public String lookup()

in log4j-jakarta-web/src/main/java/org/apache/logging/log4j/web/WebLookup.java [45:229]
158 lines of code
50 McCabe index (conditional complexity)

    public String lookup(final LogEvent event, final String key) {
        final ServletContext ctx = WebLoggerContextUtils.getServletContext();
        if (ctx == null) {
            return null;
        }

        if (key.startsWith(ATTR_PREFIX)) {
            final String attrName = key.substring(ATTR_PREFIX.length());
            final Object attrValue = ctx.getAttribute(attrName);
            return attrValue == null ? null : attrValue.toString();
        }

        if (key.startsWith(INIT_PARAM_PREFIX)) {
            final String paramName = key.substring(INIT_PARAM_PREFIX.length());
            return ctx.getInitParameter(paramName);
        }

        if (key.startsWith(REQUEST_ATTR_PREFIX)) {
            final String name = key.substring(REQUEST_ATTR_PREFIX.length());
            final ServletRequest req = getRequest();
            final Object value = req == null ? null : req.getAttribute(name);
            return value == null ? null : String.valueOf(value);
        }

        if (key.startsWith(REQUEST_HEADER_PREFIX)) {
            final String name = key.substring(REQUEST_HEADER_PREFIX.length());
            final ServletRequest req = getRequest();
            return HttpServletRequest.class.isInstance(req)
                    ? HttpServletRequest.class.cast(req).getHeader(name)
                    : null;
        }

        if (key.startsWith(REQUEST_COOKIE_PREFIX)) {
            final String name = key.substring(REQUEST_COOKIE_PREFIX.length());
            final ServletRequest req = getRequest();
            return HttpServletRequest.class.isInstance(req)
                    ? Stream.of(HttpServletRequest.class.cast(req).getCookies())
                            .filter(c -> name.equals(c.getName()))
                            .findFirst()
                            .map(Cookie::getValue)
                            .orElse(null)
                    : null;
        }

        if (key.startsWith(REQUEST_PARAMETER_PREFIX)) {
            final String name = key.substring(REQUEST_PARAMETER_PREFIX.length());
            final ServletRequest req = getRequest();
            return HttpServletRequest.class.isInstance(req)
                    ? HttpServletRequest.class.cast(req).getParameter(name)
                    : null;
        }

        if (key.startsWith(SESSION_ATTR_PREFIX)) {
            final ServletRequest req = getRequest();
            if (HttpServletRequest.class.isInstance(req)) {
                final HttpSession session = HttpServletRequest.class.cast(req).getSession(false);
                if (session != null) {
                    final String name = key.substring(SESSION_ATTR_PREFIX.length());
                    return Objects.toString(session.getAttribute(name), null);
                }
            }
            return null;
        }

        if ("request.method".equals(key)) {
            final ServletRequest req = getRequest();
            return HttpServletRequest.class.isInstance(req)
                    ? HttpServletRequest.class.cast(req).getMethod()
                    : null;
        }

        if ("request.uri".equals(key)) {
            final ServletRequest req = getRequest();
            return HttpServletRequest.class.isInstance(req)
                    ? HttpServletRequest.class.cast(req).getRequestURI()
                    : null;
        }

        if ("request.url".equals(key)) {
            final ServletRequest req = getRequest();
            return HttpServletRequest.class.isInstance(req)
                    ? HttpServletRequest.class.cast(req).getRequestURL().toString()
                    : null;
        }

        if ("request.remoteAddress".equals(key)) {
            final ServletRequest req = getRequest();
            return HttpServletRequest.class.isInstance(req)
                    ? HttpServletRequest.class.cast(req).getRemoteAddr()
                    : null;
        }

        if ("request.remoteHost".equals(key)) {
            final ServletRequest req = getRequest();
            return HttpServletRequest.class.isInstance(req)
                    ? HttpServletRequest.class.cast(req).getRemoteHost()
                    : null;
        }

        if ("request.remotePort".equals(key)) {
            final ServletRequest req = getRequest();
            return HttpServletRequest.class.isInstance(req)
                    ? Integer.toString(HttpServletRequest.class.cast(req).getRemotePort())
                    : null;
        }

        if ("request.principal".equals(key)) {
            final ServletRequest req = getRequest();
            final Principal pcp =
                    req instanceof HttpServletRequest ? ((HttpServletRequest) req).getUserPrincipal() : null;
            return pcp == null ? null : pcp.getName();
        }

        if ("session.id".equals(key)) {
            final ServletRequest req = getRequest();
            final HttpSession session = HttpServletRequest.class.isInstance(req)
                    ? HttpServletRequest.class.cast(req).getSession(false)
                    : null;
            return session == null ? null : session.getId();
        }

        if ("rootDir".equals(key)) {
            final String root = ctx.getRealPath("/");
            if (root == null) {
                final String msg =
                        "Failed to resolve web:rootDir -- " + "servlet container unable to translate virtual path "
                                + " to real path (probably not deployed as exploded";
                throw new IllegalStateException(msg);
            }
            return root;
        }

        if ("contextPathName".equals(key)) {
            final String path = ctx.getContextPath();
            if (path.trim().contains("/")) {
                final String[] fields = path.split("/");
                for (String field : fields) {
                    if (field.length() > 0) {
                        return field;
                    }
                }
                return null;
            }
            return ctx.getContextPath();
        }

        if ("contextPath".equals(key)) {
            return ctx.getContextPath();
        }

        if ("servletContextName".equals(key)) {
            return ctx.getServletContextName();
        }

        if ("serverInfo".equals(key)) {
            return ctx.getServerInfo();
        }

        if ("effectiveMajorVersion".equals(key)) {
            return String.valueOf(ctx.getEffectiveMajorVersion());
        }

        if ("effectiveMinorVersion".equals(key)) {
            return String.valueOf(ctx.getEffectiveMinorVersion());
        }

        if ("majorVersion".equals(key)) {
            return String.valueOf(ctx.getMajorVersion());
        }

        if ("minorVersion".equals(key)) {
            return String.valueOf(ctx.getMinorVersion());
        }

        if (ctx.getAttribute(key) != null) {
            return ctx.getAttribute(key).toString();
        }

        if (ctx.getInitParameter(key) != null) {
            return ctx.getInitParameter(key);
        }

        ctx.log(getClass().getName() + " unable to resolve key " + Strings.quote(key));
        return null;
    }