mathifonseca / grails-browser-detection Goto Github PK

Hi, Is it possible to nest these?

EG:
< browser:choice>
< browser:isNotWindowsMobile>
< browser:isMsie versionLower="9">
...
</ browser:isMsie>
</ browser:isNotWindowsMobile>
</ browser:choice>

Could we create a new release for Grails 2.x with the latest UserAgentUtils?

Because I want to display a message if the browser is not chrome or firefox.

I keep getting this error when building.
I only use added the plugin and got that as a consequence.

Error:(9, 10) Groovyc: Only classes and closures can be used for attribute 'value' in @grails.test.mixin.TestFor

• Grails 3.3.9
• browser-detection plugin 3.4.0
• Jetty

Our application has many instances and many requests per instance in parallel, mostly unique users. Our application is stateless, users are not guaranteed to land on the same application instance next time, there is no session-syncing between the instances.

Our load and performance tests showed after migrating from Grails 2, that there are tons of sessions now. While the specific plugin code did not change since grails 2, we didn't make to configure the session timeouts properly under Grails 3 so far, so the problem became visible.

What the code in question does:

getUserAgent() wants to check if there is already cached user agent info in the session. Probably to safe a call to safe a call of parseUserAgent().
For this it calls
request.session.getAttribute(AGENT_INFO_TOKEN)
which leads to a call of
request.getSession()
which leads to a call of
request.getSession(true)
which creates a session, if there is none.

In our scenario about 90% of the requests don't have a session at this point, unless browser-detection created one in a further call or request.

If there was no user agent session information (or in the very rare cases, where user agent string changed while the session), getUserAgent() parses the user agent string and ads user agent infos to the (newly created) session.

In our scenario it’s much more expensive to create a session for any unique user on any instance, then just parsing the user agent string on any request.

To cache the agent info for repeated calls of getUserAgent() within a single request, it would be better to store it in the request scope (request.setAttribute(AGENT_INFO_TOKEN, userAgent)).

	UserAgent getUserAgent() {

		String userAgentString = getUserAgentString()
		UserAgent userAgent = request.session.getAttribute(AGENT_INFO_TOKEN)

		// returns cached instance
		if (userAgent && userAgent.userAgentString == userAgentString) {
			return userAgent
		}

		if (userAgent && userAgent.userAgentString != userAgent) {
			log.warn "User agent string has changed in a single session!"
			log.warn "Previous User Agent: $userAgent.userAgentString"
			log.warn "New User Agent: $userAgentString"
			log.warn "Discarding existing agent info and creating new..."
		}
		else {
			log.debug "User agent info does not exist in session scope, creating..."
		}

		// fallback for users without user-agent header
		if (userAgentString == null) {
			log.warn "User agent header is not set"
			userAgentString = ""
		}

		userAgent = parseUserAgent(userAgentString)

		request.session.setAttribute(AGENT_INFO_TOKEN, userAgent)
		return userAgent
	}