feat(chart)!: Graphs are now rendered directly through query params, without creating a file.

- The default format is now jpeg instead of png
- Files are now not saved to the folder

Author: Redume

chart/function/create_chart.py

@@ -4,6 +4,7 @@
 """
 from datetime import datetime
 from typing import Optional
+from io import BytesIO
 
 from matplotlib import pyplot as plt
 from scipy.interpolate import make_interp_spline
@@ -13,11 +14,10 @@
 from database.server import Database
 from utils.config.load_config import load_config
 from utils.config.get_dsn import get_dsn
-from function.gen_unique_name import generate_unique_name
 
 config = load_config('config.hjson')
 
-async def create_chart(currency: Currency, db: Database) -> Optional[str]:
+async def create_chart(currency: Currency, db: Database) -> Optional[BytesIO]:
     """
     Generates a currency exchange rate chart based on historical data.
 
@@ -93,12 +93,9 @@ async def create_chart(currency: Currency, db: Database) -> Optional[str]:
     ax.spines['top'].set_visible(False)
     ax.spines['right'].set_visible(False)
 
-    name = await generate_unique_name(
-        f'{currency.from_currency.upper()}_{currency.conv_currency.upper()}',
-        datetime.now()
-    )
-
-    plt.savefig(f'../charts/{name}.png')
+    buf = BytesIO()
+    fig.savefig(buf, format="jpeg", bbox_inches="tight")
     plt.close(fig)
+    buf.seek(0)
 
-    return name
+    return buf

chart/function/gen_unique_name.py

@@ -4,13 +4,9 @@
 The application serves static files, provides endpoints for generating charts,
 and integrates with Plausible Analytics for tracking usage.
 """
-
-import os
-
 import uvicorn
 from fastapi import FastAPI
 from fastapi.exceptions import RequestValidationError
-from starlette.staticfiles import StaticFiles
 
 from utils.lifespan import lifespan
 from utils.config.load_config import load_config
@@ -22,15 +18,11 @@
 app = FastAPI(lifespan=lifespan)
 config = load_config('config.hjson')
 
-if not os.path.exists('../charts'):
-    os.mkdir('../charts')
-
 app.add_exception_handler(
     RequestValidationError,
     custom_validation_exception
 )
 
-app.mount('/static/charts', StaticFiles(directory='../charts/'))
 app.middleware('http')(PlausibleAnalytics())
 
 app.include_router(get_chart.router)

chart/main.py

@@ -8,15 +8,15 @@
 from datetime import datetime
 
 from fastapi import APIRouter, status, Depends, HTTPException, Request
+from fastapi.responses import StreamingResponse
 
 from schemas.currency import Currency
 from function.create_chart import create_chart
-from .get_chart_period import prepare_chart_response
 
 router = APIRouter()
 
-@router.get('/api/getChart/', status_code=status.HTTP_201_CREATED)
-async def get_chart(req: Request, currency: Currency = Depends()) -> dict:
+@router.get('/api/getChart/', status_code=status.HTTP_200_OK)
+async def get_chart(req: Request, currency: Currency = Depends()) -> StreamingResponse:
     """
     Endpoint for retrieving a currency exchange rate chart.
 
@@ -56,6 +56,12 @@ async def get_chart(req: Request, currency: Currency = Depends()) -> dict:
             detail="The start_date cannot be later than the end_date."
         )
 
-    data = await create_chart(currency, req.app.state.db)
+    chart = await create_chart(currency, req.app.state.db)
 
-    return await prepare_chart_response(req, data)
+    if chart is None:
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail='No data found.'
+        )
+
+    return StreamingResponse(chart, media_type="image/jpeg")

chart/routes/get_chart.py

@@ -9,18 +9,19 @@
 from dateutil.relativedelta import relativedelta
 
 from fastapi import APIRouter, status, Request, HTTPException, Depends
+from fastapi.responses import StreamingResponse
 
 from function.create_chart import create_chart
 from schemas.currency import Currency
 
 # pylint: disable=duplicate-code
 router = APIRouter()
 
-@router.get("/api/getChart/{period}", status_code=status.HTTP_201_CREATED)
+@router.get("/api/getChart/{period}", status_code=status.HTTP_200_OK)
 async def get_chart_period(
     req: Request,
     currency: Currency = Depends()
-    ) -> dict:
+) -> StreamingResponse:
     """
     Fetches a chart for a given currency pair and a specific period.
 
@@ -36,8 +37,6 @@ async def get_chart_period(
     :param conv_currency: The target currency in the pair (e.g., 'EUR').
     :param period: The time period for which the chart is requested
     (e.g., 'week', 'month', 'quarter', 'year').
-    :return: A response containing the chart URL or an error message 
-        if parameters are invalid.
     """
     if not currency.from_currency or not currency.conv_currency:
         raise HTTPException(
@@ -66,39 +65,10 @@ async def get_chart_period(
 
     chart = await create_chart(currency, req.app.state.db)
 
-    if not chart:
+    if chart is None:
         raise HTTPException(
             status_code=status.HTTP_400_BAD_REQUEST,
             detail='No data found.'
         )
 
-    return await prepare_chart_response(req, chart)
-
-async def prepare_chart_response(req: Request, chart_name: str) -> dict:
-    """
-    Prepares the response to return the URL of the generated chart.
-
-    If the chart data is not found, 
-        it returns a 404 error with an appropriate message.
-    Otherwise, it returns a URL to access the chart image.
-
-    :param response: The response object used to set status and message.
-    :param request: The request object used 
-        to retrieve details of the incoming request.
-    :param chart_name: The name of the generated chart 
-        (used to build the URL).
-    :return: A dictionary with the chart URL or an error message 
-        if no chart is found.
-    """
-    if not chart_name:
-        raise HTTPException(
-            status_code=status.HTTP_400_BAD_REQUEST,
-            detail='No data found.'
-        )
-
-    host = req.headers.get("host")
-    url_scheme = req.headers.get("X-Forwarded-Proto", req.url.scheme)
-
-    return {
-        'detail': f'{url_scheme}://{host}/static/charts/{chart_name}.png',
-    }
+    return StreamingResponse(chart, media_type="image/jpeg")