【NodeMCU实时天气时钟温湿度项目 7】和风天气API返回JSON数据信息的解压缩实现——ArduinoUZlib功能库

        今天是第七专题，主要内容是：导入ArduinoUZlib功能库，借助该库把从【和风天气】官网返回的经过Gzip压缩的JSON数据，进行解压缩和t解析，在串口监视器上输出解析后的JSON信息。

        如您需要了解其它专题的内容，请点击下面的链接。
        第一专题内容，请参考：连接点亮SPI-TFT屏幕和UI布局设计
        第二专题内容，请参考：WIFI模式设置及连接
        第三专题内容，请参考：连接SHT30传感器，获取并显示当前环境温湿度数据（I2C）
        第四专题内容，请参考：通过NTPClient库获取实时网络时间并显示在TFT屏幕上
        第五专题内容，请参考：获取关于城市天气实况和天气预报的JSON信息（心知天气版）
        第六专题内容，请参考：解析天气信息JSON数据并显示在 TFT 屏幕上（心知天气版）

一、【心知天气】官网JSON数据特点

        1、订阅模式。和风天气开发服务采用订阅模式，当你创建项目时，至少需要选择一种订阅。使用和风天气的服务订阅非常简单和自由，免费或者你只需要为你实际使用的部分付费。现有三种订阅模式：免费订阅、标准订阅、高级订阅。
        每种订阅模式均可获取完整的天气信息数据。区别主要体现在数据请求量和更新频率方面。

        2、经过压缩的JSON数据。通过官网API接口返回的JSON数据，是进行Gzip压缩后的JSON数据，客户端需要先进行解压缩，然后再借助ArduinoJson功能库解析出解压缩后JSON数据，比心知天气返回JSON数据增加了一个解压缩过程。
        3、获取和风天气数据的方法。如果需要获得通过官网API接口返回的天气信息数据，需要首先心知天气注册账号、创建项目、选择订阅模式，然后获取API访问密钥KEY。具体操作方法网上有很多文档可供参考，请自行查询，比如：如何获取和风天气Web API的KEY？

二、添加ArduinoUZlib功能库

        1. ArduinoUZlib 的功能。该库是从uzlib移植到Arduino框架的功能库，主要用来解压https请求服务器返回的gzip数据。这个库占用内存比较小。
        2. 添加库方法。该库暂时无法从 PlatformIO 界面  -------> Libraries 加入。
        具体方法是：（1）进入该库 Github 网站，下载 zip 压缩文件。

（2）解压 zip 文件，生 成ArduinoUZlib-main 文件夹。
        （3）将此文件夹复制到 项目目录下的 lib 文件夹内，就可以使用该库的全部功能了。

三、主要功能函数

        该库使用方法简单方便，主要是通过调用 ArduinoUZlib::decompress(inbuff, size, outbuf,outsize) 这个功能函数来实现。

size_t size = stream->available(); // 还剩下多少数据没有读完？
uint8_t inbuff[size]; // 准备一个数组来装流数据，有多少装多少
stream->readBytes(inbuff, size); // 将http流数据写入inbuff中
uint8_t *outbuf=NULL; //解压后的输出流
uint32_t outsize=0; // 解压后多大？在调用解压方法后会被赋值。
// 调用解压函数
int result=ArduinoUZlib::decompress(inbuff, size, outbuf,outsize);
// 输出解密后的数据到控制台。
Serial.write(outbuf,outsize);

        详细内容可参考该库 example 目录下的示例：StreamHttpsClientGzipDemo，用来解压缩返回的 gzip数据。       

/**StreamHTTPClient.inoCreated on: 24.05.2015*/
#include <ArduinoJson.h>
#include <Arduino.h>
#include "ArduinoUZlib.h" 
#include <ESP8266WiFi.h>
#include <ESP8266WiFiMulti.h>#include <ESP8266HTTPClient.h>
ESP8266WiFiMulti WiFiMulti;// ESP.getFreeHeap(), ESP.getMinFreeHeap(), ESP.getHeapSize(), ESP.getMaxAllocHeap()
void heap(){Serial.print("FREE_HEAP[");Serial.print(ESP.getFreeHeap());Serial.print("]\n");
}
void setup() {Serial.begin(115200);// Serial.setDebugOutput(true);Serial.println();Serial.println();Serial.println();for (uint8_t t = 4; t > 0; t--) {Serial.printf("[SETUP] WAIT %d...\n", t);Serial.flush();delay(1000);}WiFi.mode(WIFI_STA);WiFiMulti.addAP("ssid", "password");
}
void log(const char *str) {Serial.println(str);
}static uint8_t buffer[1280]={0};
size_t readBytesSize=0;void fetchBuffer() {if ((WiFiMulti.run() == WL_CONNECTED)) {std::unique_ptr<BearSSL::WiFiClientSecure> client(new BearSSL::WiFiClientSecure);client->setInsecure();Serial.print("[HTTPS] begin...\n");HTTPClient https;if (https.begin(*client, "https://192.168.2.144:8082/test")) {https.addHeader("Accept-Encoding", "gzip");Serial.print("[HTTPS] GET...\n");// start connection and send HTTP headerint httpCode = https.GET();if (httpCode > 0) {// HTTP header has been send and Server response header has been handledSerial.printf("[HTTPS] GET... code: %d\n", httpCode);// file found at serverif (httpCode == HTTP_CODE_OK) {// get length of document (is -1 when Server sends no Content-Length header)int len = https.getSize();// create buffer for readstatic uint8_t buff[128] = { 0 };// read all data from serverint offset=0;Serial.println("allocate");//  为什么这里分配内存会报错？// if(inbuf==NULL) inbuf=(uint8_t*)malloc(sizeof(uint8_t)*128);while (https.connected() && (len > 0 || len == -1)) {// get available data sizesize_t size = client->available();if (size) {// read up to 128 byteint c = client->readBytes(buff, ((size > sizeof(buff)) ? sizeof(buff) : size));// int c = client->readBytes(buff, size);// Serial.println("memcpy");memcpy(buffer+offset, buff, sizeof(uint8_t)*c);offset+=c;if(c>0 && c!=16) {log("======rb====");Serial.printf("%d,", buff[c-3]);Serial.printf("%d,", buff[c-2]);Serial.printf("%d,", buff[c-1]);log("\n======rb end====");}// write it to Serial// Serial.write(buff, c);if (len > 0) {len -= c;}}delay(1);}readBytesSize=offset;Serial.printf("offset=%d\n", offset);Serial.write(buffer, offset);Serial.print("[HTTPS] connection closed or file end.\n");}} else {Serial.printf("[HTTPS] GET... failed, error: %s\n", https.errorToString(httpCode).c_str());}https.end();} else {Serial.printf("Unable to connect\n");}}
}void loop() {uint8_t *outbuf1=NULL;// wait for WiFi connectionfetchBuffer();Serial.printf("\nAfter fetch, buffer size=%d\n", readBytesSize);delay(1000);if(readBytesSize) {// write it to Seriallog("===buf===");Serial.printf("%d,", readBytesSize-3);Serial.printf("%d,", readBytesSize-2);Serial.printf("%d,", readBytesSize-1);log("\n===buf end===");    Serial.write(buffer,readBytesSize);uint32_t out_size=0;int result=ArduinoUZlib::decompress(buffer, readBytesSize, outbuf1, out_size);printf("outsize=%d, result=\n", out_size,result);parseJSON((char*)outbuf1, out_size);// Serial.write(outbuf,out_size);}else {Serial.println("no avali size!");}
if (outbuf1!=NULL){free(outbuf1);outbuf1=NULL;
}Serial.println("Wait 10s before the next round...");delay(5000);
}void parseJSON(char *input, int inputLength) {// char* input;// size_t inputLength; (optional)DynamicJsonDocument doc(6144);DeserializationError error = deserializeJson(doc, input, inputLength);if (error) {Serial.print(F("deserializeJson() failed: "));Serial.println(error.f_str());return;}const char* code = doc["code"]; // "200"const char* updateTime = doc["updateTime"]; // "2022-12-05T15:35+08:00"const char* fxLink = doc["fxLink"]; // "http://hfx.link/1u0r1"for (JsonObject hourly_item : doc["hourly"].as<JsonArray>()) {// const char* hourly_item_fxTime = hourly_item["fxTime"]; // "2022-12-05T17:00+08:00", ...const char* hourly_item_fxTime = hourly_item["fxTime"]; // "2022-12-05T17:00+08:00", ...const char* hourly_item_temp = hourly_item["temp"]; // "15", "13", "13", "12", "11", "11", "10", "10", ...Serial.printf("%s,", hourly_item_temp);const char* hourly_item_icon = hourly_item["icon"]; // "100", "150", "150", "150", "150", "150", "150", ...const char* hourly_item_text = hourly_item["text"]; // "晴", "晴", "晴", "晴", "晴", "晴", "晴", "多云", "多云", ...const char* hourly_item_wind360 = hourly_item["wind360"]; // "22", "24", "30", "33", "33", "31", "30", ...const char* hourly_item_windDir = hourly_item["windDir"]; // "东北风", "东北风", "东北风", "东北风", "东北风", "东北风", ...const char* hourly_item_windScale = hourly_item["windScale"]; // "3-4", "3-4", "3-4", "3-4", "3-4", ...const char* hourly_item_windSpeed = hourly_item["windSpeed"]; // "16", "16", "16", "16", "14", "14", ...const char* hourly_item_humidity = hourly_item["humidity"]; // "57", "63", "63", "65", "66", "67", "68", ...const char* hourly_item_pop = hourly_item["pop"]; // "1", "3", "6", "6", "6", "6", "6", "6", "7", "7", ...const char* hourly_item_precip = hourly_item["precip"]; // "0.0", "0.0", "0.0", "0.0", "0.0", "0.0", ...const char* hourly_item_pressure = hourly_item["pressure"]; // "1013", "1013", "1012", "1012", "1012", ...const char* hourly_item_cloud = hourly_item["cloud"]; // "5", "5", "4", "4", "7", "9", "11", "33", "54", ...const char* hourly_item_dew = hourly_item["dew"]; // "7", "6", "6", "6", "5", "5", "5", "5", "5", "4", ...}Serial.println();JsonArray refer_sources = doc["refer"]["sources"];const char* refer_sources_0 = refer_sources[0]; // "QWeather"const char* refer_sources_1 = refer_sources[1]; // "NMC"const char* refer_sources_2 = refer_sources[2]; // "ECMWF"const char* refer_license_0 = doc["refer"]["license"][0]; // "CC BY-SA 4.0"}

四、和风天气JSON数据的解压缩实现

        这是个实现解压缩和风天气JSON数据的简单示例：（1）将服务器进行Gzip压缩后返回的JSON数据，接收并保存到缓冲区 buffer 中；（2）调用 ArduinoUZlib::decompress(inbuffer, size, outbuffer,outsize) 解压 buffer 中的经过压缩的JSON数据，同时将解压后JSON数据保存到输出 outbuffer 中；（3）调用 ArduinoJson 库的 deserializeJson(doc, outbuffer) 函数，对明文JSON数据进行解析，并保存到实况天气数据结构 wd 中，然后通过串口监视器输出。
        具体内容，请仔细阅读下面的代码实现。

// 实时天气
struct weather_data
{int code = -1;               // API状态码，具体含义请参考状态码String updateTime = "";      // 当前API的最近更新时间String now_obsTime = "";     // 数据观测时间String now_temp = "0";       // 温度，默认单位：摄氏度int now_feelsLike = 0;       // 体感温度，默认单位：摄氏度String now_icon = "";        // 天气状况和图标的代码，图标可通过天气状况和图标下载String now_text = "";        // 天气状况的文字描述，包括阴晴雨雪等天气状态的描述String now_wind360 = "-1";   // 风向360角度String now_windDir = "";     // 风向String now_windScale = "-1"; // 风力等级int now_windSpeed = -1;      // 风速，公里/小时int now_humidity = -1;       // 相对湿度，百分比数值int now_precip = -1;         // 当前小时累计降水量，默认单位：毫米int now_pressure = -1;       // 大气压强，默认单位：百帕int now_vis = -1;            // 能见度，默认单位：公里
} wd;void get_now_weather_data(JsonDocument &doc);size_t readBytesSize = 0;// 用来存放解压前的JSON数据
static uint8_t buffer[1280] = {0};// 用来存放解压后的JSON数据
uint8_t *outbuffer = NULL;// 获取实时天气数据
void get_now_Weather()
{// 检查WIFI是否连接if ((WiFi.status() == WL_CONNECTED)){// 准备发起请求std::unique_ptr<BearSSL::WiFiClientSecure> client(new BearSSL::WiFiClientSecure);client->setInsecure();Serial.print("[HTTPS] begin...\n");HTTPClient https;if (https.begin(*client, "https://devapi.qweather.com/v7/weather/now?key=" + key + "&location=" + cityid)){https.addHeader("Accept-Encoding", "gzip");Serial.print("[HTTPS] GET...\n");// start connection and send HTTP headerint httpCode = https.GET();if (httpCode > 0){// HTTP header has been send and Server response header has been handledSerial.printf("[HTTPS] GET... code: %d\n", httpCode);// file found at serverif (httpCode == HTTP_CODE_OK){// get length of document (is -1 when Server sends no Content-Length header)int len = https.getSize();// create buffer for readstatic uint8_t buff[128] = {0};// read all data from serverint offset = 0;//  为什么这里分配内存会报错？// if(inbuf==NULL) inbuf=(uint8_t*)malloc(sizeof(uint8_t)*128);while (https.connected() && (len > 0 || len == -1)){// get available data sizesize_t size = client->available();if (size){// read up to 128 byteint c = client->readBytes(buff, ((size > sizeof(buff)) ? sizeof(buff) : size));memcpy(buffer + offset, buff, sizeof(uint8_t) * c);offset += c;// write it to Serial// Serial.write(buff, c);if (len > 0){len -= c;}}delay(1);}readBytesSize = offset;delay(1000);if (readBytesSize){// write it to SerialSerial.write(buffer, readBytesSize);Serial.println("");uint32_t out_size = 0;ArduinoUZlib::decompress(buffer, readBytesSize, outbuffer, out_size);Serial.write(outbuffer, out_size);// 调用解析函数JsonDocument doc;DeserializationError err = deserializeJson(doc, outbuffer);if (err.code() == DeserializationError::Ok){get_now_weather_data(doc);}else{Serial.println("数据解析出错");}}else{Serial.println("no avali size!");}if (outbuffer != NULL){free(outbuffer);outbuffer = NULL;}}}else{Serial.printf("[HTTPS] GET... failed, error: %s\n", https.errorToString(httpCode).c_str());}https.end();}else{Serial.printf("Unable to connect\n");}}
}void get_now_weather_data(JsonDocument &doc)
{// 将数据保存到weahter_data 的结构体，方便后续调用Serial.println("");wd.code = doc["code"];wd.updateTime = doc["updateTime"].as<String>().substring(0, 16);wd.now_obsTime = doc["now"]["obsTime"].as<String>().substring(0, 16);wd.updateTime.replace("T", " ");wd.now_obsTime.replace("T", " ");wd.now_temp = doc["now"]["temp"].as<String>();wd.now_feelsLike = doc["now"]["feelsLike"].as<int>();wd.now_icon = doc["now"]["icon"].as<String>();wd.now_text = doc["now"]["text"].as<String>();wd.now_wind360 = doc["now"]["wind360"].as<String>();wd.now_windDir = doc["now"]["windDir"].as<String>();wd.now_windScale = doc["now"]["windScale"].as<String>();wd.now_windSpeed = doc["now"]["windSpeed"].as<int>();wd.now_humidity = doc["now"]["humidity"].as<int>();wd.now_precip = doc["now"]["precip"].as<int>();wd.now_pressure = doc["now"]["pressure"].as<int>();wd.now_vis = doc["now"]["vis"].as<int>();Serial.print("wd.code: ");Serial.println(wd.code);Serial.print("wd.updateTime: ");Serial.println(wd.updateTime);Serial.print("wd.now_obsTime: ");Serial.println(wd.now_obsTime);Serial.print("wd.now_temp: ");Serial.println(wd.now_temp);Serial.print("wd.now_feelsLike: ");Serial.println(wd.now_feelsLike);Serial.print("wd.now_icon: ");Serial.println(wd.now_icon);Serial.print("wd.now_text: ");Serial.println(wd.now_text);Serial.print("wd.now_wind360: ");Serial.println(wd.now_wind360);Serial.print("wd.now_windDir: ");Serial.println(wd.now_windDir);Serial.print("wd.now_windScale: ");Serial.println(wd.now_windScale);Serial.print("wd.now_windSpeed: ");Serial.println(wd.now_windSpeed);Serial.print("wd.now_humidity: ");Serial.println(wd.now_humidity);Serial.print("wd.now_precip: ");Serial.println(wd.now_precip);Serial.print("wd.now_pressure: ");Serial.println(wd.now_pressure);Serial.print("wd.now_vis: ");Serial.println(wd.now_vis);
}

五、解压缩JSON数据源代码下载和运行效果展示

        百度网盘下载：UZlib_Qweather_CompressedJsonData_7，  提取码：ivfq
        友情提示：（1）请务必将 ssid 和 password 修改成您所在环境的名称和密码；（2）请务必const String key 修改成您自己申请的和风天气API密钥。
        如果您能在串口监视器看到如下信息，那么恭喜您程序运行成功了。
        

参考文档
1. JSON 基本使用_json怎么用-CSDN博客
2. 如何获取和风天气Web API的KEY？（简要步骤）_天气预报web api key-CSDN博客
3. JSON——概述、JSON语法、序列化和反序列化_所有文档都可以通过json序列化吗-CSDN博客