2c3d4-5678-90ab-cdef-EXAMPLE11111";
​
const kvsHandle = cf.kvs(kvsId);
​
async function handler(event) {
    const request = event.request;
    // Use the first segment of the pathname as key
    // For example http(s)://domain/<key>/something/else
    const pathSegments = request.uri.split('/')
    const key = pathSegments[1]
    try {
        // Replace the first path of the pathname with the value of the key
        // For example http(s)://domain/<value>/something/else
        pathSegments[1] = await kvsHandle.get(key);
        const newUri = pathSegments.join('/');
        console.log(`${request.uri} -> ${newUri}`)
        request.uri = newUri;
    } catch (err) {
        // No change to the pathname if the key is not found
        console.log(`${request.uri} | ${err}`);
    }
    return request;
}