Add sensor data and WiFi support in REST API

frontend/README.md

@@ -0,0 +1,8 @@
+# CosmicPi REST API
+
+## Development
+Make sure that CosmicPi UI service does not run (`sudo systemctl stop CosmicPi-UI`), 
+navigate to `/frontend` and run:
+```
+FLASK_DEBUG=1 FLASK_APP=${PWD}/app.py python -m flask run --host=0.0.0.0
+```

frontend/app.py

@@ -0,0 +1,13 @@
+from flask import Flask, request
+from flask_restful import Api
+from .params import Params
+from .wifi import Wifi
+
+app = Flask(__name__)
+api = Api(app)
+
+api.add_resource(Params, '/params')
+api.add_resource(Wifi, '/wifi')
+
+if __name__ == '__main__':
+    app.run(debug=True)

frontend/config.py

@@ -0,0 +1,5 @@
+import configparser
+
+
+Config = configparser.ConfigParser()
+Config.read('../config/CosmicPi.config')

frontend/params.py

@@ -0,0 +1,47 @@
+from flask_restful import Resource
+from .config import Config
+import sqlite3
+
+
+SQLITE_LOCATION = Config.get("Storage", "sqlite_location")
+
+
+class Params(Resource):
+    def get(self):
+        params = {'HardwareSerial': Params._get_serial()}
+
+        # Get the latest datapoint
+        conn = sqlite3.connect(SQLITE_LOCATION, timeout=60.0)
+        cursor = conn.cursor()
+        cursor.execute("SELECT * FROM Events ORDER BY UTCUnixTime DESC, SubSeconds DESC;")
+        latest_datapoint = cursor.fetchone()
+
+        # Get column names
+        cursor.execute("PRAGMA table_info(Events);")
+        col_names = cursor.fetchall()
+        conn.close()
+
+        # Extract data
+        for i in range(0, len(col_names)):
+            # Field name
+            f_name = col_names[i][1]
+
+            # Fill in values
+            params[f_name] = latest_datapoint[i]
+        return params
+
+    @staticmethod
+    def _get_serial():
+        """
+        Extract serial from cpuinfo file
+        """
+        cpu_serial = "0000000000000000"
+        try:
+            f = open('/proc/cpuinfo', 'r')
+            for line in f:
+                if line[0:6] == 'Serial':
+                    cpu_serial = line[10:26]
+            f.close()
+        except:
+            cpu_serial = "ERROR000000000"
+        return cpu_serial

frontend/requirements.txt

@@ -0,0 +1 @@
+flask_restful

frontend/wifi.py

@@ -0,0 +1,166 @@
+from flask import request
+from flask_restful import Resource
+from .config import Config
+import subprocess
+import re
+import time
+import thread
+import urllib2
+
+
+DEFAULT_WIFI_NAME = Config.get("Default WiFi", "name")
+DEFAULT_WIFI_PASS = Config.get("Default WiFi", "password")
+WPA_SUPPLICANT_LOCATION = Config.get("MISC", "wpa_supplicant_location")
+
+
+class Wifi(Resource):
+    def get(self):
+        # Get current network
+        connected_network_name_response = ''
+        try:
+            connected_network_name_response = subprocess.check_output(['sudo', 'iwgetid'])
+        except subprocess.CalledProcessError as e:
+            err_text = 'ERROR get connected network: %s' % str(e)
+            connected_network_name_response = err_text
+            print(err_text)
+        connected_network_name_str = re.findall('\"(.*?)\"', connected_network_name_response)
+
+        if len(connected_network_name_str) < 1:
+            connected_network_name_str = ''
+        else:
+            connected_network_name_str = connected_network_name_str[0]
+
+        # Available networks
+        wifi_network_list = [connected_network_name_str]
+        available_networks_response = ''
+        try:
+            available_networks_response = subprocess.check_output(['sudo', 'iw', 'dev', 'wlan0', 'scan'])
+        except subprocess.CalledProcessError as e:
+            err_text = 'ERROR get list of networks: %s' % str(e)
+            print(err_text)
+            available_networks_response = err_text
+        available_networks_lines = available_networks_response.split('\n')
+        for availableNetworksLine in available_networks_lines:
+            if 'SSID' in availableNetworksLine:
+                essid = availableNetworksLine.replace('SSID:', '').strip()
+                wifi_network_list.append(essid)
+        wifi_network_list = filter(lambda x: x != '', wifi_network_list)
+
+        # Print everything
+        return {
+            'current': connected_network_name_str,
+            'available': wifi_network_list,
+        }
+
+    def put(self):
+        ssid = request.form['ssid']
+        password = request.form['password']
+
+        thread.start_new_thread(connect_to_wifi, (ssid, password))
+
+        msg = 'The CosmicPi will now try to connect to the WiFi "{}". ' \
+              "If no internet connection is found or the connection was not " \
+              "successful the CosmiPi will recreate the WiFi hotspot. Please " \
+              "wait at least two minutes.".format(ssid)
+        return {
+            'message': msg
+        }
+
+
+def fall_back_to_ap():
+    # empty the wpa supplicant to it's default
+    wpa_supplicant_string = "country=GB\n"  # Todo: Check, that this string in front is still correct!
+    wpa_supplicant_string += "ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev\n"
+    wpa_supplicant_string += "update_config=1\n"
+    wpa_supplicant_string += "\nnetwork={\n"
+    net = (DEFAULT_WIFI_NAME, DEFAULT_WIFI_PASS)
+    wpa_supplicant_string += '\tssid="{}"\n'.format(net[0])
+    # check if we need a password
+    if str(net[1]) == "":
+        wpa_supplicant_string += '\tpsk="{}"\n'.format(net[1])
+    wpa_supplicant_string += "}\n"
+    with open(WPA_SUPPLICANT_LOCATION, 'w') as file:
+        file.write(wpa_supplicant_string)
+    # configure controler to accept the new configuration
+    try:
+        import fcntl
+        time.sleep(2)
+        subprocess.call("wpa_cli -i wlan0 reconfigure", shell=True)
+        time.sleep(2)
+    except ImportError:
+        print("This OS is not linux enough to handle a hotspot in this way")
+
+    # restart the hotspot
+    try:
+        import fcntl
+        subprocess.call("systemctl start dnsmasq",
+                        shell=True)  # well, here we actually care if the hotspot starts, but oh well...
+        time.sleep(2)
+        subprocess.call("ifconfig wlan0 down", shell=True)
+        time.sleep(2)
+        subprocess.call("ifconfig wlan0 up", shell=True)
+    except ImportError:
+        print("This OS is not linux enough to handle a hotspot in this way")
+
+
+def connect_to_wifi(name, pw):
+    # build the string for the WPA supplicant
+    wpa_supplicant_string = "country=GB\n"    # Todo: Check, that this string in front is still correct!
+    wpa_supplicant_string += "ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev\n"
+    wpa_supplicant_string += "update_config=1\n"
+    networks = [(name, pw), (DEFAULT_WIFI_NAME, DEFAULT_WIFI_PASS)]
+    for net in networks:
+        wpa_supplicant_string += "\nnetwork={\n"
+        wpa_supplicant_string += '\tssid="{}"\n'.format(net[0])
+        # check if we need a password
+        if not str(net[1]) == "":
+            wpa_supplicant_string += '\tpsk="{}"\n'.format(net[1])
+        wpa_supplicant_string += "}\n"
+
+    # deactivate htospot and turn the WiFi back on
+    try:
+        import fcntl
+        subprocess.call("systemctl stop dnsmasq", shell=True)  # we very much don't care if this fails
+        time.sleep(2)
+        subprocess.call("ifconfig wlan0 down", shell=True)
+        time.sleep(2)
+        subprocess.call("ifconfig wlan0 up", shell=True)
+    except ImportError:
+        print("This OS is not linux enough to handle a hotspot in this way")
+    # write wpa_supplicant string to the file
+    with open(WPA_SUPPLICANT_LOCATION, 'w') as file:
+        file.write(wpa_supplicant_string)
+    # configure controler to accept the new configuration
+    try:
+        import fcntl
+        time.sleep(2)
+        subprocess.call("wpa_cli -i wlan0 reconfigure", shell=True)
+    except ImportError:
+        print("This OS is not linux enough to handle a hotspot in this way")
+
+    # wait for an internet connection (max 2 min)
+    start_time = time.time()
+    have_internet = False
+    while (have_internet == False) and ((start_time + 120) >  time.time()):
+        have_internet = internet_on()
+
+    # if we have no internet, restart the hotspot, otherwise we are done for now
+    if have_internet:
+        print("Successfully connected to the internet (yeah)")
+        # wait a bit before we send the mail
+        time.sleep(5)
+        # ToDo: This would be a good point to send a mail or something similar to the user.
+        # Just to inform them where their cosmicPi is and what's it doing
+        return
+    else:
+        print("No internet connection here, falling back to hotspot!")
+        fall_back_to_ap()
+        return
+
+
+def internet_on():
+    try:
+        urllib2.urlopen('http://heise.de', timeout=2)
+        return True
+    except urllib2.URLError:
+        return False

install_files/CosmicPi-UI.service

@@ -3,9 +3,9 @@ Description=Software for the CosmicPi UI
 
 [Service]
 # Flask Env Vars
-Environment=FLASK_APP=PATH_TO_EXECUTABLE/frontend/web_ui.py
+Environment=FLASK_APP=/home/pi/cosmicpi-rpi_V1.5/frontend/web_ui.py
 ExecStart=/usr/bin/python -m flask run --host=0.0.0.0 --port=80
-WorkingDirectory=PATH_TO_EXECUTABLE/frontend/
+WorkingDirectory=/home/pi/cosmicpi-rpi_V1.5/frontend/
 Restart=on-failure
 
 [Install]

install_files/CosmicPi-database_cleaner.service

@@ -2,8 +2,8 @@
 Description=Software for cleaning the local database from time to time, to keep it from exploding
 
 [Service]
-ExecStart=/usr/bin/python PATH_TO_EXECUTABLE/backend/database_cleaning.py
-WorkingDirectory=PATH_TO_EXECUTABLE/backend/
+ExecStart=/usr/bin/python /home/pi/cosmicpi-rpi_V1.5/backend/database_cleaning.py
+WorkingDirectory=/home/pi/cosmicpi-rpi_V1.5/backend/
 Restart=on-failure
 
 [Install]

install_files/CosmicPi-detector.service

@@ -2,8 +2,8 @@
 Description=Software for connecting to the the CosmicPi detector
 
 [Service]
-ExecStart=/usr/bin/python PATH_TO_EXECUTABLE/backend/detector_connect.py
-WorkingDirectory=PATH_TO_EXECUTABLE/backend/
+ExecStart=/usr/bin/python /home/pi/cosmicpi-rpi_V1.5/backend/detector_connect.py
+WorkingDirectory=/home/pi/cosmicpi-rpi_V1.5/backend/
 Restart=on-failure
 
 [Install]

install_files/CosmicPi-mqtt.service

@@ -2,8 +2,8 @@
 Description=Software for sending locally stored events from the CosmicPi to an MQTT srver
 
 [Service]
-ExecStart=/usr/bin/python PATH_TO_EXECUTABLE/backend/mqtt_publisher.py
-WorkingDirectory=PATH_TO_EXECUTABLE/backend/
+ExecStart=/usr/bin/python /home/pi/cosmicpi-rpi_V1.5/backend/mqtt_publisher.py
+WorkingDirectory=/home/pi/cosmicpi-rpi_V1.5/backend/
 Restart=on-failure
 
 [Install]