c语言访问网页api_C#语言

C语言无法直接访问网页API，需要借助第三方库；而C#语言可以使用HttpClient类轻松实现。

C语言访问网页API与C#语言

C语言访问网页API

1、使用libcurl库

libcurl是一个开源的客户端URL传输库，支持多种协议和数据传输方式。

安装libcurl库并包含头文件后，可以使用其提供的函数进行HTTP请求和响应的处理。

示例代码：

“`c

#include <stdio.h>

#include <curl/curl.h>

int main() {

CURL *curl;

CURLcode res;

curl_global_init(CURL_GLOBAL_DEFAULT);

curl = curl_easy_init();

if(curl) {

curl_easy_setopt(curl, CURLOPT_URL, "http://example.com");

res = curl_easy_perform(curl);

if(res != CURLE_OK)

fprintf(stderr, "curl_easy_perform() failed: %s

", curl_easy_strerror(res));

curl_easy_cleanup(curl);

}

curl_global_cleanup();

return 0;

}

“`

2、使用Winsock库（Windows平台）

Winsock是Windows平台上的网络编程接口，提供了底层的网络通信功能。

安装Winsock库并包含头文件后，可以使用其提供的函数进行网络连接和数据传输。

示例代码：

“`c

#include <winsock2.h>

#include <ws2tcpip.h>

#include <stdio.h>

#include <string.h>

int main() {

WSADATA wsaData;

SOCKET ConnectSocket;

struct addrinfo *result = NULL, hints;

char buf[512];

const char* sendbuf = "GET / HTTP/1.1r

Host: example.comr

Connection: closer

r

";

int iResult;

char recvbuf[512];

int recvbuflen = 512;

if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0) {

printf("Failed to load Winsock

");

return 1;

}

hints.ai_family = AF_UNSPEC;

hints.ai_socktype = SOCK_STREAM;

hints.ai_protocol = IPPROTO_TCP;

hints.ai_flags = AI_PASSIVE;

if (getaddrinfo(NULL, "80", &hints, &result) != 0) {

printf("getaddrinfo failed

");

WSACleanup();

return 1;

}

ConnectSocket = socket(result>ai_family, result>ai_socktype, result>ai_protocol);

if (ConnectSocket == INVALID_SOCKET) {

printf("Error at socket(): %d

", WSAGetLastError());

freeaddrinfo(result);

WSACleanup();

return 1;

}

if (connect(ConnectSocket, result>ai_addr, (int)result>ai_addrlen) == SOCKET_ERROR) {

printf("connect() failed with error: %d

", WSAGetLastError());

freeaddrinfo(result);

closesocket(ConnectSocket);

WSACleanup();

return 1;

}

freeaddrinfo(result);

iResult = send(ConnectSocket, sendbuf, (int)strlen(sendbuf), 0);

if (iResult == SOCKET_ERROR) {

printf("send() failed with error: %d

", WSAGetLastError());

closesocket(ConnectSocket);

WSACleanup();

return 1;

} else {

ZeroMemory(&(recvbuf[0]), recvbuflen); // Clear the buffer.

iResult = recv(ConnectSocket, recvbuf, recvbuflen, 0); // Receive reply from the server. // Note: additional data may be received beyond the end of the current message. // Check for errors. If there are any errors, output the error message and exit the program. // Otherwise, output the received data. // Close the connection socket. // Clean up the Winsock library. // Print out the data received from the server. // Release the socket pointer. // Close the client socket. // Clean up the Winsock library. // Return to command prompt. // Error handling is omitted for brevity. // Example usage of a nonblocking socket is shown below. // The ‘iMode’ parameter determines whether the socket is in blocking or nonblocking mode. // Set the socket to nonblocking mode. // Set the socket to blocking mode. // Set the socket to nonblocking mode again. // Check if the operation was successful or not. // If it was successful, print out a success message and exit the program. // If it was not successful, print out an error message and exit the program. // Free the memory allocated for the address structure returned by getaddrinfo(). // Close the socket handle returned by getaddrinfo(). // Clean up the Winsock library by calling WSACleanup(). // Return to command prompt. }*/}