3 research outputs found
Debugging of Web Applications with Web-TLR
Web-TLR is a Web verification engine that is based on the well-established
Rewriting Logic--Maude/LTLR tandem for Web system specification and
model-checking. In Web-TLR, Web applications are expressed as rewrite theories
that can be formally verified by using the Maude built-in LTLR model-checker.
Whenever a property is refuted, a counterexample trace is delivered that
reveals an undesired, erroneous navigation sequence. Unfortunately, the
analysis (or even the simple inspection) of such counterexamples may be
unfeasible because of the size and complexity of the traces under examination.
In this paper, we endow Web-TLR with a new Web debugging facility that supports
the efficient manipulation of counterexample traces. This facility is based on
a backward trace-slicing technique for rewriting logic theories that allows the
pieces of information that we are interested to be traced back through inverse
rewrite sequences. The slicing process drastically simplifies the computation
trace by dropping useless data that do not influence the final result. By using
this facility, the Web engineer can focus on the relevant fragments of the
failing application, which greatly reduces the manual debugging effort and also
decreases the number of iterative verifications.Comment: In Proceedings WWV 2011, arXiv:1108.208
Verificación de aplicaciones web dinámicas con Web-TLR
Web-TLR is a software tool designed for model-checking Web applications that is based on rewriting logic. Web applications are expressed as rewrite theories that can be formally verified by using the Maude built-in LTLR model-checker. Whenever a property is refuted, it produces a counterexample trace that underlies the failing model checking computation. However, the analysis (or even the simple inspection) of large counterexamples may prove to be unfeasible due to the size and complexity of the traces under examination.
This work aims to improve the understandability of the counterexamples generated by Web-TLR by developing an integrated framework for debugging Web applications that integrates a trace-slicing technique for rewriting logic theories that is particularly tailored to Web-TLR. The verification environment is also provided with a user-friendly, graphical Web interface that shields the user from unnecessary information.
Trace slicing is a widely used technique for execution trace analysis that is effectively used in program debugging, analysis and comprehension. Our trace slicing technique allows us to systematically trace back rewrite sequences modulo equational axioms (such as associativity and commutativity) by means of an algorithm that dynamically simpli es the traces by detecting control and data dependencies, and dropping useless data that do not infuence the final result. Our methodology is particularly suitable for analyzing complex, textually-large system computations such as those delivered as counter-example traces by Maude model-checkers.
The slicing facility implemented in Web-TLR allows the user to select the pieces of information that she is interested into by means of a suitable pattern-matching language supported by wildcards. The selected information is then traced back through inverse rewrite sequences. The slicing process drastically simpli es the computation trace by dropping useless data that do not influence the nal result.
By using this facility, the Web engineer can focus on the relevant fragments of the failing application, which greatly reduces the manual debugging e ort and also decreases the number of iterative verfications.Espert Real, J. (2011). Verificación de aplicaciones web dinámicas con Web-TLR. http://hdl.handle.net/10251/11219.Archivo delegad
Slicing-based debugging of web applications in rewriting logic
The pervasiveness of computing on the Internet has led to an explosive growth of
Web applications that, together with their ever-increasing complexity, have turned
their design and development in a major challenge.
Unfortunately, the huge expansion of development and utilization of Web
computation has not been paired by the development of methods, models and
debugging tools to help the developer diagnose, quickly and easily, potential
problems in a Web application. There is an urgent demand of analysis and
verification facilities capable to prevent insecure software that could cause
unavailability of systems or services, or provide access to private data or internal
resources of a given organization.
The main goal of this MSc thesis is to improve the debugging of Web applications
by embedding novel analysis and verification techniques that rely on the program
semantics. As a practical realization of the ideas, we use Web-TLR that is a
verification engine for dynamic Web applications based on Rewrite Logic. We
extend Web-TLR with a novel functionality that supports effective Web debugging
for realistic Web applications involving complex execution traces. This
functionality is based on a backward trace slicing technique that is based on
dynamic labeling.
In order to extend the class of programs covered by the debugging methodology
we formalize a generalization of the slicer to Conditional Rewriting Logic theories,
greatly simplifying the debugging task by providing a novel and sophisticated form
of pattern matching.Frechina Navarro, F. (2011). Slicing-based debugging of web applications in rewriting logic. http://hdl.handle.net/10251/15637Archivo delegad