Dealing with Large Audio Files in Flask

2023/06/22

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Are you struggling to send large audio files from your web app to Flask? If you're receiving a "413 (Request Entity Too Large)" error, there are a few things you can try.

First, make sure you've set the Flask app.config['MAX_CONTENT_LENGTH'] to a high enough value. For example, setting it to 36 * 1024 * 1024 (36mb) should work for most audio files.

If that doesn't solve the issue, you can try chunking the audio file into smaller parts before sending it to Flask. Here's an example of how to do it in JavaScript:

const CHUNK_SIZE = 16 * 1024; // 16kb chunks
const file = document.querySelector('input[type="file"]').files[0];
let start = 0;

while (start < file.size) {
  const chunk = file.slice(start, start + CHUNK_SIZE);
  const formData = new FormData();
  formData.append('chunk', chunk);

  // Send the chunk to Flask using fetch or XMLHttpRequest
  // ...

  start += CHUNK_SIZE;
}

On the Flask side, you can receive the chunks and concatenate them into the original file:

@app.route('/upload-audio', methods=['POST'])
def upload_audio():
  file = request.files['chunk']
  chunk = file.read()

  # Append the chunk to the original file
  # ...

  return 'OK'

By chunking the audio file, you can avoid hitting the MAX_CONTENT_LENGTH limit and ensure that your web app can handle large audio files without any issues.