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thrift character encoding, perl to java

I have a complex situation that I'm trying to deal with involving character encoding.
I have a perl program which is communicating with a java endpoint via thrift, the java is then using the data to make a request to a legacy php service. It's ugly, but part of a migration plan so needs to work for a short while.
In perl a thrift object is created where some of the fields of the thrift object are json encoded strings.
The problem is that when perl makes the request to java, one of the strings is as follows (this is from data:dumper and is subsequently json encoded and added to thrift):
'offer_message' => "<<>>
&&
\x{c3}\x{82}\x{c2}\x{a9}©
<script>alert(\"XSS\");</script>
https://url.com/imghp?hl=uk",
However, when this data is received on the java side the sequence \x{c3}\x{82}\x{c2}\x{a9} has been converted so in java we receive the following:
<<>>\\n&&\\nÃ�Â�Ã�©©\\n<script>alert(\"XSS\");</script>\\nhttps://www.google.com.ua/imghp?hl=uk
The problem is that if I pass the second string to the legacy php program, it fails, if I pass the string taken from the dump of the perl hash, it succeeds. So my assumption is that I need to convert the received string to another encoding (correct me if I'm wrong, I'm not sure that this is the right solution).
I've tried taking the parameters received in java and converting them to every encoding I can think of, however it doesn't work. So for example:
byte[] utf8 = templateParams.getBytes("UTF8");
normallisedTemplateParams = new String(utf8, "UTF8");
I've been varying the encoding schemes in the hope I find something that works.
What is the correct way to solve this? For a short time this messy solution is my only option while other re-engineering is happening.

The problem in the end difficult to diagnose but simple to resolve. It turned out that the package I was using to convert in Java was using java's default encoding of UTF-16. I had to modify the package and force it to use UTF-8. After that, everything worked.

Parse byte array as HTTP object

In Java, how would I convert a byte array (TCP packet payload from a pcap file) into some kind of HTTP object that I can use to get HTTP headers and content body?

One of the stupid lovely things about Java is a total lack of unsigned types. So, a good place to start would be taking your byte array and converting it into a short array to make sure that you don't have any rollover problems. (16 bits versus 8 bits per number).
From there, you could use a BufferedOutputStream to write your data to a file and parse it with one of the Java built-in XML readers, such as JaxB or DOM. BufferedOutputStream writes hex directly to a file, and can take an input of an int, byte, or short array. After you write it out, using the OutputStream it should be very simple to parse the HTML out of it.
If you need any help with any of these individual steps, I'd be happy to help.
EDIT: as maerics has pointed out, perhaps I didn't grasp what you were asking. Regardless, writing your byte array with a BufferedOutputStream is the way to go in my opinion, and I could still help you build a parser if you want.

JNetPcap can do exactly this.
Here are examples for
Opening a pcap file
Parsing http (in the example, we extract an image)
Drawback: parsing http in this library is depracated*, but that doesn't mean it doesn't work
*I can't post anymore links without more reputation. Sorry. You can Google for "jnetpcap http deprecated"

Different Content Length between C# and Java

I am trying to read a upload file from browser, then write to a remote server. But I found that the request.getheader("content-length") is different from the actual length of request.getInputStream() in JAVA. But Request.Header["Content-Length"] is same as the actual length of Request.InputStream in C#.
Could anyone try to explain the difference?

Are you sure that the situations are comparable? One pitfall might be the possibility of zipped content.
Another one might be the character encoding if one implementation counts the characters and the other one counts the bytes sent over the connection.

Is it possible to serialize an object into a plain text string and send it as a string then convert it back?

As the title says. I'm sending a message, from my server, into a proxy which is outside of my control which then sends it onto my application. All I can do is send and receive strings. Is it possible to serialize to a plain string and send in this way without an input/output stream as you would normally have?
TIA
A little more info:
public class myClass implements java.io.Serializable {
int h = "ccc";
int i = "bbbb";
String myString = "aaaa";
}
I have this class, for example. Now I want to serialize it and send it as a string inside my HTTPpost and send to the proxy, can't do anything about this stage:
HttpPost post = new HttpPost("http://www.myURL.com/send.php?msg="+msg);
Then receive the msg as a string on the other side and convert it back.
Is that easily done without to many other library?

Yes.
This is done every day using JSON and XML, just to name a few formats of strings that are easily formatted and parsed. (Read about JAXRS to know about a way to use JSON formatted strings to do this and do the transfers. Or, read about JAXB which will format as XML but doesn't halp with the communication of the strings.)
You can do it in CSV format.
You can do it in fixed with fields of characters.
Morse code isn't much of a different concept only it starts with strings and converts to short and long beeps.
The way it works is this:
There is some code to which you pass an object and it returns a string in a known format.
You send the string to the other server somehow. Some ways to send strings have limits on the length.
The other server receives the string.
Using its knowledge of the format, that other server parses out the string contents and uses it.
Some notes:
If both servers use Java (or C# or Python or PHP or whatever) the formatting and parsing become symetrical. You start with a Java object of some type and end up with a Java object in the other JVM of the same type. But that is not a given. You can store values in a custom POJO in one server and a Map in the other.
If you write code to format and parse, it seems really easy as long as the contents are simple and you don't run afoul of transmission rules. For example, if you send in the query part of an HTTP get, you can't have any ampersand characters in the string.
If you use an existing library, you take advantage of everyone else's acquired knowlege of how to do this without error.
If you use a standard format for the string, it is easy to explain what's going on to someone else. If your project works, a third server might want to be in the communication loop and if it's controlled by someone else ...
Formatting is easier than parsing. There are lots of pitfalls that other people have already solved. If you are doing this to learn ways not to do things and improve your own knowledge base, by all means, do it yourself. If you want rock solid performance, use an existing and standard library and format.

Take a look at XStream. It serializes into XML, and is very simple to use.
Take a look at there Two Minute Tutorial

Yes it is possible. You can use ajax to to serialize the string to a json object and have it back to the server using an ajax.post event (javascript event).

Developing a (file) exchange format for java

I want to come up with a binary format for passing data between application instances in a form of POFs (Plain Old Files ;)).
Prerequisites:
should be cross-platform
information to be persisted includes a single POJO & arbitrary byte[]s (files actually, the POJO stores it's names in a String[])
only sequential access is required
should be a way to check data consistency
should be small and fast
should prevent an average user with archiver + notepad from modifying the data
Currently I'm using DeflaterOutputStream + OutputStreamWriter together with InflaterInputStream + InputStreamReader to save/restore objects serialized with XStream, one object per file. Readers/Writers use UTF8.
Now, need to extend this to support the previously described.
My idea of format:
{serialized to XML object}
{delimiter}
{String file name}{delimiter}{byte[] file data}
{delimiter}
{another String file name}{delimiter}{another byte[] file data}
...
{delimiter}
{delimiter}
{MD5 hash for the entire file}
Does this look sane?
What would you use for a delimiter and how would you determine it?
The right way to calculate MD5 in this case?
What would you suggest to read on the subject?
TIA.

It looks INsane.
why invent a new file format?
why try to prevent only stupid users from changing file?
why use a binary format ( hard to compress ) ?
why use a format that cannot be parsed while being received? (receiver has to receive entire file before being able to act on the file. )
XML is already a serialization format that is compressable. So you are serializing a serialized format.

Would serialization of the model (if you are into MVC) not be another way? I'd prefer to use things in the language (or standard libraries) rather then roll my own if possible. The only issue I can see with that is that the file size may be larger than you want.

1) Does this look sane?
It looks fairly sane. However, if you are going to invent your own format rather than just using Java serialization then you should have a good reason. Do you have any good reasons (they do exist in some cases)? One of the standard reasons for using XStream is to make the result human readable, which a binary format immediately loses. Do you have a good reason for a binary format rather than a human readable one? See this question for why human readable is good (and bad).
Wouldn't it be easier just to put everything in a signed jar. There are already standard Java libraries and tools to do this, and you get compression and verification provided.
2) What would you use for a delimiter and how determine it?
Rather than a delimiter I'd explicitly store the length of each block before the block. It's just as easy, and prevents you having to escape the delimiter if it comes up on its own.
3) The right way to calculate MD5 in this case?
There is example code here which looks sensible.
4) What would you suggest to read on the subject?
On the subject of serialization? I'd read about the Java serialization, JSON, and XStream serialization so I understood the pros and cons of each, especially the benefits of human readable files. I'd also look at a classic file format, for example from Microsoft, to understand possible design decisions from back in the days that every byte mattered, and how these have been extended. For example: The WAV file format.

Let's see this should be pretty straightforward.
Prerequisites:
0. should be cross-platform
1. information to be persisted includes a single POJO & arbitrary byte[]s (files actually, the POJO stores it's names in a String[])
2. only sequential access is required
3. should be a way to check data consistency
4. should be small and fast
5. should prevent an average user with archiver + notepad from modifying the data
Well guess what, you pretty much have it already, it's built-in the platform already:Object Serialization
If you need to reduce the amount of data sent in the wire and provide a custom serialization ( for instance you can sent only 1,2,3 for a given object without using the attribute name or nothing similar, and read them in the same sequence, ) you can use this somehow "Hidden feature"
If you really need it in "text plain" you can also encode it, it takes almost the same amount of bytes.
For instance this bean:
import java.io.*;
public class SimpleBean implements Serializable {
private String website = "http://stackoverflow.com";
public String toString() {
return website;
}
}
Could be represented like this:
rO0ABXNyAApTaW1wbGVCZWFuPB4W2ZRCqRICAAFMAAd3ZWJzaXRldAASTGphdmEvbGFuZy9TdHJpbmc7eHB0ABhodHRwOi8vc3RhY2tvdmVyZmxvdy5jb20=
See this answer
Additionally, if you need a sounded protocol you can also check to Protobuf, Google's internal exchange format.

You could use a zip (rar / 7z / tar.gz / ...) library. Many exists, most are well tested and it'll likely save you some time.
Possibly not as much fun though.

I agree in that it doesn't really sound like you need a new format, or a binary one.
If you truly want a binary format, why not consider one of these first:
Binary XML (fast infoset, Bnux)
Hessian
google packet buffers
But besides that, many textual formats should work just fine (or perhaps better) too; easier to debug, extensive tool support, compresses to about same size as binary (binary compresses poorly, and information theory suggests that for same effective information, same compression rate is achieved -- and this has been true in my testing).
So perhaps also consider:
Json works well; binary support via base64 (with, say, http://jackson.codehaus.org/)
XML not too bad either; efficient streaming parsers, some with base64 support (http://woodstox.codehaus.org/, "typed access API" under 'org.codehaus.stax2.typed.TypedXMLStreamReader').
So it kind of sounds like you just want to build something of your own. Nothing wrong with that, as a hobby, but if so you need to consider it as such.
It likely is not a requirement for the system you are building.

Perhaps you could explain how this is better than using an existing file format such as JAR.
Most standard files formats of this type just use CRC as its faster to calculate. MD5 is more appropriate if you want to prevent deliberate modification.

Bencode could be the way to go.
Here's an excellent implementation by Daniel Spiewak.
Unfortunately, bencode spec doesn't support utf8 which is a showstopper for me.
Might come to this later but currently xml seems like a better choice (with blobs serialized as a Map).