We've written a requests-like library for web interfacing named Adafruit_CircuitPython_Requests. This library allows you to send HTTP/1.1 requests without "crafting" them and provides helpful methods for parsing the response from the server.
# SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT
import adafruit_connection_manager
import board
import busio
from adafruit_wiznet5k.adafruit_wiznet5k import WIZNET5K
from digitalio import DigitalInOut
import adafruit_requests
cs = DigitalInOut(board.D10)
spi_bus = busio.SPI(board.SCK, MOSI=board.MOSI, MISO=board.MISO)
# Initialize ethernet interface with DHCP
radio = WIZNET5K(spi_bus, cs)
# Initialize a requests session
pool = adafruit_connection_manager.get_radio_socketpool(radio)
ssl_context = adafruit_connection_manager.get_radio_ssl_context(radio)
requests = adafruit_requests.Session(pool, ssl_context)
TEXT_URL = "http://wifitest.adafruit.com/testwifi/index.html"
JSON_GET_URL = "http://httpbin.org/get"
JSON_POST_URL = "http://httpbin.org/post"
print("Fetching text from %s" % TEXT_URL)
with requests.get(TEXT_URL) as response:
print("-" * 40)
print("Text Response: ", response.text)
print("-" * 40)
print("Fetching JSON data from %s" % JSON_GET_URL)
with requests.get(JSON_GET_URL) as response:
print("-" * 40)
print("JSON Response: ", response.json())
print("-" * 40)
data = "31F"
print(f"POSTing data to {JSON_POST_URL}: {data}")
with requests.post(JSON_POST_URL, data=data) as response:
print("-" * 40)
json_resp = response.json()
# Parse out the 'data' key from json_resp dict.
print("Data received from server:", json_resp["data"])
print("-" * 40)
json_data = {"Date": "July 25, 2019"}
print(f"POSTing data to {JSON_POST_URL}: {json_data}")
with requests.post(JSON_POST_URL, json=json_data) as response:
print("-" * 40)
json_resp = response.json()
# Parse out the 'json' key from json_resp dict.
print("JSON Data received from server:", json_resp["json"])
print("-" * 40)
The code initializes a request object using a socket and the requests interface.
HTTP GET with Requests
The code makes a HTTP GET request to Adafruit's WiFi testing website - http://wifitest.adafruit.com/testwifi/index.html.
To do this, we'll pass the URL into requests.get(). We're also going to save the response from the server into a variable named response. The call to requests.get() is wrapped in a loop which retries 3 times in the event of a failed request.
While we requested data from the server, we'd like to see what the server responded with. Since we already saved the server's response, we can read it back. Luckily for us, requests automatically decodes the server's response into human-readable text. You can read it back by calling response.text.
Lastly, we'll perform a bit of cleanup by calling response.close(). This closes, deletes, and collect's the response's data.
print("Fetching text from %s"%TEXT_URL)
while not response:
try:
response = requests.get(TEXT_URL)
failure_count = 0
except AssertionError as error:
print("Request failed, retrying...\n", error)
failure_count += 1
if failure_count >= attempts:
raise AssertionError("Failed to resolve hostname, \
please check your router's DNS configuration.")
continue
print('-'*40)
print("Text Response: ", response.text)
print('-'*40)
response.close()
While some servers respond with text, some respond with json-formatted data consisting of attribute–value pairs.
CircuitPython_Requests can convert a JSON-formatted response from a server into a CPython dict object.
We can also fetch and parse json data. We'll send a HTTP get to a url we know returns a json-formatted response (instead of text data).
Then, the code calls response.json() to convert the response to a CPython dict.
print("Fetching JSON data from %s"%JSON_GET_URL)
while not response:
try:
response = requests.get(JSON_GET_URL)
failure_count = 0
except AssertionError as error:
print("Request failed, retrying...\n", error)
failure_count += 1
if failure_count >= attempts:
raise AssertionError("Failed to resolve hostname, \
please check your router's DNS configuration.")
continue
print('-'*40)
print("JSON Response: ", response.json())
print('-'*40)
response.close()
HTTP POST with Requests
Requests can also POST data to a server by calling the requests.post method, passing it a data value.
data = '31F'
print("POSTing data to {0}: {1}".format(JSON_POST_URL, data))
while not response:
try:
response = requests.post(JSON_POST_URL, data=data)
failure_count = 0
except AssertionError as error:
print("Request failed, retrying...\n", error)
failure_count += 1
if failure_count >= attempts:
raise AssertionError("Failed to resolve hostname, \
please check your router's DNS configuration.")
continue
print('-'*40)
json_resp = response.json()
# Parse out the 'data' key from json_resp dict.
print("Data received from server:", json_resp['data'])
print('-'*40)
response.close()
You can also post json-formatted data to a server by passing json_data into the requests.post method.
json_data = {"Date" : "July 25, 2019"}
print("POSTing data to {0}: {1}".format(JSON_POST_URL, json_data))
while not response:
try:
response = requests.post(JSON_POST_URL, json=json_data)
failure_count = 0
except AssertionError as error:
print("Request failed, retrying...\n", error)
failure_count += 1
if failure_count >= attempts:
raise AssertionError("Failed to resolve hostname, \
please check your router's DNS configuration.")
continue
print('-'*40)
json_resp = response.json()
# Parse out the 'json' key from json_resp dict.
print("JSON Data received from server:", json_resp['json'])
print('-'*40)
response.close()
Page last edited February 25, 2025
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