Monday, 14 March 2016

One day getaway from Salt Lake City

I am writing this blog as a guide so that someone in similar situation as me can plan and enjoy similar trip. This weekend was the beginning of the spring break and I badly wanted to get out of the city. Just wanted go anywhere. Having moved to USA recently, I don't have a driving license which immediately ruled out a road trip and I was left with only option to rely on public transport. Turns out Utah has really great public transport service. The nearest place that came to mind that I can go to was Park City. Park City is famous for it's world class ski resorts (it has America's largest ski resort) but I don't know how to ski plus I was planning for a one day trip so that ruled out skiing. A quick google search about activities in Park City introduced me to Utah Olympic Park. As you might know, Salt Lake City was host of 2002 Winter Olympics and this olympic park was built for different winter sports competitions. Turns out it is still operational and they have really fun seasonal activities for visitors. This seemed exciting so I along with my friend decided to go to the Olympic Park. Since we had to rely on public transport, we took the PC-SLC Connect early morning around 7:30 AM and started our journey. Utah Olympic Park is situated 9 miles before Park City on the way to Park City from Salt Lake City. So we got down at Kimball Junction and decided to hike the 3 miles to the Olympic Park. The weather was a little cold but not too harsh. After some breakfast at some local coffee shop, we started the hike to the park. It took us around 1/1.5 hours to reach to there. You could see the whole North Snyderville Basin from up there.
We reached there around 11 AM but the rides were not going to start until 1 PM (in winter the rides are from 1 PM to 6 PM). We had some time to kill. Apparently, the Olympic park also has a mini museum kind of setup of 2002 Olympic plus some insights into the powder snow of Utah. It was informative. After that we decided to go further up and have a look around the park. Luckily, we reached the bobsled trek on the top of the park where some international paralympic athletes were practicing bobsledding. It was fun to watch the sport for the first time that too with real athletes. I even recorded one of them at the starting line. It's not very clear but you can see the player shoot off on the track. Please ignore the conversation in the video :P
video
Well after that we came down and bought tickets for extreme tubing and extreme ziplining. Tubing is kind of same as water tubing that you might have done at water parks. The only difference here is it's done on mountain peak covered with snow instead of water flowing down from slide. Extreme ziplining was more fun. We took a lift (lift is covered in the ziplining ticket) to reach to the top of a peak. The guy there strepped us properly in the gear and we came shooting down on the ropes. It was a lot of fun. Here is the video that I shop while on the zipline. 

video

After that we had some fries at the cafe and started our down hike back to Kimball Junction. Throughout the hike you can enjoy the scenic basin and beautiful mountains in the background. Really wonderful experience. We reached the bus stop at Kimball Junction at around 4:45 PM and took the 5:15 PM bus back to Salt Lake City. We were tired but happy with one day getaway from study. A nice beginning to the Spring Break. I hope this blog helps someone to plan their own trip. 



Thursday, 13 September 2012

Hacking Gaia

Mozilla's Firefox OS also known as b2g is an awesome feat from the community towards its goal to provide platform for innovation and creativity. It was a necessary step considering the growth of mobile market. Smart phone is a front which lacks an open and powerful OS, which let's you hack into every aspect of the user experience(There is Android but it's not that easy to customize it.). In b2g, just by changing a CSS file or by modifying a JavaScript file, you can change the look and functionality of your phone dramatically.

B2g uses Gaia for it's UI. Gaia is all Html5,CSS and JavaScript. It can even run on a desktop browser(except the ). The whole OS is far from first release but you can start creating apps for it right now and try them on emulator, your desktop browser(for development purpose) or on your phone.

There are two steps for building  b2g and start working on an app. I have tried these steps on Linux and works for an emulator.

Building B2G:

If you don't want the pain of sitting around your laptop for hours, waiting for the compilation to finish, you can directly download latest version of b2g from here.
If you still want to compile it by yourself then go ahead else skip to next part.

Getting the source code from mozilla-central:

 hg clone http://hg.mozilla.org/mozilla-central src  
 If you encounter an 'Command not found hg' you need to install Mercurial: https://developer.mozilla.org/en/Installing_Mercurial  

Update the code:
 cd src  
 hg pull && hg update  

Create a '.mozconfig' file in mozilla-central source directory and paste following in the file. Also read comments and act accordingly.

  mk_add_options MOZ_OBJDIR=../build   
  #Here put NUMBER_OF_CORES_IN_YOUR_PROCESSOR+1 in place of '9'  
  mk_add_options MOZ_MAKE_FLAGS="-j9 -s"  
  ac_add_options --enable-application=b2g   
  ac_add_options --disable-libjpeg-turbo   
  # This option is required if you want to be able to run Gaia's tests   
  ac_add_options --enable-tests   
  # turn on mozTelephony/mozSms interfaces   
  # Only turn this line on if you actually have a dev phone   
  # you want to forward to. If you get crashes at startup,   
  # make sure this line is commented.   
  #ac_add_options --enable-b2g-ril

Now, build:

 make -f client.mk build  
If you face any errors or difficulty in this step, refer this for required library installation and other difficulties, but DO NOT change the '.mozconfig' file.

Now you can go and have some coffee or even a nap because this is going to take long.

Building Gaia Profile:

First, clone repository from Github and update it:

 git clone https://github.com/mozilla-b2g/gaia gaia  
 cd gaia  
 git fetch  
 git merge origin/master  

Compile it:
 make  

Now, if you have downloaded nightly build of b2g then run:

 /path/to/b2g -profile profile  
else:
 ../build/dist/bin/b2g -profile profile  

 


All the apps are in /gaia/apps directory.

Steps to add a new app:

To create and test a new app on the emulator, create a new directory under apps directory.
Add your Html,CSS and JavaScript code in the directory and create a 'manifest.webapp' file with necessary information about the app. You can checkout  pre-installed apps manifest files for reference.
After doing that, append your app details in the file gaia/webapps.js. Like if your app name is 'HelloWorld', then you will make a directory named 'helloworld' in gaia/apps directory and put all you app code there.
Now create a 'manifest.webapp' file in 'helloworld' directory and fill in necessary details like app name, developer name, orientation, language localisation etc.
Now append following in webapps.js file where all the apps are added to a js object:

 "helloworld": {  
   "origin": rootPath.replace('%%%', 'helloworld'),  
   "installOrigin": "http://helloworld.localhost.org:8080",  
   "receipt": null,  
   "installTime": 132333986000,  
   "manifestURL": "http://helloworld.localhost.org:8080/manifest.webapp"  
  }  

Now run following in gaia directory:

 make install-gaia
/path/to/b2g -profile profile

Now you can run your app in emulator and check it out.
You can find more details about running Gaia on phone or on a browser here.

Monday, 20 August 2012

Networking Dashboard v01

Networking Dashboard is a tool that shows internals of networking of Firefox. It's an add-on that I have made as part of GSoC project and can be used by typing 'about:networking-dashboard' in URL bar after installing this add-on. It shows current open connections with host names, how many of them are active/idle, if they are using SPDY or not, if they are using SSL or not, DNS cache entries, total data sent and received, data related to WebSocket connections etc. I have blogged about it in detail in my previous post.
Following are some screen shots which might give you some idea about the tool.
Timeline shows graphical view of total data sent and received after starting the add-on.
One feature that I couldn't implement as part of add-on is header window which shows sent and received headers of the packets Http connections.

I have used jQuery and flot - a pure Javascript plotting library for jQuery -  for building the add-on. I can make the add-on available but it won't work because back end part of the code hasn't been migrated to mozilla-central yet.

Http Connections

Socket Connections

DNS cache entries

WebSocket connections


Timeline showing graph of total data sent and received



Monday, 13 August 2012

GSoC update

So far I have finally finished implementing back-end interfaces- nsIHttpConnectionLog.idl, nsiWebSocketConnectionLog.idl, nsISocketLog.idl and nsIDNSEntries.idl. for Networking Dashboard.
Now, only thing remains is a UI for the add-on using these interfaces. It's very important part of the project since it will make sense of the json strings returned by these interfaces. Without a UI they are merely strings of data. I will probably be using jquery UI for this. It will be a tabular UI, a tab per interface/feature. Implementation of UI will conclude my GSoC project.

Thursday, 12 July 2012

Update of GSoC Till Midterm Evaluation

I have been working on Networking Dashboard for quite a while now and I think the back end part of the project is nearly done. It involves porting out information related to connections of different protocols(HTTP,WebSocket,etc.) through different interfaces.
This blog is an update on how much has been done so far and what am I going to get done in future.

What has been done so far?
So far I have implemented four interfaces. Every interface returns a JSON string containing different information in different fields.

1) nsIHttpConnectionLog.idl :- This interface returns following information related to current HTTP connections in form of a JSON string,

host : Host name of the HTTP connection
- port : port no. of the connection
- spdy : If connection using spdy or not
- active : rtt(Round Trip Time) and ttl(Time To Live) of active connections in respective fields
- idle : rtt and ttl of idle connections in respective fields


The connection data has been collected from nsHttpConnectionMgr.h where data related to http connection is maintained in form of a hash table.
Following is the example of a JSON string which is returned from this interface after opening www.google.com followed by www.twitter.com:
 {  
   "host" : ["mail.google.com","www.google-analytics.com","accounts.google.com","api.twitter.com","ocsp.thawte.com","localhost","accounts.youtube.com","a0.twimg.com","www.mozilla.org","ssl.gstatic.com","ssl.google-analytics.com","gmail.com","scribe.twitter.com","twitter.com","mail.google.com"],  
   "port" : [443,80,443,80,80,80,443,80,80,443,443,80,80,80,80],  
   "active" : [{  
     "rtt" : [0],  
     "ttl" : [145]  
   },  
   {  
     "rtt" : [],  
     "ttl" : []  
   },  
   {  
     "rtt" : [0],  
     "ttl" : [143]  
   },  
   {  
     "rtt" : [],  
     "ttl" : []  
   },  
   {  
     "rtt" : [],  
     "ttl" : []  
   },  
   {  
     "rtt" : [],  
     "ttl" : []  
   },  
   {  
     "rtt" : [0],  
     "ttl" : [144]  
   },  
   {  
     "rtt" : [],  
     "ttl" : []  
   },  
   {  
     "rtt" : [],  
     "ttl" : []  
   },  
   {  
     "rtt" : [0],  
     "ttl" : [144]  
   },  
   {  
     "rtt" : [0],  
     "ttl" : [145]  
   },  
   {  
     "rtt" : [],  
     "ttl" : []  
   },  
   {  
     "rtt" : [],  
     "ttl" : []  
   },  
   {  
     "rtt" : [],  
     "ttl" : []  
   },  
   {  
     "rtt" : [],  
     "ttl" : []  
   }],  
   "idle" : [{  
     "rtt" : [],  
     "ttl" : []  
   },  
   {  
     "rtt" : [0],  
     "ttl" : [95]  
   },  
   {  
     "rtt" : [],  
     "ttl" : []  
   },  
   {  
     "rtt" : [0],  
     "ttl" : [86]  
   },  
   {  
     "rtt" : [0],  
     "ttl" : [79]  
   },  
   {  
     "rtt" : [],  
     "ttl" : []  
   },  
   {  
     "rtt" : [],  
     "ttl" : []  
   },  
   {  
     "rtt" : [0,0,0,0],  
     "ttl" : [89,86,85,85]  
   },  
   {  
     "rtt" : [],  
     "ttl" : []  
   },  
   {  
     "rtt" : [],  
     "ttl" : []  
   },  
   {  
     "rtt" : [],  
     "ttl" : []  
   },  
   {  
     "rtt" : [0],  
     "ttl" : [75]  
   },  
   {  
     "rtt" : [0],  
     "ttl" : [86]  
   },  
   {  
     "rtt" : [0],  
     "ttl" : [85]  
   },  
   {  
     "rtt" : [0],  
     "ttl" : [75]  
   }],  
   "spdy" : [true,false,true,false,false,false,true,false,false,true,true,false,false,false,false]  
 }  
Empty ttl and rtt array means that that there is no connection with the host.
You can have a better look at it using any online JSON editor. Sorry for posting such long JSON. It looks ugly if I don't format it this way.


2) nsIWebSocketConnectionLog.idl :- This interface returns following information related to current WebSocket connections in form of a JSON string,

- hostport : Host name and port of the WebSocket connection
- msgsent : No. of messages sent
- msgreceived : No. of messages received
- encrypted : If the connection secure or not

There is no maintained data available for WebSocket. So all the data related to the connections is maintained at the implementation of the interface(in file nsWebSocketConnectionLog.h) Every time a new connection is made with new host or an old connection is closed, an entry is made or removed from the database if an instance of the interface has been created.

I found websites using WebSocket from www.websocket.org.
Here is one example of JSON string returned from the interface after opening http://rumpetroll.com/ and wandering around a little bit and after that http://www.kaazing.me :

 {  
   "hostport" : ["rumpetroll.motherfrog.com:8180","demo.kaazing.com"],  
   "msgsent" : [76,8],  
   "msgreceived" : [99,223],  
   "encrypted" : [false,true]  
 }  
3) nsISocketLog.idlThis interface returns following information related to current Socket connections in form of a JSON string,

- host : peer host ip
- port : peer host port
- tcp : if the connection is TCP or not

Data related to socket is collected from nsSocketTransportService2.h.
The data returned after opening www.google.com and http://twitter.com/
in above example is:
 {  
   "host" : ["74.125.236.102","199.59.149.243","124.124.201.161","199.59.150.41","124.124.201.161","124.124.201.161","124.124.201.161","199.59.150.7","74.125.236.98","74.125.236.117","173.194.36.30","74.125.236.111","209.85.175.84","74.125.236.118","199.7.51.72","74.125.236.117"],  
   "port" : [20480,20480,20480,20480,20480,20480,20480,20480,47873,47873,47873,47873,47873,20480,20480,20480],  
   "tcp" : [true,true,true,true,true,true,true,true,false,false,false,false,false,true,true,true]  
 }  
This data is not much I am hoping to add some more fields(like total data sent and received) to this interface.
4) nsDNSEntries.idl - This interface returns cached entries in DNS cache with  
    following fields,

- hostname : name of the host
- hostaddr : ip address of the host
- family : ip address family(ipv4 or ipv6)
- expiration : time when the cache entry expires(in minutes)

Well, this interface is near completion(believe me,it is). One little difficulty is stopping me from posting it's output here. May be I post it in the comment after it's done. It's going to contain above fields.

This concludes what I have completed so far.
I have been maintaining a mozilla-central repository at bitbucket.org and committing to my updates to branch 'Networking Dashboard'. You can have a look at it if you want. To test these interfaces, i have made a temporary addon using jetpack without any GUI.

What am I going to do next?
First of all I am going to finish the DNS interface.
Since basic interfaces have been implemented, I can now start working on GUI part of the addon. On the way of doing that, I might need to make differences to the interfaces or add some new data.
I also want to include time stamps, size of data sent/received to above interfaces of different protocols. These two feature are very important to the addon. I will work on them after I am done giving a face to the 'Networking Dashboard' addon.

This was an overview of my GSoC work so far. I have learnt a lot of new things about networking and Mozilla internals throughout this period. Thanks for reading. I hope you download my addon in future :)

Saturday, 16 June 2012

Update on GSoC (May 21 - May 13)

I have ported out connection data related to protocols like HTTP,WebSocket and also related to sockets to javascript.

Now I data related to these protocols can be accessed through new interfaces.
Data related to different protocol in particular are -

HTTP -            Host name,  Port no., No. of active connections, No. of idle
                        connections, if connection is using SPDY or not (In future - socket
                        identifiers for particular connections, RTT for connections, TTL etc.)
WebSocket -   Host name, Port no. (In future - No of messages sent so far)

Socket -          Socket identifier and packets sent or received via that socket can be 
                        seen. (Not perfect right now.)

We can search for different HTTP connections for their packets in Socket data via identifiers.
Next, I might add a new interface over all of these interface which combines all of these data and returns a single JSON string. We can also do some calculations using these data.


Sunday, 20 May 2012

Update on GSoC (May 7 - May 20)

Though the coding period starts from 21st May, I have started working on new IDL as part of my project.
I started working from 7th May. My first try is to get Http connection data like- hostname, port, No. of active connections, No. of idle connections. In first week I was getting my head around how to create a new idl, xpcom module, etc. Later on I came to know that I don't have to create new module, I can add new idl to Network module. So, now I have created my new idl and implemented it in c++. Only thing lest is to test it and see if I am getting Http connection data in a javascript or not. But it's not that easy. It seams that firefox doesn't allow use of UniversalXPConnect in a normal javascript. So now I have two options, either use jsctypes(which will take me time to understand) or create an add on to access the idl. I am going with the latter. Right now I am facing some difficulties in developing new add on with a nightly build but I will get over it.