Added custom binding support

packages/core/src/server.js

@@ -114,6 +114,11 @@ export class Server extends http.Server {
     });
   }
 
+  // return host bind address - defaults to 0.0.0.0
+  get host() {
+    return process.env.PERCY_SERVER_HOST || '0.0.0.0';
+  }
+
   // return the listening port or any default port
   get port() {
     return super.address()?.port ?? this.#defaultPort;
@@ -122,7 +127,7 @@ export class Server extends http.Server {
   // return a string representation of the server address
   address() {
     let port = this.port;
-    let host = 'http://localhost';
+    let host = `http://${this.host}`;
     return port ? `${host}:${port}` : host;
   }
 
@@ -131,7 +136,7 @@ export class Server extends http.Server {
     return new Promise((resolve, reject) => {
       let handle = err => off() && err ? reject(err) : resolve(this);
       let off = () => this.off('error', handle).off('listening', handle);
-      super.listen(port, handle).once('error', handle);
+      super.listen(port, this.host, handle).once('error', handle);
     });
   }
 

packages/core/test/unit/server.test.js

@@ -20,6 +20,43 @@ describe('Unit / Server', () => {
     await new Promise(r => setImmediate(setImmediate, r));
   });
 
+  describe('#host', () => {
+    beforeEach(async () => {
+      await server.listen(9000);
+      server.route('get', '/test/:path', (req, res) => res.text(req.params.path));
+    });
+
+    it('returns the host', async () => {
+      expect(server.host).toEqual('0.0.0.0');
+
+      // test connection via 0.0.0.0
+      await expectAsync(request('/test/foo', 'GET')).toBeResolvedTo('foo');
+
+      // test connection via localhost
+      let { request } = await import('../helpers/request.js');
+      await expectAsync(request(new URL(path, 'localhost'), 'GET')).toBeResolvedTo('foo');
+    });
+
+    describe('with PERCY_SERVER_HOST set', () => {
+      beforeEach(() => {
+        process.env.PERCY_SERVER_HOST = 'localhost';
+      });
+
+      afterEach(() => {
+        delete process.env.PERCY_SERVER_HOST;
+      });
+
+      it('uses correct host', async () => {
+        // test connection via localhost
+        await expectAsync(request('/test/foo', 'GET')).toBeResolvedTo('foo');
+
+        // test connection via 0.0.0.0
+        let { request } = await import('../helpers/request.js');
+        await expectAsync(request(new URL(path, '0.0.0.0'), 'GET')).toBeRejected();
+      });
+    });
+  });
+
   describe('#port', () => {
     it('returns the provided default port when not listening', () => {
       expect(server.port).toEqual(8000);