Mark Foster's Blog

SELinux will block PHP/Apache from connecting to PostgreSQL (and probably any other DB) by default on some Linux distributions. If you are trying to get PHP to connect to a PostreSQL DB on a linux box for the first time and you are sure your pg_hba.conf on the target box is setup correctly then try this:

setsebool -P httpd_can_network_connect 1

This should configure SELinux to allow Apache/PHP to connect to other hosts.

I just finished testmywireless.com. It is a mobile-targeted website that allows you to test your wireless bandwidth on mobile phones or tablets that do not have Flash support (I.e. iPhone) without installing an app. It is intended to be used as a comparison shopping tool for folks in the market for smartphones and tablets. To test broadband performance, disable Wi-Fi on the device, open a browser and go to testmywireless.com. Press “Test My Connection” to test the device’s broadband connection performance.

The site also allows you test the browser’s support for modern web standards and search for service providers near your location. The service provider search uses your current GPS location (with your permission) and shows each provider’s advertised upload and download speeds which you can compare with your connection test results. You can also search by postal code or city, state. The FCC/NTIA National BroadBand Map API is used to find service providers and their advertised bandwidth speeds.

It was a good little project to tinker with jQuery Mobile, integrate with a couple API’s, and learn more about JavaScript Asynchronous programming in general. It is not nearly as flashy as some of the existing bandwidth test tools and there are still some quirks and bugs to work out but it seems work pretty well for the most part. If you have a chance to try the site out, I would be interested in your feedback.

The National Telecommunications and Information Administration (NTIA) in collaboration with the FCC has published a series of broadband maps on a new site called National Broadband Map (NBM). These maps show what broadband services are available throughout the United States as well as other interesting broadband data.

Hit this link and click the “Explorer the Map” option on their main page to see a map of the US with shaded areas where selected broadband services are available. You can click different selections above the map to toggle the various broadband technologies. To see other maps such as advertised versus actual broadband speeds click on the “Show Gallery” option in the lower right hand corner.

Rochester, NY does pretty well on advertised versus actual although there a few slower than advertised points here and there. Upload performance data is also available. Usually the cable and DSL providers don’t brag much about upload performance likely because in most cases it is lousy compared to download performance. I think upload performance will become more important to the typical internet user than it as in the past now that people are sharing their pictures and video online.

The NBM site use a variety of open source technologies including:

• JQuery – My favorite JavaScript library.
• Modernizr – A JavaScript library to detect browser capabilities.
• OpenLayers – Provides a JavaScript API to display WFS and WMS GIS layers.
• GeoServer – A Java based server software that provides WFS and WMS services.

What is particularly interesting about the site is the developer resources. They provide a series of API’s you can call from your own web applications to use their data. Output formats include XML, JSON, and JSONP implementations. If you want to use the data locally without the APIs you can download it.

I do have a couple criticisms regarding the maps and ironically, they are bandwidth related. The first is that there are too many tiles returned when viewing the default map of the US. I noticed the map was a little slow to fill in. When I enabled Firebug and clicked on the “Explore the Map” option off the main page, over 500 tiles were pulled down. In fact, Firefox/Firebug became unresponsive. I would expect less than 30 256×256 tiles need to be pulled down for a reasonably sized browser window. I wager there is something goofy going on like a bounding box not set for the area displayed.

My second criticism is that the site is not using gzip to compress JavaScript files. Modern web applications tend to lay on the JavaScript pretty heavy and this one is no exception. OpenLayers.js is nearly 1MB all by itself. By enabling gzip on sites with large JavaScript files you can significantly improve site performance. This is a good topic for a future post.

Overall I think the National Broadband Map Site is an excellent resource. It provides very useful data on broadband technologies/speeds, makes this data available via APIs or download, and also demonstrates a variety of open source web application technologies.

Is it worth the $20 million that contractors were paid to build the map? I would say certainly not at first glance but I would want to hear the whole story before I jump to conclusions. I.e. how much of that $20 million was spent on actual development? I am much more skeptical of the alleged $293 million required to collect the data.

If you are running Microsoft Security Essentials with real-time protection enabled on a machine running ThinkVantage Access Connections you might notice the MsMpEng.exe service consuming most of your CPU time. This will cause your Lenevo laptop to run obnoxiously slow. Allegedly this issue was fixed with a new version of Access Connections but on a laptop I was working on the problem persisted even after I updated Access Connections.

If logging is enabled in Access Connections the “AccConnAdvanced.html” file will continuously be updated. Microsoft Security Essentials appears to then scan this file over and over again after each change. This is probably causing the processor to burn your precious battery life away. This way Lenovo can sell more battery pack upgrades.

There are two ways to fix this: Add an exception to Microsoft Security Essentials or disable logging in Access Connections.

If you want to continue logging Access Connection activity you can add an exclusion in Microsoft Security Essentials:

1. Open up Microsoft Security Essentials and click on the “Settings” tab.
2. Select “Excluded files and locations”.
3. Click the “Browse…” button and select the “AccConnAdvanced.html” which, should be under “C:\Program Files\ThinkPad\ConnectUtilities\” by default. Click “OK”.
4. Click “Add” and then “Save changes”. MsMpEng.exe CPU utilization should then drop to around 0%.

Here is how you can disable logging in Access Connections (at least on Windows XP).

1. Launch Access Connections: “Start”->”Programs”->”ThinkVantage”->”Access Connections”.
2. Once Access Connections is up switch the view to “Advanced” by clicking the “Advanced” button in the upper right hand corner.
3. Click the “Tools” tab and then “Diagnostics” and then the “Event Log” tab on the Diagnostics Tools screen.
4. Click “Disable Logging” and then click “Close”. The AccConnAdvanced.html file should no longer grow and MsMpEng.exe CPU utilization should drop to nearly 0%.

I recently started tinkering with the Appcelerator Titanium Development Platform and have run into a couple quirks.

Web Inspector will not Launch

If you create a Titanium project on any drive other than C:\ on a Windows system, you will not be able to launch the Web Inspector. This is a apparently a known bug in Titanium Developer.

Conflicting PHP Installations

If you attempt to launch a Titanium Appcelerator PHP app in Titanium Developer on a Windows system that already has a local PHP installation, you may see the following error:

Don’t bother re-installing anything. What is likely happening is that your pre-existing PHP installation added a “PHPRC” environment variable that points to your existing PHP install folder. I think Titanium’s command line PHP instance sees this variable and then attempts to use the php.ini file in that path. Your existing PHP installation folder does not likely have the PHP settings and/or module paths that Titanium needs so it breaks.

To fix this without renaming your current PHP installation folder you can delete the “PHPRC” environment variable. Your existing PHP installation should work fine without it because PHP will look for the php.ini file in the same folder it is running from. To delete the “PHPRC” environment variable on Windows 7, click Windows Start, right click “Computer”, left click “Properties” -> “Advanced system settings” -> “Environment Variables…” -> select “PHPRC” under “System variables”, and then click “Delete”.

Hopefully you can now launch your Titanium application without an error and your existing PHP installation will continue to work normally.