Specification and verification of data-driven web services

Abstract

We study data-driven Web services provided by Web sites interacting with users or applications. The Web site can access an underlying database, as well as state information updated as the interaction progresses, and receives user input. The structure and contents of Web pages, as well as the actions to be taken, are determined dynamically by querying the underlying database as well as the state and inputs. The properties to be verified concern the sequences of events (inputs, states, and actions) resulting from the interaction, and are expressed in linear or branching-time temporal logics. The results establish under what conditions automatic verification of such properties is possible and provide the complexity of verification. This brings into play a mix of techniques from logic and automatic verification.

Browser-Based Enforcement of Interface Contracts in Web Applications with BeepBeep

“…BeepBeep's LTL-FO + allows first-order quantification over XPath expressions to fetch values inside messages, store them and compare them at a later time. Contrarily to similar message-based logics, such as LTL-FO [4], there is no restriction on the use of temporal operators inside quantifiers, and vice versa. BeepBeep can handle arbitrary nested structures; no upper bound on the arity of the messages needs to be fixed in advance.…”

Specifying and Reasoning About Dynamic Access-Control Policies

“…These diverse sources suggest that (i) the environment must be a transition system, to model the program's execution and the passage of time, and (ii) each state must consist of an instance of the edb relations referred to by the policy. This model is therefore in the family of recent work on representing programs as transitions over relations [2,13,41,44]. Because our model is general enough to handle most forms of environment information, we focus on the general model and ignore finer distinctions in the rest of this paper.…”

“…When formulas do interleave these, the logic gets complicated if the domains of the structures at different states are allowed to vary (this phenomenon is familiar from predicate modal logic). For problems that require such formulas, - is a sublanguage of linear predicate temporal logic that avoids the difficulty with varying-domain models, yet is rich enough to express many properties of interest [13,41].…”

“…The body of a goal is precisely a database query: to evaluate the goal at a particular state in a model is to evaluate the associated Boolean query on the database of facts at that state. Model checking algorithms for first-order temporal logics subsume this problem [13,41]. Given that goal reachability is a very useful and special case of first-order model checking, however, it is worth understanding the complexity of goal checking.…”

“…They provide propositional temporal logic verification, but do not consider policy comparison. Abiteboul et al verify - properties against web services modeled as graphs over relational facts [2,13]. Our work includes a model of the facts over time whereas theirs assumes that the facts are arbitrary (within a given schema).…”