# General helper methods
<a name="general-helper-methods"></a>

This page provides additional helper methods inside CloudFront Functions. To use these methods, create a CloudFront function using JavaScript runtime 2.0.

```
import cf from 'cloudfront';
```

For more information, see [JavaScript runtime 2.0 features for CloudFront Functions](functions-javascript-runtime-20.md).

## `edgeLocation` metadata
<a name="edge-location-metadata"></a>

This method requires using the `cloudfront` module.

**Note**  
You can only use this method for viewer-request functions. For viewer-response functions, this method is empty.

Use this JavaScript object to obtain the edge location airport code, expected [Regional Edge Cache](HowCloudFrontWorks.md#CloudFrontRegionaledgecaches) region or the CloudFront server IP address used to handle the request. This metadata is available only the viewer request event trigger.

```
cf.edgeLocation = {
    name: SEA
    serverIp: 1.2.3.4
    region: us-west-2
}
```

The `cf.edgeLocation` object can contain the following:

**name**  
The three-letter [IATA code](https://en.wikipedia.org/wiki/IATA_airport_code) of the edge location that handled the request.

**serverIp**  
The IPv4 or IPv6 address of the server that handled the request.

**region**  
The CloudFront Regional Edge Cache (REC) that the request is *expected* to use if there is a cache miss. This value is not updated in the event that the expected REC is unavailable and a backup REC is used for the request. This doesn't include the Origin Shield location being used, except in cases when the primary REC and the Origin Shield are the same location.

**Note**  
CloudFront Functions isn't invoked a second time when CloudFront is configured to use origin failover. For more information, see [Optimize high availability with CloudFront origin failover](high_availability_origin_failover.md).

## `rawQueryString()` method
<a name="raw-query-string-method"></a>

This method doesn't require the `cloudFront` module.

Use the `rawQueryString()` method to retrieve the unparsed and unaltered query string as a string.

**Request**

```
function handler(event) {
    var request = event.request;
    const qs = request.rawQueryString();
}
```

**Response**

Returns the full query string of the incoming request as a string value without the leading `?`. 
+ If there isn't a query string, but the `?` is present, the functions returns an empty string. 
+ If there isn't a query string and the `?` isn't present, the function returns `undefined`.

**Case 1: Full query string returned (without leading `?`)**  
Incoming request URL: `https://example.com/page?name=John&age=25&city=Boston`  
`rawQueryString()` returns: `"name=John&age=25&city=Boston"`

**Case 2: Empty string returned (when `?` is present but without parameters)**  
Incoming request URL: `https://example.com/page?`  
`rawQueryString()` returns: `""`

**Case 3: `undefined` returned (no query string and no `?`)**  
Incoming request URL: `https://example.com/page`  
`rawQueryString()` returns: `undefined`