Add Jump Start example stock-api-fastapi (#65)

* Add Jump Start example stock-api-fastapi

* Bump app version for release

* Add minimumConnectVersion

Author: cgraham-rs

.github/workflows/extensions.yml

@@ -34,6 +34,7 @@ jobs:
             quarto-stock-report-python: extensions/quarto-stock-report-python/**
             portfolio-dashboard: extensions/portfolio-dashboard/**
             quarto-document: extensions/quarto-document/**
+            stock-api-fastapi: extensions/stock-api-fastapi/**
 
   # Runs for each extension that has changed from `simple-extension-changes`
   # Lints and packages in preparation for tests and and release.

extensions/stock-api-fastapi/README.md

@@ -0,0 +1,16 @@
+# FastAPI Stock Pricing Service
+
+## About this example
+
+An API allows you to turn your models into production services that other tools and teams can use. APIs are a great way for software engineering teams to use your models without translating them into different languages.
+
+
+## Learn more
+
+* [FastAPI Introduction](https://fastapi.tiangolo.com/)
+* [FastAPI Documentation](https://fastapi.tiangolo.com/tutorial/)
+
+## Requirements
+
+* Posit Connect license allows API publishing
+* Python version 3.11 or higher

extensions/stock-api-fastapi/main.py

@@ -0,0 +1,79 @@
+# -*- coding: utf-8 -*-
+import os
+from datetime import date
+from typing import List
+
+import numpy as np
+import pandas as pd
+from fastapi import FastAPI, HTTPException
+from pydantic import BaseModel, Field
+
+prices = pd.read_csv(
+    os.path.join(os.path.dirname(__file__), "prices.csv"),
+    index_col=0,
+    parse_dates=True,
+)
+
+
+def validate_ticker(ticker):
+    if ticker not in prices["ticker"].unique():
+        raise HTTPException(status_code=404, detail="Ticker not found")
+
+
+class Tickers(BaseModel):
+    tickers: list = Field(title="All available stock tickers")
+
+
+class Stock(BaseModel):
+    ticker: str = Field(..., title="Ticker of the stock")
+    price: float = Field(..., title="Latest price of the stock")
+    volatility: float = Field(..., title="Latest volatility of the stock price")
+
+
+class Price(BaseModel):
+    date: date
+    high: float = Field(..., title="High price for this date")
+    low: float = Field(..., title="Low price for this date")
+    close: float = Field(..., title="Closing price for this date")
+    volume: int = Field(..., title="Daily volume for this date")
+    adjusted: float = Field(..., title="Split-adjusted price for this date")
+
+
+app = FastAPI(
+    title="Stocks API",
+    description="The Stocks API provides pricing and volatility data for a "
+    "limited number of US equities from 2010-2018",
+)
+
+
+@app.get("/stocks", response_model=Tickers)
+async def tickers():
+    tickers = prices["ticker"].unique().tolist()
+    return {"tickers": tickers}
+
+
+@app.get("/stocks/{ticker}", response_model=Stock)
+async def ticker(ticker: str):
+    validate_ticker(ticker)
+
+    latest = prices.last_valid_index()
+    ticker_prices = prices[prices["ticker"] == ticker]
+    current_price = ticker_prices["close"][latest:].iloc[0].round(2)
+    current_volatility = np.log(
+        ticker_prices["adjusted"] / ticker_prices["adjusted"].shift(1)
+    ).var()
+
+    return {
+        "ticker": ticker,
+        "price": current_price,
+        "volatility": current_volatility,
+    }
+
+
+@app.get("/stocks/{ticker}/history", response_model=List[Price])
+async def history(ticker: str):
+    validate_ticker(ticker)
+
+    ticker_prices = prices[prices["ticker"] == ticker]
+    ticker_prices.loc[:, "date"] = ticker_prices.index.to_numpy()
+    return ticker_prices.to_dict("records")

extensions/stock-api-fastapi/manifest.json

@@ -0,0 +1,44 @@
+{
+  "version": 1,
+  "locale": "en_US.UTF-8",
+  "metadata": {
+    "appmode": "python-fastapi",
+    "entrypoint": "main"
+  },
+  "extension": {
+    "name": "stock-api-fastapi",
+    "title": "FastAPI Stock Pricing Service",
+    "description": "APIs are a great way for software engineering teams to use your models without translating them into different languages",
+    "homepage": "https://github.com/posit-dev/connect-extensions/tree/main/extensions/stock-api-fastapi",
+    "tags": [],
+    "minimumConnectVersion": "2025.04.0",
+    "version": "1.0.0"
+  },
+  "environment": {
+    "python": {
+      "requires": ">=3.11, <4"
+    }
+  },
+  "python": {
+    "version": "3.11.7",
+    "package_manager": {
+      "name": "pip",
+      "version": "24.2",
+      "package_file": "requirements.txt"
+    }
+  },
+  "files": {
+    "requirements.txt": {
+      "checksum": "9b9389b1c871e9fe179877c446861cd9"
+    },
+    "README.md": {
+      "checksum": "a33766bf7a7ff5fe0b4c9fc5fe583468"
+    },
+    "main.py": {
+      "checksum": "7618d24f4c382163cdd224930e9b24c1"
+    },
+    "prices.csv": {
+      "checksum": "e0bc27e3dd358c360863807e09079985"
+    }
+  }
+}