无法使用WifiClientSecure将https协议与ESP8266连接

Question

我正在尝试通过unwiredlabs获得ESP8266的位置。我跟随了这个introduction。这是我的arduino代码：

#include <ESP8266HTTPClient.h>
#include  <ArduinoJson.h>
#include "ESP8266WiFi.h"

char myssid[] = "Your wifi/hotspot name";
char mypass[] = "Your password";

const char* Host = "www.unwiredlabs.com";
String endpoint = "/v2/process.php";

String token = "d99cccda52ec0b";

String jsonString = "{\n";

double latitude = 0.0;
double longitude = 0.0;
double accuracy = 0.0;

void setup(){
    Serial.begin(115200);

    // Set WiFi to station mode and disconnect from an AP if it was previously connected
    WiFi.mode(WIFI_STA);
    WiFi.disconnect();
    Serial.println("Setup done");

    // We start by connecting to a WiFi network
    Serial.print("Connecting to ");
    Serial.println(myssid);
    WiFi.begin(myssid, mypass);

    while (WiFi.status() != WL_CONNECTED) {
        delay(500);
        Serial.print(".");
    }
    Serial.println(".");
}

void loop() {
    char bssid[6];
    DynamicJsonBuffer jsonBuffer;

    // WiFi.scanNetworks will return the number of networks found
    int n = WiFi.scanNetworks();
    Serial.println("scan done");

    if (n == 0 ) {
        Serial.println("No networks available");
    } else {
        Serial.print(n);
        Serial.println(" networks found");
    }

      // now build the jsonString...
      jsonString = "{\n";
      jsonString += "\"token\" : \"";
      jsonString += token;
      jsonString += "\",\n";
      jsonString += "\"id\" : \"saikirandevice01\",\n";
      jsonString += "\"wifi\": [\n";
      for (int j = 0; j < n; ++j) {
          jsonString += "{\n";
          jsonString += "\"bssid\" : \"";
          jsonString += (WiFi.BSSIDstr(j));
          jsonString += "\",\n";
          jsonString += "\"signal\": ";
          jsonString += WiFi.RSSI(j);
          jsonString += "\n";
          if (j < n - 1) {
              jsonString += "},\n";
          } else {
              jsonString += "}\n";
          }
      }
      jsonString += ("]\n");
      jsonString += ("}\n");
      Serial.println(jsonString);

      WiFiClientSecure client;

      //Connect to the client and make the api call
      Serial.println("Requesting URL: https://" + (String)Host + endpoint);
      if (client.connect(Host, 443)) {
          Serial.println("Connected");
          client.println("POST " + endpoint + " HTTP/1.1");
          client.println("Host: " + (String)Host);
          client.println("Connection: close");
          client.println("Content-Type: application/json");
          client.println("User-Agent: Arduino/1.0");
          client.print("Content-Length: ");
          client.println(jsonString.length());
          client.println();
          client.print(jsonString);
          delay(500);
      }

      //Read and parse all the lines of the reply from server
      while (client.available()) {
          String line = client.readStringUntil('\r');
          JsonObject& root = jsonBuffer.parseObject(line);
          if (root.success()) {
              latitude    = root["lat"];
              longitude   = root["lon"];
              accuracy    = root["accuracy"];

              Serial.println();
              Serial.print("Latitude = ");
              Serial.println(latitude, 6);
              Serial.print("Longitude = ");
              Serial.println(longitude, 6);
              Serial.print("Accuracy = ");
              Serial.println(accuracy);
          }
      }

      Serial.println("closing connection");
      Serial.println();
      client.stop();

      delay(5000);
}

当代码已刷新到esp8266时，表明无法连接到https://www.instructables.com/v2/process.php。

ESP串行输出：

... // some initial setup string
Requesting URL: https://unwiredlabs.com/v2/process.php
// if connected, "connected" was printed here, but not
closing connection

然后，我尝试在Chrome浏览器中使用网址https://unwiredlabs.com/v2/process.php。这是消息：

{
status: "error",
message: "Invalid request",
balance: 0,
help: "Check for misplaced commas and use double quotes to encapsulate strings"
}

这证明该URL存在，但是当我尝试Postman时，它显示：

然后，我关闭了邮递员的SSL certificate verifycation。它以403 Forbidden错误响应。因此，我认为引起问题的原因是WifiClientSecure的SSL证书验证。

任何人都可以帮忙吗？

Answer 1

SSL-至少是此代码尝试使用它的方式-要求您尝试连接的站点的指纹。在尝试连接到该站点之前，代码需要告知其客户端对象该站点的指纹。

第1步：从站点手动检索指纹：我在Chrome浏览器中浏览到https://www.unwiredlabs.com并复制了该证书，然后在Windows的git bash中使用openSSL提取了指纹：

openssl x509 -noout -fingerprint -sha1 -inform pem -in certificate-file.cer > fingerprint.txt

然后我编辑了生成的fingerprint.txt文件，用空格替换了每个'：'。

在网上搜索有关如何使用Chrome或您使用的任何浏览器复制引用证书的详细信息。

[步骤2：编辑代码以将指纹添加到草图：我添加了常量“ sslFingerprint”，并在调用client.connect（）之前添加了对client.setFingerprint（）的调用。

然后我删除了与连接到站点无关的代码，创建了一个示例Sketch，该示例说明了与unwiredlabs.com的成功连接：

#include <ESP8266HTTPClient.h>
#include "ESP8266WiFi.h"

// The SSL Fingerprint of https://www.unwiredlabs.com
// Certificate expires ‎October ‎9, ‎2020
const char *sslFingerprint
  = "C3 3E 2F 21 CB 15 4E 02 D5 27 E5 F6 EF FB 31 AE 91 51 A3 5D";

char myssid[] = "yourWiFiSSID";
char mypass[] = "yourWiFiPassword";

const char* Host = "www.unwiredlabs.com";
String endpoint = "/v2/process.php";

void setup() {
  Serial.begin(9600);

  // Set WiFi to station mode and disconnect from an AP if it was previously connected
  WiFi.mode(WIFI_STA);
  WiFi.disconnect();
  Serial.println("Setup done");

  // We start by connecting to a WiFi network
  Serial.print("Connecting to ");
  Serial.println(myssid);
  WiFi.begin(myssid, mypass);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println(".");
}

void loop() {
  WiFiClientSecure client;

  //Connect to the client and make the api call
  Serial.println("Requesting URL: https://" + (String)Host + endpoint);
  client.setFingerprint(sslFingerprint);
  if (client.connect(Host, 443)) {
    Serial.println("Connected");
  }
  Serial.println("closing connection");
  Serial.println();
  client.stop();

  delay(5000);
}

[在Sparkfun ESP8266 Thing Dev板上运行时，Sketch会产生以下输出：

......
Requesting URL: https://www.unwiredlabs.com/v2/process.php
Connected
closing connection