Issue unlocking a trezor

app.py

from flask import Flask, render_template_string, request, redirect
from hwilib import commands
from hwilib.devices import trezor

app = Flask(__name__)

template = """
<div>Locked? {{ locked }}</div>
<form action="/" method="post">
    <label for="pin">Pin:</label>
    <input type="text" id="pin" name="pin">
    <button type="submit">Unlock Trezor</button>
</form>
"""

@app.route('/', methods=['GET', 'POST'])
def home():
    devices = commands.enumerate()
    if request.method == 'GET':
        for device in devices:
            if device['type'] == 'trezor':
                locked = device['needs_pin_sent']
                if locked:
                    client = trezor.TrezorClient(device['path'])
                    client.prompt_pin()
                break
        return render_template_string(template, locked=locked)
    else:
        for device in devices:
            if device['type'] == 'trezor':
                client = trezor.TrezorClient(device['path'])
                result = client.send_pin(request.form['pin'])['success']
                print("Unlocked?", result)
        return redirect('/')

if __name__ == '__main__':
    app.run()

cli.py

from hwilib import commands
from hwilib.devices import trezor

devices = commands.enumerate()

for device in devices:
    if device['type'] == 'trezor':
        client = trezor.TrezorClient(device['path'])
        print(device['path'])

client.prompt_pin()
pin = input('enter pin: ')
print(client.send_pin(pin))

This works:

from hwilib import commands
from hwilib.devices import trezor

devices = commands.enumerate()

for device in devices:
    if device['type'] == 'trezor':
        client = trezor.TrezorClient(device['path'])
        print(device['path'])

client.prompt_pin()
# del client

pin = input('enter pin: ')
print(repr(pin))

devices = commands.enumerate()
for device in devices:
    if device['type'] == 'trezor':
        print(device['path'])
        client = trezor.TrezorClient(device['path'])

print(client.send_pin(pin))

But if you uncomment the del client it fails in exactly the same way as the UI.

Also, this works:

from flask import Flask, render_template_string, request, redirect
from hwilib import commands
from hwilib.devices import trezor

app = Flask(__name__)

template = """
<div>Locked? {{ locked }}</div>
<form action="/" method="post">
    <label for="pin">Pin:</label>
    <input type="text" id="pin" name="pin">
    <button type="submit">Unlock Trezor</button>
</form>
"""

devices = commands.enumerate()
for device in devices:
    if device['type'] == 'trezor':
        client = trezor.TrezorClient(device['path'])
        break

@app.route('/', methods=['GET', 'POST'])
def home():
    devices = commands.enumerate()
    if request.method == 'GET':
        for device in devices:
            if device['type'] == 'trezor':
                locked = device.get('needs_pin_sent', False)
                if locked:
                    client.prompt_pin()
                break
        return render_template_string(template, locked=locked)
    else:
        for device in devices:
            if device['type'] == 'trezor':
                result = client.send_pin(request.form['pin'])['success']
                print('success?', result)
        return redirect('/')

if __name__ == '__main__':
    app.run()

Just has 1 TrezorClient instance.

So in some circumstances you can re-instantiate the TrezorClient (cli.py here) but you can't delete the client prompted the pin, re-instantiate and send the pin.

Threading problem if anyone ever comes across this. Flask runs handlers in threads by default and HWI isn't thread-safe.