I believe i'm dealing with a lambda, so https://docs.aws.amazon.com/apigateway/latest/developerguide/how-to-cors.html "enabling cors support for lambda..." would be relevent. i created an option method, though i suppose i should test that theory.

https://docs.aws.amazon.com/apigateway/latest/developerguide/apigateway-test-cors.html Looks like it might be useful, ill try to get some feedback next.

Have you read through https://docs.datomic.com/cloud/tech-notes/cors-lambda-proxy.html

I see in your forum post you have seen the tech note. Since you can successfully curl the end point. When you do that locally do you receive the expected headers?

@U0508JRJC thanks a lot for the response. It looks like i do get the expected headers from curl:

< HTTP/2 200 
< date: Sun, 13 Jun 2021 00:39:24 GMT
< content-type: application/edn
< content-length: 847
< x-amzn-requestid: ef6a364c-55a7-430b-a2c0-8b2ede0e7bc5
< access-control-allow-origin: *
< access-control-allow-headers: Authorization, Content-Type
< x-amz-apigw-id: A1oFbEOxiYcFutA=
< access-control-allow-methods: GET, PUT, PATCH, POST, DELETE, OPTIONS
< x-amzn-trace-id: Root=1-60c553bc-5652c3b90fe79f8437318ff7;Sampled=0
<

➜  ion-starter git:(add-pomodoro-mode) curl -v  -d :hat 
*   Trying 3.23.22.174:443...
* TCP_NODELAY set
* Connected to  (3.23.22.174) port 443 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
* successfully set certificate verify locations:
*   CAfile: /etc/ssl/certs/ca-certificates.crt
  CApath: /etc/ssl/certs
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
* TLSv1.3 (IN), TLS handshake, Server hello (2):
* TLSv1.2 (IN), TLS handshake, Certificate (11):
* TLSv1.2 (IN), TLS handshake, Server key exchange (12):
* TLSv1.2 (IN), TLS handshake, Server finished (14):
* TLSv1.2 (OUT), TLS handshake, Client key exchange (16):
* TLSv1.2 (OUT), TLS change cipher, Change cipher spec (1):
* TLSv1.2 (OUT), TLS handshake, Finished (20):
* TLSv1.2 (IN), TLS handshake, Finished (20):
* SSL connection using TLSv1.2 / ECDHE-RSA-AES128-GCM-SHA256
* ALPN, server accepted to use h2
* Server certificate:
*  subject: CN=*.
*  start date: Aug 29 00:00:00 2020 GMT
*  expire date: Sep 28 12:00:00 2021 GMT
*  subjectAltName: host "" matched cert's "*."
*  issuer: C=US; O=Amazon; OU=Server CA 1B; CN=Amazon
*  SSL certificate verify ok.
* Using HTTP2, server supports multi-use
* Connection state changed (HTTP/2 confirmed)
* Copying HTTP/2 data in stream buffer to connection buffer after upgrade: len=0
* Using Stream ID: 1 (easy handle 0x55ebe17c7e10)
> POST /dev/datomic/ HTTP/2
> Host: 
> user-agent: curl/7.68.0
> accept: */*
> content-length: 4
> content-type: application/x-www-form-urlencoded
> 
* Connection state changed (MAX_CONCURRENT_STREAMS == 128)!
* We are completely uploaded and fine
< HTTP/2 200 
< date: Sun, 13 Jun 2021 00:39:24 GMT
< content-type: application/edn
< content-length: 847
< x-amzn-requestid: ef6a364c-55a7-430b-a2c0-8b2ede0e7bc5
< access-control-allow-origin: *
< access-control-allow-headers: Authorization, Content-Type
< x-amz-apigw-id: A1oFbEOxiYcFutA=
< access-control-allow-methods: GET, PUT, PATCH, POST, DELETE, OPTIONS
< x-amzn-trace-id: Root=1-60c553bc-5652c3b90fe79f8437318ff7;Sampled=0
< 
[[#:inv{:sku "SKU-51", :size :small, :color :yellow}]
 [#:inv{:sku "SKU-47", :size :xlarge, :color :blue}]
 [#:inv{:sku "SKU-39", :size :medium, :color :blue}]
 [#:inv{:sku "SKU-19", :size :small, :color :green}]
 [#:inv{:sku "SKU-55", :size :medium, :color :yellow}]
 [#:inv{:sku "SKU-15", :size :xlarge, :color :red}]
 [#:inv{:sku "SKU-35", :size :small, :color :blue}]
 [#:inv{:sku "SKU-27", :size :large, :color :green}]
 [#:inv{:sku "SKU-63", :size :xlarge, :color :yellow}]
 [#:inv{:sku "SKU-3", :size :small, :color :red}]
 [#:inv{:sku "SKU-43", :size :large, :color :blue}]
 [#:inv{:sku "SKU-59", :size :large, :color :yellow}]
 [#:inv{:sku "SKU-31", :size :xlarge, :color :green}]
 [#:inv{:sku "SKU-7", :size :medium, :color :red}]
 [#:inv{:sku "SKU-11", :size :large, :color :red}]
 [#:inv{:sku "SKU-23", :size :medium, :color :green}]]
* Connection #0 to host  left intact

I do believe your issue is with the fetch call. You want to provide js as the argument. Perhaps something like

(js/fetch ""
          (clj->js {:mode    "cors"
                    :method  "POST"
                    :headers {"Content-Type" "text/plain"}
                    :body    ":hat"}))

@U0DJ4T5U1 ^

Your clearly right that I would need to pass the map to clj to js. I was using lambs island fetch and I forgot to change the args when I switched to pure JS.

Happens to all of us 🙂