怎么用C实现Http POST功能向Http服务器上传文件

用socket就行了。

和服务器建立请求。

然后发送请求报文"\r\n\r\n"结束之后是数据。

post分为,application/x-www-form-urlencoded和multipart/form-data boundary=

要是上传文件,就得使用multipart/form-data boundary=...

服务器那边根据boundary来解析出数据。

C语言发post请求数据程序， 工作需要，网上查资料N篇，作为半路出家学编程的，走过了N个坑，终于完成以下的测试程序。

使用了curl的库, 这样无论在windows或者在linux都可以使用.

win下的编程环境是TDM-GCC-64, 怎样安装，也是另一个话题。需要这个的请自行上网查询怎样安装.

linux 下是gcc环境，最好先安装curl开发包，目的就是需要curl.h等文件, 怎样安装，也是另一个话题。

废话不说，以下是正式程序.

#include

#include

#include

#include

struct string {

char *ptr

size_t len

}

void init_string(struct string *s) {

s->len = 0

s->ptr = malloc(s->len + 1)

if (s->ptr == NULL) {

fprintf(stderr, "malloc() failed ")

exit(EXIT_FAILURE)

}

s->ptr[0] = ''

}

size_t writefunc(void *ptr, size_t size, size_t nmemb, struct string *s)

{

size_t new_len = s->len + size * nmemb

s->ptr = realloc()(s->ptr, new_len + 1)

if (s->ptr == NULL) {

fprintf(stderr, "realloc() failed ")

exit(EXIT_FAILURE)

}

memcpy(s->ptr + s->len, ptr, size*nmemb)

s->ptr[new_len] = ''

s->len = new_len

return size * nmemb

}

CURLcode curl_post_req(char *url, char *postParams,struct curl_slist *headers, char *response)

{

CURL *curl

curl = curl_easy_init()//初始化

// curl返回值

CURLcode res

if (curl)

{

struct string s

init_string(&s)

curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers)

//curl_easy_setopt(curl, CURLOPT_URL, "http://httpbin.org/post")

curl_easy_setopt(curl, CURLOPT_URL, url)

curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, writefunc)

curl_easy_setopt(curl, CURLOPT_WRITEDATA, &s)

curl_easy_setopt(curl, CURLOPT_POST, 1)//设置CURLOPT_POST之后必须带有POST数据

curl_easy_setopt(curl, CURLOPT_POSTFIELDS, postParams)

//不接收响应头数据0代表不接收 1代表接收

curl_easy_setopt(curl, CURLOPT_HEADER, 0)

curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L)

//CURLOPT_VERBOSE的值为1时，会显示详细的调试信息

curl_easy_setopt(curl, CURLOPT_VERBOSE, 0)

curl_easy_setopt(curl, CURLOPT_READFUNCTION, NULL)

curl_easy_setopt(curl, CURLOPT_NOSIGNAL, 1)

//设置超时时间，以秒来计算 CURLOPT_CONNECTTIMEOUT是连接超时

curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT, 10)

curl_easy_setopt(curl, CURLOPT_TIMEOUT, 10)

// https ssl 时需要用到，如果是 http 可以注释掉

curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L)

curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0L)

res = curl_easy_perform(curl)

//printf(" =>%s=>=>", s.ptr)

sprintf(response," =>%s ", s.ptr)

free(s.ptr)

curl_slist_free_all(headers)

}

curl_easy_cleanup(curl)

return res

}

int main(int argc, const char *argv[])

{

// http 请求头, 构造

printf(" start... ")

struct curl_slist *headers1 = NULL

headers1 = curl_slist_append(headers1, "User-Agent: Mozilla/5.0 (Windows NT 10.0WOW64Trident/7.0rv:11.0) like Gecko")

headers1 = curl_slist_append(headers1, "Content-Type:application/x-www-form-urlencodedcharset=UTF-8")

char url_post0[100] = "https://www.lpfrx.com/"

// 查找的字符串 ： delphi

char paramsLogin0[100] = "s=delphi"

char resPost0[40960] = ""

CURLcode res3 = curl_post_req(url_post0, paramsLogin0, headers1,resPost0)

if (res3 == CURLE_OK)

{

printf("data: %s" ,resPost0)

}

printf(" end... ")

return 0

}

// win 下cmd下运行乱码，请先执行 chcp 65001 转成 utf8. 默认是chcp 936

// win: 运行目录下需要zlib.dll libcurl.dll

// curl-Library 是我自己的目录，放在当前的程序目录下，win下的curl.h 也是需要自己去找，如果有python编程环境的话，也安装了curl库的话，应该可能会有curl.h的库路径

// win: gcc -o curlpostlpfrx curlpost_lpfrx.c -I ./curl-Library/include -L ./curl-Library/lib -lcurl

//linux: gcc -o curlpostlpfrx curlpost_lpfrx.c -lcurl

CInternetSession m_winet(NULL,1,INTERNET_OPEN_TYPE_DIRECT,NULL,NULL,0)

CHttpConnection *pConnection

CHttpFile *pFile

pConnection = m_winet.GetHttpConnection("expert.csdn.net")

CString strHeaders, tempStr,str

str="name=*******&pass=******&type=1"

//strHeaders = _T("Content-Type: application/x-www-form-urlencoded")

pFile=pConnection->OpenRequest(CHttpConnection::HTTP_VERB_POST,

"/member/logon.asp")

pFile->AddRequestHeaders("Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/vnd.ms-powerpoint, application/vnd.ms-excel, application/msword, */*")

pFile->AddRequestHeaders("User-Agent: Mozilla/4.0 (compatibleMSIE 5.01Windows NT 5.0)")

pFile->AddRequestHeaders("Content-Type: application/x-www-form-urlencoded")

pFile->SendRequest(

NULL,0,

(LPVOID)(LPCTSTR)str, str.GetLength())

上面是登陆部分，然后用InternetGetCookie获得COOKIES以后把它AddRequestHeaders里面再SendRequest出去OpenRequest(CHttpConnection::HTTP_VERB_POST,

"/member/logon.asp")里的CHttpConnection::HTTP_VERB_POST控制是POST还是GET，最好截包分析一下。发帖子需要加COOKIES

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