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24 August 2008

Locatable: Some stats

Locatable has been on Cydia for about a week now, and thanks to BigBoss I can see that there have been over 5,000 downloads (some of these are people upgrading from 0.1 to 0.2, of course). I've also done some analysis of the visitors to the Featured Sites page. First of all, I'm impressed by how far around the globe the jailbroken iPhone has traveled. Within just the last 12 hours there have been visitors from over 50 countries -- here are the top ones: 1. U.S. (18%) 2. France (7%) 3. Mexico (7%) 4. Brazil (6%) 5. U.K. (6%) 6. Spain (4%) 7. Canada (4%) 8. Slovakia (3%) 9. Italy (3%) 10. Norway (3%) Traffic is overwhelmingly (95%) coming from iPhones as opposed to iPods Touch, as you might expect for an app that is most useful with GPS when you're out and about; on the other hand, so far usage is still fairly evenly split between WiFi and mobile networks. In other news: I've got a heavily reworked version of Relocatable just about ready to go that makes it very easy to do the location tracking hack posted previously. It also does a far better job of getting accurate GPS readings, though it takes a little longer. I'm working on incorporating the same technique into Locatable and I'd like to start adding some more management preferences, such as the ability to have trusted sites that you aren't continually prompted for (much the same as the way the iPhone works for applications that request to read your location: after a couple of checks, it assumes you're fine with it). If you have other feature ideas please comment! n.b. If you have a working iphone-gcc toolchain installed, the Makefiles are set up so you can build your own copies of Locatable and Relocatable from source now, and the changes mentioned above for Relocatable are checked in.

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21 August 2008

Location tracking using Relocatable

"Relocatable" is the location-gathering daemon add-on to "Locatable" (currently they're bundled together for distribution purposes on Cydia; an AppStore version will only contain Locatable as it's not permissible to install daemon processes through the official program). Relocatable is set up to run at 10-minute intervals and gather location data in the background. This means location data is typically available to the browser on a jailbroken phone without having to launch the Locatable app proper. Several of you have asked if there's a way to do a scheduled publish of your location to a destination server of your choice based on the data that Relocatable collects. The answer is a definite yes, and Mike Carambat emailed me the following solution:
Requirements 1. Jailbroken iPhone 2. Install "Locatable" from Cydia 3. Make sure you have "SQLLite" from Cydia 4. Make sure you have "cURL" from Cydia 5. A server based facility to store the data captured from your phone Concept Basically, "Locatable" is a springboard app which uses Core Location to capture GPS coordinates. The cool thing about it, is that it stores them in a SQLite database which is then easily accessible. You query this database via the sqlite3 command and pipe its results to cURL which forwards the data to your server. Instructions 1. Create a shell script called "pushgps" on your iphone which you will invoke on a periodic basis. Put it in the /usr/bin/ on your iphone. This shell script looks like this: ---------- start ---------- #! /bin/sh curl -d POS="`sqlite3 /var/mobile/Library/WebKit/Databases/http_lbs.tralfamadore.com_0/*.db 'select latitude, longitude from location where tag = "Current"'`" http://www.yourserverhere.com/path_to_gps_recorder ----------- end ----------- (replace the "yourserverhere" and "path_to_gps_recorder" with YOUR server and recording software. (see below for ideas on doing this) Don't forget to: chmod 755 pushgps 2. Next, create a plist file /System/Library/LaunchDaemons/com.whatever.pushgps.plist which contains: ---------- start ---------- <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> <dict> <key>Label</key> <string>com.whatever.pushgps</string> <key>ProgramArguments</key> <array> <string>/usr/bin/pushgps</string> </array> <key>StartInterval</key> <integer>600</integer> </dict> </plist> ----------- end ----------- (replace the "whatever"s with your name, company name, domain, or whatever. This is just an identifier. the 600 refers to every 10 minutes. change if needed. Locatable's interval defaults to 10 minutes, but can be changed as well in its plist file (same directory)) 3. Create software to record the GPS data You'll need to post the coordinate data to *somewhere* online. No, I'm not gonna do it for you. Get your own server ;) Maybe the folks at www.instamapper.com would be open at some point to do this for us. I wrote a simple perl script called gps.pl which runs on my server which simply records and time/date stamps the data. Something like this: ---------- start ----------
#!/usr/bin/perl # GPS Recorder $maxhistory=1000; # Total number of locations to store if ($ENV{"REQUEST_METHOD"} eq 'GET') {$buffer=$ENV{"QUERY_STRING"};} else {read (STDIN, $buffer, $ENV{"CONTENT_LENGTH"});} @vars=split(/&/,$buffer); foreach $var (@vars) { ($name, $value)=split (/=/,$var); $name =~ tr/+/ /; $name =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C", hex($1))/eg; $value =~ tr/+/ /; $value =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C", hex($1))/eg; chomp($name); chomp($value); $stuff{$name}=$value; } if (exists ($stuff{'POS'})) { ($lat,$long)=split(/\|/,$stuff{'POS'}); chomp($lat); chomp($long); &GetDateTime; open (STUFF, "gpslocation.txt"); @lines=; close (STUFF); $numlines=@lines; $sp=0; if (($numlines-$maxhistory)>-1) { $sp=$numlines-$maxhistory; } open (STUFF, ">gpslocation.txt"); for ($i=$sp; $i<$numlines; $i++) { chomp($lines[$i]);
print STUFF "$lines[$i]\n";
} print STUFF "$date\t$time\t$lat\t$long\n"; close (STUFF); print "Content-type: text/plain\n\n"; print "Latitude: $lat\n"; print "Longitude: $long\n"; exit(0); } print "Content-type: text/plain\n\n"; print "ERROR"; exit(0); sub GetDateTime { ($second, $minute, $hour, $dayofmonth, $month, $year, $weekday, $dayofyear, $isdst) = localtime(time); $year=($year+1900); $month++; $date=sprintf("%02D",$month)."/".sprintf("%02D",$dayofmonth)."/".sprintf("%04D",$year); $time=sprintf("%02D",$hour).":".sprintf("%02D",$minute).":".sprintf("%02D",$second); }
----------- end -----------
Thanks Mike! Update (1 Sep 08): While this method still works (and it provides a good example of a server-side script to handle the data), as of version 0.3 Relocatable allows you to specify a command to execute each time a location fix is acquired, so there's no need to use the pushgps part. See this post for details.

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15 August 2008

Sneak peek

I'm close to a beta release for Locatable, and I'm excited enough about it that I wanted to give a quick preview, from a tech-centric point of view. Locatable is an application and geolocation federation service that let you share your location (GPS coordinates, or any decent facsimile thereof) from your iPhone or iPod Touch to any web site, via the built-in Safari browser. It takes advantage of the new client-side storage capabilities of Safari to allow some very nice anonymity and privacy features -- notably, the user's location is never stored on the server side, with the service at lbs.tralfamadore.com acting as a gateway to storage on the device. There's a lot to say about this and its relationship to similar services such as MyLoki (Skyhook) and FireEagle (Yahoo!). Both of those could be integrated, as can just about any existing location-based service. Anyway, check out the concept and check back for more updates soon.

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