The Bare-Bones Live Coding Demonstration (as given at XP Days 2012 in Kiev)

1. Bare-knuckle web
development
XP Days Ukraine
Johannes Brodwall, Chief scientist
Exilesoft Global

2. • Bare-knuckle
philosophy
• Demonstration of bare-
knuckle web in Java
• Further directions

3. Part I:

4. The bare-knuckle
philosophy

5. High impact with
low ceremony

6. • Framework light
• Test-driven
• No calculators

7. Light on framework

8. Frameworks solve 80%
of the job…

9. … and makes the rest 10
times as hard

10. “Why did Hibernate
suddenly slow down?”

11. “How do I implement a
custom SOAP header
with JAX-WS?”

12. “How to do X with Spring”

13. @AutoWire + package scan
with 100s of beans

14. Test-driven

15. No more architecture than
what’s needed

16. Fast feedback cycle – also
in the future

17. Don’t use a
calculator…

18. Part II:

19. Demo: Phonebook
web app

20. Test driving

21. WebDriver browser = createWebDriver();
browser.get(url);
browser.findElement(By.linkText("Add contact")).click();
browser.findEleme(By.name("fullName")).sendKeys("Vader");
browser.findEleme(By.name("phoneNumber")).sendKeys("27");
browser.findEleme(By.name("saveContact")).click();
browser.findElement(By.linkText("Find contact")).click();
browser.findElem(By.name("nameQuery")).sendKeys("vader");
browser.findElement(By.name("nameQuery")).submit();
assertThat(browser.findElem(By.id("contacts")).getText())
.contains("555-33274-7827");

22. Server server = new Server(0);
server.setHandler(
new WebAppContext("src/main/webapp", "/contacts"));
server.start();
int port = server.getConnectors()[0].getLocalPort();
String url = "http://localhost:" + port + "/contacts";

23. <web-app version="2.5“>
<servlet>
<servlet-name>contactServlet</servlet-name>
<servlet-class>
com.exilesoft.bareknuckleweb.ContactServlet
</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>contactServlet</servlet-name>
<url-pattern>contact/*</url-pattern>
</servlet-mapping>
</web-app>

24. public class ContactServlet extends HttpServlet {
}

25. @Test
public void shouldShowAddForm() throws Exception {
ContactServlet servlet = new ContactServlet();
HttpServletRequest req = mock(HttpServletRequest.class);
HttpServletResponse resp = mock(HttpServletResponse.class);
StringWriter html = new StringWriter();
when(resp.getWriter()).thenReturn(new PrintWriter(html));
when(req.getPathInfo()).thenReturn("/create.html");
servlet.doGet(req, resp);
verify(resp).setContentType("text/html");
assertThat(html.toString())
.contains("<form method='post'")
.contains("<input type='text' name='fullName'")
.contains("<input type='text' name='phoneNumber'")
.contains("<input type='submit' name='createContact'");
}

26. Refactoring

27. void showFindPage(String q, PrintWriter writer) {
Document doc = Xml.read("contact/index.html");
doc.selectFirst("[name=nameQuery]").val(nameQuery);
Element contactsEl = doc.select("#contacts");
Element template = contactsEl.select(".contact");
contactsEl.clear();
for (Contact contact : contactRepository.find(q)) {
contactsEl.add(
template.copy().text(contact.print()));
}
doc.write(writer);
}

28. .NET

29. [TestMethod]
public void ShouldFindSavedContacts()
{
var server = new WebServer();
server.Start("http://localhost:12380/");
var url = "http://localhost:12380";
var browser = new SimpleBrowser.WebDriver.SimpleBrowserDriver();
browser.Url = url + "/contacts";
browser.FindElement(By.LinkText("Add contact")).Click();
browser.FindElement(By.Name("fullName")).SendKeys("Darth Vader");
browser.FindElement(By.Name("phoneNumber")).SendKeys("555-33274-7827");
browser.FindElement(By.Name("saveContact")).Click();
browser.FindElement(By.LinkText("Find contact")).Click();
browser.FindElement(By.Name("nameQuery")).SendKeys("vader");
browser.FindElement(By.Name("nameQuery")).Submit();
browser.FindElement(By.Id("contacts")).Text.Should()
.Contain("555-33274-7827");
}

30. public class WebServer
{
public void Start(string baseAddress)
{
var config =
new HttpSelfHostConfiguration(baseAddress);
config.Routes.MapHttpRoute(
"web Default",
"{controller}/{id}",
new { id = RouteParameter.Optional });
using (var server = new HttpSelfHostServer(config))
{
server.OpenAsync().Wait();
Console.WriteLine("Press Enter to quit.");
Console.ReadLine();
}
}
}

31. Part III:

32. Further directions

33. Norwegian
agricultural
authority

34. Java web application with
an MVC architecture

35. Controllers:
• Create a view
• Retrieve model from repo
• Set model on view
• Render view

36. View example:

37. @Override
public void render(HttpServletResponse resp) throws IOException {
Match document = $("html",
head(),
$("img").attr("src", "/sms-varsel/Sparebank1.jpg"),
$("h1", "Internet bank simulator"),
$("form").attr("method", "post").append(
hiddenField(this.bankNum, "bankNum"),
hiddenField(this.customerId, "customerId"),
$("h2", "Set Mobile Phone Number"),
phoneNumberField(this.phoneNumber),
$("h2", "Account numbers"),
accountNumbersField(this.accountNumbers),
$("h2", "Payment account"),
paymentAccountField(this.defaultAccount),
$("h2", "Save changes"),
$("div",
$("input").attr("type", "submit").attr("value", "Store")).attr("nam
e", "update")));
resp.setContentType("text/html");
resp.setCharacterEncoding("UTF-8");
resp.getWriter().write(document.toString());
}

38. Match document = $("html",
head(),
$("img").attr("src", "/logo.jpg"),
$("h1", “Page name"),
$("form").attr("method", "post").append(
hiddenField(this.bankNum, "bankNum"),
hiddenField(this.customerId, "customerId"),
$("h2", "Save changes"),
$("div",
$("input").attr("type", "submit")
.attr("value", "Store"))
.attr("name", "update")));

39. Norwegian Power
Transmission
System Operator

40. Universal repository
Universal service
Commands and Queries
One domain model

41. No Spring – 100 KLOC

42. Single-jar deployment
• Includes scripts
• Includes Jetty

43. public class StatnettWebServer {
private final org.eclipse.jetty.server.Server server;
public ContactWebServer(int port) {
server = new Server(port);
server.setHandler(new WebAppContext(“…", "/statnett"));
}
void start() throws Exception {
server.start();
}
String getUrl() {
int port = server.getConnectors()[0].getLocalPort();
return "http://localhost:" + port + "/contacts";
}
public static void main(String[] args) throws Exception {
StatnettWebServer server = new StatnettWebServer(10080);
server.start();
System.out.println(server.getUrl());
}
}

44. SpareBank1

45. 10 web service
clients

46. HttpURLConnection
JOOX

47. @Override
public String getCountryByIp(String ipAddress) throws
Exception {
Document soapRequest =
soapElement("S:Envelope",
$("S:Body",
wsxElement("wsx:GetGeoIP",
$("wsx:IPAddress", ipAddress))));
Document soapResponse
endpoint.postRequest(getSOAPAction(), soapRequest);
return $(soapResponse).xpath("/Envelope/Body/*")
.xpath("GetGeoIPResult/CountryName").text();
}

48. public Document postRequest(String soapAction, Document soapRequest) {
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
connection.setDoInput(true);
connection.setDoOutput(true);
connection.addRequestProperty("SOAPAction", soapAction);
connection.addRequestProperty("Content-Type", "text/xml");
$(soapRequest).write(connection.getOutputStream());
int responseCode = connection.getResponseCode();
if (isErrorResponse(responseCode)) {
String response = toString(connection.getErrorStream());
String responseContentType = connection.getContentType();
if (responseContentType.startsWith("text/xml")) {
return response;
}
throw new ServiceCommunicationException(
"On POST to " + url + ": " + responseCode + " "
+ connection.getResponseMessage() + ": " + response);
}
return $(connection.getInputStream()).document();
d}

49. Conclusion:

50. YAGNI

51. No calculator
until…

52. Don’t use a framework
you couldn’t have
written yourself

53. Thank you
jbr@exilesoft.com
http://johannesbrodwall.com
http://exilesoft.com
http://twitter.com/jhannes