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lab_app_v9.py
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lab_app_v9.py
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'''
FILE NAME
lab_app.py
Version 9
1. WHAT IT DOES
This version adds support for Plotly.
2. REQUIRES
* Any Raspberry Pi
3. ORIGINAL WORK
Raspberry Full Stack 2018, Peter Dalmaris
4. HARDWARE
* Any Raspberry Pi
* DHT11 or 22
* 10KOhm resistor
* Breadboard
* Wires
5. SOFTWARE
Command line terminal
Simple text editor
Libraries:
from flask import Flask, request, render_template, sqlite3
Python 3
6. WARNING!
None
7. CREATED
8. TYPICAL OUTPUT
A simple web page served by this flask application in the user's browser.
The page contains the current temperature and humidity.
A second page that displays historical environment data from the SQLite3 database.
The historical records can be selected by specifying a date range in the request URL.
The user can now click on one of the date/time buttons to quickly select one of the available record ranges.
The user can use Jquery widgets to select a date/time range.
The user can explore historical data to Plotly for visualisation and processing.
// 9. COMMENTS
--
// 10. END
'''
from flask import Flask, request, render_template
import time
import datetime
import sys
import Adafruit_DHT
import arrow
import sqlite3
app = Flask(__name__)
app.debug = True # Make this False if you are no longer debugging
@app.route("/")
def hello():
return "Hello World!"
@app.route("/lab_temp")
def lab_temp():
humidity, temperature = Adafruit_DHT.read_retry(Adafruit_DHT.AM2302, 17)
if humidity is not None and temperature is not None:
return render_template("lab_temp.html",temp=temperature,hum=humidity)
else:
return render_template("no_sensor.html")
@app.route("/lab_env_db", methods=['GET']) #Add date limits in the URL #Arguments: from=2015-03-04&to=2015-03-05
def lab_env_db():
temperatures, humidities, timezone, from_date_str, to_date_str = get_records()
print ("QUERY STRING: %s" % request.query_string)
# Create new record tables so that datetimes are adjusted back to the user browser's time zone.
time_adjusted_temperatures = []
time_adjusted_humidities = []
for record in temperatures:
local_timedate = arrow.get(record[0], "YYYY-MM-DD HH:mm:ss").to(timezone)
time_adjusted_temperatures.append([local_timedate.format('YYYY-MM-DD HH:mm:ss'), round(record[2],2)])
for record in humidities:
local_timedate = arrow.get(record[0], "YYYY-MM-DD HH:mm:ss").to(timezone)
time_adjusted_humidities.append([local_timedate.format('YYYY-MM-DD HH:mm:ss'), round(record[2],2)])
print ("rendering lab_env_db.html with: %s, %s, %s" % (timezone, from_date_str, to_date_str))
return render_template("lab_env_db.html", timezone = timezone,
temp = time_adjusted_temperatures,
hum = time_adjusted_humidities,
from_date = from_date_str,
to_date = to_date_str,
temp_items = len(temperatures),
query_string = request.query_string, #This query string is used
#by the Plotly link
hum_items = len(humidities))
def get_records():
from_date_str = request.args.get('from',time.strftime("%Y-%m-%d 00:00")) #Get the from date value from the URL
to_date_str = request.args.get('to',time.strftime("%Y-%m-%d %H:%M")) #Get the to date value from the URL
timezone = request.args.get('timezone','Etc/UTC');
range_h_form = request.args.get('range_h',''); #This will return a string, if field range_h exists in the request
range_h_int = "nan" #initialise this variable with not a number
print ("REQUEST:")
print (request.args)
try:
range_h_int = int(range_h_form)
except:
print ("range_h_form not a number")
print ("Received from browser: %s, %s, %s, %s" % (from_date_str, to_date_str, timezone, range_h_int))
if not validate_date(from_date_str): # Validate date before sending it to the DB
from_date_str = time.strftime("%Y-%m-%d 00:00")
if not validate_date(to_date_str):
to_date_str = time.strftime("%Y-%m-%d %H:%M") # Validate date before sending it to the DB
print ('2. From: %s, to: %s, timezone: %s' % (from_date_str,to_date_str,timezone))
# Create datetime object so that we can convert to UTC from the browser's local time
from_date_obj = datetime.datetime.strptime(from_date_str,'%Y-%m-%d %H:%M')
to_date_obj = datetime.datetime.strptime(to_date_str,'%Y-%m-%d %H:%M')
# If range_h is defined, we don't need the from and to times
if isinstance(range_h_int,int):
arrow_time_from = arrow.utcnow().shift(hours=-range_h_int)
arrow_time_to = arrow.utcnow()
from_date_utc = arrow_time_from.strftime("%Y-%m-%d %H:%M")
to_date_utc = arrow_time_to.strftime("%Y-%m-%d %H:%M")
from_date_str = arrow_time_from.to(timezone).strftime("%Y-%m-%d %H:%M")
to_date_str = arrow_time_to.to(timezone).strftime("%Y-%m-%d %H:%M")
else:
#Convert datetimes to UTC so we can retrieve the appropriate records from the database
from_date_utc = arrow.get(from_date_obj, timezone).to('Etc/UTC').strftime("%Y-%m-%d %H:%M")
to_date_utc = arrow.get(to_date_obj, timezone).to('Etc/UTC').strftime("%Y-%m-%d %H:%M")
conn = sqlite3.connect('/var/www/lab_app/lab_app.db')
curs = conn.cursor()
curs.execute("SELECT * FROM temperatures WHERE rDateTime BETWEEN ? AND ?", (from_date_utc.format('YYYY-MM-DD HH:mm'), to_date_utc.format('YYYY-MM-DD HH:mm')))
temperatures = curs.fetchall()
curs.execute("SELECT * FROM humidities WHERE rDateTime BETWEEN ? AND ?", (from_date_utc.format('YYYY-MM-DD HH:mm'), to_date_utc.format('YYYY-MM-DD HH:mm')))
humidities = curs.fetchall()
conn.close()
return [temperatures, humidities, timezone, from_date_str, to_date_str]
def validate_date(d):
try:
datetime.datetime.strptime(d, '%Y-%m-%d %H:%M')
return True
except ValueError:
return False
if __name__ == "__main__":
app.run(host='0.0.0.0', port=8080)