Using aspect-oriented PHP to implement crosscutting concerns in a collaborative web system

Abstract

Aspect-Oriented Programming (AOP) is a new technology that was proposed to improve separation of concerns in software development. AOP's main focus is to use aspect modules to implement concerns that would be generally scattered across the system and tangled with other modules (crosscutting concerns). Although much research has focused on AOP's application to traditional software development, little has been done towards its application to Web development. Aspect-oriented PHP (aoPHP) is an addition to PHP that allows the use of AOP in the Web development context. In this paper we describe an application of aoPHP to show that AOP can also be effectively used in the Web development context. In particular, we have implemented two crosscutting concerns in a collaborative Web system named CoTeia: the access control and the version control functionalities. Furthermore, we discuss how AOP can enhance the design of Web applications by reasoning on the refactored system.

Systems Evolution and Software Reuse in Object-Oriented Programming and Aspect-Oriented Programming

“…• AOP "increases understandability and eases the maintenance burden, because modules tend to be more cohesive and less coupled" [22]. It is commonly acknowledged that designs with low coupling and high cohesion lead to software that is both, more reusable and more maintainable.…”

Reusable aspect components for web applications

“…For example, the following is a code snippet of an aspect quoted from [16], and the aspect adds access control before editing contents of Web pages for the Wiki-based collaborative system CoTeia implemented in PHP.…”

“…The aspect includes two advice descriptions; $chkAdv for displaying a login page to not authenticated users (lines 7-11) and $authAdv for performing the authentication (lines [13][14][15][16]. The $chkAdv capture all page accesses only when a user has not been authenticated, using combination with $reqAllPC and the IfPointcut which is a pointcut designator which captures join points only when the specified condition is fulfilled (lines 8,9).…”

Teste estrutural de integração de programas orientados a aspectos: uma abordagem baseada em conjuntos de junção para AspectJ

“…Na próxima seção é discutida a linguagem de propósito geral AspectJ, que apoia os mecanismos de referência estrutural (por meio dos descritores de conjuntos de junção) e temporal (por meio dos adendos) comentados anteriormente, possibilitando a modularização de interesses transversais. Apesar de existirem outras linguagens OA, inclusive para aplicação em outros contextos -como o da Web (Lemos et al, 2006b) -AspectJ tem sido a mais difundida e utilizada.…”