以Http GET取得網路時間

本文利用D1 mini，連接網路後，截取網路時間。可利用的網路有二，均以http GET取的JSON格式回應。

1. http://worldclockapi.com/api/json/utc/now

此網頁回應的是世界協調時間(UTC, Coordinated Universal Time)，與台北的時區不同，需自行+8。該網頁回應的JSON碼如下：

1. {
2.   "$id": "1",
3.   "currentDateTime": "2022-01-02T13:45Z",
4.   "utcOffset": "00:00:00",
5.   "isDayLightSavingsTime": false,
6.   "dayOfTheWeek": "Sunday",
7.   "timeZoneName": "UTC",
8.   "currentFileTime": 132856047568459540,
9.   "ordinalDate": "2022-2",
10.   "serviceResponse": null
11. }

2. http://worldtimeapi.org/api/timezone/Asia/Taipei

此網頁回應的資訊較多，可取得Taipei時區目前的時間（datetime）以及UTC時間（utc_datetime），還可取得星期幾（day_of_week）、每年中第幾天（day_of_year）以及每年中第幾周（week_number）的資訊，但在跨年當周的周數計算可能會有出入。

1. {
2.   "abbreviation": "CST",
3.   "client_ip": "112.78.66.92",
4.   "datetime": "2022-01-02T21:46:12.324416+08:00",
5.   "day_of_week": 0,
6.   "day_of_year": 2,
7.   "dst": false,
8.   "dst_from": null,
9.   "dst_offset": 0,
10.   "dst_until": null,
11.   "raw_offset": 28800,
12.   "timezone": "Asia/Taipei",
13.   "unixtime": 1641131172,
14.   "utc_datetime": "2022-01-02T13:46:12.324416+00:00",
15.   "utc_offset": "+08:00",
16.   "week_number": 52
17. }

下圖為執行結果。

使用Flagblock的圖控程式以及Arduino 程式碼如下。

1. // Flag's Block 產生的草稿碼
2. 
   
3. #include <ESP8266WiFi.h>
4. #include <ESP8266WebServer.h>
5. #include "data/webpages.h"
6. #include <FlagHTTPClient.h>
7. #include <ArduinoJson.h>
8. #include <FlagJSON.h>
9. 
   
10. String time_JSON_response;
11. String datetime;
12. String day_of_week;
13. String date;
14. String time_now;
15. String week_day;
16. ESP8266WebServer _esp8266WebServer(80);
17. FlagHTTPClient _httpClient;
18. JsonVariant _jsonRoot;
19. DynamicJsonBuffer _jsonBuffer;
20. 
    
21. void handleRoot() {
22. #ifndef WEBPAGE_IN_PROGMEM
23.   _esp8266WebServer.send(200, "text/html", mainPage);
24. #else
25.   _esp8266WebServer.send_P(200, PSTR("text/html"), mainPage);
26. #endif
27. }
28. 
    
29. void handleNotFound() {
30. #ifndef WEBPAGE_IN_PROGMEM
31.   _esp8266WebServer.send(404, "text/html", errorPage);
32. #else
33.   _esp8266WebServer.send_P(404, PSTR("text/html"), errorPage);
34. #endif
35. }
36. 
    
37. void handleSetting() {
38. #ifndef WEBPAGE_IN_PROGMEM
39.   _esp8266WebServer.send(200, "text/html", settingPage);
40. #else
41.   _esp8266WebServer.send_P(200, PSTR("text/html"), settingPage);
42. #endif
43. }
44. 
    
45. int _httpGET(String url) {
46.   _httpClient.end();
47.   _httpClient.begin(url);
48.   _httpClient.setTimeout(30000);
49.   return _httpClient.GET();
50. }
51. 
    
52. void Get_Internet_Time() {
53.   time_JSON_response = _httpClient.getString();
54.   _jsonBuffer.clear();
55.   _jsonRoot = _jsonBuffer.parse(time_JSON_response);
56.   datetime = flagJSON.getJSONDataAsString(_jsonRoot, u8"datetime");
57.   day_of_week = flagJSON.getJSONDataAsString(_jsonRoot, u8"day_of_week");
58.   date = datetime.substring(0, 10);
59.   time_now = datetime.substring(11, 19);
60.   if (day_of_week == u8"0") {
61.     week_day = u8"Sunday";
62.   } else if (day_of_week == u8"1") {
63.     week_day = u8"Monday";
64.   } else if (day_of_week == u8"2") {
65.     week_day = u8"Tuesday";
66.   } else if (day_of_week == u8"3") {
67.     week_day = u8"Wednesday";
68.   } else if (day_of_week == u8"4") {
69.     week_day = u8"Thursday";
70.   } else if (day_of_week == u8"5") {
71.     week_day = u8"Friday";
72.   } else if (day_of_week == u8"6") {
73.     week_day = u8"Saturday";
74.   }
75.   Serial.println((String(u8"date: ") + String(date)));
76.   Serial.println((String(u8"day: ") + String(week_day)));
77.   Serial.println((String(u8"time: ") + String(time_now)));
78.   Serial.println(u8"");
79. }
80. 
    
81. 
    
82. // setup() 會先被執行且只會執行一次
83. void setup() {
84.   Serial.begin(9600);
85. 
    
86.   WiFi.begin(u8"YUPIN", u8"0987654321");
87.   while (!((WiFi.status() == WL_CONNECTED))) {
88.     delay(1000);
89.     Serial.println(u8"connecting ...");
90.   }
91.   Serial.println((WiFi.localIP().toString()));
92.   _esp8266WebServer.on("/", handleRoot);
93.   _esp8266WebServer.onNotFound(handleNotFound);
94.   _esp8266WebServer.on("/setting", handleSetting);
95.   _esp8266WebServer.begin();
96.   time_JSON_response = u8"";
97.   datetime = u8"";
98.   date = u8"";
99.   time_now = u8"";
100.   day_of_week = u8"";
101.   week_day = u8"";
102. 
     
103. }
104. 
     
105. // loop() 裡面的程式會不斷重複執行
106. void loop() {
107.   if (_httpGET(u8"http://worldtimeapi.org/api/timezone/Asia/Taipei") > 0) {
108.     Get_Internet_Time();
109.   }
110.   delay(500);
111. 
     
112. }