October 2013 – cuteprogramming

Google DevFest Singapore 2013

October 15, 2013December 22, 2013 by Chun Lin, posted in Arduino, Event, Experience

I attended the first Google DevFest in 2008. It should be the first Google hackathon in South East Aaia (Oops, Asia). During the event, we got the chance to try out the new APIs, such as Google Maps API and YouTube API. That was how I started one of my favourite personal projects, the YouTube RePlayer (latest version is hosted on OpenShift at http://replayer-chunlin.rhcloud.com/).

The GUI of YouTube Re-Player (Localhost) 1.0 — YouTube Re-Player (Localhost) 1.0, the first version of the app which was done after attending Google DevFest 2008

This year, Google DevFest was back to Singapore again on last Saturday. So, I decided to attend to get inspired and explore new ideas and opportunities to network. The topics of this year event are listed below.

Intro to OpenCV in Android;
Android Permission Architecture: Invisible Security Threats;
Managing Arduinos with Androids;
Running Android OS on Raspberry Pi (nothing much covered);
Angular JS (I skipped the AngularJS talk to take some rest);
Google BigQuery with Cloud Storage;
Google Developers.

Before going into each of the topics above, I would like to comment about the (free) food offered in the event. In the 2008 event, the organizer dabao Singapore chicken rice only for us as dinner. This year, they provided delicious breakfast, lunch, and afternoon tea!

Talk #1: Intro to OpenCV in Android

The talk was given by Badrinath Kulkarni, an Android developer from GDG Bangalore. The talk basically just covered some general image processing functions available in OpenCV as well as steps to install the OpenCV library in Eclipse for Android app development.

He started the tutorial by showing us a simple and frequently used image processing operation, image smoothing. He demo it using the medianBlur() to reduce noise of the image taken with a smartphone camera.

Image Registration is also covered in this talk. The reason to do Image Registration is to find out a geometrical transformation that aligns points in one view of an object in an image with corresponding points in another view of that object. There are some online resources that discuss Image Registration in detail.

In short, this is more like a talk about image processing. However, the speaker does have an interesting blog at http://ibadrinath.in/.

Talk #2: Android Permission Architecture: Invisible Security Threats

Even though Android applications by default do not have access to phone number, browser history, and other user’s private information on the phone, the applications can request for access to this information at install time. The options that the users can choose are only grant all access requested or not install the application. So, this talk basically covered the problems of having over-privileged Android applications in the market.

The talk was delivered by Jiten Jain from India. During his talk, he further demonstrated how he could easily get the contact information, messages, and account usernames of the users using his Android app. Yup, now it is important to find out what the apps on our phone can actually do. Not just graphical implementation of the apps, but all the tasks that can be done by the apps.

Talk #3: Managing Arduinos with Androids

This is another interesting talk in the event. In fact, it’s very enjoyable. It was given by Harish Pillay from Red Hat. I think he was named a SPRING Singapore’s award recipient just three months ago.

The talk basically focused on how Annikken Andee, an Arduino bluetooth add-on shield, gives developers an easier way to make Android to interact with the physical world. Annikken Andee can communicate with the Annikken Andee Android app via bluetooth.

Here is a 2-minute short interesting video explaining what Annikken Andee is.

By the way, just a fun fact: The language that we use to program the Arduino board is C/C++ but the IDE is written in Java.

Fun fact #2: Even high school students in Malaysia know Arduino. So please learn Arduino if you don’t know about it. =P

Talk #4: Google BigQuery with Cloud Storage

The first lesson learnt from this talk given by Dr S P T Krishnan from I²R is that Google BigQuery is not a magic wand. Hmm, I thought it was a magic. Oh well.

The first time I heard about Big Data was during the Linus Lee’s talk on Analytics Stack at Twitter back in January. He shared with us the role and responsibilities of a data scientist and the working evironment in Twitter. For more details about his talk, there is an online article about it at e27.

After Linus Lee’s talk, I tried out Google BigQuery at https://bigquery.cloud.google.com/. If you would like to play with Google BigQuery, perhaps you can find more about BigQuery and go through the quickstarts first.

Talk #5: Google Developers

The cool applications done by developers is available at https://developers.google.com/showcase/.

There was a YouTube video shared with us during the talk also. It is about how Google Play helps Colopl, a very cool Japanese company.

A Fruitful Event

Because of Google DevFest 2008, I got to know more about the cool Google APIs, which later help me on developing many useful applications on my own. This time, the event once again opens my eyes to the exciting new technologies out there. Yup, so I am looking forward to the next Google DevFest. =)

Presentation Materials from Google DevFest Singapore 2013

Morning Sessions

Afternoon Sessions

Photos of the Event

https://plus.google.com/photos/118002244286788294009/albums/5934101450469153025?sqi=116183805383104277986&sqsi=569a5eaf-3753-4187-9983-ff0fd7d8d371

IE Is Being Mean to Me: Episode 2 – Uppercase HTML Tag

October 15, 2013October 15, 2013 by Chun Lin, posted in Experience, Internet Explorer, JavaScript

It’s my mistake again. It’s morning and I realized my little code as shown below did not work properly on IE 7 and IE8.

var i = $('#someStuff').html().indexOf("<a>");

It turns out that in IE 7 and IE 8, the HTML tags returned by .html() are all in uppercase. Thus the result is not as expected. Luckily, this is not the case anymore in the latest version, IE 10. So, in order to solve the problem, the code has to be modified to be as follows by converting the result to have lowercase.

var i = $('#someStuff').html().toLowerCase().indexOf("<a>");

Actually this is an known issue in older version of IE. It’s just that I forgot about it.

Meanwhile, I also found some interesting articles about this.

In the past, there were people having a debate on whether the weird behavior of innerHTML or html() in IE 7/8 is a feature or bug. For example, there is a discussion on this in 2008: Bug of Feature – Live .innerHTML in IE.

Currently, XHTML1.0 is still an implemented standard in most of the Internet browsers. In XHTML 1.0: The Extensible HyperText Markup Language (Second Edition), it points out that XHTML documents must use lower case for all HTML element and attribute names. This difference is necessary because XML is case-sensitive e.g. <li> and <LI> are different tags.

For CSS, even though its syntax is not case-sensitive, since element names are not under the control of CSS, the element names used in CSS are also case-sensitive in XHTML (but not HTML).

Anyway, I would like to thank Microsoft engineers for making IE 10 to do the right things. Here is a promo video of IE 10.

Using Amazon SES SMTP to Send Email

October 15, 2013 by Chun Lin, posted in Amazon Web Services, Experience

In December 2011, Amazon Web Services added a new feature to help sending email in a easy and cost saving way through the Amazon SES (Simple Email Service). They provided the SMTP interface to allow users to directly use their existing SMTP to do mass emailing without the need to change the users’ existing programs. So, I decided to try it out.

Amazon SES can be found in the AWS Management Console. If this is the first use, there will be message saying the SES account currently only had “sandbox” access. Although full access to the Amazon SES API is available in the sandbox mode, only 200 emails, at most, to be sent out each day. Also, the email addresses of sender and recipients can only be those from the verified email addresses and domains. Thus, there is a need to request a production access to the Amazon SES.

To apply for the production access, we need to submit a registration form to Amazon. After that, their team will review the application before approving it. For my previous application, they approved it the day after I submitted the form. Thus, the reviewing process is actually very fast. The registration form is simple. We only need to provide some user information as well as the types of emails that will be sent using Amazon SES, such as marketing, subscription, transactional, and system notifications.

After the application is approved, we have to create SMTP credentials to start sending emails. The credentials will be used when we connect to the Amazon SES SMTP interface later. To do so, just click on the “SMTP Settings” tab located at the left hand side of the web page. The SMTP credentials created can all be found in the AWS Identity and Access Management (IAM) page.

After all these have been done, we just need to use the SMTP credential in our existing programs to send emails.

The good thing about Amazon SES is that the sending quota is 10,000 for each day. In addition, Amazon SES will automatically increase the sending limits as we continue to send greater quantities of email. The maximum of message size is 10MB per message, including the attachments in the email. Unfortunately, the maximum number of recipients per email is only 50, unlike Google Apps for Business allowing up to 99 addresses in To, Cc, and Bcc fields of a single email. For more details about the sending limits in Amazon SES, please visit its official documentation page.

Finally, there are graphs available to understand the statistics regarding the number of emails that are sent successfully, rejected, bounced back or marked as complaints. There is a thing that needs to be taken note is that if there are too many bounces and complaints, our Amazon SES account would be terminated. Thus, it is necessary to keep monitoring the bounce and complaint rates and keep them as low as possible. Currently, the average bounce rate of one of my SES accounts is around 0.5% and the average complaint rate is less than 0.5%. It should still be fine, I guess?

So, why are there bounces and complaints? As stated on Amazon SES FAQs, bounces are usually caused by attempting to send a nonexistent recipient. For complaints, they arise when our emails go into recipients’ spam box. That means the recipients indicate that they do not want to receive our message. Normally, a notification email will be sent from Amazon (complaints@email-abuse.amazonses.com) to tell us to look into the problem and recommend us to stop emailing to those email accounts.

Yup, this concludes what I have learnt so far about the Amazon SES. Besides smtp.gmail.com, now there is another option to choose to use as SMTP.