14 Jun 2009 |
Category: Snippets
Yahoo Maps-based Geocoding
I recently had to create online maps for an art gallery, specifically for their exhibits. So I decided to use the Yahoo API to grab the coordinates based upon the data that was being sent to the model and save this to the database. Here's how I did it.
First, the model has to be aware of the Yahoo AppID. I set this as a variable within the model itself, but you can set it in the url.
<?php
class Exhibit extends AppModel {
var $name = 'Exhibit';
var $yahooApiID = 'YOURAPPIDHERE';
}
?>
Next we should probably actually get the Latitude and Longitude for the data. I am assuming you have the correct fields defined in your exhibits table. The CREATE TABLE query is shown below
CREATE TABLE `exhibits` (
`id` int(11) unsigned NOT NULL auto_increment
`address` varchar(50) default NULL,
`city` varchar(20) default NULL,
`state_id` int(3) unsigned default NULL,
`zipcode` int(5) default NULL,
`lattitude` varchar(20) default NULL,
`longitude` varchar(20) default NULL
PRIMARY KEY (`id`),
) ENGINE=InnoDB DEFAULT CHARSET=utf8
Now that you have the proper fields, we'll REALLY get the Latitude and Longitude. Below is the entire Model class relating to Exhibits:
<?php
class Exhibit extends AppModel {
var $name = 'Exhibit';
function beforeValidate(){
$curl = false;
// Start constructing the URL
$q = 'http://local.yahooapis.com/MapsService/V1/geocode?appid=';
// Adding apiid
$q .= $this->yahooApiID;
// Adding Street
$q .= '&street='.$this->data['Exhibit']['address'];
// Adding City
$q .= '&city='.$this->data['Exhibit']['city'];
// Adding State
//ClassRegistry::init('State')->getState($this->data['Exhibit']['state_id'])
$q .= '&state='.ClassRegistry::init('State')->getState($this->data['Exhibit']['state_id']);
// Adding Zip
$q .= '&zip='.$this->data['Exhibit']['zipcode'];
// If We had a location, we would do the following instead:
// $q .= '&location='.rawurlencode($this->data['Exhibit']['location']);
// Setting Output to xml
$q .= '&output=php';
$q = str_replace(' ', '%20', $q);
//Using cURL or file_get_contents
if ($curl){
$c = curl_init();
curl_setopt($c, CURLOPT_URL, $q);
curl_setopt($c, CURLOPT_RETURNTRANSFER, 1);
$phpContent = trim(curl_exec($c));
curl_close($c);
} else {
$phpContent = file_get_contents($q);
}
$phpContent = unserialize($phpContent);
$this->data['Exhibit']['lattitude'] = $phpContent['ResultSet']['Result']['Latitude'];
$this->data['Exhibit']['longitude'] = $phpContent['ResultSet']['Result']['Longitude'];
}
?>
I have allowed you to use either cURL or fopen. For cURL, you need to have that installed on your server, and for fopen, you need to have allow_url_fopen set to true in php.ini. Just giving options in case you can't do one or the other :)
You'll notice that when I get the State for this location, I initialize the model via ClassRegistry. Just out of habit. I also don't have a relationship to the State in my model, which is why I did this. Read about Containable (and BindModel for extra points!) for more information. The code for that call in the State model is as follows:
<?php
class State extends AppModel{
var $name = 'State';
function getState($state = null){
$state = $this->find('first',
array(
'recursive' => -1,
'fields' => array(
'State.title'
),
'conditions' => array('State.id' => $state)
)
);
return $state['State']['title'];
}
}
?>
So lets review:
- I set my AppID somehow
- Made sure my model contained the proper fields
- Added some code to the beforeValidate
- Updated two fields (latitude and longitude) in my model
- Made getting the State (depending upon state_id) a bit easier
You can now use the Latitude and Longitude in the views just as any other model data.
I realize that you might be thinking "This should be a behavior or something, I'll end up replicating this several times!" Well good. You make the behavior and I'll take credit! In all seriousness though, there is already a Geocode Model on the bakery that should be made into a behavior. This was just a quick fix before I converted it into a Behavior for my own usage :)