鸿蒙OpenHarmony hi3516开发板，标准系统调用外部Rest接口_openharmony libcurl

已实现了标准系统拍照和云服务文字识别的研究，现需要验证在OpenHarmony标准设备上，开发一个应用程序，通过调用OpenHarmony已集成的libcurl，封装2个方法，实现对外网http reset接口（get/post）调用。作为后期调用AI云服务的基础。

本次已经使用OpenHarmony 3.1 Beta的代码，仍然使用润和HiSpark Taurus AI Camera(Hi3516d)开发板套件

步骤1 下载OpenHarmony源代码

repo init -u git@gitee.com:openharmony/manifest.git -b refs/tags/OpenHarmony-v3.1-Beta --no-repo-verify
repo sync -c
repo forall -c 'git lfs pull'

步骤2 增加代码调用http服务

2.1 在applications\standard\httptest新增httptest.cpp，封装httpGet,httpPost方法调用Rest接口

#include<stdio.h>
#include<curl/curl.h>
#include<string>
 
using namespace std;
 
static size_t receive_data(void *contents, size_t size, size_t nmemb, void *stream);
// http get
static CURLcode httpGet(const std::string & strUrl, std::string & strResponse,int nTimeout);
// htpp post 
static CURLcode httpPost(const std::string & strUrl, std::string szJson,std::string & strResponse,int nTimeout);
 
static size_t receive_data(void *contents, size_t size, size_t nmemb, void *stream){
    string *str = (string*)stream;
    (*str).append((char*)contents, size*nmemb);
    return size * nmemb;
}
 
 
 
static CURLcode httpGet(const std::string & strUrl, std::string & strResponse,int nTimeout){
    CURLcode res;
    CURL* pCURL = curl_easy_init();
 
    if (pCURL == NULL) {
        return CURLE_FAILED_INIT;
    }
 
    curl_easy_setopt(pCURL, CURLOPT_URL, strUrl.c_str());
    //curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
    curl_easy_setopt(pCURL, CURLOPT_NOSIGNAL, 1L);
    curl_easy_setopt(pCURL, CURLOPT_TIMEOUT, nTimeout);
    curl_easy_setopt(pCURL, CURLOPT_NOPROGRESS, 1L);
    curl_easy_setopt(pCURL, CURLOPT_WRITEFUNCTION, receive_data);
    curl_easy_setopt(pCURL, CURLOPT_WRITEDATA, (void*)&strResponse);
    res = curl_easy_perform(pCURL);
    curl_easy_cleanup(pCURL);
    return res;
}
 
static CURLcode httpPost(const std::string & strUrl, std::string szJson,std::string & strResponse,int nTimeout){
    CURLcode res;
    char szJsonData[1024];
    memset(szJsonData, 0, sizeof(szJsonData));
    strcpy(szJsonData, szJson.c_str());
    CURL* pCURL = curl_easy_init();
    struct curl_slist* headers = NULL;
    if (pCURL == NULL) {
        return CURLE_FAILED_INIT;
    }
 
    CURLcode ret;
    ret = curl_easy_setopt(pCURL, CURLOPT_URL, strUrl.c_str());
//    std::cout << ret << std::endl;
 
    ret = curl_easy_setopt(pCURL, CURLOPT_POST, 1L);
    headers = curl_slist_append(headers,"content-type:application/json");
 
    ret = curl_easy_setopt(pCURL, CURLOPT_HTTPHEADER, headers);
 
    ret = curl_easy_setopt(pCURL, CURLOPT_POSTFIELDS, szJsonData);
    //curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
    ret = curl_easy_setopt(pCURL, CURLOPT_TIMEOUT, nTimeout);
 
    ret = curl_easy_setopt(pCURL, CURLOPT_WRITEFUNCTION, receive_data);
 
    ret = curl_easy_setopt(pCURL, CURLOPT_WRITEDATA, (void*)&strResponse);
 
    res = curl_easy_perform(pCURL);
    curl_easy_cleanup(pCURL);
    return res;
}
 
 
int main()
{
    printf("hello test http\n");
 
    //string strURL = "http://14.215.177.39";
    //string strURL = "http://www.baidu.com";
    string strResponse;
    CURLcode nRes = huaweiCloud.httpGet(strURL, strResponse,300);
 
    //size_t nSrcLength = strResponse.length();
 
    if (nRes == CURLE_OK){
         printf("OK OK OK\n");
    }else{
        printf("result = %d\n",nRes);
    }
 
    printf("%s\n",strResponse.c_str());
 
 
    printf("end test http\n");
 
    return 0;
}

2.2 在applications\standard\httptest新增Build.gn，编译httptest，依赖libcurl

import("//build/ohos.gni")
import("//drivers/adapter/uhdf2/uhdf.gni")
 
ohos_executable("httptest") {
  sources = [
    "httptest.cpp",
    "huaweicloud.cpp"
  ]
  subsystem_name = "applications"
  part_name = "prebuilt_hap"
 
  include_dirs = [
    "//third_party/curl/include"
  ]
 
 
  deps = [
    "//third_party/curl:curl"
  ]
}

步骤3 修改配置，增加编译组件

修改applications\standard\hap\ohos.build

module_list里增加 "//applications/standard/httptest:httptest"

步骤4 修改配置，增加编译组件

./build.sh --product-name Hi3516DV300 --ccache

步骤5 DNS修改

目前发现如果请求外部网络是带域名时，会报“无法解析代理”的错误，因此当前只能手动配置DNS服务，或者在配置修改后再编译。这里只写出镜像编译后的修改方式。

mount -oremount,rw  /    #使etc目录下可写
echo "nameserver 202.96.128.86">/etc/resolv.conf  #写入DNS服务地址

步骤6  执行验证

使用串口连接，执行bin目录下的httptest

cd bin
./httptest

源代码

MyOpenHarmonySample: 我的OpenHarmonySample代码 - Gitee.com