carhartl · November 16, 2022 08:29
diff --git a/ingress.yaml b/ingress.yaml
 # The rewrite rule for nginx is to pick the first capture group’s match $1 from the path matcher.
 #
 # In the path matcher regex there are 2 capture groups (the inner groups are not captured):
 # /(...)|(.*)
 #  ^$1   ^$2
 #
 # So when we match anything that starts with "/api/" or ends with one of "css"/"js"/"png" this will
 # populate $1 and nginx passes the url unaltered upstream (-> /$1). If there is no such match, we match
 # everything else through the alternation: (.*) to populate $2, but we throw $2 away (we don't make use
 # of it in the rewrite target! An empty capture group, in this second scenario $1, will turn into an
 # empty string in the rewrite expression, thus "/$1" becomes "/", which is going to load the SPA in
 # this case. In the browser the url won’t change and the client-side router takes over.
 apiVersion: networking.k8s.io/v1
 kind: Ingress
 metadata:
  name: ingress
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /$1
 spec:
  ingressClassName: nginx
  rules:
    - host: example.com
      http:
        paths:
          - path: "/((?:api/.*|.*(?:css|js|png)$))|(.*)"
            pathType: Prefix
            backend:
              service:
                name: service
                port:
                  number: 8888
	# The rewrite rule for nginx is to pick the first capture group’s match $1 from the path matcher.
	#
	# In the path matcher regex there are 2 capture groups (the inner groups are not captured):
	# /(...)\|(.*)
	# ^$1 ^$2
	#
	# So when we match anything that starts with "/api/" or ends with one of "css"/"js"/"png" this will
	# populate $1 and nginx passes the url unaltered upstream (-> /$1). If there is no such match, we match
	# everything else through the alternation: (.*) to populate $2, but we throw $2 away (we don't make use
	# of it in the rewrite target! An empty capture group, in this second scenario $1, will turn into an
	# empty string in the rewrite expression, thus "/$1" becomes "/", which is going to load the SPA in
	# this case. In the browser the url won’t change and the client-side router takes over.
	apiVersion: networking.k8s.io/v1
	kind: Ingress
	metadata:
	name: ingress
	annotations:
	nginx.ingress.kubernetes.io/rewrite-target: /$1
	spec:
	ingressClassName: nginx
	rules:
	- host: example.com
	http:
	paths:
	- path: "/((?:api/.\|.(?:css\|js\|png)$))\|(.*)"
	pathType: Prefix
	backend:
	service:
	name: service
	port:
	number: 8888