Web service

In this part of the project you will implement a simple web service based on the transformations and queries made in the first four parts. A web service is simply a program that can be contacted via some internet protocol and offers to do some kind of processing or computation.

Input and output

In our scenario the web service is simply a program that takes as input:

Some bibliographic data (in XML-bib or BibTeX format)
A description of one of the queries/transformations you have implemented, i.e., either:
- The number of a query and any parameters, or
- The desired format (XML-bib or XHTML) that the (entire) bibliographic data file should be returned in.

The web service returns the result of the query on the data as an XML file. Whenever the web service transforms BibTeX to XML-bib you should use your schema to verify the soundness of your transformation. You may choose to define schemas for the various types of XML output, but this is not mandatory.

A simple web service in Java

We recommend you to base your web service on sockets in Java (see documentation for java.net library). You may do this by modifying a simple java program that implements a file server. You should only have to modify a small part of the program.

Note: One group has had the problem that Java's readline() method did not return null when there was no more data from the socket. A solution is to look for an explicit sign that the end of the transmission has been reached, e.g., a string of the form ---------...------6f123a123.

You can use the Multiclient java program to test your web service. To run the multiclient type:

java MultiClient <host> <port>

where <host> is an identifier for the web server host and <port> is the number of the port used for the socket. The IT-C firewall seems to block most ports on student machines. However, one can test the web service and client together on a single machine by using the identifier 127.0.0.1 and any available port number (e.g., choose a random number in the range 10000 to 20000).

Encoding of data

The file server uses the HTTP protocol. You may choose any encoding you like of the data sent to and from the web service. One choice that makes the last part of the core project easier is to base the encoding on HTTP, and use the same encoding of query parameters as that generated by the HTML form used for the web interface. In that way you can use the web service directly from the browser.