# Source aliases

Source aliases are named, portable references to [Data Connection sources](../../data-connection/set-up-source/index.md). By referring to a source by its alias key instead of a specific source identifier, you decouple your function logic from any one source. This keeps your functions portable across environments.

## Import a source

To import a source:

1. Open a TypeScript v2 or Python code repository and navigate to the **Resource imports** panel.

2. Select the **Ontology SDK** tab.

3. Select **Add > Sources**.

   ![The Add dropdown in the Resource imports panel showing the Sources option.](../../../assets/e1deff8cfd1677573f652a1295efe6acd6f1de70108a4d0b97ee7a04a26ddc44.webp)

4. Search for and select the source to import, then choose **Confirm selection**.

## Add a source alias

After importing a source, you can add an alias to it:

1. In the **Resource imports** panel, locate the source under **Sources**.
2. Select **Add alias** below the source name.

   ![The Resource imports panel showing an imported source with an option to add an alias.](../../../assets/a36d6d1bd405bb79f3ef646b18ff7f55623e8d5410c8487c3f978d0971544823.webp)

:::callout{theme="warning"}
Alias keys must be unique within the repository.
:::

## Edit a source alias

To edit an existing source alias, navigate to the **Sources** section in the **Resource imports** panel. Select the pen icon next to the alias to edit it inline.

![The Resource imports panel showing a source alias with an option to edit it.](../../../assets/547d0e05d6f88a506e193422165ce0565c671fd8d44f7740b040a5bc6d20b48b.webp)

## Use a source alias in code

To use a source alias in your function, reference the alias by its key wherever you declare and retrieve the source. Pass the alias key to the `sources` configuration and to `getSource` (TypeScript v2) or `get_source` (Python):

```typescript tab="TypeScript v2"
import { getSource, getHttpsConnection, getFetch } from "@palantir/functions-sources";

export const config = {
    sources: ["demoSource"]
}

async function myExternalFunction(): Promise<string> {
    const source = await getSource("demoSource");
    const { url } = getHttpsConnection(source);
    const fetch = await getFetch(source);

    const response = await fetch(url);

    return response.text();
}
```

```python tab="Python"
from functions.api import function
from functions.sources import get_source


@function(sources=["demoSource"])
def my_external_function() -> str:
    source = get_source("demoSource")
    url = source.get_https_connection().url
    client = source.get_https_connection().get_client()
    response = client.get(url)
    return response.text
```

If you need the resource identifier (RID) of the source that an alias resolves to, use the `Aliases.source` utility in TypeScript v2 or the `source` utility in Python. Read the resolved RID from the `.rid` property:

```typescript tab="TypeScript v2"
import { Aliases } from "@osdk/functions";

const sourceRid = Aliases.source("demoSource").rid;
```

```python tab="Python"
from functions.aliases import source

source_rid = source("demoSource").rid
```

For more information about using sources in functions, including accessing credentials and using pre-configured clients, see [Make API calls from functions](../api-calls/index.md).

## Use source aliases with Marketplace

When you add a function that uses source aliases to a [Marketplace product](../marketplace-functions/index.md), each aliased source appears as a configurable input under **Data connection sources**. Installers can map each input source to an available source in their environment during installation, without needing to modify the function source code.

![A Marketplace product showing a Data Connection source as a configurable input.](../../../assets/e0113eed2a4ea779ff8fb1869ab039f778cec46193cc4d174d506301db05a611.webp)

### Set a description

To help installers understand which source to provide, you can add a description to the source input. Select the source under **Inputs** to open the **Details** panel, then enter a description on the **General** tab.

![The Details panel for a source input showing a description field.](../../../assets/01a808fe73fb4e9e15c4f1a5e9b93e5b3e489217407619cf548783b7f18400e8.webp)

### Installation experience

During installation, installers see the source description and can select a source appropriate for their environment. Marketplace remaps the selected source to the defined alias automatically, so the function code remains untouched.

![The installation view showing a source alias with a description and options to change the source or scope it to a namespace.](../../../assets/00096d43ebb6090b8f7fd096e7438e946e34350decf23da21139e3e78c48026f.webp)