文章目录
- 树莓派上操作
- 使用Python创建Http服务器
- 使用树莓派做WeMos的后台
- 树莓派做http服务器
-
- WeMos发送HTTP请求
- WeMos连接wifi
- WeMos发送HTTP请求
树莓派上操作
使用Python创建Http服务器
from flask import Flask
app = Flask(__name__)
@app.route('/')
def hello_world():
return 'Hello, World!'
if __name__ == '__main__':
app.run(host = "0.0.0.0", port = '3009')
使用树莓派做WeMos的后台
树莓派做http服务器
- 作用
- 使用flask，在树莓派上创建一个简单的web服务器
- wemos提出HTTP的get请求取汇报数据
代码
# 默认访问‘/data’路径时会调用下属的函数
""" pi_backend.py
This is a REST relay server running on the Pi for the Arduino to relay data
to on the way to the Cloud. Effectively functions as a gateway for
the edge devices.
"""
from flask import Flask, request, render_template, Response
#import client #uncomment when integrating with the client.py API
# Create the flask app
app = Flask(__name__)
# This is for the callback, which should be defined to
# with the following signature:
# def callback(temp, humid, light)
#
_callback_ = None
# Create just a single route to read data from the Arduino
@app.route('/data', methods = ['GET'])
def addData():
''' The one and only route. It extracts the
data from the request, converts to float if the
data is not None, then calls the callback if it is set
'''
global _callback_
tempStr = request.args.get('temp')
humidStr = request.args.get('humid')
lightStr = request.args.get('light')
temp = float(tempStr) if tempStr else None
humid = float(humidStr) if humidStr else None
light = float(lightStr) if lightStr else None
if _callback_:
_callback_(temp = temp, humid = humid, light = light)
return "OK", 200
def set_callback(callback):
''' Sets the callback.
@param callback The callback with signature def callback(temp, humid,
light)
'''
global _callback_
_callback_ = callback
def demo_callback(temp, humid, light):
''' Demo callback that just prints the data passed in.
'''
if temp is not None:
print("nTemperature = %3.2f" % temp)
if humid is not None:
print("Humidity = %3.2f" % humid)
if light is not None:
print("Light = %3.2f" % light)
if temp is None and humid is None and light is None:
print("n*** Called without any parameters. ***")
print("n")
def main():
set_callback(demo_callback)
app.run(host = "0.0.0.0", port = '3009')
if __name__ == '__main__':
main()
WeMos发送HTTP请求
- 说明
- WeMos和Pi能够通过局域网实现互通，上文中已经设置了树莓派作为服务器，当前部分需要通过WeMos发送HTTP请求
WeMos连接wifi
#include
#include
#include
const char* ssid = "ChinaNet-G3GN201"; //Your Wifi's SSID
const char* password = "qq7729577855"; //Wifi Password
void setup(void){
Serial.begin(115200);
WiFi.begin(ssid, password);
Serial.println("");
// Wait for connection
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
Serial.println("");
Serial.print("Connected to ");
Serial.println(ssid);
Serial.print("IP address: ");
Serial.println(WiFi.localIP());
}
void loop(void){
}
WeMos发送HTTP请求
- 在之前的例子上，创建http请求的相关代码，为了模仿实际传感器产生数据的过程，每5秒发送一个数据。
#include
#include
#include
const char* ssid = "ChinaNet-G3GN201"; //Your Wifi's SSID
const char* password = "qq7729577855"; //Wifi Password
WiFiClient wifiClient;
const char* piAt = "http://192.168.1.248:3009/"; //change to your Pi's IP
void setup(void){
Serial.begin(115200);
WiFi.begin(ssid, password);
Serial.println("");
// Wait for connection
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
Serial.println("");
Serial.print("Connected to ");
Serial.println(ssid);
Serial.print("IP address: ");
Serial.println(WiFi.localIP());
}
void loop(void){
Serial.print("Sending...");
if (WiFi.status() == WL_CONNECTED){
HTTPClient http;
String url = piAt;
url += "data?temp=31.2&humid=76&light=87"; //hardcoded values for example only
http.begin(wifiClient,url);
int returnCode = http.GET(); //perform a HTTP GET request
if (returnCode > 0){
String payload = http.getString();
Serial.println(payload);
}
http.end();
} else {
Serial.println("WiFi disconnected");
}
delay(5000); //Five second delay
}
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