👷🏻‍♀️ make sources something to configure

config.py.example

@@ -1,22 +1,56 @@
 import os
 import random
 import string
+from datetime import datetime, timedelta
+
 
 def random_choices(population, k):
     """Emulate random.choices for Python < 3.6"""
     return [random.choice(population) for _ in range(k)]
 
+
+def mp3_sources(data_dir, pattern, kbits):
+    def start_time_for_source_fn(fn):
+        return datetime.strptime(fn, pattern)
+
+    def length_for_source_fn(fn):
+        size = os.stat(os.path.join(data_dir, fn)).st_size
+        length = timedelta(minutes=size / (1000*kbits/8) / 60)
+        return length
+
+    # Get a sorted list of all source files with start time and length
+    sources = []
+    for fn in os.listdir(data_dir):
+        try:
+            start_time = start_time_for_source_fn(fn)
+            length = length_for_source_fn(fn)
+            sources.append({'fn': os.path.join(data_dir, fn), 'start_time': start_time, 'length': length})
+        except ValueError:
+            pass
+    return sources
+
+
 class Config:
     SECRET_KEY = os.environ.get('SECRET_KEY') or \
             ''.join(random_choices(string.ascii_letters, k=20))
-    DATA_DIR   = os.environ.get('DATA_DIR') or '/var/tmp/prolefeeder-test-data'
     OUT_DIR    = os.environ.get('OUT_DIR') or '/var/tmp/prolefeeder-test-out'
     MAX_LENGTH = os.environ.get('MAX_LENGTH') or 180
-    KBITS      = os.environ.get('KBITS') or 128
 
     DEBUG      = False
 
-    if not os.path.exists(DATA_DIR):
-        raise RuntimeError("DATA_DIR does not exist")
     if not os.path.exists(OUT_DIR):
         raise RuntimeError("OUT_DIR does not exist")
+
+    # Here's the interesting part: configuring the source.
+    #
+    # We need to return a list of dicts of source files with metadata, e.g.
+    # [ {"fn": "/path/to/foo-20:01.mp3", "start_time": datetime(...), "length": timedelta(hours=1)} ]
+
+    data_dir   = os.environ.get('DATA_DIR') or '/var/tmp/prolefeeder-test-data'
+    kbits      = os.environ.get('KBITS') or 128
+    pattern    = 'qfhi-%Y%m%d-%H%M.mp3'
+
+    if not os.path.exists(data_dir):
+        raise RuntimeError("DATA_DIR does not exist")
+
+    SOURCES = mp3_sources(data_dir, pattern, kbits)

generate-test-data.py

@@ -10,7 +10,7 @@ def generate_test_file(fn, delta):
         'ffmpeg',
         '-f', 'lavfi',
         '-i', 'sine=frequency=1000:duration=%d' % delta.total_seconds(),
-        '-b:a', '%dk' % Config.KBITS,
+        '-b:a', '%dk' % Config.kbits,
         fn
     ])
 
@@ -21,7 +21,7 @@ delta = timedelta(hours=1)
 
 t = start
 while t < end:
-    fn = os.path.join(Config.DATA_DIR, 'qfhi-{:04d}{:02d}{:02d}-{:02d}{:02d}.mp3'.format(
+    fn = os.path.join(Config.data_dir, 'qfhi-{:04d}{:02d}{:02d}-{:02d}{:02d}.mp3'.format(
             t.year, t.month, t.day, t.hour, t.minute))
     print(fn)
     generate_test_file(fn, delta)

prolefeeder.py

@@ -86,24 +86,9 @@ def download_file(filename):
 def prepare_download(form):
     """Prepare a download given the user's request form"""
 
-    def start_time_for_source_fn(fn):
-        return datetime.strptime(fn, 'qfhi-%Y%m%d-%H%M.mp3')
-
-    def length_for_source_fn(fn):
-        size = os.stat(os.path.join(app.config['DATA_DIR'], fn)).st_size
-        length = timedelta(minutes=size / (1000*app.config['KBITS']/8) / 60)
-        return length
-
     # Get a sorted list of all source files with start time and length
-    sources = []
-    for fn in os.listdir(app.config['DATA_DIR']):
-        try:
-            start_time = start_time_for_source_fn(fn)
-            length = length_for_source_fn(fn)
-            sources.append({'fn': fn, 'start_time': start_time, 'length': length})
-        except ValueError:
-            pass
-    sources = sorted(sources, key=lambda s: s['start_time'])
+    sources = sorted(Config.SOURCES, key=lambda s: s['start_time'])
+    print(sources)
 
     # Only interested in the source files from the start file
     start_index = None
@@ -128,8 +113,7 @@ def prepare_download(form):
     c = [
         'ffmpeg', '-y',
         '-ss', str(ss),
-        '-i', 'concat:' + '|'.join(
-            [os.path.join(app.config['DATA_DIR'], s['fn']) for s in sources]),
+        '-i', 'concat:' + '|'.join(s['fn'] for s in sources),
         '-codec', 'copy',
         '-t', str(form.length.data * 60),
         os.path.join(app.config['OUT_DIR'], output_filename)