Wio Terminal HTTP 连接
本文将演示如何在 Wio Terminal 上通过 WiFi 建立 HTTP 连接（包括 HTTPS）。Wio Terminal 配备的无线网卡是 Realtek RTL8720，在开始本次学习之前，请确保你已经阅读 Wio Terminal 网卡固件更新，并完成固件更新和 Arduino 依赖库的安装。
Wi-Fi HTTP 客户端
下面这个示例首先将 Wio Terminal 配置为 STA 模式，然后连接指定的 Wi-Fi 接入点（AP），连接成功后发送一个 HTTP GET 请求，并从 Web server 中接收 HTTP 响应。为了简单地测试本示例，你可以在 PC 上使用 Python 启动一个简单的 Web 服务器。
1、将以下内容复制并保存在您的本地磁盘中，并将其命名为 index.html。
<html>
<body>
Hello World!
</body>
</html>
2、打开 Shell 终端，切换到 index.html 所在目录，运行下面命令启动一个简单的 Python HTTP 服务器。
python -m SimpleHTTPServer 80 # For Python 2
python3 -m http.server 80 # For Pyhton 3
注意：Python2 和 Python3 的命令不一样。
3、将 Arduino 代码中的 ssid 和 password 修改为你的 WiFi 网络参数，将 host 修改为 Web 服务器的 IP 地址。
4、编译上传到 Wio Terminal，打开串口监视器观察。
#include <rpcWiFi.h>
const char* ssid = "yourNetworkName";
const char* password = "yourNetworkPassword";
void setup() {
Serial.begin(115200);
while(!Serial); // Wait for Serial to be ready
delay(1000);
// Set WiFi to station mode and disconnect from an AP if it was previously connected
WiFi.mode(WIFI_STA);
WiFi.disconnect();
delay(2000);
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.println("Connecting to WiFi..");
}
Serial.println("Connected to the WiFi network");
Serial.print("IP Address: ");
Serial.println (WiFi.localIP()); // prints out the device's IP address
}
void loop() {
const uint16_t port = 80; // Default port
const char* host = "192.168.0.10"; // Target Server IP Address
Serial.print("Connecting to ");
Serial.println(host);
// Use WiFiClient class to create TCP connections
WiFiClient client;
if (!client.connect(host, port)) {
Serial.println("Connection failed.");
Serial.println("Waiting 5 seconds before retrying...");
delay(5000);
return;
}
// This will send a request to the server
//uncomment this line to send an arbitrary string to the server
//client.print("Send this data to the server");
//uncomment this line to send a basic document request to the server
client.print("GET /index.html HTTP/1.1\n\n"); // sending HTTP GET request
int maxloops = 0;
//wait for the server's reply to become available
while (!client.available() && maxloops < 1000) {
maxloops++;
delay(1); //delay 1 msec
}
if (client.available() > 0) {
//read back one line from the server
String line = client.readString(); // Read from the server response
// Proceed various line-endings
line.replace("\r\n", "\n");
line.replace('\r', '\n');
line.replace("\n", "\r\n");
Serial.println(line);
} else {
Serial.println("client.available() timed out ");
}
Serial.println("Closing connection.");
client.stop();
Serial.println("Waiting 5 seconds before restarting...");
delay(5000);
}
运行效果如下：
Wi-Fi HTTPS 连接
由于 HTTP 是明文传输，为了提高 Web 的安全性，需要使用 HTTPS。下面示例就来演示一下，如何在 Wio Terminal 上建立 HTTPS 连接。掌握了这个技能，你就可以连接到几乎所有网站并获取需要的数据。
注意：将 ssid 和 password 修改为你的 WiFi 网络。
#include <rpcWiFi.h>
#include <WiFiClientSecure.h>
const char* ssid = "yourNetworkName"; // your network SSID
const char* password = "yourNetworkPassword"; // your network password
const char* server = "www.example.com"; // Server URL
const char* test_root_ca = \
"-----BEGIN CERTIFICATE-----\n"
"MIIDrzCCApegAwIBAgIQCDvgVpBCRrGhdWrJWZHHSjANBgkqhkiG9w0BAQUFADBh\n"
"MQswCQYDVQQGEwJVUzEVMBMGA1UEChMMRGlnaUNlcnQgSW5jMRkwFwYDVQQLExB3\n"
"d3cuZGlnaWNlcnQuY29tMSAwHgYDVQQDExdEaWdpQ2VydCBHbG9iYWwgUm9vdCBD\n"
"QTAeFw0wNjExMTAwMDAwMDBaFw0zMTExMTAwMDAwMDBaMGExCzAJBgNVBAYTAlVT\n"
"MRUwEwYDVQQKEwxEaWdpQ2VydCBJbmMxGTAXBgNVBAsTEHd3dy5kaWdpY2VydC5j\n"
"b20xIDAeBgNVBAMTF0RpZ2lDZXJ0IEdsb2JhbCBSb290IENBMIIBIjANBgkqhkiG\n"
"9w0BAQEFAAOCAQ8AMIIBCgKCAQEA4jvhEXLeqKTTo1eqUKKPC3eQyaKl7hLOllsB\n"
"CSDMAZOnTjC3U/dDxGkAV53ijSLdhwZAAIEJzs4bg7/fzTtxRuLWZscFs3YnFo97\n"
"nh6Vfe63SKMI2tavegw5BmV/Sl0fvBf4q77uKNd0f3p4mVmFaG5cIzJLv07A6Fpt\n"
"43C/dxC//AH2hdmoRBBYMql1GNXRor5H4idq9Joz+EkIYIvUX7Q6hL+hqkpMfT7P\n"
"T19sdl6gSzeRntwi5m3OFBqOasv+zbMUZBfHWymeMr/y7vrTC0LUq7dBMtoM1O/4\n"
"gdW7jVg/tRvoSSiicNoxBN33shbyTApOB6jtSj1etX+jkMOvJwIDAQABo2MwYTAO\n"
"BgNVHQ8BAf8EBAMCAYYwDwYDVR0TAQH/BAUwAwEB/zAdBgNVHQ4EFgQUA95QNVbR\n"
"TLtm8KPiGxvDl7I90VUwHwYDVR0jBBgwFoAUA95QNVbRTLtm8KPiGxvDl7I90VUw\n"
"DQYJKoZIhvcNAQEFBQADggEBAMucN6pIExIK+t1EnE9SsPTfrgT1eXkIoyQY/Esr\n"
"hMAtudXH/vTBH1jLuG2cenTnmCmrEbXjcKChzUyImZOMkXDiqw8cvpOp/2PV5Adg\n"
"06O/nVsJ8dWO41P0jmP6P6fbtGbfYmbW0W5BjfIttep3Sp+dWOIrWcBAI+0tKIJF\n"
"PnlUkiaY4IBIqDfv8NZ5YBberOgOzW6sRBc4L0na4UU+Krk2U886UAb3LujEV0ls\n"
"YSEY1QSteDwsOoBrp+uvFRTp2InBuThs4pFsiv9kuXclVzDAGySj4dzp30d8tbQk\n"
"CAUw7C29C79Fv1C5qfPrmAESrciIxpg0X40KPMbp1ZWVbd4=\n"
"-----END CERTIFICATE-----\n";
// You can use x.509 client certificates if you want
//const char* test_client_key = ""; //to verify the client
//const char* test_client_cert = ""; //to verify the client
WiFiClientSecure client;
void setup() {
//Initialize serial and wait for port to open:
Serial.begin(115200);
while(!Serial); // Wait for Serial to be ready
delay(1000);
Serial.print("Attempting to connect to SSID: ");
Serial.println(ssid);
WiFi.begin(ssid, password);
// attempt to connect to Wifi network:
while (WiFi.status() != WL_CONNECTED) {
Serial.print(".");
// wait 1 second for re-trying
delay(1000);
}
Serial.print("Connected to ");
Serial.println(ssid);
client.setCACert(test_root_ca);
//client.setCertificate(test_client_key); // for client verification
//client.setPrivateKey(test_client_cert); // for client verification
Serial.println("\nStarting connection to server...");
if (!client.connect(server, 443)) {
Serial.println("Connection failed!");
} else {
Serial.println("Connected to server!");
// Make a HTTP request:
client.println("GET https://www.example.com HTTP/1.0");
client.println("Host: www.example.com");
client.println("Connection: close");
client.println();
while (client.connected()) {
String line = client.readStringUntil('\n');
if (line == "\r") {
Serial.println("headers received");
break;
}
}
// if there are incoming bytes available
// from the server, read them and print them:
while (client.available()) {
char c = client.read();
if (c == '\n') {
Serial.write('\r');
}
Serial.write(c);
}
client.stop();
}
}
void loop() {
// do nothing
}
要获取网站的根 CA 证书，你可以在终端（Linux Bash Shell）中运行以下命令：
openssl s_client -showcerts -verify 5 -connect www.example.com:443 < /dev/null
提示：用目标网站的 URL 替换 www.example.com。
如果命令无法执行，请检查是否已经安装 openssl 软件包。
sudo apt update
sudo apt install openssl