c语言http上传文件,C语言实现HTTP文件上传功能

在C语言中实现HTTP文件上传功能，可以使用libcurl库。以下是一个简单的示例：

首先，确保已经安装了libcurl库。在Ubuntu系统中，可以使用以下命令安装：

```bash

sudo apt-get install libcurl4-openssl-dev

```

接下来，创建一个名为`http_upload.c`的C文件，并添加以下代码：

```c

#include

#include

#include

#include

size_t write_data(void *ptr, size_t size, size_t nmemb, FILE *stream) {

size_t written = fwrite(ptr, size, nmemb, stream);

return written;

}

int main(void) {

CURL *curl;

FILE *fp;

char url[BUFSIZ];

char outfilename[] = "uploaded_file";

char infilename[] = "input_file";

char data[BUFSIZ];

// 设置请求头

CURLcode res;

curl_global_init(CURL_GLOBAL_DEFAULT);

res = CURLE_OK;

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

curl_setopt(curl, CURLOPT_POSTFIELDS, "file=@" + infilename);

curl_setopt(curl, CURLOPT_UPLOAD, 1L);

curl_setopt(curl, CURLOPT_READDATA, &infilename);

curl_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);

curl_setopt(curl, CURLOPT_WRITEDATA, &outfilename);

curl_setopt(curl, CURLOPT_TIMEOUT, 5L);

curl_setopt(curl, CURLOPT_NOPROGRESS, 0L);

curl_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L);

curl_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L);

curl_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0L);

// 初始化CURL对象

res = curl_easy_init(curl);

if (res != CURLE_OK) {

fprintf(stderr, "curl_easy_init() failed: %sn", curl_easy_strerror(res));

exit(EXIT_FAILURE);

}

// 执行请求

res = curl_easy_perform(curl);

if (res != CURLE_OK) {

fprintf(stderr, "curl_easy_perform() failed: %sn", curl_easy_strerror(res));

exit(EXIT_FAILURE);

}

// 获取响应数据

res = curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &response_code);

if (res != CURLE_OK) {

fprintf(stderr, "curl_easy_getinfo() failed: %sn", curl_easy_strerror(res));

exit(EXIT_FAILURE);

}

// 关闭CURL对象

curl_easy_cleanup(curl);

// 读取响应数据

fp = fopen(outfilename, "wb");

if (fp == NULL) {

fprintf(stderr, "Failed to open file for writing: %sn", strerror(errno));

exit(EXIT_FAILURE);

}

// 写入响应数据

memset(data, 0, sizeof(data));

strncpy(data, response_code, sizeof(data));

fwrite(data, sizeof(char), strlen(data), fp);

fclose(fp);

// 释放资源

curl_global_cleanup();

return 0;

}

```

编译并运行程序：

```bash

gcc http_upload.c -o http_upload -lcurl

./http_upload

```

注意：这个示例仅用于演示目的，实际应用中可能需要根据具体需求进行修改。