feat(api): Descriptive error messages (#21 - @AaronBenDaniel)

Co-authored-by: AaronBenDaniel <144371000+AaronBenDaniel@users.noreply.github.com>

.gitignore

@@ -4,3 +4,4 @@ venv
 data
 *ipynb
 build
+.vscode

src/api/src/create_book.py

@@ -111,9 +111,6 @@ async def retrieve_story(story_id: int, cookies: Optional[dict] = None) -> dict:
         async with session.get(
             f"https://www.wattpad.com/api/v3/stories/{story_id}?fields=tags,id,title,createDate,modifyDate,language(name),description,completed,mature,url,isPaywalled,user(username),parts(id,title),cover"
         ) as response:
-            if not response.ok:
-                if response.status in [404, 400]:
-                    return {}
             response.raise_for_status()
 
             body = await response.json()
@@ -132,9 +129,6 @@ async def fetch_part_content(part_id: int, cookies: Optional[dict] = None) -> st
         async with session.get(
             f"https://www.wattpad.com/apiv2/?m=storytext&id={part_id}"
         ) as response:
-            if not response.ok:
-                if response.status in [404, 400]:
-                    return ""
             response.raise_for_status()
 
             body = await response.text()
@@ -151,9 +145,6 @@ async def fetch_cover(url: str, cookies: Optional[dict] = None) -> bytes:
         else ClientSession(headers=headers, cookies=cookies)
     ) as session:  # Don't cache requests with Cookies.
         async with session.get(url) as response:
-            if not response.ok:
-                if response.status in [404, 400]:
-                    return bytes()
             response.raise_for_status()
 
             body = await response.read()

src/api/src/main.py

@@ -1,8 +1,14 @@
+"""WattpadDownloader API Server."""
+
 from typing import Optional
+import tempfile
 from pathlib import Path
+from io import BytesIO
 from enum import Enum
-from fastapi import FastAPI
+from aiohttp import ClientResponseError
+from fastapi import FastAPI, Request
 from fastapi.responses import FileResponse, HTMLResponse, StreamingResponse
+from fastapi.staticfiles import StaticFiles
 from ebooklib import epub
 from create_book import (
     retrieve_story,
@@ -13,9 +19,6 @@ from create_book import (
     wp_get_cookies,
     fetch_story_id,
 )
-import tempfile
-from io import BytesIO
-from fastapi.staticfiles import StaticFiles
 
 app = FastAPI()
 BUILD_PATH = Path(__file__).parent / "build"
@@ -36,6 +39,28 @@ def home():
     return FileResponse(BUILD_PATH / "index.html")
 
 
+@app.exception_handler(ClientResponseError)
+def download_error_handler(request: Request, exception: ClientResponseError):
+    match exception.status:
+        case 400 | 404:
+            return HTMLResponse(
+                status_code=404,
+                content='This story does not exist, or has been deleted. Support is available on the <a href="https://discord.gg/P9RHC4KCwd" target="_blank">Discord</a>',
+            )
+        case 429:
+            # Rate-limit by Wattpad
+            return HTMLResponse(
+                status_code=429,
+                content='The website is overloaded. Please try again in a few minutes. Support is available on the <a href="https://discord.gg/P9RHC4KCwd" target="_blank">Discord</a>',
+            )
+        case _:
+            # Unhandled error
+            return HTMLResponse(
+                status_code=500,
+                content='Something went wrong. Yell at me on the <a href="https://discord.gg/P9RHC4KCwd" target="_blank">Discord</a>',
+            )
+
+
 @app.get("/download/{download_id}")
 async def handle_download(
     download_id: int,
@@ -44,7 +69,6 @@ async def handle_download(
     username: Optional[str] = None,
     password: Optional[str] = None,
 ):
-
     if username and not password or password and not username:
         return HTMLResponse(
             status_code=422,
@@ -69,10 +93,11 @@ async def handle_download(
         case DownloadMode.part:
             story_id = await fetch_story_id(download_id, cookies)
 
-    metadata = await retrieve_story(story_id, cookies)
     book = epub.EpubBook()
 
+    metadata = await retrieve_story(story_id, cookies)
     set_metadata(book, metadata)
+
     await set_cover(book, metadata, cookies=cookies)
 
     async for title in add_chapters(