feat: add database connection with modified endpoints

main.py

@@ -1,27 +1,57 @@
-from fastapi import FastAPI
-from .models import UrlPayload
-from .utils import generate_shortcode
+import os
+
+from sqlalchemy.exc import IntegrityError
+from fastapi import FastAPI, HTTPException
+from fastapi.responses import RedirectResponse
+
+from dependencies.models import UrlMapping
+from dependencies.database import database, Base, engine
+from schemas import UrlPayload
+from utils import generate_shortcode
 
 app = FastAPI()
 
-# temporary data store
-url_mapping = {}
+@app.on_event("startup")
+async def startup():
+    await database.connect()
+    Base.metadata.create_all(bind=engine) # TODO: create all tables if not present (ONLY DEVELOPMENT)
+
+@app.on_event("shutdown")
+async def shutdown():
+    await database.disconnect()
+
+
 
 @app.get("/{shortcode}")
-async def get_original_url(shortcode: str):
-    if shortcode in url_mapping:
-        return {"original_url": url_mapping[shortcode]}
+async def redirect_to_original_url(shortcode: str):
+    # TODO: do validation check for valid shortcode
+    if not shortcode:
+        raise HTTPException(status_code=400, detail="Shortcode is not valid")
+
+    query = UrlMapping.__table__.select().where(UrlMapping.shortcode == shortcode)
+    url_mapping = await database.fetch_one(query)
+
+    if url_mapping:
+        return RedirectResponse(url=url_mapping.url, status_code=302)
     else:
         raise HTTPException(status_code=404, detail="Shortcode not found")
 
-
-@app.post("/shorten/")
-async def create_short_url(url_payload: UrlPayload):
-    original_url = url_payload.url
+@app.post("/shorten")
+async def create_url_shortcode(url_payload: UrlPayload):
+    original_url = str(url_payload.url) # convert to string from HttpUrl
     shortcode = generate_shortcode()
 
-    if shortcode in url_mapping:
-        raise HTTPException(status_code=409, detail="Shortcode already in use")
+    try:
+        query = UrlMapping.__table__.insert().values({
+            "url": original_url,
+            "shortcode": shortcode
+        })
+        await database.execute(query)
 
-    url_mapping[shortcode] = str(original_url)
-    return {"shortcode": shortcode, "original_url": original_url}
+        return {"shortcode": shortcode, "original_url": original_url}
+    except IntegrityError as e:
+        if 'shortcode' in str(e):
+            raise HTTPException(status_code=409, detail="Shortcode already in use")
+        else:
+            raise HTTPException(status_code=500, detail="Internal Server Error")
+