Raible Designs

Friday June 26, 2009

The good ol' Job Hunt Just over two years ago, I wrote about the good ol' job hunt. Today, I find myself in a very similar situation. My Evite gig ends in a couple hours and I'm heading to The Cabin on Monday for a month of vacation. Similar to last time, there are opportunities out there, but most of them come through recruiters.

I have to admit - it seems like I got lucky the last couple times I tried to find a gig. I simply blogged I was looking and found myself negotiating with companies a few days later. Getting laid off from LinkedIn was awesome in that a few companies contacted me about hiring the whole team the next day. The ability to blog-and-get-a-gig was a great way to cut out the middle-man.

Unfortunately, I think I got spoiled by my blog-and-get-a-gig success. I figured it would happen again this time...

Not so much.

I don't know if it's because of the down economy or because I took the year off from speaking at conferences. Regardless, I'm in an interesting situation since I signed a 1-year lease on an office in downtown Denver. It's easy to market to companies in Denver, but if I land a gig here, there's a good chance the client is going to want me in the office everyday. That leaves me wondering: what's the best way to market to companies outside of Colorado? My ideal contract is one that 1) allows me to work remotely and 2) only requires me to travel once or twice a month.

I believe my ideal gigs are out there, but I think it's difficult to convince companies I'm a good remote worker. In an attempt to convince them otherwise, I'd like to offer recommendations from my last two clients.

"Matt contributed dramatically to the engineering practice at Evite, both directly and indirectly. Directly, he lead the effort to define and prove a successful new web UI architecture for us. Indirectly, he brought senior engineering talent into the organization, and energized the existing team. We are significantly better positioned to deliver on our Product goals as a result of having worked with Matt. I'd love to work with him again someday." David Thomas, VP of Technology, Evite

"Matt has unique abilities in the realm of software engineering. He brings great energy, an amazing breadth of knowledge in UI technologies, along with a can-do attitude that's refreshing to interact with. He is a great leader and communicator. In addition, Matt can apply his deep understanding of the technologies in question pragmatically to the engineering problem at hand, leading his team in execution and delivery. He's an excellent technical visionary to complement any team." Arnold Goldberg, Vice President Platform Engineering, LinkedIn

If you're looking to hire someone with my skills, let me know - there's a good chance you'll be glad you did. Posted in Java at Jun 26 2009, 03:30:42 PM MDT 8 Comments

Thursday June 25, 2009

How to use GWT 2.0 with Maven and Generate SOYC Reports One of the most interesting features coming in GWT 2.0 is code splitting and the ability to use GWT.runAsync() to reduce the size of your application's initial download. This week, I learned how to use GWT 2.0 with my GWT 1.6/Maven project. Below are instructions on how to build and use the latest GWT with Maven.

• Checkout GWT and setup GWT_TOOLS.
• Set a GWT_VERSION environment variable to 2.0.0-SNAPSHOT (export GWT_VERSION=2.0.0-SNAPSHOT).
• Build GWT with the ant command.
• After building completes, install the GWT artifacts into your local Maven repository using the following commands:

  mvn install:install-file -DgroupId=com.google.gwt \
  -DartifactId=gwt-user -Dversion=2.0.0-SNAPSHOT \
  -Dpackaging=jar -Dfile=build/lib/gwt-user.jar
  
  mvn install:install-file -DgroupId=com.google.gwt \
  -DartifactId=gwt-servlet -Dversion=2.0.0-SNAPSHOT \
  -Dpackaging=jar -Dfile=build/lib/gwt-servlet.jar
  
  mvn install:install-file -DgroupId=com.google.gwt \
  -DartifactId=gwt-dev -Dversion=2.0.0-SNAPSHOT \
  -Dclassifier=mac -Dpackaging=jar -Dfile=build/lib/gwt-dev-mac.jar
  
  mkdir temp
  tar -zxf build/dist/gwt-mac-2.0.0-SNAPSHOT.tar.gz -C temp
  cd temp/gwt-mac-2.0.0-SNAPSHOT
  zip -0 gwt-mac-2.0.0-SNAPSHOT.zip lib*.jnilib
  cd ../..
  
  mvn install:install-file -DgroupId=com.google.gwt \
  -DartifactId=gwt-dev -Dversion=2.0.0-SNAPSHOT \
  -Dclassifier=mac-libs -Dpackaging=zip \
  -Dfile=temp/gwt-mac-2.0.0-SNAPSHOT/gwt-mac-2.0.0-SNAPSHOT.zip
  

  Thanks to Jason for his help with this script.
• Modify the pom.xml of your GWT project to use the the gwt-maven-plugin from Codehaus. Of course, you'll need to modify the <runTarget> to fit your project.

  <plugin>
      <groupId>org.codehaus.mojo</groupId>
      <artifactId>gwt-maven-plugin</artifactId>
      <version>1.1</version>
      <configuration>
          <runTarget>org.appfuse.gwt.mvc.${entry.point}/${entry.point}.html</runTarget>
      </configuration>
      <executions>
          <execution>
              <goals>
                  <goal>compile</goal>
                  <goal>test</goal>
              </goals>
          </execution>
      </executions>
  </plugin>
  

• Modify your dependencies to match the ones below. With the Codehaus plugin, dependencies are much more concise.

  <dependency>
      <groupId>com.google.gwt</groupId>
      <artifactId>gwt-servlet</artifactId>
      <version>${gwt.version}</version>
      <scope>compile</scope>
  </dependency>
  <dependency>
      <groupId>com.google.gwt</groupId>
      <artifactId>gwt-user</artifactId>
      <version>${gwt.version}</version>
      <scope>provided</scope>
  </dependency>
  

• Add <gwt.version>2.0.0-SNAPSHOT</gwt.version> to the properties section of your pom.xml.
• At this point, you should be able to compile your project with mvn gwt:compile and run it in hosted mode using mvn gwt:run.

Generate SOYC Reports
In Google's code splitting documentation, it mentions The Story of Your Compile (SOYC). From the documentation:

To obtain a SOYC report for your application, there are two steps necessary. First, add -soyc to the compilation options that are passed to the GWT compiler. This will cause the compiler to emit raw information about the compile to XML files in an -aux directory beside the rest of the compiled output. In that directory, you will see an XML file for each permutation and a manifest.xml file that describes the contents of all the others.

The second step is to convert that raw information into viewable HTML. This is done with the SoycDashboard tool.

The first step is not currently possible with the gwt-maven-plugin, so I created a patch for it.

If you patch the gwt-maven-plugin and install it locally, make sure and change the version in your pom.xml to 1.2-SNAPSHOT.

To use the SoycDashboard tool, you'll need to install the gwt-soyc-vis.jar.

mvn install:install-file -DgroupId=com.google.gwt \
-DartifactId=gwt-soyc-vis -Dversion=2.0.0-SNAPSHOT \
-Dpackaging=jar -Dfile=build/lib/gwt-soyc-vis.jar

Now you can generate SOYC reports with mvn gwt:compile -Dgwt.compiler.soyc=true. You can also add <soyc>true</soyc> to the <configuration> section of the gwt-maven-plugin.

The second step (converting the raw information into viewable HTML) is possible using java from the command-line, or by using the exec-maven-plugin. Here's the (lengthy) command-line version:

java -Xmx1024m -cp /Users/mraible/.m2/repository/com/google/gwt/gwt-soyc/2.0.0-SNAPSHOT/gwt-soyc-2.0.0-SNAPSHOT.jar:/Users/mraible/.m2/repository/com/google/gwt/gwt-dev/2.0.0-SNAPSHOT/gwt-dev-2.0.0-SNAPSHOT-mac.jar com.google.gwt.soyc.SoycDashboard -resources ~/.m2/repository/com/google/gwt/gwt-soyc/2.0.0-SNAPSHOT/gwt-soyc-2.0.0-SNAPSHOT.jar -out target/soyc-report target/extra/org.appfuse.gwt.mvc.MVC/soycReport/stories0.xml.gz target/extra/org.appfuse.gwt.mvc.MVC/soycReport/dependencies0.xml.gz target/extra/org.appfuse.gwt.mvc.MVC/soycReport/splitPoints0.xml.gz

In this example, I'm using the files from stories0.xml.gz, dependencies0.xml.gz, splitPoints0.xml.gz. In the soycReport output directory, there's 5 of each these files and I'm not sure what the difference between reports is. Hopefully someone on the GWT team can elaborate. The exec-maven-plugin version is as follows:

<plugin>
    <groupId>org.codehaus.mojo</groupId>
    <artifactId>exec-maven-plugin</artifactId>
    <version>1.1</version>
    <configuration>
        <executable>java</executable>
        <arguments>
            <argument>-cp</argument>
            <argument>
                ${settings.localRepository}/com/google/gwt/gwt-soyc/2.0.0-SNAPSHOT/gwt-soyc-2.0.0-SNAPSHOT.jar:${settings.localRepository}/com/google/gwt/gwt-dev/2.0.0-SNAPSHOT/gwt-dev-2.0.0-SNAPSHOT-${platform}.jar
            </argument>
            <argument>com.google.gwt.soyc.SoycDashboard</argument>
            <argument>-out</argument>
            <argument>target/soyc-report</argument>
            <argument>-resources</argument>
            <argument>
                ${settings.localRepository}/com/google/gwt/gwt-soyc/2.0.0-SNAPSHOT/gwt-soyc-2.0.0-SNAPSHOT.jar
            </argument>
            <argument>${project.build.directory}/extra/org.appfuse.gwt.mvc.MVC/soycReport/stories0.xml.gz</argument>
            <argument>${project.build.directory}/extra/org.appfuse.gwt.mvc.MVC/soycReport/dependencies0.xml.gz</argument>
            <argument>${project.build.directory}/extra/org.appfuse.gwt.mvc.MVC/soycReport/splitPoints0.xml.gz</argument>
        </arguments>
    </configuration>
</plugin>

After configuring this plugin in your project, you should be able to run mvn gwt:compile exec:exec and open the generated report (at target/soyc-report/SoycDashboard-index.html). Currently, there doesn't seem to be much documentation on SOYC. Fred Sauer's recent presentation talks a bit about SOYC and GWT.runAsync(), but that's about it.

To figure out how to use GWT 2.0 with Maven, I used my GWT MVC Example project. The first SOYC report I generated said the initial download was 108,967 KB. To integrate GWT.runAsync(), I modified all the project's controllers so their handleEvent() methods changed from this:

public void handleEvent(AppEvent event) {
    onViewHome(event);
}

To this:

public void handleEvent(final AppEvent event) {
    GWT.runAsync(new RunAsyncCallback() {
        public void onFailure(Throwable throwable) {
            Window.alert(throwable.getMessage());
        }

        public void onSuccess() {
            onViewHome(event);
        }
    });
}

When I generated a new SOYC report, the initial download size was reduced to 56,718 KB. Furthermore, I was able to see that my "Leftovers code" consisted of 63,175 KB. I'm sure there's better ways to split my project using GWT.runAsync(), but I'm happy to see I was able to reduce the initial download by 50%.

If you'd like to try GWT 2.0, you can can download my gwt-mvc example project. To build/run this project, you'll need to 1) build and install GWT, 2) patch gwt-maven-plugin and 3) run mvn gwt:compile exec:exec to generate the SOYC report. In an ideal world, the gwt-maven-plugin can be enhanced to generate the SOYC report (rather than using the exec-maven-plugin). In the meantime, I think it's pretty cool that you can try out GWT 2.0 features while they're still being developed. Posted in Java at Jun 25 2009, 11:45:04 PM MDT 6 Comments

Wednesday June 24, 2009

JSON Parsing with JavaScript Overlay Types in GWT A reader recently asked:

I would love to see a snippet of how to eval the JSON coming from RequestBuilder into the OverlayTypes. What is the mapping like? I used OverlayTypes to read in static data that I render into the head section of the hosted page, which is pretty easy and fast, but I don't know how to do this "reading" dynamically at runtime.

If you're not familiar with GWT's Overlay Types (added in 1.5), see Getting to really know GWT, Part 2: JavaScript Overlay Types. In our project, we're using Overlay Types to simplify JSON parsing and make our application lean-and-mean as possible.

First of all, we have a JSOModel class that acts as our overlay type:

import java.util.HashSet;
import java.util.Set;

import com.google.gwt.core.client.JavaScriptObject;
import com.google.gwt.core.client.JsArray;
import com.google.gwt.core.client.JsArrayString;

/**
 * Java overlay of a JavaScriptObject.
 */
public abstract class JSOModel extends JavaScriptObject {

    // Overlay types always have protected, zero-arg constructors
    protected JSOModel() {
    }

    /**
     * Create an empty instance.
     * 
     * @return new Object
     */
    public static native JSOModel create() /*-{
        return new Object();
    }-*/;

    /**
     * Convert a JSON encoded string into a JSOModel instance.
     * <p/>
     * Expects a JSON string structured like '{"foo":"bar","number":123}'
     *
     * @return a populated JSOModel object
     */
    public static native JSOModel fromJson(String jsonString) /*-{
        return eval('(' + jsonString + ')');
    }-*/;

    /**
     * Convert a JSON encoded string into an array of JSOModel instance.
     * <p/>
     * Expects a JSON string structured like '[{"foo":"bar","number":123}, {...}]'
     *
     * @return a populated JsArray
     */
    public static native JsArray<JSOModel> arrayFromJson(String jsonString) /*-{
        return eval('(' + jsonString + ')');
    }-*/;

    public final native boolean hasKey(String key) /*-{
        return this[key] != undefined;
    }-*/;

    public final native JsArrayString keys() /*-{
        var a = new Array();
        for (var p in this) { a.push(p); }
        return a;
    }-*/;

    @Deprecated
    public final Set<String> keySet() {
        JsArrayString array = keys();
        Set<String> set = new HashSet<String>();
        for (int i = 0; i < array.length(); i++) {
            set.add(array.get(i));
        }
        return set;
    }

    public final native String get(String key) /*-{
        return "" + this[key];
    }-*/;

    public final native String get(String key, String defaultValue) /*-{
        return this[key] ? ("" + this[key]) : defaultValue;
    }-*/;

    public final native void set(String key, String value) /*-{
        this[key] = value;
    }-*/;

    public final int getInt(String key) {
        return Integer.parseInt(get(key));
    }

    public final boolean getBoolean(String key) {
        return Boolean.parseBoolean(get(key));
    }

    public final native JSOModel getObject(String key) /*-{
        return this[key];
    }-*/;

    public final native JsArray<JSOModel> getArray(String key) /*-{
        return this[key] ? this[key] : new Array();
    }-*/;
}

This class alone allows you to easily parse JSON returned in a callback. For example, here's an example of parsing Twitter's User Timeline in my OAuth with GWT application.

private class TwitterApiCallback implements RequestCallback {
    public void onResponseReceived(Request request, Response response) {
        if (response.getStatusCode() == 200) {
            JsArray<JSOModel> data = JSOModel.arrayFromJson(response.getText());
            List<JSOModel> statuses = new ArrayList<JSOModel>();
            for (int i = 0; i < data.length(); i++) {
                statuses.add(data.get(i));
            }

            // populate textarea with returned statuses
            for (JSOModel status : statuses) {
                payload.setValue(payload.getValue() + status.get("text") + "\n\n");
            }
            
            Label success = new Label("API call successful!");
            success.setStyleName("success");
            form.add(success);
        } else {
            onError(request, new RequestException(response.getText()));
        }
    }

    public void onError(Request request, Throwable throwable) {
        Window.alert("Calling API failed. " + OAuthPage.STANDARD_ERROR + "\n\n" + throwable.getMessage());
    }
}

To simply things even more, we created a BaseModel class that can be extended.

import java.util.Map;
import java.util.HashMap;

import com.google.gwt.core.client.JsArrayString;
import com.google.gwt.user.client.Element;
import com.google.gwt.user.client.DOM;

public abstract class BaseModel {

    protected JSOModel data;

    public BaseModel(JSOModel data) {
        this.data = data;
    }

    public String get(String field) {
        String val = this.data.get(field);
        if (val != null && "null".equals(val) || "undefined".equals(val)) {
            return null;
        } else {
            return escapeHtml(val);
        }
    }

    public Map<String, String> getFields() {
        Map<String, String> fieldMap = new HashMap<String, String>();

        if (data != null) {
            JsArrayString array = data.keys();

            for (int i = 0; i < array.length(); i++) {
                fieldMap.put(array.get(i), data.get(array.get(i)));
            }
        }
        return fieldMap;
    }

    private static String escapeHtml(String maybeHtml) {
        final Element div = DOM.createDiv();
        DOM.setInnerText(div, maybeHtml);
        return DOM.getInnerHTML(div);
    }
}

You can extend this class and create model objects that represent a more Java-like view of your data. For example, I could create a Status class with the following code:

public class Status extends BaseModel {
    
    public Status(JSOModel data) {
        super(data);
    }

    public String getText() {
        return get("text");
    }
}

Then I could change my JSON parsing in TwitterApiCallback to be:

    private class TwitterApiCallback implements RequestCallback {
    public void onResponseReceived(Request request, Response response) {
        if (response.getStatusCode() == 200) {
            JsArray<JSOModel> data = JSOModel.arrayFromJson(response.getText());
            List<Status> statuses = new ArrayList<Status>();
            for (int i = 0; i < data.length(); i++) {
                Status s = new Status(data.get(i));
                statuses.add(s);
            }

            // populate textarea with returned statuses
            for (Status status : statuses) {
                payload.setValue(payload.getValue() + status.getText() + "\n\n");
            }

            Label success = new Label("API call successful!");
            success.setStyleName("success");
            form.add(success);
        } else {
            onError(request, new RequestException(response.getText()));
        }
    }

    public void onError(Request request, Throwable throwable) {
        Window.alert("Calling API failed. " + OAuthPage.STANDARD_ERROR + "\n\n" + throwable.getMessage());
    }
}

That's how we're doing lightweight JSON parsing with GWT. I've updated my GWT with OAuth demo with this code. You can also download the source. Please let me know if you have any questions. Posted in Java at Jun 24 2009, 09:52:49 AM MDT 3 Comments

Thursday June 18, 2009

Implementing OAuth with GWT I've heard about OAuth for quite some time, but never had an opportunity to implement it on a project. For a good explanation of what OAuth is, see its Introduction. Here's an excerpt:

...it allows you the User to grant access to your private resources on one site (which is called the Service Provider), to another site (called Consumer, not to be confused with you, the User). While OpenID is all about using a single identity to sign into many sites, OAuth is about giving access to your stuff without sharing your identity at all (or its secret parts).

The reason I needed OAuth was to interact with the Google Contacts API. I've always hated how sites make you import all your contacts from Gmail. I wanted to develop a system that'd let you simply read your contacts from Google in real-time.

Since the application I'm working on uses GWT, I chose to implement an OAuth client in GWT. After googling for "gwt oauth", I found two examples. Unfortunately, neither worked out-of-the-box.

The good news is I did manage to create a working solution. The bad news is it only seems to work at random. That's right folks, I created a solution that only works 50% of the time. I'm somewhat embarrassed to post it here, but I also realize the power of open source and community. By sharing, I hope we can find the flaws in my logic and come up with a solution for all GWT applications.

The best project for OAuth libraries seems to be oauth on Google Code. However, you'll notice that there is no JavaScript implementation listed on the homepage. I did look at the Java implementation, but quickly realized it wouldn't be usable in GWT. Therefore, I opted for the JavaScript implementation.

OAuth consists of several steps. The following diagram explains the authentication flow nicely.

In a nutshell, you have to complete the following steps:

1. Get a token from the service provider.
2. Redirect user to service provider to grant access and redirect back to application.
3. Request access token to access protected resources.
4. Access protected resources and pull/push data.

To access a service provider's OAuth service, you'll likely need to start by registering your application. For Google, OAuth Authentication for Web Applications is an excellent resource. Google's OAuth Playground is a great way to with the Google Data APIs after you've registered.

Now that you know how OAuth works, let's look at how I implemented it with GWT. I started by adding the necessary JavaScript references to my *.gwt.xml file.

<script src="http://oauth.googlecode.com/svn/code/javascript/oauth.js"/>
<script src="http://oauth.googlecode.com/svn/code/javascript/sha1.js"/>

Next, I needed a way to sign the request. I tried to use Sergi Mansilla's OAuth.java for this, but discovered issues with how the parameters were being written with GWT 1.6. I opted for Paul Donnelly's makeSignedRequest function instead. By adding this to my application's HTML page, I'm able to call it using the following JSNI method:

public native static String signRequest(String key, String secret, String tokenSecret, String url) /*-{
    return $wnd.makeSignedRequest(key, secret, tokenSecret, url);
}-*/;

After the URL is signed, it needs to be sent to the provider to get a request token. To do this, I used GWT's RequestBuilder and created a send() method:

protected void send(RequestCallback cb, String URL) {
    RequestBuilder builder = new RequestBuilder(RequestBuilder.GET, URL);
    builder.setTimeoutMillis(10000);
    builder.setCallback(cb);
    
    Request req = null;
    try {
        req = builder.send();
    } catch (RequestException e) {
        cb.onError(req, e);
    }
}

If you try this with Google's Request Token URL in GWT's hosted mode, nothing will happen. Compile/browse to Safari and you'll still see nothing. Try it in Firefox and you'll see the following.

To workaround browsers' Same Origin PolicyI added a proxy servlet to send the requests. I started with Jason Edwards's ProxyServlet and modified it to fit my needs. I then registered it in both *.gwt.xml and web.xml.

<servlet path="/google/" class="org.appfuse.gwt.servlet.AlternateHostProxyServlet"/>

Now, before calling the send() method, I replace the start of the URL so the request would be routed through the servlet.

public void getToken(RequestCallback cb) {
    String url = signRequest(provider.getConsumerKey(), 
                             provider.getConsumerSecret(), 
                             "", provider.getRequestTokenURL());
    url = url.replace("https://www.google.com/", "/google/");
    send(cb, url);
}

When the request returns, I create two cookies by calling a createOAuthCookies() method with the payload returned:

public static String[] createOAuthCookies(String data) {
    String oauth_token = data.substring(data.indexOf("oauth_token=") + 12);
    oauth_token = oauth_token.substring(0, oauth_token.indexOf("&"));

    String oauth_token_secret = data.substring(data.indexOf("oauth_token_secret=") + 19);

    Cookies.setCookie("oauth_token", URL.decode(oauth_token));
    Cookies.setCookie("oauth_token_secret", URL.decode(oauth_token_secret));
    return new String[]{oauth_token, oauth_token_secret};
}

The next step is to authorize the token. This is where things got tricky with my proxy servlet and I had to add some special logic for GWT. Google was sending back a 302 with a Location header, but it wasn't hitting the onResponseReceived() method in my callback. For this reason, I had to change it to a 200 status code and add the redirect location to the body. I also discovered that sometimes they'd return an HTML page with a <meta http-equiv="refresh" ...> tag. When using Twitter, I discovered the full HTML for the allow/deny page was returned. Below is the callback I'm using. WindowUtils is a class I got from Robert Hanson and the gwt-widget project.

public void onResponseReceived(Request request, Response response) {
    String text = response.getText();
    if (response.getStatusCode() == 200 && response.getText().startsWith("http")) {
        WindowUtils.changeLocation(response.getText());
    } else {
        // look for meta-tag that refreshes and grab its URL
        if (text.contains("";
            String url = text.substring(text.indexOf(tokenToStartWith) + tokenToStartWith.length());
            url = url.substring(0, url.indexOf(tokenToEndWith) + tokenToEndWith.length());
            WindowUtils.changeLocation(url);
        } else {
            // Twitter returns a full HTML page, so redirect to the authorize URL manually
            if (provider instanceof Twitter) {
                String url = provider.getAuthorizeTokenURL();
                url = url.replace("$1", OAuthRequest.getAuthToken());
                url = url.replace("$2", DefaultRequest.getCurrentLocation());
                WindowUtils.changeLocation(url);
            } else {
                onError(request, new RequestException(text));
            }
        }
    }
}

public void onError(Request request, Throwable caught) {
    Window.alert("Calling authorize token failed. " + OAuthPage.STANDARD_ERROR + "\n\n" + caught.getMessage());
}

The 3rd step is to get an access token. The most important thing to remember when you do this is to include the "oauth_token_secret" value when signing the request.

signRequest(provider.getConsumerKey(), provider.getConsumerSecret(), 
            getAuthTokenSecret(), url);

After this completes with a 200, I create the cookies again (since oauth_token and oauth_token_secret are returned in the body), then call the API to get a list of contacts. The ContactsRequests class is responsible for making the call. The DefaultRequest class contains the send() method as well as utility methods to get the cookie values of the oauth tokens.

public class ContactsRequest extends DefaultRequest {
    private static final String GOOGLE_CONTACTS_URL = 
        "http://www.google.com/m8/feeds/contacts/default/thin?oauth_token=$1";
    private OAuthProvider provider;

    public ContactsRequest(OAuthProvider provider) {
        this.provider = provider;
    }

    public void getContacts(RequestCallback cb) {
        String url = GOOGLE_CONTACTS_URL.replace("$1", getAuthToken());
        url = signRequest(provider.getConsumerKey(), provider.getConsumerSecret(), 
                          getAuthTokenSecret(), url);

        String proxiedURLPrefix = "/contacts/";
        // allow for deploying at /gwt-oauth context
        if (WindowUtils.getLocation().getPath().contains("gwt-oauth")) {
            proxiedURLPrefix = "/gwt-oauth" + proxiedURLPrefix;
        }

        url = url.replace("http://www.google.com/", proxiedURLPrefix);

        send(cb, url);
    }
}

If all goes well, the response contains the data you requested and it's used to populate a textarea (at least in this demo application). Of course, additional processing needs to occur to parse/format this data into something useful.

This all sounds pretty useful for GWT applications, right? I believe it does - but only if it works consistently. I sent a message to the OAuth Google Group explaining the issues I've had.

I'm trying to use the JavaScript API to authenticate with OAuth from a GWT application. I've got it working with both Google and Twitter's OAuth implementations. However, it seems to fail to sign the URL at random. In other words, it works 1 out of 3 times. ... Any idea why this could be happening?

I received a response with a cleaner makeSignedRequest() function. I tried it and, unfortunately, it seems to be equally unreliable. I suspect the problem is with the OAuth JavaScript implementation, GWT's interpretation of it, or that OAuth isn't as mature as it appears to be. I'd like to think one of the first two causes the problem.

To make it easier to create a robust example of GWT and OAuth, I created a gwt-oauth project you can download or view online. Please keep in mind the demo is likely to be flakey. If you're persistent and try enough times, it's likely to work. Firefox seems to succeed moreso than Safari or Chrome. If you have any suggestions for improving this example, please let me know. Posted in Java at Jun 18 2009, 01:59:13 PM MDT 2 Comments

Monday June 15, 2009

Enhancing Evite.com with GWT and Grails On my LinkedIn Profile, it says my current gig is a SOFEA consultant at a stealth-mode startup.

SOFEA Consultant, Stealth Mode Startup, Los Angeles, CA. December 2008 -- Present.

OK, I lied. It's not a startup, it's a well-known company that helps you plan parties. For the last 5+ months, my UI team from LinkedIn has been working with Evite.com to enhance portions of their site with a SOFEA architecture.

In January, we started evaluating Ajax Frameworks and came to the conclusion that GWT was right for us. After we chose the UI framework, other team members chose Grails and memcached to develop scalable RESTful services. The architecture we implemented involves using GWT's RequestBuilder to talk to Grails' services, which cache almost all their JSON output in memcached.

To see an example of a feature we developed with GWT, see Evite's Design Gallery. I personally worked on this feature and very much enjoyed becoming a GWT aficionado in the process. GWT's zero-turnaround feature made doing pure client-side work a lot of fun. It's definitely something I'd like to continuing doing at my next gig.

Everyone from Evite is very happy with what we've been able to do with GWT and Grails. We have a stateless architecture and are quickly able to develop both client-side and server-side features. We've learned to scale the client by using out-of-the-box GWT components. We've scaled Grails by caching as much as possible. We serve up Ads and Analytics using the same JavaScript mechanisms that traditional server-side frameworks use.

At the end of this month, my gig with Evite comes to an end. I'll be spending a few weeks at my family's cabin in Montana and then it's on to the next big thing. What's the next big thing? I'm not sure yet, hence the reason for writing this. If you're looking to develop a GWT application, introduce a SOFEA architecture at your company, or simply adopt some open source frameworks, I'd love to help out. Drop me a line and let's start a conversation. Posted in Java at Jun 15 2009, 07:41:37 AM MDT 9 Comments

Friday June 05, 2009

Creating a Facebook-style Autocomplete with GWT Have you used the "To:" widget on on Facebook or LinkedIn when composing a message? It's an autocompleter that looks up contact names and displays them as you type. It looks like a normal textbox (a.k.a. <input type="text">), but wraps the contact name to allow you to easily delete it. Here's a screenshot of what Facebook's widget looks like.

Last week, I was asked to create a similar widget with GWT. After searching the web and not finding much, I decided to try writing my own. The best example I found on how to create this widget was from James Smith's Tokenizing Autocomplete jQuery Plugin. I used its demo to help me learn how the DOM changed after you selected a contact.

GWT's SelectBox allows you to easily create an autocompleter. However, it doesn't have support for multiple values (for example, a comma-delimited list). The good news is it's not difficult to add this functionality using Viktor Zaprudnev's HowTo. Another feature you might want in a SelectBox is to populate it with POJOs. GWT SuggestBox backed by DTO Model is a good blog post that shows how to do this.

Back to the Facebook Autocompleter. To demonstrate how to create this widget in GWT, I put together a simple application. You can view the demo or download it. The meat of this example is in an InputListWidget. After looking at the jQuery example, I learned the widget was a <div> with a unordered list (<ul>). It starts out looking like this:

<ul class="token-input-list-facebook">
    <li class="token-input-input-token-facebook">
        <input type="text" style="outline-color: -moz-use-text-color; outline-style: none; outline-width: medium;"/>
    </li>
</ul>

I did this in GWT using custom BulletList and ListItem widgets (contained in the download).

final BulletList list = new BulletList();
list.setStyleName("token-input-list-facebook");

final ListItem item = new ListItem();
item.setStyleName("token-input-input-token-facebook");

final TextBox itemBox = new TextBox();
itemBox.getElement().setAttribute("style", 
        "outline-color: -moz-use-text-color; outline-style: none; outline-width: medium;");

final SuggestBox box = new SuggestBox(getSuggestions(), itemBox);
box.getElement().setId("suggestion_box");

item.add(box);
list.add(item);

After tabbing off the input, I noticed that it was removed and replaced with a <p> around the value and a <span> to show the "x" to delete it. After adding a couple items, the HTML is as follows:

<ul class="token-input-list-facebook">
    <li class="token-input-token-facebook">
        <p>What's New Scooby-Doo?</p>
        <span class="token-input-delete-token-facebook">x</span>
    </li>
    <li class="token-input-token-facebook">
        <p>Fear Factor</p>
        <span class="token-input-delete-token-facebook">x</span>
     </li>
     <li class="token-input-input-token-facebook">
         <input type="text" style="outline-color: -moz-use-text-color; outline-style: none; outline-width: medium;"/>
     </li>
</ul>

To do this, I created a deselectItem() method that triggers the DOM transformation.

private void deselectItem(final TextBox itemBox, final BulletList list) {
    if (itemBox.getValue() != null && !"".equals(itemBox.getValue().trim())) {
        /** Change to the following structure:
         * <li class="token-input-token-facebook">
         * <p>What's New Scooby-Doo?</p>
         * <span class="token-input-delete-token-facebook">x</span>
         * </li>
         */

        final ListItem displayItem = new ListItem();
        displayItem.setStyleName("token-input-token-facebook");
        Paragraph p = new Paragraph(itemBox.getValue());

        displayItem.addClickHandler(new ClickHandler() {
            public void onClick(ClickEvent clickEvent) {
                displayItem.addStyleName("token-input-selected-token-facebook");
            }
        });

        Span span = new Span("x");
        span.addClickHandler(new ClickHandler() {
            public void onClick(ClickEvent clickEvent) {
                list.remove(displayItem);
            }
        });

        displayItem.add(p);
        displayItem.add(span);
        
        list.insert(displayItem, list.getWidgetCount() - 1);
        itemBox.setValue("");
        itemBox.setFocus(true);
    }
}

This method is called after selecting a new item from the SuggestBox:

box.addSelectionHandler(new SelectionHandler() {
    public void onSelection(SelectionEvent selectionEvent) {
        deselectItem(itemBox, list);
    }
});

I also added the ability for you to type in an e-mail address manually and to delete the previous item when you backspace from the input field. Here's the handler that calls deselectItem() and allows deleting with backspace:

// this needs to be on the itemBox rather than box, or backspace will get executed twice
itemBox.addKeyDownHandler(new KeyDownHandler() {
    public void onKeyDown(KeyDownEvent event) {
        if (event.getNativeKeyCode() == KeyCodes.KEY_ENTER) {
            // only allow manual entries with @ signs (assumed email addresses)
            if (itemBox.getValue().contains("@"))
                deselectItem(itemBox, list);
        }
        // handle backspace
        if (event.getNativeKeyCode() == KeyCodes.KEY_BACKSPACE) {
            if ("".equals(itemBox.getValue().trim())) {
                ListItem li = (ListItem) list.getWidget(list.getWidgetCount() - 2);
                Paragraph p = (Paragraph) li.getWidget(0);

                list.remove(li);
                itemBox.setFocus(true);
            }
        }
    }
});

I'm happy with the results, and grateful for the jQuery plugin's CSS. However, it still has one issue that I haven't been able to solve: I'm unable to click on a list item (to select it) and then delete it (with the backspace key). I believe this is because I'm unable to give focus to the list item. Here's the code that highlights the item and you can see the commented-out code that doesn't work.

displayItem.addClickHandler(new ClickHandler() {
    public void onClick(ClickEvent clickEvent) {
        displayItem.addStyleName("token-input-selected-token-facebook");
    }
});

/** TODO: Figure out how to select item and allow deleting with backspace key
displayItem.addKeyDownHandler(new KeyDownHandler() {
    public void onKeyDown(KeyDownEvent event) {
        if (event.getNativeKeyCode() == KeyCodes.KEY_BACKSPACE) {
            list.remove(displayItem);
        }
    }
});
displayItem.addBlurHandler(new BlurHandler() {
    public void onBlur(BlurEvent blurEvent) {
        displayItem.removeStyleName("token-input-selected-token-facebook");
    }
});
*/

If you know of a solution to this issue, please let me know. Feel free to use this widget and improve it as you see fit. I'd love to see this as a native widget in GWT. In the meantime, here's the GWT Facebook-style Autocomplete demo and code. Posted in Java at Jun 05 2009, 07:05:10 AM MDT 10 Comments

Thursday June 04, 2009

The End of the Colorado Software Summit It looks like the Colorado Software Summit has come to an end.

To Our Friends and Supporters,

In these challenging economic times, business has slowed, many companies have had to resort to layoffs and/or closures, and everyone has been tightening their belts. Unfortunately, Colorado Software Summit has not been immune to this downturn. As have so many companies and individuals, we too have experienced a severe decline in our business, and as a result we are not able to continue producing this annual conference.

This year would have been our 18th conference, and we had planned to continue through our 20th in 2011, but instead we must end it now. [Read More]

I first attended this conference in October 2005. I enjoyed it so much, I returned again in 2006, 2007 and 2008. As I mentioned last year, this was my favorite conference.

The reason I like it so much is because it's an annual gathering (this will be my 4th year) with friends and it's somewhat like a vacation, except you get to learn a lot.

While I'm sad to see it go, I completely understand Wayne and Peggy's decision. If you ever attended this conference, I encourage you to join the Colorado Software Summit LinkedIn Group. To see all my posts from the talks I attended at this conference, see my softwaresummit-tagged entries.

To Wayne and Peggy: thanks for all the great memories and for putting together such an excellent conference. Cheers to you both! Posted in Java at Jun 04 2009, 02:39:20 PM MDT 2 Comments

Thursday April 23, 2009

Ajax Framework Analysis Results Way back in January, I wrote about how my colleagues and I were evaluating Ajax frameworks to build a SOFEA-style architecture. To make our choice, we used the following process:

1. Choose a short list of frameworks to prototype with.
2. Create an application prototype with each framework.
3. Document findings and create a matrix with important criteria.
4. Create presentation to summarize document.
5. Deliver document, presentation and recommendation.

When I wrote that entry, we had just finished step 2 and were starting step 3. I first wrote this blog post a week later, when we delivered step 5. Here is the comparison and conclusion sections of the analysis document we composed.

Framework Comparison
In order to evaluate the different frameworks against important criteria, we created a matrix with weights and ranks for each framework. This matrix shows how our weighting and rankings lead us to the winner for our project. You can view this matrix online or see below for a summary.

Note: Criteria whose values were identical across all candidates were weighted at zero. Charting capability was weighted at zero b/c we decided to use Flash for this.

This matrix indicates that GWT is the best candidate for our team to develop SOFEA-style applications with. In addition to the matrix, below are graphs that illustrate interesting (and possibly meaningless) statistics about each project.

Conclusion
After working with the various frameworks, we believe that all the frameworks were very good and could be used to write applications with. If all weights are equal, these frameworks were almost even when compared against our evaluation criteria. The graph below illustrates this.

Even after applying the weighted criteria, the evenness doesn't change a whole lot.

Without considering the even or weighted criteria, we believe the decision all comes down to what the developers on the project feel they will be most comfortable with. If you're developing with Dojo or YUI, chances are you're dressing up existing HTML and possibly using progressive enhancement to add more rich functionality. On the other hand, Ext JS and GWT are similar to Swing programming where you build the UI with code (JavaScript for Ext JS, Java for GWT).

The tools available for JavaScript development have gotten increasingly better in recent years. IntelliJ IDEA has a JavaScript Editor that provides many of the same features as its Java editor. Aptana Studio also has excellent support for authoring and debugging JavaScript. However, we believe the Java debugging and authoring support in IDEs is much better. Furthermore, we are more familiar with organizing code in Java projects and feel more comfortable in this development environment.

Based on this evaluation, we believe that GWT is the best framework for our team to develop SOFEA-style applications with.

Flash Forward to Today...
The core GWT library from Google doesn't have a whole lot of widgets, nor do they look good out-of-the-box. So early on, we experimented with two alternative implementations that continue to leverage GWT concepts and tools:

• GXT: a GWT version of Ext JS
• SmartGWT: a GWT version of SmartClient

Unfortunately, over the past few months, we've found that both of these implementations are too heavy for our requirements, mostly because of the file size of the generated JavaScript code. For example, a feature I wrote generated a 275K *.cache.html file using GXT. After determining that was too slow to give users the initial "pop", I re-wrote it without GXT. After a day, we had an application with *.cache.html files of 133K. Yes, that's over a 50% reduction in size!*

Because of these findings, we are proceeding with the core GWT library from Google and adding in new components as needed. It is cool to know you can make a UI "pop" with GWT, as long as you stick to the core - close-to-the-metal - components. For those applications that can afford an initial "loading..." state, I'd definitely recommend looking at GXT and SmartGWT.

* To make refactoring easier, I copied GXT MVC into our source tree and modified all imports.

Posted in Java at Apr 23 2009, 08:34:44 PM MDT 49 Comments

Sunday April 05, 2009

My Drunk on Software Interview Back in February, I met up with James Ward and Jon Rose for a Drunk on Software interview. We enjoyed some good beer and had a great conversation about SOFEA, open source and RIA. See larger video here.

Posted in Java at Apr 05 2009, 10:23:57 PM MDT 8 Comments

Wednesday March 25, 2009

Optimizing a GWT Application with Multiple EntryPoints Building a GWT application is an easy way for Java Developers to write Ajax applications. However, it can be difficult to release a GWT application to production before it's finished. One of the most important things I've learned in Software Development is to get a new application into production as soon as possible. Not only does getting it from dev → qa → prod verify your process works, it also can do a lot to test the viability of the new application.

One of the biggest issues with GWT applications is size. The project I'm working on compiles Java to JavaScript and creates ~570K *.cache.html files (one for each modern browser). These files end up being around 180K gzipped. I believe this is an OK size for an entire application. However, if you're going to release early, release often with GWT, chances are you'll just want to release one feature at a time.

When the first feature was completed on my project, the *.cache.html files were around 300K. Rather than using branches to release to QA and UAT, bug fixes and new features were developed on trunk. Unfortunately, the QA and UAT process took several weeks longer than expected so by the time the feature was ready to release, the *.cache.html files had grown to around ~570K. The reason the file had grown so much was because it included all of the other features.

Earlier this week, while running to a dentist appointment, I thought of a solution to this problem. The basic idea was to optimize the compilation process so only the to-be-released feature was included. Even better, the solution didn't require more modularization. The results:

Before: *.cache.html -> 569K, gzipped 175K
After: *.cache.html -> 314K, gzipped 100K

According to my calculations, that's a 56% reduction in size. How did I do it?

1. Created a new FeatureName.java EntryPoint with only the to-be-released features imported.
2. Created a new FeatureName.gwt.xml that references the new EntryPoint.
3. Copied old (kitchen-sink) EntryPoint.html to FeatureName.html and changed the reference to the nocache.js file.
4. Created a Maven profile that allows using -PFeatureName to build a FeatureName-only module.

One downside to doing things this way is it's possible to create a WAR that has the same name and different features. Surely the Maven Overlords would frown upon this. Since this is just a temporary solution to release features incrementally, I'm not too worried about it. A possible workaround is to create different WAR names when a feature's profile is activated. I believe the true "Maven way" would be to make the "kitchen sink" application into a JAR and have several WAR modules with the different EntryPoints. Seems a bit complicated to me.

Other than this Maven publishing issue, the only other issue I can foresee is keeping the two EntryPoints and HTML files in synch. Then again, the separate files allow a feature to be customized for the release and can be deleted when its no longer needed.

What do you think? Do you know of a better way to compile a GWT application so it only contains certain features? Posted in Java at Mar 25 2009, 04:00:37 PM MDT 8 Comments