# Use a header as an object key in Apollo Connector Mapping?
**URL:** https://community.apollographql.com/t/use-a-header-as-an-object-key-in-apollo-connector-mapping/8853
**Category:** Connectors
**Tags:** connectors
**Created:** [April 4, 2025, 7:03pm UTC](https://community.apollographql.com/t/use-a-header-as-an-object-key-in-apollo-connector-mapping/8853 "2025-04-04T19:03:39Z")
**Posts on this page:** 8
**Page:** 1
### Author:  [@andywgarcia](https://community.apollographql.com/u/andywgarcia)
#### Post date: [April 4, 2025, 7:03pm UTC](https://community.apollographql.com/t/use-a-header-as-an-object-key-in-apollo-connector-mapping/8853/1 "2025-04-04T19:03:39Z")
I need to use a header value `AcceptLanguage` as a reference for a key value in a mapping response.
Given the following REST response
```auto
{
"data": {
"item": {
"details": {
"latest": {
"variation": {
"id": "args id",
"props": [
{
"key": "variant-name",
"val": {
"en-US": "en us version of the val"
}
}
]
}
}
}
}
}
}
```
And the following variables
```auto
{
"$args": {
"id": "arg id"
},
"$this": {
"headers": {
"AcceptLanguage": "en-US"
}
}
}
```
And the following mapping
```auto
$.data.item.details.latest.variation {
id
props -> first.val {
key: $this.headers.AcceptLanguage
}
}
```
I currently get the following response
```auto
{
"id": "args id",
"key": "en-US"
}
```
However, I am wanting it to be
```auto
{
"id": "args id",
"key": "en us version of the val"
}
```
How can I use the header as a reference to a specific field in the response object?
Things I have tried:
```auto
$.data.item.details.latest.variation {
id
props -> first.val {
key: $($this.headers.AcceptLanguage)
}
}
```
results in
```auto
{
"id": "args id",
"key": "en-US"
}
```
```auto
$.data.item.details.latest.variation {
id
props -> first.val {
key: "$($this.headers.AcceptLanguage)"
}
}
```
fails with error `Property ."$($this.headers.AcceptLanguage)" not found in object`
In a related question, I actually need to have the header be `Accept-Language`, but I haven’t been able to figure out how to escape the `-` character.
---
### Author:  [@Andrew\_McGivery](https://community.apollographql.com/u/Andrew_McGivery)
#### Post date: [April 4, 2025, 7:49pm UTC](https://community.apollographql.com/t/use-a-header-as-an-object-key-in-apollo-connector-mapping/8853/2 "2025-04-04T19:49:24Z")
Hey @andywgarcia !
So this is absolutely something we want you to be able to do and is on our roadmap! Specifically, a `get` method is on our proposed list of arrow methods:
```auto
key: $->get($this.headers.AcceptLanguage)
```
Or a more simple example:
```auto
$->echo({"a": "hello"})->get("a")
```
Additionally, we’re looking at making a new `$request.headers.*` variable available as well which may also fit your use case better if you’d like to take request headers and use them for response mapping.
---
### Author:  [@Andrew\_McGivery](https://community.apollographql.com/u/Andrew_McGivery)
#### Post date: [April 4, 2025, 7:55pm UTC](https://community.apollographql.com/t/use-a-header-as-an-object-key-in-apollo-connector-mapping/8853/3 "2025-04-04T19:55:58Z")
Just replying to add that a possible workaround, if you know all the languages ahead of time, would be to use `match`. Not ideal but might get you through until we have better options!
```auto
$.data.item.details.latest.variation {
id
props -> first.val {
key: $this.headers.AcceptLanguage->match(
["en-US", $.'en-US']
# ... etc
)
}
}
```
---
### Author:  [@andywgarcia](https://community.apollographql.com/u/andywgarcia)
#### Post date: [April 4, 2025, 8:01pm UTC](https://community.apollographql.com/t/use-a-header-as-an-object-key-in-apollo-connector-mapping/8853/4 "2025-04-04T20:01:33Z")
Thank you!
This workaround will do for now.
We are definitely looking forward to the -\>get function
For reference of the second part of the question of `AcceptLanguage` vs `Accept-Language`, it works by just wrapping it in quotes
`$this.headers."Accept-Language"`
---
### Author:  [@andywgarcia](https://community.apollographql.com/u/andywgarcia)
#### Post date: [April 4, 2025, 8:31pm UTC](https://community.apollographql.com/t/use-a-header-as-an-object-key-in-apollo-connector-mapping/8853/5 "2025-04-04T20:31:17Z")
Actually, after putting this in the schema (rather than using it in the playground), there appears to be a discrepancy between the two.
`$this.headers` does not work in the live schema, but it does not work when composing with `rover dev`
---
### Author:  [@lennyburdette](https://community.apollographql.com/u/lennyburdette)
#### Post date: [April 8, 2025, 7:27pm UTC](https://community.apollographql.com/t/use-a-header-as-an-object-key-in-apollo-connector-mapping/8853/6 "2025-04-08T19:27:14Z")
Hey Andy, what is `$this.headers`? The `$this` variable refers to the type the connector is attached to — does your type have a `headers` field?
---
### Author:  [@andywgarcia](https://community.apollographql.com/u/andywgarcia)
#### Post date: [April 8, 2025, 8:59pm UTC](https://community.apollographql.com/t/use-a-header-as-an-object-key-in-apollo-connector-mapping/8853/7 "2025-04-08T20:59:20Z")
This is both mine and ChatGPTs misunderstanding of the mapping. Before I learned that accessing headers from the selection was not a feature that is available yet, it was thought to be the place where I can access header values.
---
### Author:  [@lennyburdette](https://community.apollographql.com/u/lennyburdette)
#### Post date: [April 8, 2025, 9:46pm UTC](https://community.apollographql.com/t/use-a-header-as-an-object-key-in-apollo-connector-mapping/8853/8 "2025-04-08T21:46:01Z")
That explains it! As Andrew mentioned, we’re planning to support `$request` and `$response` variables in the mapping to provide access to headers. It’s partially implemented and should be available in the coming months!