# Refreshing live data layers

It's common to have data update on a regular basis, such as every week or every month. Instead of having to re-upload and style the new data, it can be very convenient to simply refresh a layer using a new data source.

{% hint style="warning" %}
A layer must have finished uploading successfully before it can be refreshed
{% endhint %}

## Refreshing a layer with a file

{% hint style="info" %}
Refreshing a file is a single function call using the `felt-python` library.
{% endhint %}

Just like [regular file uploads](/rest-api/uploading-files-and-urls.md), refreshing a layer with a new file is a two-step process:

### 1. Request a refresh via the Felt API

Perform a `POST` request to receive an S3 presigned URL which you can later upload your files to:

{% tabs %}
{% tab title="Python" %}

```python
import requests

# Your API token should look like this:
# api_token = "felt_pat_ABCDEFUDQPAGGNBmX40YNhkCRvvLI3f8/BCwD/g8"
api_token = "<YOUR_API_TOKEN>"
map_id = "<YOUR_MAP_ID>"
layer_id = "<YOUR_LAYER_ID>"

r = requests.post(
  f"http://felt.com/api/v2/maps/{map_id}/layers/{layer_id}/refresh",
  headers={"Authorization": f"Bearer {api_token}"}
)
assert r.ok
presigned_upload = r.json()
```

{% endtab %}

{% tab title="felt-python" %}

```python
import os

from felt_python import refresh_file_layer

# Setting your API token as an env variable can save
# you from repeating it in every function call
os.environ["FELT_API_TOKEN"] = "<YOUR_API_TOKEN>"

map_id = "<YOUR_MAP_ID>"
layer_id = "<YOUR_LAYER_ID>"
new_file_name = "<PATH_TO_NEW_FILE>"

refresh_file_layer(
    map_id=map_id,
    layer_id=layer_id,
    file_name=new_file_name
)
```

{% endtab %}
{% endtabs %}

### 2. Upload your file(s) to Amazon s3

{% tabs %}
{% tab title="Python" %}

```python
# This code is a continuation of the previous Python code block
# and assumes you already have a "presigned_upload" variable
url = presigned_upload["url"]
presigned_attributes = presigned_upload["presigned_attributes"]
# A 204 response indicates that the upload was successful
with open(YOUR_FILE_WITH_EXTENSION, "rb") as file_obj:
    output = requests.post(
        url,
        # Order is important, file should come at the end
        files={**presigned_attributes, "file": file_obj},
    )
```

{% endtab %}

{% tab title="felt-python" %}

```python
# Nothing! Uploading a file is a single step with the felt-python library
```

{% endtab %}
{% endtabs %}

## Refreshing a layer with a URL

Similar to [a URL upload](/rest-api/uploading-files-and-urls.md), refreshing an existing URL layer is just a matter of making a single `POST` request:

{% tabs %}
{% tab title="curl" %}

```bash
# Your API token and map ID should look like this:
# FELT_API_TOKEN="felt_pat_ABCDEFUDQPAGGNBmX40YNhkCRvvLI3f8/BCwD/g8"
FELT_API_TOKEN="<YOUR_API_TOKEN>"
MAP_ID="<YOUR_MAP_ID>"
LAYER_ID="<YOUR_LAYER_ID>"

curl -L \
  -X POST \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer ${FELT_API_TOKEN}" \
  "https://felt.com/api/v2/maps/${MAP_ID}/layers/${LAYER_ID}/refresh"
```

{% endtab %}

{% tab title="Python" %}

```python
import requests

# Your API token and map ID should look like this:
# api_token = "felt_pat_ABCDEFUDQPAGGNBmX40YNhkCRvvLI3f8/BCwD/g8"
api_token = "<YOUR_API_TOKEN>"
map_id = "<YOUR_MAP_ID>"
layer_id = "<YOUR_LAYER_ID>"

r = requests.post(
  f"http://felt.com/api/v2/maps/{map_id}/layers/{layer_id}/refresh",
  headers={"Authorization": f"Bearer {api_token}"}
)
assert r.ok
print(r.json())
```

{% endtab %}

{% tab title="felt-python" %}

```python
from felt_python import refresh_url_layer

refresh_url_layer(map_id, layer_id)
```

{% endtab %}
{% endtabs %}


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