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Divya Kambhatla

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Recent posts by Divya Kambhatla

Hello Ron,

 You are correct. The server was not expecting a HelloPacket from the client..for it to send a WHORU packet. Just a connection would be sufficient.

  As you suggested , I ran my program without the first Hello Packet and i got a SUCCESS message from the server..

Output::

Message received from the server is WHORU:9832481028

constructing the Identification packet to be sent to server...

The first part of response is WHORU

The second part of response is 9832481028

Identification packet that will be sent to the server is IAM:9832481028:sampleuser@gmail.com:at

Message received from the server is SUCCESS:743204

However, I am doubtful as to what needs to be done further more with the dump that the server will send me..

The protocol at http://challenge.airtime.com:2324/instructions goes as follows:

"Once the server sends the success packet, it will begin sending the entire satellite dump over the socket.

In order to help understand the transmission, we have stolen an excerpt of a secret document that may help.
   2.1

      Each packet has the following structure:
        0   4   8   12
        +---+---+---+=============================+
        |SEQ|CHK|LEN|…LEN bytes of raw Linear PCM |
        +---+---+---+=============================+

     CHK (Checksum)
        The 32-bit checksum is calculated by XOR'ing each 32-bit chunk of
        the 4 byte big-endian sequence number(SEQ) and data.  If LEN is
        not a multiple of 4, the byte 0xAB shall be used in place of the
        missing bytes only for the purpose of calculating the checksum.

Hint: Next steps will become apparent once you are able to understand the transmission. Hint: Some interesting websites that may be useful for your mission are FFmpeg and Audacity "

I am not sure in what format the dump would be coming in..I tried to get that into String with the below code snippet


and all i can see in my Line variable are special characters . I have attached a snapshot of what dump I received from the server in file ServerDumpAsString.jpeg      

Some people who have taken this puzzle (https://github.com/devmach/airtime-challenge and https://github.com/navio/airtime-challenge-2) are collecting the dump as a .raw file and they suggest using a third party tool to decode the message... Also some of their code in java script shows that they are trying to parse the entire dump ? I am not sure the protocol actually suggests parsing the dump and then decoding it...not sure if i am understanding the further steps correctly Also, i dont understand how we would be able to parse the dump when everything is in special characters...

Requesting your expertise and kind guidance to help me understand further steps...

Thank You.
4 years ago
Ok Ron,I get what you are saying...I will definitely try that out and get back to you... Thank you so much...
4 years ago
Ohhh... could you please suggest/explain why the server is resetting my connection.. And what can I do to stop this reset from happening.
4 years ago
Hello Ron,

"Hello Airtime Challenge" is sent only initially to get a handshake response from the tcpip server. Once I get an initial handshake response from the server, as WHORU:<somenumber1> I then construct an identification packet as IAM:<somenumber1>:<user email>:at\n and send this to the server expecting a success<somenumber1>...

The second time I send a message to the server, ie. Once a connection is established , I construct the identification packet to send it to the server...

Thank you. Please do let me know if you need more clarification...
4 years ago
Hi All,

I am trying to come up with a solution to the Airtime Coding Challenge at http://challenge.airtime.com:2324/instructions in Java.
Basic Scenario is as follows:

Step1: Connect to the TCP server at challenge.airtime.com:2323
Step 2: Upon connection, the server will send you a handshake packet: "WHORU:<challenge number>\n" without quotes, encoded in UTF-8.
Step 3: You must then send an identification packet: "IAM:<challenge number>:<user email address>:at\n" without quotes, encoded in UTF-8.
Step 4: If the identification was successful, the server will respond with a success packet containing your identification code. "SUCCESS:<identification code>\n" without quotes, encoded in UTF-8.

My Code is as follows:


I am unable to go past sending the Identification Packet to the server. I only get a Null from the tcp server for my Identification Packet instead of "SUCCESS:<identification code>\n"

The output i get is as follows:

The Output i receive is as below:

Message sent to the server is Hello AirTime Challenge!

Message received from the server is WHORU:4741557577

constructing the Identification packet to be sent to server...

The first part of response is WHORU

The second part of response is 4741557577

Identification packet that will be sent to the server is IAM:4741557577:sampleuser@gmail.com:at

Message received from the server is null

I am unable to understand why I am getting a NULL from the server in response to my identification packet...

Please help!!

Thanks.
4 years ago
Hi,

I am using PdfTextExtractor from iText5.0.5 to extract content from a PDF. But i see that sometimes, multiple words get concatenated together. Could anyone let me know why this is happening and if it is a problem with the iText jar. Also, is there any work around for this issue.?

Any inputs would be greatly appreciated.

Thanks,
Divya.
Hi,

Could anyone let me know if it is possible to extract only the header content from all pages of a PDF using Pdfbox (Pdfbox 1.2.0)?

Thanks.
Hi,

Could anyone Please let me know if there is a way to read an existing PDF using PDFReader and know which is a Header, which part is a footer, which content is a watermark and which part belongs to the Body Content of the PDF usign iText5.0.5. I have so far not yet come across any class/method in iText which provides such facilites , but i may have missed something, since i am new to this API.

Waiting for expert comments,
Thanks in advance.
Divya.

I addition to the above, could anyone please help me know how the Pdf page could be split into the header, footer and its trailer. When i analysed the iText source code , i came across the above info and also a PdfBody class. But i am not understanding how exactly i could go about creating a PdfBody and extract the text content out of it.

Thank You,
Divya.
9 years ago
Hi,

I want to extract the text out of a PDF using iText5.0.5. The problem is when i extract text, all the text,including page numbers, figure titles, pae titles get extracted. I am completely new to the iText api. Could anyone please let me know if there is any method/interface in iText which could help extract ONLY the text content (or) atleast let me know how i could identify if the page numbers, page titles, figure titles also come under as page text?

Thanks in advance!
Divya.
9 years ago
Hi,

I want to extract the text out of a PDF using iText5.0.5. The problem is when i extract text, all the text,including page numbers, figure titles, pae titles get extracted. I am completely new to the iText api. Could anyone please let me know if there is any method/interface in iText which could help extract ONLY the text content (or) atleast let me know if the page numbers, page titles, figure titles also come under as page text?

Thanks in advance!
Divya.
9 years ago
Hi,

As suggested, I have created a post for the same in icefaces and the post can be accessed at http://www.icefaces.org/JForum/posts/list/0/18525.page

Awaiting your expert comments.

Thank You,
Divya.
Hi,

i am sorry i am not being able to attach any pdfs here. i get a message saying "Files with the extension .pdf are not allowed as attachment in the message." Please let me know where i can post this pdf.?

Thank You,
Divya.
Hi Patrick,

I have sent a copy of the pdf to your email. i hope that is ok with you. i believe that there is indeed extractable data in the pdf because i am being able to extract the content using iText , except that it has a problem with 2 columned PDFs , the one i emailed you. Eagerly awaiting your expert comments.

Thanks in advance,
Divya.
In addition to the above:

I had also tried finding about other APIs which have such facilities,like for eg: the CAM::PDF package provided by CPAN. This provides pdf text extraction facility but i am not sure how it would handle watermarked PDFs.So i could have a perl script doing the job, and i could program my application to invoke the script, do the extraction job and get the extracted content back to the application.

So if you could please provide me some insight about any web-service (or) online tools which could be accessed via application (or) other APIs / packages which provide such facilities and which could be invoked via java, it would be really helpful.

Thank You,
Divya.