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

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

Part I:

The bare-knuckle philosophy

High impact with low ceremony

Framework light Test-driven No calculators

Light on framework

Frameworks solve 80% of the job…

… and makes the rest 10 times as hard

“Why did Hibernate suddenly slow down?”

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

“How to do X with Spring”

@AutoWire + package scan with 100s of beans

Test-driven

No more architecture than what’s needed

Fast feedback cycle – also in the future

Don’t use a calculator…

Part II:

Demo: Phonebook web app

Test driving

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(" ");

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

contactServlet com.exilesoft.bareknuckleweb.ContactServlet contactServlet contact/*

public class ContactServlet extends HttpServlet { }

@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'"); }

Refactoring

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); }

.NET

[TestMethod] public void ShouldFindSavedContacts() { var server = new WebServer(); server.Start(" var url = " 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(" "); 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(" "); }

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(); }

Part III:

Further directions

Norwegian agricultural authority

Java web application with an MVC architecture

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

View example:

@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("name", "update"))); resp.setContentType("text/html"); resp.setCharacterEncoding("UTF-8"); resp.getWriter().write(document.toString()); }

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")));

Norwegian Power Transmission System Operator

Universal repository Universal service Commands and Queries One domain model

No Spring – 100 KLOC

Single-jar deployment Includes scripts Includes Jetty

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 " + port + "/contacts"; } public static void main(String[] args) throws Exception { StatnettWebServer server = new StatnettWebServer(10080); server.start(); System.out.println(server.getUrl()); }

SpareBank1

10 web service clients

HttpURLConnection JOOX

@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(); }

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}

Conclusion:

YAGNI

No calculator until…

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

Thank you