You don't need that CORS request

Re:You don't need that CORS request by herpderperator on Monday January 03, 2022 @01:39PM (#29784464)

CloudFront Distributions cannot pass the request to CloudFront Functions before sending to the origin. In other words, they cannot be used to modify origin request/responses. They can only modify the viewer request/responses. [0]

Only Lambda@Edge can help the scenario which I provided, which is also AWS's recommended solution. [1]

[0] https://docs.aws.amazon.com/AmazonCloudFront/latest/Develope...

[1] https://aws.amazon.com/blogs/architecture/serving-content-us...

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Re:You don't need that CORS request by forty on Monday January 03, 2022 @02:45PM (#29785533)

From your link [0] "URL redirects or rewrites" is a supported use case.

For stripping /api/ from the path, I don't know what would be the benefit of doing it at the origin request, rather than at the viewer request?

Cloudfront functions are pretty new, so some older docs might still reference lamdba@edge only.

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Re:You don't need that CORS request by herpderperator on Tuesday January 04, 2022 @08:58PM (#29803977)

The origin request is your backend. The viewer request is the one you're requesting from the client. You want the viewer to have /api. You want the origin to not have /api.

Therefore stripping must be performed on the origin request, which is not supported by CloudFront Functions.

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Re:You don't need that CORS request by forty on Saturday January 08, 2022 @02:00AM (#29849331)

Both the viewer request and origin request hook both happen early enough that you can update the path

See https://docs.aws.amazon.com/AmazonCloudFront/latest/Develope...

I have used lamdba@edge and our primary use case was to rewrite url (to add languages information for example) so I'm sure it works in viewer request events.

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Re:You don't need that CORS request by herpderperator on Saturday January 08, 2022 @01:32PM (#29854609)

No. Please see the many other responses I gave to other comments. It does not work because the viewer request is the request the viewer views. If you change the URL of the viewer request, CloudFront sends a 301 accordingly. In other words, changing /api/blah to /blah in the "Viewer Request" part results in CloudFront injecting a `301 location: /blah` and the client doesn't hit your backend because they got redirected. The client instead hits your frontend as a result of your URL rewrite. There is a very clear difference between viewer and origin. If you could rewrite origin requests at the viewer level there would not be any difference between the two. This is the difference. Viewer is what the client sees. Origin is what the backend sees.

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Re:You don't need that CORS request by forty on Monday January 10, 2022 @03:04AM (#29871814)

My understanding is that you would need to rewrite the url and update the origin.

I could be wrong as I did this lambda@edge a while ago, but the main difference between the two request event is that viewer request is done in all cases, while origin request is done only in case of cache miss.

[EDIT] you are right, updating the origin is indeed something that cannot be done on the viewer side. My bad, I should have checked earlier.

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Re:You don't need that CORS request by ep103 on Monday January 03, 2022 @01:53PM (#29784663)

Personally, I did it with templates in api gateway, as at least then I'm not paying for the cpu time to do these sorts of manipulation. But yes, stuff like this made me really shake my head at 'the cloud'

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