Retrieve exchange rates
The ECB has an XML feed with EURO exchange rates to other currencies. It is updated daily.
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How to: Upgrade CarrierWave to 3.x
While upgrading CarrierWave from version 0.11.x to 3.x, we encountered some very nasty fails. Below are the basic changes you need to perform and some behavior you may eventually run into when upgrading your application. This aims to save you some...
Interacting with a Microsoft Exchange server from Ruby
Microsoft Exchange service administrators can enable Exchange Web Services (EWS) which is a rather accessible XML API for interacting with Exchange. This allows you to rea...
Retrieve the total number of records when paginating with will_paginate
When you use will_paginage to paginate a scope, and you want to obtain the total number of records matched before pagination, you can use total_entries:
users = User.active.paginate
puts users....
MySQL: For each group, retrieve a comma-separated list of values in a given column
The technique described in this card has an important caveat: The result of GROUP_CONCAT is truncated to the maximum length that is given by the group_concat_max_len system variable, which has a default value of 1024. **This will cause hor...
How Exchange handles multipart/alternative emails
In Rails, you can very easily send emails with HTML and plaintext bodies.
However, if you're trying to debug those using your normal email account, you might be o...
Exchange messages between Javascript and Flash
Flash movies (.swf files) can talk with Javascript code embedded in the same HTML page. There are two ways to do this:
- The preferred way is to use the [ExternalInterface](http://livedocs.adobe.com/flash/9.0/ActionScriptLangRefV3/flash/external/...
Retrieve the SQL query a scope would produce in ActiveRecord
Rails 3
User.active.to_sql
Rails 2
Use either the Edge Rider or fake_arel gem to get #to_sql backported to Rails 2.
If you don't want to use ...
Git: Retrieve a file from a different branch or commit
To access files from another branch or past commit without doing a complete checkout, you can either use
git show branch:file
git show commit:file
to display, or check out the file into your working directory with
git checkout bra...
Guide to localizing a Rails application
Localizing a non-trivial application can be a huge undertaking. This card will give you an overview over the many components that are affected.
When you are asked to give an estimate for the effort involved, go through the list below and check wh...
vague puppet error messages with broken yaml files
If you get one of this errors:
Error: Could not retrieve catalog from remote server: Error 400 on SERVER: (<unknown>): found character that cannot start any token while scanning for the next token at line 1297 column 3
Warning: Not using ...