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# Oracle & HTTP Call

An oracle helps you to do external HTTP calls to an API.

* You can register an oracle with only one line of code:

```
// SYNTAX
oracle(name, permission, base_url).

// EXAMPLE
oracle(coindesk, r, 'api.coindesk.com/v1/bpi').
```

{% hint style="warning" %}

* The oracle`name`must be in *snake\_case* **OR** *camelCase*

* The second parameter should always be**`r`**(only *READ* permission is available ATM)
  {% endhint %}

* Then, you must use the ***get\_http()*** predicate whenever you want to get data from the oracle:

```
// SYNTAX
get_http(oracle_name, path, Output).

// EXAMPLE
prompt :-
    get_http(coindesk, '/currentprice.json', Output),
    set(coindesk, Output).
```

{% hint style="warning" %}
The Output name must be in **PascalCase.**
{% endhint %}