pfalcon/notes-pico

Flask Notes sample application ported to the Pycopy's picoweb web micro-framework

notes-pico

Notes Pico is a simple note-taking web application. It was originally written by Charles Leifer as a demo of how to write a simple, but slick web application using the Flask web micro-framework. The application is described in the blog post http://charlesleifer.com/blog/saturday-morning-hack-a-little-note-taking-app-with-flask/ . Notes Pico is a port of this application to the [Picoweb](https://github.com/pfalcon/picoweb/) web pico-framework for Pycopy (https://github.com/pfalcon/pycopy), a minimalist Python implementation. It was ported by Paul Sokolovsky.

Deploying on Pycopy "Unix" version

To install and run the application, you should install Pycopy "Unix" port as described at https://github.com/pfalcon/pycopy . Once you have pycopy executable in your PATH (recommended, but not strictly necessary), change directory to where you want to install the app (~/tmp/ should be good for a quick test) and install notes-pico package:

pycopy -m upip install -p app notes-pico

app (argument of -p option) is a subdirectory into which to install the application. To run the app, execute:

MICROPYPATH=app pycopy -m notes_pico

This will initialize note storage and output a URL to open in a browser:

* Running on http://127.0.0.1:8081/

Open the link and start adding notes (after typing text press "Add note" button or press Ctrl+Enter). Note that Picoweb port is intended to be simple and low-resource, so supports only plain-text notes, unlike the original Flask application.

Deploying on embedded Pycopy targets

Notes Pico can also run on "embedded" (microcontroller) Pycopy targets with networking capabilities and suitable heap size (TBC). As Notes Pico is full-stack application and contains relatively a lot of code, the only realistic way to deploy it on such systems is using "frozen bytecode" approach, where pre-compiled Python modules are made part of the binary firmware image to flash on the target. Instructions below use Pycopy ESP8266 port as an example.

1. cd pycopy/ports/esp8266
2. pycopy -m upip install -p modules notes-pico
3. make
4. make deploy (see README in the directory for more params)
5. Boot ESP8266 module, run following commands at the device prompt.
6. import notes_pico.__main__
7. notes_pico.__main__.main(host="0.0.0.0")
8. Connect with a web browser to http://`DEVICE_IP:8081, where `DEVICE_IP is an IP address of ESP8266 device. (Consult Pycopy ESP8266 port documentation for network connection setup.)

Storage backends

Notes Pico supports 3 storage backends:

• BTree
• Filesystem
• SQLite3

As a first step towards portability to Pycopy microcontroller versions, the default backend for the package installed from PyPI via the commands in the previous section is BTree database. The notes are stored in notes.db database file of the current directory, in BerkeleyDB 1.x format.

If you would like to try filesystem/SQLite3 backend, you'll need to checkout https://github.com/pfalcon/notes-pico and edit file notes_pico/config.py. The repository has a convenience Makefile to install dependencies and run the application, similar to the effect achieved by the commands above.

Known issues and limitations

As mentioned above, Picoweb port of the application supports only plain-text notes, no formatting, images or videos.

Embedded targets support is experimental, added in version 0.8.

notes-pico's Issues

micropython-logging is missing in upip package dependencies

I was following the readme, but I had to install additional dependency to be able to start the server, after step #2 micropython -m upip install -p modules notes-pico:
micropython -m upip install -p modules micropython-logging

Always 404 on Arch Linux x86_64

From micropython/micropython#836 (comment) by @dpgeorge:

@pfalcon Okay, I can verify that the fix to select works. But notes-pico (actually picoweb) returns 404 always, I think because of bytes/str difference, trying to compare requested b'/' with '/'.

Running on Unix: AttributeError: 'module' object has no attribute 'deque'

Following the instructions to run the app on Unix, I got this traceback. Probably this is not an issue on notes_pico but rather for picoweb or uasyncio ? Maybe there are some version incompatibilities involved?

Traceback (most recent call last):
  File "app/notes_pico/__main__.py", line 21, in <module>
  File "app/notes_pico/__main__.py", line 18, in main
  File "app/picoweb/__init__.py", line 283, in run
  File "app/uasyncio/core.py", line 224, in get_event_loop
  File "app/uasyncio/__init__.py", line 21, in __init__
  File "app/uasyncio/core.py", line 30, in __init__
AttributeError: 'module' object has no attribute 'deque'

I tried it on Ubuntu 16.04 running inside WSL and Ubuntu Mate on a Rasperry Pi...