Adding Whisper model validation.

software/source/server/services/stt/local-whisper/stt.py

@@ -5,11 +5,11 @@ Defines a function which takes a path to an audio file and turns it into text.
 from datetime import datetime
 import os
 import contextlib
+import platform
 import tempfile
 import shutil
 import ffmpeg
 import subprocess
-
 import urllib.request
 
 
@@ -56,21 +56,92 @@ def install(service_dir):
         print("Whisper Rust executable already exists. Skipping build.")
 
     WHISPER_MODEL_PATH = os.path.join(service_dir, "model")
-
     WHISPER_MODEL_NAME = os.getenv("WHISPER_MODEL_NAME", "ggml-tiny.en.bin")
+    while not valid_model(WHISPER_MODEL_PATH, WHISPER_MODEL_NAME):
+        print(f"Downloading Whisper model '{WHISPER_MODEL_NAME}'.")
         WHISPER_MODEL_URL = os.getenv(
             "WHISPER_MODEL_URL",
             "https://huggingface.co/ggerganov/whisper.cpp/resolve/main/",
         )
-
-    if not os.path.isfile(os.path.join(WHISPER_MODEL_PATH, WHISPER_MODEL_NAME)):
         os.makedirs(WHISPER_MODEL_PATH, exist_ok=True)
         urllib.request.urlretrieve(
             f"{WHISPER_MODEL_URL}{WHISPER_MODEL_NAME}",
             os.path.join(WHISPER_MODEL_PATH, WHISPER_MODEL_NAME),
         )
     else:
-        print("Whisper model already exists. Skipping download.")
+        print(f"Whisper model '{WHISPER_MODEL_NAME}' installed.")
+
+
+def valid_model(model_path: str, model_file: str) -> bool:
+    # Try to validate model through cryptographic hash comparison
+
+    model_file_path = os.path.join(model_path, model_file)
+    if not os.path.isfile(model_file_path):
+        return False
+
+    # Download details file and get hash
+    details_file = f"https://huggingface.co/ggerganov/whisper.cpp/raw/main/{model_file}"
+    try:
+        with urllib.request.urlopen(details_file) as response:
+            body_bytes = response.read()
+    except:
+        print("Internet connection not detected. Skipping validation.")
+        return True
+
+    lines = body_bytes.splitlines()
+    colon_index = lines[1].find(b':')
+    details_hash = lines[1][colon_index + 1:].decode()
+
+    # Generate model hash using native commands
+    model_hash = None
+    system = platform.system()
+    if system == 'Darwin':
+        shasum_path = shutil.which('shasum')
+        model_hash = subprocess.check_output(
+            f"{shasum_path} -a 256 {model_file_path} | cut -d' ' -f1",
+            text=True,
+            shell=True
+        )
+    elif system == 'Linux':
+        sha256sum_path = shutil.which('sha256sum')
+        model_hash = subprocess.check_output(
+            f"{sha256sum_path} {model_file_path} | cut -d' ' -f1",
+            text=True,
+            shell=True
+        )
+    elif system == 'Windows':
+        comspec = os.getenv("COMSPEC")
+        if comspec.endswith('cmd.exe'): # Most likely
+            certutil_path = shutil.which('certutil')
+            first_op = f"{certutil_path} -hashfile {model_file_path} sha256"
+            second_op = 'findstr /v "SHA256 CertUtil"' # Prints only lines that do not contain a match.
+            model_hash = subprocess.check_output(f"{first_op} | {second_op}", text=True, shell=True)
+        else:
+            first_op = f"Get-FileHash -LiteralPath {model_file_path} -Algorithm SHA256"
+            subsequent_ops = "Select-Object Hash | Format-Table -HideTableHeaders | Out-String"
+            model_hash = subprocess.check_output([
+                'pwsh',
+                '-Command',
+                f"({first_op} | {subsequent_ops}).trim().toLower()"
+                ],
+                text=True
+            )
+    else:
+        print(f"System '{system}' not supported. Skipping validation.")
+        return True
+
+    if details_hash == model_hash.strip():
+        print(f"Whisper model '{model_file}' file is valid.")
+    else:
+        msg = f'''
+            The model '{model_file}' did not validate. STT may not function correctly.
+            The model path is '{model_path}'.
+            Manually download and verify the model's hash to get better functionality.
+            Continuing.
+        '''
+        print(msg)
+
+    return True
 
 
 def convert_mime_type_to_format(mime_type: str) -> str: