Added support for historical data

README.md

@@ -9,6 +9,7 @@ pip install fear-and-greed
 ```
 
 # Usage example
+## Fetch Current Fear & Greed Index
 
 ```python
 import fear_and_greed
@@ -22,11 +23,37 @@ Returns a three-element namedtuple with (a) the current value of the Fear & Gree
 FearGreedIndex(
     value=31.4266,
     description='fear',
-    last_update=datetime.datetime(2022, 4, 25, 16, 51, 9, 254000, tzinfo=datetime.timezone.utc)),
+    last_update=datetime.datetime(2022, 4, 25, 16, 51, 9, 254000, tzinfo=datetime.timezone.utc),
  )
 ```
 
-Requests to CNN's website are locally [cached](https://pypi.org/project/requests-cache/) for 1m.
+## Fetch Historical Fear & Greed Data
+
+```python
+historical_data = fear_and_greed.historical()
+```
+The historical function provides a list of historical Fear & Greed Index values, each with its corresponding description and timestamp.
+
+```python
+[
+    FearGreedIndex(
+        value=80.0,
+        description='extreme greed',
+        last_update=datetime.datetime(2022, 4, 20, 0, 0, 0, tzinfo=datetime.timezone.utc)
+    ),
+    FearGreedIndex(
+        value=60.5,
+        description='greed',
+        last_update=datetime.datetime(2022, 4, 21, 0, 0, 0, tzinfo=datetime.timezone.utc)
+    )
+]
+...
+```
+
+## Features
+* Fetch the current Fear & Greed Index value along with its description and timestamp.
+* Retrieve historical Fear & Greed Index data to analyze trends.
+* Uses locally [cached](https://pypi.org/project/requests-cache/) requests to CNN's website for 1 minute to minimize network usage.
 
 [![Test workflow](https://github.com/vterron/fear-and-greed/actions/workflows/test.yml/badge.svg)](https://github.com/vterron/fear-and-greed/actions/workflows/test.yml)
 [![PyPI badge](https://img.shields.io/pypi/v/fear-and-greed?color=blue)](https://pypi.org/project/fear-and-greed/)

src/fear_and_greed/__init__.py

@@ -1,3 +1,3 @@
-from .cnn import FearGreedIndex, get
+from .cnn import FearGreedIndex, get, historical
 
 __version__ = "0.4"

src/fear_and_greed/cnn.py

@@ -62,3 +62,28 @@ def get(fetcher: Fetcher = None) -> FearGreedIndex:
         description=response["rating"],
         last_update=datetime.datetime.fromisoformat(response["timestamp"]),
     )
+
+def historical(fetcher: Fetcher = None) -> dict:
+    """Returns CNN's Fear & Greed Index historical data."""
+
+    if fetcher is None:
+        fetcher = Fetcher()
+
+    response = fetcher().get("fear_and_greed_historical", {})
+    fear_greed_historical = []
+
+    if "data" not in response:
+        raise ValueError("No historical data found")
+
+    historical_data = response["data"]
+    for data in historical_data:
+        fear_greed_historical.append(FearGreedIndex(
+            value=data["y"],
+            description=data["rating"],
+            last_update=datetime.datetime.fromtimestamp(data["x"] / 1000),
+        ))
+
+    fear_greed_historical.sort(key=lambda x: x.last_update)
+
+    return fear_greed_historical
+

tests/test_cnn.py

@@ -37,6 +37,34 @@ def test_get(self):
         )
         self.assertEqual(got, want)
 
+    def test_historical(self):
+        with open(FAKE_JSON_RESPONSE_GOLDEN_FILE, "rt") as fd:
+            # Lambda is evaluated lazily, force JSON load while file is open.
+            content = json.load(fd)
+            fake_fetcher = lambda: content
+        got = cnn.historical(fetcher=fake_fetcher)
+
+        self.assertEqual(len(got), 269)
+
+        first_five = [
+            cnn.FearGreedIndex(51.03333333333334, "neutral", datetime.datetime.fromtimestamp(1619395200.0)),
+            cnn.FearGreedIndex(52.79999999999999, "neutral", datetime.datetime.fromtimestamp(1619481600.0)),
+            cnn.FearGreedIndex(54.133333333333326, "neutral", datetime.datetime.fromtimestamp(1619568000.0)),
+            cnn.FearGreedIndex(58.93333333333334, "greed", datetime.datetime.fromtimestamp(1619654400.0)),
+            cnn.FearGreedIndex(49.26666666666667, "neutral", datetime.datetime.fromtimestamp(1619740800.0))
+        ]
+
+        self.assertEqual(got[:5], first_five)
+
+        last_five = [
+            cnn.FearGreedIndex(41.1246, "fear", datetime.datetime.fromtimestamp(1650585600.0)),
+            cnn.FearGreedIndex(40.1512, "fear", datetime.datetime.fromtimestamp(1650672000.0)),
+            cnn.FearGreedIndex(40.1512, "fear", datetime.datetime.fromtimestamp(1650758400.0)),
+            cnn.FearGreedIndex(30.8254, "fear", datetime.datetime.fromtimestamp(1650844800.0)),
+            cnn.FearGreedIndex(30.8254, "fear", datetime.datetime.fromtimestamp(1650903669.254))
+        ]
+
+        self.assertEqual(got[-5:], last_five)
 
 if __name__ == "__main__":
     absltest.main()