cloudfront ESI / lambda html body replace

Question

Hi,

as i know, now seem cloudfront not support ESI.
and we are seeing whether we can use lambda to replace html body.
eg:         body = body.replace('', ``);

but, seem also not work.

any function we can call to replace?

since i think if we can replace, then we can write script in lambda and then get sth in server to replace ${nonce} variable and then send to client.

do u think is workable?

Regards

Answer

Hi Simon,

Lambda@Edge allows you to run Lambda functions to customize the content delivered through your CloudFront distribution.

Example of a Node.js Lambda@Edge function:

```
'use strict';

exports.handler = (event, context, callback) => {
    const response = event.Records[0].cf.response;
    const headers = response.headers;

// only modify HTML content !!
    if (headers['content-type'] && headers['content-type'][0].value.includes('text/html')) {
        let body = response.body;

// generate a nonce value - you could generate a dynamic value
        const nonce = 'generatedNonceValue';

// replace the placeholder in the body then update it
        body = body.replace('', ``);

response.body = body;
    }

// return
    callback(null, response);
};

```

Hope this helps.

Answer

Hi,

is it for lambda node v16, v18 or v20? 
and after make, i pout in Viewer request, Viewer response, Origin request or Origin response in cloudfront?

Regards

Answer

since i try to use body.replace before and seem make cloudfront return 503.

cloudfront ESI / lambda html body replace

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