feat(api): normalise OpenAPI server metadata

Co-Authored-By: Virgil <virgil@lethean.io>

client.go

@@ -230,6 +230,7 @@ func (c *OpenAPIClient) loadSpec() error {
 			}
 		}
 	}
+	c.servers = normaliseServers(c.servers)
 
 	if c.baseURL == "" {
 		for _, server := range c.servers {

client_test.go

@@ -278,8 +278,9 @@ info:
   title: Test API
   version: 1.0.0
 servers:
+  - url: " `+srv.URL+` "
   - url: /
-  - url: `+srv.URL+`
+  - url: " `+srv.URL+` "
 paths:
   /hello:
     get:

openapi.go

@@ -37,17 +37,12 @@ func (sb *SpecBuilder) Build(groups []RouteGroup) ([]byte, error) {
 		},
 	}
 
-	if len(sb.Servers) > 0 {
-		servers := make([]map[string]any, 0, len(sb.Servers))
-		for _, server := range sb.Servers {
-			if server == "" {
-				continue
-			}
-			servers = append(servers, map[string]any{"url": server})
-		}
-		if len(servers) > 0 {
-			spec["servers"] = servers
+	if servers := normaliseServers(sb.Servers); len(servers) > 0 {
+		out := make([]map[string]any, 0, len(servers))
+		for _, server := range servers {
+			out = append(out, map[string]any{"url": server})
 		}
+		spec["servers"] = out
 	}
 
 	// Add component schemas for the response envelope.

openapi_test.go

@@ -779,9 +779,10 @@ func TestSpecBuilder_Good_Servers(t *testing.T) {
 		Title:   "Test",
 		Version: "1.0.0",
 		Servers: []string{
-			"https://api.example.com",
+			" https://api.example.com ",
 			"/",
 			"",
+			"https://api.example.com",
 		},
 	}
 
@@ -800,7 +801,7 @@ func TestSpecBuilder_Good_Servers(t *testing.T) {
 		t.Fatalf("expected servers array, got %T", spec["servers"])
 	}
 	if len(servers) != 2 {
-		t.Fatalf("expected 2 non-empty servers, got %d", len(servers))
+		t.Fatalf("expected 2 normalised servers, got %d", len(servers))
 	}
 
 	first := servers[0].(map[string]any)

options.go

@@ -134,7 +134,7 @@ func WithSwagger(title, description, version string) Option {
 // server list through both the runtime Swagger UI and exported OpenAPI files.
 func WithSwaggerServers(servers ...string) Option {
 	return func(e *Engine) {
-		e.swaggerServers = append([]string(nil), servers...)
+		e.swaggerServers = normaliseServers(servers)
 	}
 }
 

servers.go

@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: EUPL-1.2
+
+package api
+
+import "strings"
+
+// normaliseServers trims whitespace, removes empty entries, and preserves
+// the first occurrence of each server URL.
+func normaliseServers(servers []string) []string {
+	if len(servers) == 0 {
+		return nil
+	}
+
+	cleaned := make([]string, 0, len(servers))
+	seen := make(map[string]struct{}, len(servers))
+
+	for _, server := range servers {
+		server = strings.TrimSpace(server)
+		if server == "" {
+			continue
+		}
+		if _, ok := seen[server]; ok {
+			continue
+		}
+		seen[server] = struct{}{}
+		cleaned = append(cleaned, server)
+	}
+
+	if len(cleaned) == 0 {
+		return nil
+	}
+
+	return cleaned
+}

swagger_test.go

@@ -263,7 +263,7 @@ func TestSwagger_Good_UsesServerMetadata(t *testing.T) {
 
 	e, err := api.New(
 		api.WithSwagger("Server API", "Server metadata test", "1.0.0"),
-		api.WithSwaggerServers("https://api.example.com", "/", ""),
+		api.WithSwaggerServers(" https://api.example.com ", "/", "", "https://api.example.com"),
 	)
 	if err != nil {
 		t.Fatalf("unexpected error: %v", err)
@@ -293,7 +293,7 @@ func TestSwagger_Good_UsesServerMetadata(t *testing.T) {
 		t.Fatalf("expected servers array, got %T", doc["servers"])
 	}
 	if len(servers) != 2 {
-		t.Fatalf("expected 2 servers, got %d", len(servers))
+		t.Fatalf("expected 2 normalised servers, got %d", len(servers))
 	}
 
 	first := servers[0].(map[string]any)