changed responses into simple zero arg lambda, remove Response object from flask limiter error message, add else to getter/adder, ID validation to YouTube stream

I was noticing that a lot of the Responses I was creating were literal duplicates, so I decided to move them all into a function so I could change them all at will. This could support optional args later so I could generate better and more concise Responses.

app/sound.py

@@ -8,6 +8,13 @@ import re
 import json
 import subprocess
 
+# Selection of Lambdas for creating new responses
+# Not sure if Responses change based on Request Context, but it doesn't hurt.
+getBadRequest = lambda : Response('Bad request', status=400, mimetype='text/plain')
+getNotImplemented = lambda : Response('Not implemented', status=501, mimetype='text/plain')
+getInvalidID = lambda : Response('Invalid ID', status=400, mimetype='text/plain')
+getNotDownloaded = lambda : Response('Media not yet downloaded', status=400, mimetype='text/plain')
+
 # Retrieves the YouTubeAudio object relevant to the mediaid if available. If not, it facilitates the creation and writing of one.
 # Also helps with access times.
 def get_youtube(mediaid):
@@ -15,13 +22,14 @@ def get_youtube(mediaid):
     if audio is not None:
         audio.access()
         return audio # sets the access time to now
-    audio = YouTubeAudio(id=mediaid)
-    audio.fill_metadata()
-    audio.download()
-    # Commit and save new audio object into the database
-    db.session.add(audio)
-    db.session.commit()
-    return audio
+    else:
+            audio = YouTubeAudio(id=mediaid)
+            audio.fill_metadata()
+            audio.download()
+            # Commit and save new audio object into the database
+            db.session.add(audio)
+            db.session.commit()
+            return audio
 
 # Under the request context, it grabs the same args needed to decide whether the stream has been downloaded previously
 # It applies rate limiting differently based on service, and whether the stream has been accessed previously
@@ -37,17 +45,20 @@ def downloadLimiter():
 
 # Streams back the specified media back to the client
 @app.route('/stream/<service>/<mediaid>')
-@limiter.limit(downloadLimiter, error_message=Response('Rate limit hit', status=429, mimetype='text/plain'))
+@limiter.limit(downloadLimiter, error_message='Rate Limit Hit')
 def stream(service, mediaid):
     if service == 'youtube':
-        audio = get_youtube(mediaid)
-        return send_file(audio.getPath(alt=True), attachment_filename=audio.filename)
+        if YouTubeAudio.isValid(mediaid):
+            audio = get_youtube(mediaid)
+            return send_file(audio.getPath(alt=True), attachment_filename=audio.filename)
+        else:
+            return getInvalidID()
     elif service == 'soundcloud':
-        return Response('Not implemented', status=501, mimetype='text/plain')
+        return getNotImplemented()
     elif service == 'spotify':
-        return Response('Not implemented', status=501, mimetype='text/plain')
+        return getNotImplemented()
     else:
-        return Response('Bad request', status=400, mimetype='text/plain')
+        return getBadRequest()
 
 # Returns the duration of a specific media
 @app.route('/duration/<service>/<mediaid>')
@@ -56,11 +67,11 @@ def duration(service, mediaid):
         duration = get_youtube(mediaid).duration
         return Response(str(duration), status=200, mimetype='text/plain')
     elif service == 'soundcloud':
-        return Response('Not implemented', status=501, mimetype='text/plain')
+        return getNotImplemented()
     elif service == 'spotify':
-        return Response('Not implemented', status=501, mimetype='text/plain')
+        return getNotImplemented()
     else:
-        return Response('Bad request', status=400, mimetype='text/plain')
+        return getBadRequest()
 
 # Returns a detailed JSON export of a specific database entry.
 # Will not create a new database entry where one didn't exist before.
@@ -70,14 +81,14 @@ def status(service, mediaid):
         audio = YouTubeAudio.query.get(mediaid)
         if audio is None:
             if YouTubeAudio.isValid(mediaid):
-                return Response('Media not yet downloaded', status=400, mimetype='text/plain')
+                return getNotDownloaded()
             else:
-                return Response('Invalid ID', status=400, mimetype='text/plain')
+                return getInvalidID()
         else:
             return Response(audio.toJSON(), status=200, mimetype='application/json')
     elif service == 'soundcloud':
-        return Response('Not implemented', status=501, mimetype='text/plain')
+        return getNotImplemented()
     elif service == 'spotify':
-        return Response('Not implemented', status=501, mimetype='text/plain')
+        return getNotImplemented()
     else:
-        return Response('Bad request', status=400, mimetype='text/plain')
+        return getBadRequest()