# Using Custom Entity Types

Custom types allow integrations to receive any data that can be defined with a regular expression. To use a custom type you must define the custom type in your configuration file.

## Define Custom Type in Config

In the example below we setup an integration configuration that identifies strings that match a special hostname naming convention.

{% code title="config/config.js" %}

```javascript
{
    name: "Hostname Lookup",
    acronym: "HOST",
    description: "A sample integration that uses a custom regex to lookup hostnames and IPs",
    entityTypes: ['IPv4'],
    customTypes:[
        {
            key: 'hostname',
            regex: /[a-z]+_host/
        }
    ]
}
```

{% endcode %}

## Test for Custom Type

Now in the main module's `doLookup` method we can test if the type is `custom` or `IPv4` and take the appropriate action.

{% code title="integration.js" %}

```javascript
function doLookup(entities, options, cb){
    let lookupResults = [];
    async.each(entities, function(entity, next){
        if(entity.type === 'IPv4'){
            // do IPv4 lookup logic here
            next(null);
        }else if(entity.type === 'custom'){
            // do hostname lookup logic here
            next(null);
        }
    }, function(err){
        cb(err, lookupResults);
    });    
}
```

{% endcode %}

{% hint style="info" %}
Note that since the only custom type we defined is `hostname` we know that if the `type` property is `custom` then the entity must be a hostname entity.
{% endhint %}

## Multiple Custom Types

If you have defined multiple custom types you can use javascript's `Array.indexOf` to test for specific types.

For example, if we have defined the custom types `hostnameLinux` and `hostnameWindows` we could test for the entity type in our `doLookup` method using the following:

{% code title="integration.js" %}

```javascript
function doLookup(entities, options, cb){
    let lookupResults = [];
    async.each(entities, function(entity, next){
        if(entity.types.indexOf('custom.hostnameLinux') >= 0){
            // do hostnameLinux lookup logic here
            next(null);
        }else {
            // do hostnameWindows lookup here 
            next(null);
        }
    }, function(err){
        cb(err, lookupResults);
    });    
}
```

{% endcode %}

{% hint style="info" %}
Note that custom types are prepended with `custom.`. This means if you want to check for the custom type `hostnameLinux` you must look for the type `custom.hostnameLinux`. Likewise, `hostnameWindows` would be stored in the `types` property as `custom.hostnameWindows`.
{% endhint %}