download file func

opencv-motion-detect/downloadFile.cpp

+#include <spdlog/spdlog.h>
+#include <curl/curl.h>
+#include <string>
+
+using namespace std;
+
+namespace netutils {
+// private
+static void libcurlInit()
+{
+    static bool inited = false;
+    if(inited == false) {
+        curl_global_init(CURL_GLOBAL_ALL);
+        inited = true;
+    }
+}
+
+//private
+static size_t write_data(void *ptr, size_t size, size_t nmemb, void *stream)
+{
+    size_t written = fwrite(ptr, size, nmemb, (FILE *)stream);
+    return written;
+}
+// https://curl.haxx.se/libcurl/c/url2file.html
+int downloadFile(string fileUrl, string outUrl)
+{
+    CURL *curl;
+    FILE *fp;
+    libcurlInit();
+
+    /* init the curl session */
+    curl = curl_easy_init();
+
+    /* set URL to get here */
+    curl_easy_setopt(curl, CURLOPT_URL, fileUrl.c_str());
+
+    /* Switch on full protocol/debug output while testing */
+    curl_easy_setopt(curl, CURLOPT_VERBOSE, 0);
+
+    /* disable progress meter, set to 0L to enable and disable debug output */
+    curl_easy_setopt(curl, CURLOPT_NOPROGRESS, 1L);
+
+    /* send all data to this function  */
+    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);
+
+    /* open the file */
+    fp = fopen(outUrl.c_str(), "wb");
+    if(fp) {
+        /* write the page body to this file handle */
+        curl_easy_setopt(curl, CURLOPT_WRITEDATA, fp);
+        auto res = curl_easy_perform(curl);
+        if(res != CURLE_OK){
+            spdlog::error("failed to upload files: {}", curl_easy_strerror(res));
+            return -1;
+        }
+
+        /* close the header file */
+        fclose(fp);
+    }
+
+    /* cleanup curl stuff */
+    curl_easy_cleanup(curl);
+    //curl_global_cleanup();
+
+    return 0;
+}
+}
+
+int main()
+{
+    netutils::downloadFile("https://curl.haxx.se/libcurl/c/url2file.html", "a.html");
+}
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