Add flat/nested to bitwarden prelogin route (#3544)

docs/bitwarden.md

@@ -31,9 +31,9 @@ to `https://<instance>/bitwarden`.
 ### POST /bitwarden/api/accounts/prelogin
 
 It allows the client to know the number of KDF iterations to apply when hashing
-the master password. It can also tell if the login via OIDC is mandatory, and
-if the vault is empty (when both conditions are true, the onboarding process is
-a bit different).
+the master password. It can also tell if the login via OIDC is mandatory, if
+the vault is empty (when both conditions are true, the onboarding process is a
+bit different), and if flat or nested subdomains are used.
 
 #### Request
 
@@ -61,7 +61,8 @@ Content-Type: application/json
   "Kdf": 0,
   "KdfIterations": 10000,
   "OIDC": false,
-  "HasCiphers": true
+  "HasCiphers": true,
+  "FlatSubdomains": true
 }
 ```
 

web/bitwarden/bitwarden.go

@@ -50,11 +50,13 @@ func Prelogin(c echo.Context) error {
 	if resp, err := couchdb.NormalDocs(inst, consts.BitwardenCiphers, 0, 1, "", false); err == nil {
 		hasCiphers = resp.Total > 0
 	}
+	flat := config.GetConfig().Subdomains == config.FlatSubdomains
 	return c.JSON(http.StatusOK, echo.Map{
-		"Kdf":           setting.PassphraseKdf,
-		"KdfIterations": setting.PassphraseKdfIterations,
-		"OIDC":          !passwordAuth,
-		"HasCiphers":    hasCiphers,
+		"Kdf":            setting.PassphraseKdf,
+		"KdfIterations":  setting.PassphraseKdfIterations,
+		"OIDC":           !passwordAuth,
+		"HasCiphers":     hasCiphers,
+		"FlatSubdomains": flat,
 	})
 }