A bridge is an interface that allows rss-bridge to create a RSS feed from a website.
The bridge is a PHP file, located in the `bridges/` folder.
##Specifications
A rss bridge must extend the `BridgeAbstract` class, and implement the following functions :
* The `loadMetadatas` function, described below,
* The `getCacheDuration` function, describing the time during which rss-bridge will output cached values instead of re-generating a RSS feed.
* The `collectData` function, also described below.
##The `collectData` function
This function takes as a parameter an array called `$param`, that is automatically filled with values from the user, according to the values setted in `loadMetadatas`.
This function is the place where all the website scrapping and the RSS feed generation process will go.
The RSS elements are stored in the class variable `items[]`.
Every RSS element is an instance of the `Item` class.
This function is the one used by rss-bridge core to determine the name, maintainer name, website, last updated date... of the bridge, and the user parameters.
### Basic metadatas.
The basic metadatas are the following :
```PHP
$this->maintainer
$this->name
$this->uri
$this->description
$this->update
```
The default values are the following :
```PHP
$this->name = "Unnamed bridge";
$this->uri = "";
$this->description = 'No description provided';
$this->maintainer = 'No maintainer';
```
### Parameters
Parameters use a JSON-like format, which is parsed and transformed to HTML `<form>` by rss-bridge.
These datas goes into the `$this->parameters` array, which is not mandatory if your bridge doesn't take any parameter.
Every possible usage of a bridge is an array element.
The array can be a key-based array, but it is not necessary. The following syntaxes are hereby correct :
```PHP
$this->parameters[] = ...
$this->parameters['First usage of my bridge'] = ...
```
### Format specifications
Every `$this->parameters` element is a JSON array (`[ ... ]`) containing every input.
It needs the following elements to be setted :
* name, the input name as displayed to the user
* identifier, which will be the key in the `$param` array for the corresponding data.
Hence, the most basic parameter definition is the following:
```PHP
$this->parameters =
'[
{
"name" : "Username",
"identifier" : "u"
}
]';
```
####Optional parameters
Here is a list of optional parameters for the input :
Parameter Name | Parameter values | Description
---------------|------------------|------------
type|text, number, list, checkbox| Type of the input, default is text
required| true | Set this if you want your attribute to be required
values| [ {"name" : option1Name, "value" : "option1Value"}, ...] | Values list, required with the 'list' type
