Web Services Pipeline

Tags: soft-eng

Is the most common software architecture for CGI based web [see page 13, applications].

In this model the web-browsers uses HTML forms to pass URL-encoded strings to a CGI program, which commonly fetch or modify data in the database, and then returns a response. There's generally a high level of coupling across the layers.

\begin{figure}
  \centering
  \begin{tikzpicture}[
    every text node part/.style={align=center, rectangle},
    pkg/.style={scale=1.6},
    line/.style={very thick, dashed}]

    \begin{umlpackage}[pkg]{Web}\end{umlpackage}
    \begin{umlpackage}[pkg, right=1.2cm of Web]{CGI}\end{umlpackage}
    \begin{umlpackage}[pkg, right=1.2cm of CGI]{DB}\end{umlpackage}
    \node at (Web.center)
      {HTML pages \\ HTML forms \\ URL Encoded strings};
    \node at (CGI.center)
      {addItem.cgi \\ editItem.cgi \\ undoItem.cgi \\ exitItem.cgi};
    \node at (DB.center)
      {MySQL Commands};

    \draw[line, <->] (Web) -- (CGI);
    \draw[line, <->] (CGI) -- (DB);
  \end{tikzpicture}
  \caption{Web Services Pipeline.}
\end{figure}