Tag Archives: Grails

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September 26, 2010

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Gotchas, HowTo

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Redirecting to .com (without confusing CloudFoundry…)

It’s a two-for-one today – a “gotcha” and a “how to” all rolled into one, this time about redirecting in a Grails filter.

Much like my favicon woes my initial attempt to redirect to a primary domain (a .com without the “www” prefix) had some unexpected consequences when deployed to a live server on CloudFoundry – I started getting warnings that my site had gone down!

In this post I’ll hopefully save you the panic of CloudFoundry telling you that your site’s not responding when you try to rationalise your domain names!

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September 13, 2010

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Gotchas

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When localhost is not the same as 127.0.0.1 a MySQL Connection Gotcha

Setting up MySQL connection pooling has been standard stuff in server-side apps for as long as I’ve been writing them, so I was at a loss when, every 5 days or so, my newly deployed app died with this exception:

Exception in thread "main" 
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: 
Communications link failure

Last packet sent to the server was 0 ms ago.

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September 6, 2010

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Gotchas, Grails

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Spring Secutiry (ACEGI) Plugin and Favicon Permissions

Here’s a quick gotcha for you. You set up a favicon in the root of your web app, as is the convention, and when you log in you are redirected to a picture of your favicon or you are asked to download it… Weird.

Odds on you’ve installed the Spring Security plugin and forgotten to give permission to the favicon file in the root and the result is that on login Spring Security redirects you to the first restricted item that was requested by the browser – the favicon.

The solution? Easy, set the favicon path to IS_AUTHENTICATED_ANONYMOUSLY in your SecurityConfig.groovy (or database):

controllerAnnotationStaticRules = [
    ...
    '/favicon.ico' : ['IS_AUTHENTICATED_ANONYMOUSLY'],
    ...
]
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June 16, 2010

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Gotchas

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Upgrading Grails from 1.2.2 to 1.3.1

The usually simple upgrade process in Grails has caused me a few headaches in moving from 1.2.2 to 1.3.1. I skipped the 1.3 upgrade because there were a few people having issues on the mailing list but yesterday I bit the bullet and encountered a couple of problems.

I think the release notes for Grails 1.3.x have been unusually poor so this post has the issues I’ve encountered in the hope that you won’t go quite as mad as I have. I’ll keep it updated if I find more problems. Continue reading →

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April 2, 2010

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Grails, Tutorials

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19 Comments

Sending Asynchronous HTML Email in Grails with ActiveMQ, JMS and Gmail

Sending email asynchronously is an essential part of most Web applications and there are many ways in which to implement it. In this post I’ve chosen to demonstrate how to set up JMS, ActiveMQ and Gmail with the Grails Mail plugin to provide asynchronous email capabilities while only having to write a few lines of code, all thanks to some great plugins. I’ll also show the fantastic Grails Mail templating feature which uses GSP views to generate HTML emails along with a solution for one of the big bugs with it too!

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March 15, 2010

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Grails, Tutorials

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Simple Aspects using Annotations in Grails

Aspect Oriented Programming is a concept which will be familiar to users of the Spring Framework as one of its core features. However, the details of how to get AOP working in Grails appear thin on the ground, so in this post I will show how to set up a simple aspect then configure and apply it using attributes. I will assume some familiarity with Spring AOP so I won’t explain the terminology or general concepts since they are exactly the same  in Java as they are in Grails. Continue reading →

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March 10, 2010

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Grails, HowTo

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Updating the Logged in User with Acegi/Spring Security in Grails

Following on from my post on how to log in a user using the Grails Acegi/Spring Security plugin I stumbled into a new use for the same code when I tried to update a user’s own details while logged in. The security plugin caches the user’s domain object so any changes are not seen until the next login (wholly unhelpful when you’re trying to implement account management on a Website!).

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March 2, 2010

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Gotchas, Grails

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When My Grails App Got Stuck in a Recompilation Loop

The first sign something was wrong was the JVM bombing out with a “java.lang.OutOfMemoryError: PermGen space” error. All I’d done was change a gsp, so I restarted and after a long wait the same thing happened and it was then I noticed that the compiler just kept recompiling 4 classes in a loop until the JVM bombed.

This had happened to me once before when I’d managed to set the time incorrectly on my PC so some of my files appeared to be modified in the future. However this time I’d not done anything of the sort.

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