FiPy demo server implementation for the BOB project

This is a small demo implementation of a webserver running on the FiPy.

It is intended as a reference backend implementation for a JavaScript based frontend.

Setup

WiFi settings

For easy use I recommend to set up the WLan on the FiPy to be reachable from your PC. All headers are set to communicate with the API without running into problems with CORS.

To setup the WLan open boot.py and set

    _WLAN_SSID = ''
    _WLAN_PASSWORD = ''
    _WLAN_ENCRYPTION = network.WLAN.WPA2

If you need additional options please refer to the PyCom documentation.

The WLan settings are only set in boot.py! The WLan configuration in the JSON file is supposed to be the primary configuration but it'd be annoying to lose the connection while testing.

Installation

Install the pymakr plugin for Atom/VSCode as described here. Afterwards open this folder in your editor and click upload in the pymakr command bar.

If you want to reset your FiPy connect to the REPL and run

import os
os.mkfs('/flash')

How to find the FiPys IP

FiPy REPL

If you have access to the REPL you can find the IP with

import network
w = network.WLAN(id=0)
w.ifconfig()[0]

Using nmap (Linux only)

First open a console window. Find your PCs IP address with

ip addr | grep 'inet '

Then type

nmap -sn [YOUR IP ADDRESS]/24

This will display all devices in your LAN. If one device is called espressif it is your FiPy. If there is no such device listed you have to try all IP addresses.

Configuration via JSON

The API is based around a single JSON file where the settings for your program are stored. The JSON file is structured with sections and subsections e.g.:

{
    "networking": {
        "wlan": {
            "ssid": "Foo",
            "password": "Bar"
        }
    }
}

This block could then be read with a GET request to http://[your_fipy_ip]/api/config/networking/wlan.

Implemented methods

Each url http://[your_fipy_ip]/api/config/[section]/[subsection] implements the methods GET, POST, DELETE and OPTIONS.

GET

As described above the server responds with the JSON block from the file settings.json. If section or subsection are not found it returns a empty JSON object with status 404.

POST

You can write JSON to a section/subsection with an POST request. This overwrites an existing block so make sure you include all keys you need. On success the server returns a JSON object {"status": "saved"}. Try it with

curl -d '{"this": "is", "test": "data"}' http://[your_fipy_ip]]/api/config/test/testdata
curl http://[your_fipy_ip]]/api/config/test/testdata

** In the future a PUT method should be implemented to edit/update a section without overwriting the whole block. **

DELETE

A DELETE request deletes the whole block from the JSON file. On success it returns a JSON object {"status": "deleted"}. If the section/subsection is not found it returns an empty JSON objkect with status code 404. Try it with:

curl -X DELETE http://[your_fipy_ip]]/api/config/test/testdata

Now try deleting it again and display the response header:

curl -I -X DELETE http://[your_fipy_ip]]/api/config/test/testdata

OPTIONS

The options method is needed for the CORS preflight request

Implemented sensors

Currently three sensors are implemented:

• DS1820: Temperature
• HX711: Weight
• BME280: Temperature, Pressure, Humidity (over I2C)

The pins used are set in the file `settings.json'.

Routes

A sensor can be read with a GET request to e.g. http://[your_fipy_ip]]/api/sensors/ds1820.