Add notes about testing required headers

Author: code-asher

README.md

@@ -42,12 +42,20 @@ Run `./code-marketplace --help` for a full list of options.
 ### Exposing the marketplace
 
 The marketplace must be put behind TLS otherwise code-server will reject
-connecting to the API. This could mean using a reverse proxy like NGINX or Caddy
-with your own domain and certificates or using a service like Cloudflare.
+connecting to the API. This could mean using a TLS-terminating reverse proxy
+like NGINX or Caddy with your own domain and certificates or using a service
+like Cloudflare.
 
 When hosting the marketplace behind a reverse proxy set either the `Forwarded`
-header or both the `X-Forwarded-Host` and `X-Forwarded-Proto` headers. These are
-used to generate absolute URLs to extension assets in API responses.
+header or both the `X-Forwarded-Host` and `X-Forwarded-Proto` headers. These
+headers are used to generate absolute URIs to extension assets in API responses.
+One way to test this is to make a query and check one of the URIs in the
+response:
+
+```
+$ curl 'https://example.com/api/extensionquery' -H 'Accept: application/json;api-version=3.0-preview.1' --compressed -H 'Content-Type: application/json' --data-raw '{"filters":[{"criteria":[{"filterType":8,"value":"Microsoft.VisualStudio.Code"}],"pageSize":1}],"flags":439}' | jq .results[0].extensions[0].versions[0].assetUri
+"https://example.com/assets/vscodevim/vim/1.24.1"
+```
 
 The marketplace does not support being hosted behind a base path; it must be
 proxied at the root of your domain.

helm/README.md

@@ -18,14 +18,28 @@ You will need to configure `ingress` in [values.yaml](./values.yaml) to expose t
 marketplace on an external domain or change `service.type` to get yourself an
 external IP address.
 
-It is recommended to configure `ingress` with TLS or put the external IP behind
-a TLS-terminating reverse proxy because code-server will refuse to connect to
-the marketplace if it is not behind HTTPS.
+The marketplace must be put behind TLS otherwise code-server will reject
+connecting to the API. This could mean configuring `ingress` with TLS or putting
+the external IP behind a TLS-terminating reverse proxy.
 
 More information can be found at these links:
 
-https://kubernetes.io/docs/concepts/services-networking/service/#publishing-services-service-types
-https://kubernetes.io/docs/concepts/services-networking/ingress/
+- https://kubernetes.io/docs/concepts/services-networking/service/#publishing-services-service-types
+- https://kubernetes.io/docs/concepts/services-networking/ingress/
+
+When hosting the marketplace behind a reverse proxy set either the `Forwarded`
+header or both the `X-Forwarded-Host` and `X-Forwarded-Proto` headers (the
+default `ingress` already takes care of this). These headers are used to
+generate absolute URIs to extension assets in API responses. One way to test
+this is to make a query and check one of the URIs in the response:
+
+```
+$ curl 'https://example.com/api/extensionquery' -H 'Accept: application/json;api-version=3.0-preview.1' --compressed -H 'Content-Type: application/json' --data-raw '{"filters":[{"criteria":[{"filterType":8,"value":"Microsoft.VisualStudio.Code"}],"pageSize":1}],"flags":439}' | jq .results[0].extensions[0].versions[0].assetUri
+"https://example.com/assets/vscodevim/vim/1.24.1"
+```
+
+The marketplace does not support being hosted behind a base path; it must be
+proxied at the root of your domain.
 
 ## Adding/removing extensions