New Year Bug Bites
By Benjamin Goldstein
January 6, 2011
Happy New Year! And what would a new year be without a new year bug bite? This year we had one where figuring out the species wasn’t easy.
On January 2nd one of our ecommerce clients reported that starting with the new year a number of customers weren’t able to complete their web orders because of credit card security code failures. Looking in the Interchange server error logs we indeed found a significant spike in the number of CVV2 code verification failures (Payflow Pro gateway error code “114”) starting January 1st.
We hadn’t made any programming or configuration changes on the system in the recent days. We double-checked to make sure: nope, no code changes. So it had to be a New Year’s bug and presumably something with the Payflow Pro gateway or banks further upstream. We checked error logs for other customers to see if they were being similarly impacted, but they weren’t. Our client contacted PayPal (the vendor for Payflow Pro) and they reported there were no problems with their system. The failures must indeed be card failures or a problem with the website according to them. We further checked our code looking for what we could possibly have done that might be the cause, …
analytics ecommerce interchange javascript
jQuery code for making a block level element clickable while maintaining left/middle/right clicking
By Ron Phipps
January 4, 2011
While working on a recent redesign for a client we needed the ability to click on a div and have it function as a link to a product page. The initial implementation used the jQuery plugin BigTarget.js. The plugin searches within the div for a link and when the div is clicked changes the location to the link that is found. This plugin worked fine and was fairly easy to setup, however there was one drawback that we found once it was released in the wild. Most people expect to be able to right click, middle click, shift click, and control click to get the context-sensitive menu, open in a new window, or open in a new tab.
Enter Superlink.js, a jQuery plugin that uses a cool trick of moving the location of a link to the location of the mouse within the block level element (such as a div, li, tr, td, etc.). With this implementation the mouse is actually over a link so that the various ways of clicking function as expected. Initially I started moving the clickable area within a table, as shown in the example, but then quickly realized there was no reason this shouldn’t work within a div or li. One other neat thing with this plugin is that the events attached to the block will continue to …
javascript jquery tips
Version Control Visualization and End Point in Open Source
By Steph Skardal
January 3, 2011
Over the weekend, I discovered an open source tool for version control visualization, Gource. I decided to put together a few videos to showcase End Point’s involvement in several open source projects.
Here’s a quick legend to help understand the videos below:
| The branches and nodes correlate to directories and files, respectively. In the case of the image to the left, the repository has a main directory with several files and three directories. One of the child directories has one file and the other two have multiple files. |
| A big dot represents a person, and a flash connecting the person and a file signifies a commit. |
| White + blue dots represent current End Point employees. |
| White + grey dots represent former End Point employees. |
| White dots represent other people, out there! |
The Videos
Interchange from endpoint on Vimeo.
Bucardo from endpoint on Vimeo.
One of the articles that references Gource suggests that the videos can be used to visualize and analyze the community involvement of a project (open source or not). One might also be able to qualitatively analyze the stability of project file architecture …
git interchange postgres spree open-source
Character encoding in perl: decode_utf8() vs decode('utf8')
By David Christensen
December 31, 2010
When doing some recent encoding-based work in Perl, I found myself in a situation which seemed fairly unexplainable. I had a function which used some data which was encoded as UTF-8, ran Encode::decode_utf8() on said data to convert to Perl’s internal character format, then converted the “wide” characters to the numeric entity using HTML::Entities::encode_entities_numeric(). Logging/printing of the data on input confirmed that the data was properly formatted UTF-8, as did running iconv -f utf8 -t utf8 output.log >/dev/null for the purposes of review.
However when I ended up processing the data, it was as if I had not run the decode function at all. In this case, the character in question was € (unicode code point U+20AC). The expected behavior from encode_entities_numeric() would be to turn any of the hi-bit characters in the perl string (i.e. all Unicode code points > 0x80) into the corresponding numeric entity (€ - € in this case). However instead of that specific character’s numeric entity appearing in the output, the entities which appeared were: ⬠i.e., the raw UTF-8 encoded value for €, with each octet being treated as an independent character instead of part of the …
database interchange perl
SearchToolbar and dropped Interchange sessions
By Ron Phipps
December 22, 2010
A new update to Interchange’s robots.cfg can be found here. This update adds “SearchToolbar” to the NotRobotUA directive which is used to exclude certain user agent strings when determining whether an incoming request is from a search engine robot or not. The SearchToolbar addon for IE and FireFox is being used more widely and we have received reports that users of this addon are unable to add items to their cart, checkout, etc. You may remember a similiar issue with the Ask.com toolbar that we discussed in this post. If you are using Interchange you should download the latest robots.cfg and restart Interchange.
ecommerce interchange
Using “diff” and “git” to locate original revision/source of externally modified files
By David Christensen
December 18, 2010
I recently ran into an issue where I had a source file of unknown version which had been substantially modified from its original form, and I wanted to find the version of the originating software that it had originally come from to compare the changes. This file could have come from any number of the 100 tagged releases in the repository, so obviously a hand-review approach was out of the question. While there were certainly clues in the source file (i.e., copyright dates to narrow down the range of commits to review) I thought up and used this technique:
Here are our considerations:
- We know that the number of changes to the original file is likely small compared to the size of the file overall.
- Since we’re trying to uncover a likely match for the purposes of reviewing, exactness is not required; i.e., if there are lines in common with future releases, we’re interested in the changes, so a revision with the fewest number of changes is preferred over finding the exact version of the file that this was originally based on.
The basic thought, then, is that we want to take the content of the unversioned file (i.e., the file that was changed) and find the revision of the …
development git
Dissecting a Rails 3 Spree Extension Upgrade
By Steph Skardal
December 16, 2010
A while back, I wrote about the release of Spree 0.30.* here and here. I didn’t describe extension development in depth because I hadn’t developed any Rails 3 extensions of substance for End Point’s clients. Last month, I worked on an advanced reporting extension for a client running on Spree 0.10.2. I spent some time upgrading this extension to be compatible with Rails 3 because I expect the client to move in the direction of Rails 3 and because I wanted the extension to be available to the community since Spree’s reporting is fairly lightweight.
Just a quick rundown on what the extension does: It provides incremental reports such as revenue, units sold, profit (calculated by sales minus cost) in daily, weekly, monthly, quarterly, and yearly increments. It reports Geodata to show revenue, units sold, and profit by [US] states and countries. There are also two special reports that show top products and customers. The extension allows administrators to limit results by order date, “store” (for Spree’s multi-site architecture), product, and taxon. Finally, the extension provides the ability to export data in PDF or CSV format using the Ruport gem. One thing to note is that this …
ecommerce rails spree
PostgreSQL 9.0 High Performance Review
By David Christensen
November 30, 2010
I recently had the privilege of reading and reviewing the book PostgreSQL 9.0 High Performance by Greg Smith. While the title of the book suggests that it may be relevant only to PostgreSQL 9.0, there is in fact a wealth of information to be found which is relevant for all community supported versions of Postgres.
Acheiving the highest performance with PostgreSQL is definitely something which touches all layers of the stack, from your specific disk hardware, OS and filesystem to the database configuration, connection/data access patterns, and queries in use. This book gathers up a lot of the information and advice that I’ve seen bandied about on the IRC channel and the PostgreSQL mailing lists and presents it in one place.
While seemingly related, I believe some of the main points of the book could be summed up as:
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Measure, don’t guess. From the early chapters which cover the lowest-level considerations, such as disk hardware/configuration to the later chapters which cover such topics as query optimization, replication and partitioning, considerable emphasis is placed on determining the metrics by which to measure performance before/after specific changes. This is the only way to …
database optimization performance postgres