Fix bug where form was posting to the wrong path

Signed-off-by: Margo Crawford <margaretc@vmware.com>

internal/oidc/login/get_login_handler.go

@@ -28,6 +28,7 @@ type PageData struct {
 	HasAlertError bool
 	AlertMessage  string
 	Title         string
+	PostPath      string
 }
 
 func NewGetHandler(upstreamIDPs oidc.UpstreamIdentityProvidersLister) HandlerFunc {
@@ -44,6 +45,7 @@ func NewGetHandler(upstreamIDPs oidc.UpstreamIdentityProvidersLister) HandlerFun
 			HasAlertError: alertError != "",
 			AlertMessage:  message,
 			Title:         "Pinniped",
+			PostPath:      r.URL.Path, // the path for POST is the same as for GET
 		})
 		if err != nil {
 			return err

internal/oidc/login/get_login_handler_test.go

@@ -98,7 +98,7 @@ func TestGetLogin(t *testing.T) {
 		tt := test
 		t.Run(tt.name, func(t *testing.T) {
 			handler := NewGetHandler(tt.idps)
-			target := "/login?state=" + tt.encodedState
+			target := "/some/path/login?state=" + tt.encodedState
 			if tt.errParam != "" {
 				target += "&err=" + tt.errParam
 			}
@@ -126,7 +126,7 @@ func getHTMLResult(errorBanner string) string {
 <h1>Pinniped</h1>
 <p>some-ldap-idp</p>
 %s
-<form action="/login" method="post">
+<form action="/some/path/login" method="post" target="_parent">
 
     <div>
         <label for="username"><b>Username</b></label>

internal/oidc/login/login_form.gohtml

@@ -15,7 +15,7 @@ SPDX-License-Identifier: Apache-2.0
         <span>{{.AlertMessage}}</span>
     </div>
 {{end}}
-<form action="/login" method="post">
+<form action="{{.PostPath}}" method="post" target="_parent">
 
     <div>
         <label for="username"><b>Username</b></label>