TfL API - 对HTTP GET请求没有响应（arduino / esp8266）

Question

我正在尝试使用ESP8266 WiFi模块显示来自TfL API的信息。为此，我修改了提供的示例（成功接收数据）并修改了主机和网址。它编译，但我没有得到对请求的回复。

使用邮递员为网址提供无错误代码。

参见下面的代码;谢谢你的帮助

/*
 *  HTTP over TLS (HTTPS) example sketch
 *
 *  This example demonstrates how to use
 *  WiFiClientSecure class to access HTTPS API.
 *  We fetch and display the status of
 *  esp8266/Arduino project continuous integration
 *  build.
 *
 *  Created by Ivan Grokhotkov, 2015.
 *  This example is in public domain.
 */

#include <ESP8266WiFi.h>
#include <WiFiClientSecure.h>
#include <WiFiClient.h>
#include <ArduinoJson.h>

const char* ssid     = "VM*******";
const char* password = "v******";

const char* host = "api.tfl.gov.uk";
const int httpsPort = 80;

// Use web browser to view and copy
// SHA1 fingerprint of the certificate
const char* fingerprint = "CF 05 98 89 CA FF 8E D8 5E 5C E0 C2 E4 F7 E6 C3 C7 50 DD 5C";

void setup() {
  Serial.begin(115200);
  Serial.println();
  Serial.print("connecting to ");
  Serial.println(ssid);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());

  // Use WiFiClientSecure class to create TLS connection
  WiFiClient client;
  Serial.print("connecting to ");
  Serial.println(host);
  if (!client.connect(host, httpsPort)) {
    Serial.println("connection failed");
    return;
  }

//https fingerprint verification
  //if (client.verify(fingerprint, host)) {
  //  Serial.println("certificate matches");
  //} else {
  //  Serial.println("certificate doesn't match");
  //}

  String url = "/StopPoint/940GZZLUODS/Arrivals?mode=tube";
  Serial.print("requesting URL: ");
  Serial.println(url);

  client.print(String("GET ") + url + " HTTP/1.1\r\n" +
               "Host: " + host + "\r\n" +
               "User-Agent: BuildFailureDetectorESP8266\r\n" +
               "Connection: close\r\n\r\n");

  Serial.println("request sent");
  StaticJsonBuffer<200> jsonBuffer;
  while (client.connected()) {
    String line = client.readString();
    Serial.println("processing response...");
    if (line == "\r") {
      Serial.println("headers received");
      break;
    }
  }
  String line = client.readString();
  Serial.println("processing response...");
  JsonObject& root = jsonBuffer.parseObject(line);
  Serial.print(line);
  if (line.startsWith("{\"state\":\"success\"")) {
    Serial.println("esp8266/Arduino CI successfull!");
  } else {
    Serial.println("esp8266/Arduino CI has failed");
  }
  const char*  lineID = root["lineID"];
  Serial.println("reply was:");
  Serial.println("==========");
  Serial.println(line);
  Serial.print(lineID);
  Serial.println("==========");
  Serial.println("closing connection");
}

void loop() {
}