Web On Rails

Hi Guys, it has been a long time since I last posted. I had worked on several things since then, and have couple of posts pending/draft. One of those posts is related to Ultrasphinx, when it is used with STI models.

For those who are new to Ultrasphinx: Ultrasphinx is a rails plugin and client to the Sphinx(full text search engine) written by Evan Weaver. More about Ultrasphinx here.

Lets get into the situation. Consider a STI case where we are using ultrasphinx to index several fields:

Now assume we have following data in posts table:

and now in application root:

By this point we have created sphinx configuration file, indexed all records from ultrasphinx models and started sphinx search daemon.

Now open script/console and create and fire a query to find some articles:

Here when you run the query you get an exception, because it is trying to find an article with id 5, which actually a story type not article. So why it is trying to find such article?

Now have a look into config/ultrasphinx/development.conf file. Under section “source articles_main” you’ll get “SELECT (posts.id * 3 + 0) AS id, ‘’ AS article_title, posts.body AS body, ‘Article’ AS class, 0 AS class_id, posts.title AS title FROM posts WHERE posts.id >= $start AND posts.id <= $end GROUP BY posts.id" Which is a SQL to get record to index.

If you check it carefully you'll findout that it should select all articles record to index but unfortunately it is selecting all records from table and considering them as articles. To fix it you need to modify this query and add "posts.type = 'Article'" in where condition. So the query should be "SELECT (posts.id * 3 + 0) AS id, '' AS article_title, posts.body AS body, 'Article' AS class, 0 AS class_id, posts.title AS title FROM posts WHERE (posts.type = 'Article') and posts.id >= $start AND posts.id <= $end GROUP BY posts.id"

But still there is a problem. If you do this manually you have to do it again and again whenever you issue "rake ultrasphinx:configure" because this configuration file will be overwritten.

Better option is to add conditions in models as is_indexed options like:

and it worked fine.

Manik gave me an idea to write a patch for ultrasphinx to add such conditions automatically in case of STI. So may be another post related to ultrasphinx will be soon ;-)

Update: Here is the patch Git patch: Fix STI Issue. After applying this patch you need not to add conditions explicitly for such case. It will automatically check and add conditions for STI.

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I have been using Git from last few days, and faced following errors while committing:

1) Trailing whitespace
2) Indent SP followed by a TAB
3) Unresolved merge conflict

The first error “Trailing whitespace” is because of carriage-return/line-feed(windows style line feed/end). To resolve this problem comment following lines(58-60) in .git/hooks/pre-commit file:

The second one “Indent SP followed by a TAB” is because of leading spaces/tabs. To resolve this problem comment following lines(61-63) in .git/hooks/pre-commit file:

The third one “Unresolved merge conflict” is because of seven or more successive occurrence of = or < or > characters. Major chances of having seven = character in README or doc files. To resolve this problem replace following line(64) in .git/hooks/pre-commit file:

by

These tricks worked for me, I hope it could help you.

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I have been using “Annotate Models” rails plugin written by Dave Thomas since I found it around one and half year ago. It really helps while writing fixtures. But if you use RSpec you might miss schema info at the top of your rspec fixture file as I do. So, today I modify the plugin file so that it prepends schema info to spec file and fixture file. Below are the links of patch file:

svn patch to add schema info to spec file and spec fixture file
git patch to add schema info to spec file and spec fixture file

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Git is getting popular in Rails community these days, as there were being many changes in rails to support Git.
Git is a open sourse fast version controller system. It was originally designed by Linus Torvalds to handle large projects. It was inspired by Monotone & BitKeeper. It is a distributed version controlling system. It gives you ability to commit, traverse into history while being offline. Actually every working copy of Git is a full-fledged repository. It has no central server like SVN. One can share his working-copy/repository by using various protocols like ssh, http, ftp etc. One thing I like about Git over SVN is that the size of Git’s repository, which is smaller compared to SVN.

I gave an introductory presentation in VinSol. I am sharing it with you, this is not very explanatory as I focused on speech more. Please share your views.

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You may have noticed by now, that in Rails 2.0 changeset 7422, you can specify columns you want to add/remove in your migration by passing attribute:type pairs to the migration generator.

For example, lets assume that we need to add a column ‘role’ in users table(User model). In this case generate a migration like:

Output:

Here AddRoleToUser plays the main role. ‘Add’ specifies the we want to add column(s) and ‘User’ separated by ‘To’ specifies the table.

Similarly, if we need to remove a column ‘role’ :

Output:

Here RemoveRoleFromUser plays the main role. ‘Remove’ specifies the we want to remove column(s) and ‘User’ separated by ‘From’ specifies the table.

Isn’t it cool?

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