{5} Setfive - Talking to the World - Page 55 of 66 - Ramblings on code, startups, and everything in between

We’ve been using Jeff Hui’s very awesome jquery.blank plugin for sometime over at Setfive HQ. What blank() is allow you to basically move the labels for text inputs into the input themselves (to save space). We use this technique frequently for login boxes in headers since it’s easier not to have to stick in labels next to text boxes.

The problem is, you can’t use blank() on a password field since a password field won’t display clear text (obviously). To get around this, I’ve always manually stuck in a “shadow” text box next to the password field and toggled the text box or password box in order to make blank() work correctly.

Anyway, I finally got tired of doing this so I decided to patch the plugin to do this automatically. Jeff incorporated the code back into blank() and it’s available on GitHub here.

Happy coding.

Recently we’ve been working on a new project that requires caching of both views and database queries. One of the problems I came across I wanted to Result Cache an query I was using for a pager. This caused a couple of problems, one being I needed to be able to clear the cache by its prefix so we would never have a stale cache. Doctrine has a built in deleteByPrefix call for this, however on a pager how do I get it so that it will use a result cache, but still use different indexes for different pages? The following code would not work:

Well here the problem is everything is being cached as as the ‘comment_index’ cache, so if you passed that query to a pager, and told it to be on the second page, it’d see the ‘comment_index’ cache exists, and use that. A simple way around this is:

  // Query build...
 ->useResultCache(true,sfConfig::get('app_comment_cache'),'comment_index_'.$page);

In this example page is the parameter you are passing the query and the Doctrine pager to tell it what page cache to look at.

Then a very weird problem was occurring, I was getting more queries if I USED the cache than if I didn’t. Very weird. It seemed that one of the joins object did not seem to be getting stored in the cache. The join looked something like this:

The problem was the profile object was not getting stored in the result cache and thus causing a query each time it was called from the user object. After much hunting around, a long time in #doctrine, and a few leads from a couple of people, it turns out, by default, Doctrine will only serialize the immediate relation to the main object (in this case ‘sc’). However, you can make it so that it will serialize objects further down the line by overriding the function serializeReferences to return true in the class you want to serialize references from. In my example this is the User class. Since our application will never only need the ‘User’ class to be serialized on a result cache I completely overrode the function and made it always return true

Of course you can set this on a per object instance via $user->serializeReferences(true). Overriding the method the way I did you need to be careful as you could potentially waste a ton of storage space in your result cache.

Hope this saves someone some head banging and confusion on how using a cache could actually cause more queries if not stored properly.

Recently for a project we had the following situation: Users have their own specific databases, however each database has the same schema. Since there are an unlimited number of databases this prevented us from using databases.yml to define which tables need to go to which databases. The user’s database connection would be defined at run time and we needed only certain tables to be bound to that connection. A bunch of googling turned not much up, mostly talking about defining it in the databases.yml file. After a little bit of searching through some of the Doctrine documentation I came across bindComponent. This allows you to tell a model to use a specific connection. For example:

The above would bind the model ‘SomeModel’ to the connection ‘UsersConnection’. To make this so that it is automatically done each time it is executed a good place to add it is a custom filter.

Also if you plan on storing the user’s database passwords it is a good practice to encrypt them. Look into possibly using the class sfCrypt for this.

Recently for a client we had a very peculiar problem: a nightly script which checked if a person has done a certain action that day was always flagging everyone. We tested the script multiple times on our servers and it always worked fine. The query had something similar to this:

SELECT * FROM action_table WHERE DATE(action_table.time)=DATE(NOW())

Well after a while of trouble shooting we found out that the system clock on the clients server was skewed and in the wrong time zone. We synced the machines clock and update its time zone. Before it had been in UTC time and we switched it over to EST. What is interesting is that MySQL did not respect the new time zone of the clock, it was still reporting as if the system was set to UTC. We then did a soft restart(reload) on the MySQL service, but it still maintained that it was in a UTC timezone and not EST. It took a hard restart of the MySQL service to have it respect the EST timezone.

All in all, as far as we can tell you need to restart the MySQL service to have it respect a new timezone.

Recently I received an email from Davert. He noted that the sfSCMIgnoresTaksPlugin would not work on Windows as Windows has a different directory separator. He sent over a patch which uses PHP’s DIRECTORY_SEPARATOR instead of the coded “/”. This makes the plugin compatible on Windows. Thanks Davert. You can read more about the plugin and download the most recent release at http://www.symfony-project.org/plugins/sfSCMIgnoresTaskPlugin.

jQuery blank() modified for password fields

Using Doctrine Result Cache With Two Deep Relations

Doctrine Multiple Connections and Specific Tables

MySQL and System Time

sfSCMIgnoresTaskPlugin for Symfony released, windows compatible!