From 0ef9d8a3955f64f9e156feaf7a3eef0b1bb56c82 Mon Sep 17 00:00:00 2001
From: Adrien YHUEL <adrien.yhuel@gmail.com>
Date: Wed, 4 Dec 2024 11:50:16 +0100
Subject: [PATCH] feat: :sparkles: Add ability to extend or replace existing
 servers in the OpenAPI spec

---
 README.md  |  2 ++
 openapi.go | 38 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/README.md b/README.md
index a0da3c3..6134389 100644
--- a/README.md
+++ b/README.md
@@ -52,6 +52,8 @@ Reports any errors as a `{openapi.error}` [placeholder](https://caddyserver.com/
 | `validate_servers`       | Enable server validation. Accepts `true`, `false` or just the directive which enables validation. Default is `true`. |
 | `log_error`              | Toggles error logging. Default is `false` |
 | `check`                  | Enable validation of the request parameters; include one or more of the following directives in the body:`req_params`, `req_body` and `resp_body`. `resp_body` only validates `application/json` payload. Note that validating the request body will implicitly set `req_params` |
+| `additional_servers`     | List of servers to add to openapi spec for request validation |
+| `replace_servers`        | Make additional_servers replace existing servers in OpenAPI spec |
 
 Errors are reported in the following [placeholders](https://caddyserver.com/docs/caddyfile/concepts#placeholders). You can use them in other [directives](https://caddyserver.com/docs/caddyfile/directives) like [`respond`](https://caddyserver.com/docs/caddyfile/directives/respond)
 
diff --git a/openapi.go b/openapi.go
index 3864508..02b9d13 100644
--- a/openapi.go
+++ b/openapi.go
@@ -33,6 +33,8 @@ const (
 	TOKEN_LOG_ERROR        = "log_error"
 	TOKEN_VALIDATE_SERVERS = "validate_servers"
 	TOKEN_CHECK            = "check"
+	TOKEN_ADD_SERVERS      = "additional_servers"
+	TOKEN_REPLACE_SERVERS  = "replace_servers"
 	VALUE_REQ_PARAMS       = "req_params"
 	VALUE_REQ_BODY         = "req_body"
 	VALUE_RESP_BODY        = "resp_body"
@@ -57,6 +59,15 @@ type OpenAPI struct {
 	// Enable server validation
 	ValidateServers bool `json:"valid_servers,omitempty"`
 
+	// A list of additional servers to be considered valid when
+	// when performing the request validation. The additional servers
+	// are added to the servers in the OpenAPI specification.
+	// Default is empty list
+	AdditionalServers []string `json:"additional_servers,omitempty"`
+
+	// Make AdditionalServers replace existing servers in spec
+	ReplaceServers bool `json:"replace_servers,omitempty"`
+
 	oas    *openapi3.T
 	router routers.Router
 
@@ -125,6 +136,20 @@ func (oapi *OpenAPI) Provision(ctx caddy.Context) error {
 	}
 
 	if oapi.ValidateServers {
+
+		if oapi.ReplaceServers && len(oapi.AdditionalServers) != 0 {
+			oas.Servers = make([]*openapi3.Server, 0)
+		}
+
+		for i, s := range oapi.AdditionalServers {
+			server := &openapi3.Server{
+				URL:         s,
+				Description: fmt.Sprintf("Additional server: %d", i),
+				Variables:   make(map[string]*openapi3.ServerVariable),
+			}
+			oas.Servers = append(oas.Servers, server)
+		}
+
 		oapi.log("List of servers")
 		for _, s := range oas.Servers {
 			oapi.log(fmt.Sprintf("- %s #%s", s.URL, s.Description))
@@ -171,6 +196,8 @@ func (oapi *OpenAPI) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
 	oapi.LogError = false
 	oapi.ValidateServers = true
 	oapi.Check = nil
+	oapi.AdditionalServers = make([]string, 0)
+	oapi.ReplaceServers = false
 
 	// Skip the openapi directive
 	d.Next()
@@ -229,6 +256,17 @@ func (oapi *OpenAPI) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
 				return err
 			}
 
+		case TOKEN_ADD_SERVERS:
+			oapi.AdditionalServers = d.RemainingArgs()
+
+		case TOKEN_REPLACE_SERVERS:
+			if d.NextArg() {
+				b, err := strconv.ParseBool(d.Val())
+				if nil == err {
+					oapi.ReplaceServers = b
+				}
+			}
+
 		default:
 			return d.Errf("unrecognized subdirective: '%s'", token)
 		}