do variable substitutions in server urls

openapi-to-har.js

@@ -410,6 +410,17 @@ const getBaseUrl = function (openApi, path, method) {
   if (openApi.paths[path][method].servers)
     return openApi.paths[path][method].servers[0].url;
   if (openApi.paths[path].servers) return openApi.paths[path].servers[0].url;
+
+  if (openApi.servers && openApi.servers.length > 0) {
+    let firstServer = openApi.servers[0];
+    let url = firstServer.url;
+    const variables = firstServer.variables || {};
+    Object.keys(variables).forEach((variable) => {
+      url = url.replace(`{${variable}}`, variables[variable].default);
+    });
+    return url;
+  }
+
   if (openApi.servers) return openApi.servers[0].url;
 
   let baseUrl = '';

test/form_data_example.json

@@ -17,7 +17,12 @@
   },
   "servers": [
     {
-      "url": "http://petstore.swagger.io/api"
+      "url": "http://{hostname}/api",
+      "variables": {
+        "hostname": {
+          "default": "petstore.swagger.io"
+        }
+      }
     }
   ],
   "paths": {

test/test.js

@@ -219,6 +219,21 @@ test('Generate snippet with multipart/form-data', function (t) {
   t.end();
 });
 
+test('If a server has url with variables those should be substituted', function (t) {
+  const result = OpenAPISnippets.getEndpointSnippets(
+    FormDataExampleReferenceAPI,
+    '/pets',
+    'patch',
+    ['csharp_restsharp']
+  );
+  const snippet = result.snippets[0].content;
+  t.true(
+    /new RestClient\("http:\/\/petstore.swagger.io\/api\/pets"/.test(snippet)
+  );
+  t.false(/{hostname}/.test(snippet));
+  t.end();
+});
+
 test('Generate snippet with multipart/form-data with array', function (t) {
   const result = OpenAPISnippets.getEndpointSnippets(
     FormDataExampleReferenceAPI,