数据速率最好为15次/秒。接收的数据是47个元素的字符串。
#include <ESP8266WiFi.h>
#include <WiFiClient.h>
// WiFi information
const char WIFI_SSID[] = "my-wlan";
const char WIFI_PSK[] = "123qwe123qwe";
// Remote site information
const char http_site[] = "10.13.137.144";
const int http_port = 8080;
// Pin definitions
const int LED_PIN = 16;
// Global variables
WiFiClient client;
String readString, readString1 ;
int x=0;
byte led_statuss = 0;
void setup() {
// Set up serial console to read web page
Serial.begin(115200);
Serial.print("Thing GET Example");
// Set up LED for debugging
pinMode(LED_PIN, OUTPUT);
// Connect to WiFi
connectWiFi();
}
//////////////////////////loop///////////////////////////////////////
void loop() {
int time=millis();
getPage();
delay(100);
// If there are incoming bytes, print them
int lines_received = 0;
while(client.available()) {
String line = client.readStringUntil('\n');
if (lines_received == 7) {
String k =(line.substring(0,line.length())); // removes headers from the server response
Serial.println(k); // prints the raw data
int time1 = millis()-time;
Serial.print("Time is ");
Serial.println(time1); // shows how much time the function takes
}
lines_received++;
}
// Do nothing
//Serial.println("Finished Thing GET test");
}
// Attempt to connect toFi///////////////////////////////////////////////////////////
void connectWiFi() {
byte led_status = 0;
// Set WiFi mode to station (client)
WiFi.mode(WIFI_STA);
// Initiate connection with SSID and PSK
WiFi.begin(WIFI_SSID, WIFI_PSK);
// Blink LED while we wait for WiFi connection
while ( WiFi.status() != WL_CONNECTED ) {
digitalWrite(LED_PIN, led_status);
led_status ^= 0x01;
delay(100);
}
// Turn LED on when we are connected
digitalWrite(LED_PIN, HIGH);
}
// Perform an HTTP GET request to a remote page//////////////////////////////////////////
bool getPage() {
// Attempt to make a connection to the remote server
if ( !client.connect(http_site, http_port) ) {
return false;
}
// Make an HTTP GET request
//client.print("GET /cars" + "HTTP/1.1 \r\n" + "Host: " + "10.13.137.154" + "\r\n" + "Connection: close\r\n\r\n");
client.println("GET /cars HTTP/1.1");
client.print("Host: ");
client.println(http_site);
client.println("Connection: Close");
client.println();
delay(100); //some put delay, but why and how long?
return true;
}
我们从服务器执行GET请求，并从中过滤出原始数据标头和响应为：
Thing GET Example1;62.91;43.55;190.03;5.59;20.00;44.26;861503022
Time is 228
1;62.91;43.55;190.04;0.00;20.00;43.79;861503920
Time is 926
1;62.91;43.55;190.03;0.00;20.00;44.26;861504988
Time is 1050
1;62.91;43.55;190.08;5.76;20.00;43.83;861505980
Time is 1011
1;62.91;43.55;190.07;0.00;20.00;43.82;861506983
Time is 992
1;62.91;43.55;190.04;0.00;20.00;43.79;861508012
Time is 1036
1;62.91;43.55;190.11;0.00;20.00;43.86;861510045
Time is 2020
1;62.91;43.55;190.05;0.00;20.00;43.80;861510274
Time is 222
1;62.91;43.55;190.07;0.00;20.00;43.82;861511306
Time is 1026
1;62.91;43.55;190.07;0.00;20.00;43.82;861512410
Time is 1108
1;62.91;43.55;190.04;0.00;20.00;43.79;861512605
Time is 219
1;62.91;43.55;190.03;0.00;20.00;44.26;861512840
Time is 214
1;62.91;43.55;190.06;0.00;20.00;43.81;861513842
Time is 996
似乎ESP无法获得GET响应速度更快。时间以毫秒为单位。如果延迟大约为400毫秒，我确实设法使它正常工作。
提高程序速度的最佳方法是什么？
#1 楼
您应该通过使用Connection: Keep-Alive
而不是
Connection: Close
来避免在getPage（）方法上进行长时间的连接重置。这样可以节省很多。
评论
在getPage函数中，如果删除延迟或显着减小延迟会发生什么？通常，它不能提高性能，只是对于某些GET而言，它可以使速度更快，但是同样，您还有900、1000ms的延迟。我试图在另一个ESP上复制一个简单的Web服务器，并在另一个ESP上复制一个客户端，并且在那里工作得很好。响应约为20-50ms。所以我猜想它与网络有关。
通讯是通过工作场所常见的wi-fi完成的。
您是否真的需要在每次需要页面时进行连接？您不能一次连接并保持连接，然后重新连接以防连接丢失或过期吗？
您必须为此使用HTTP吗？对于此用例而言，它效率极低，不仅是因为存在保持连接问题。