cURL – 将输出变为变量？

我目前正在使用这个C代码：

CURL *curl; CURLcode res; curl = curl_easy_init(); if (curl) { curl_easy_setopt(curl, CURLOPT_URL, "http://my-domain.org/"); res = curl_easy_perform(curl); curl_easy_cleanup(curl); } 

它在控制台上打印输出。 如何获得相同的输出，但是将其读入字符串？ （这可能是一个基本问题，但我还不了解libcurl API ……）

谢谢你的帮助！

麦克风

Answer 1

您需要传递一个函数和缓冲区以将其写入缓冲区。

 /* setting a callback function to return the data */ curl_easy_setopt(curl_handle, CURLOPT_WRITEFUNCTION, write_callback_func); /* passing the pointer to the response as the callback parameter */ curl_easy_setopt(curl_handle, CURLOPT_WRITEDATA, &response); /* the function to invoke as the data recieved */ size_t static write_callback_func(void *buffer, size_t size, size_t nmemb, void *userp) { char **response_ptr = (char**)userp; /* assuming the response is a string */ *response_ptr = strndup(buffer, (size_t)(size *nmemb)); } 

请在这里查看更多信息。

Answer 2

你需要一个写回调函数。 我使用这种函数来读取响应，错误并能够提供我自己的头文件：

 size_t write_data(void *ptr, size_t size, size_t nmemb, void *stream) { std::string buf = std::string(static_cast(ptr), size * nmemb); std::stringstream *response = static_cast(stream); response->write(buf.c_str(), (std::streamsize)buf.size()); return size * nmemb; } bool CurlGet( const std::string &url, const std::vector &headers, std::stringstream &response, std::string &error) { curl_global_init(CURL_GLOBAL_ALL); curl_slist *headerlist = NULL; std::vector::const_iterator it; for (it = headers.begin(); it < headers.end(); it++) { headerlist = curl_slist_append(headerlist, it->c_str()); } CURL *curl = curl_easy_init(); char ebuf[CURL_ERROR_SIZE]; curl_easy_setopt(curl, CURLOPT_URL, url.c_str()); curl_easy_setopt(curl, CURLOPT_NOPROGRESS, 1); curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, ebuf); curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data); curl_easy_setopt(curl, CURLOPT_WRITEDATA, &response); curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headerlist); CURLcode res = curl_easy_perform(curl); curl_easy_cleanup(curl); curl_slist_free_all(headerlist); if (res != CURLE_OK) error = ebuf; else error.clear(); return res == CURLE_OK; } 

Answer 3

这可以使用

 curl_easy_setopt(easyhandle, CURLOPT_WRITEFUNCTION, write_data); 

它设置一个回调函数write_data ，它是一个带签名的函数

 size_t write_data(void *buffer, size_t size, size_t nmemb, void *userp); 

如果你想让userp成为你在程序中使用的一些内部结构，请调用

 curl_easy_setopt(easyhandle, CURLOPT_WRITEDATA, &internal_struct); 

获取指向internal_struct的指针传递给write_data每次调用。

Answer 4

嗨，我从回调函数解决返回代码23的问题，从回调函数返回大小。

见下面的代码：

 /* setting a callback function to return the data */ curl_easy_setopt(curl_handle, CURLOPT_WRITEFUNCTION, write_callback_func); /* passing the pointer to the response as the callback parameter */ curl_easy_setopt(curl_handle, CURLOPT_WRITEDATA, &response); /* the function to invoke as the data recieved */ size_t static write_callback_func(void *buffer, size_t size, size_t nmemb, void *userp) { char **response_ptr = (char**)userp; /* assuming the response is a string */ *response_ptr = strndup(buffer, (size_t)(size *nmemb)); return ((size_t)(size *nmemb)); //if you not send return value of size it will show you ERROR CODE 23return curl_easy_perform(); } 

Answer 5

其他一些例子都不适用于我。
这是我最终做的事情：

 size_t static curl_write(void *buffer, size_t size, size_t nmemb, void *userp) { userp += strlen(userp); // Skipping to first unpopulated char memcpy(userp, buffer, nmemb); // Populating it. return nmemb; } int GetCurl() { CURL *curl; CURLcode res; char *s = (char *) malloc(512); curl = curl_easy_init(); if (curl) { curl_easy_setopt(curl, CURLOPT_URL, "http://www.google.com"); curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, curl_write); curl_easy_setopt(curl, CURLOPT_WRITEDATA, s); res = curl_easy_perform(curl); curl_easy_cleanup(curl); } printf("GREAT SUCCESS!! Your string is %s\n", s); }