c - libcurl - PUT 问题后的 POST

Question

我正在使用 libcurl 在 C 中编写一个 http 客户端。但是，当我重新使用相同的句柄来传输 PUT 后跟 POST 时，我遇到了一个奇怪的问题。示例代码如下:

#include <curl/curl.h>

void send_a_put(CURL *handle){
    curl_easy_setopt(handle, CURLOPT_UPLOAD, 1L); //PUT
    curl_easy_setopt(handle, CURLOPT_INFILESIZE, 0L);
    curl_easy_perform(handle);        
}

void send_a_post(CURL *handle){
    curl_easy_setopt(handle, CURLOPT_POST, 1L);  //POST
    curl_easy_setopt(handle, CURLOPT_POSTFIELDSIZE, 0L);         
    curl_easy_perform(handle);        
}

int main(void){
    CURL *handle = curl_easy_init();

    curl_easy_setopt(handle, CURLOPT_URL, "http://localhost:8888/");
    curl_easy_setopt(handle, CURLOPT_HTTPHEADER, 
                     curl_slist_append(NULL, "Expect:"));

    curl_easy_setopt(handle, CURLOPT_VERBOSE, 1L); //for debug 

    send_a_put(handle);
    send_a_post(handle);

    curl_easy_cleanup(handle);
    return 0;
}

问题是，它发送了 2 个 PUT，而不是先发送一个 PUT，然后发送一个 POST:

> PUT / HTTP/1.1
Host: localhost:8888
Accept: */*
Content-Length: 0

< HTTP/1.1 200 OK
< Date: Wed, 07 Dec 2011 04:47:05 GMT
< Server: Apache/2.0.63 (Unix) PHP/5.3.2 DAV/2
< Content-Length: 0
< Content-Type: text/html

> PUT / HTTP/1.1
Host: localhost:8888
Accept: */*
Content-Length: 0

< HTTP/1.1 200 OK
< Date: Wed, 07 Dec 2011 04:47:05 GMT
< Server: Apache/2.0.63 (Unix) PHP/5.3.2 DAV/2
< Content-Length: 0
< Content-Type: text/html

更改顺序使两次传输都正确发生(即 send_a_post() 然后是 send_a_put())。如果我在 PUT 之后或 POST 之前发送 GET，一切都很好。仅当 PUT 后跟 POST 时才会出现此问题。

有人知道为什么会这样吗？

Answer 1

“如果您发出 POST 请求，然后想使用相同的重复使用句柄发出 HEAD 或 GET，则必须使用 CURLOPT_NOBODY 或 CURLOPT_HTTPGET 或类似方式明确设置新的请求类型。”

来自 the documentation

编辑:实际上比这更简单。你需要像这样在调用之间重置你的选项:

void
send_a_put (CURL * handle)
{
  curl_easy_setopt (handle, CURLOPT_POST, 0L);    // disable POST
  curl_easy_setopt (handle, CURLOPT_UPLOAD, 1L);  // enable PUT
  curl_easy_setopt (handle, CURLOPT_INFILESIZE, 0L);
  curl_easy_perform (handle);
}

void
send_a_post (CURL * handle)
{
  curl_easy_setopt (handle, CURLOPT_UPLOAD, 0L);  // disable PUT
  curl_easy_setopt (handle, CURLOPT_POST, 1L);    // enable POST
  curl_easy_setopt (handle, CURLOPT_POSTFIELDSIZE, 0L);
  curl_easy_perform (handle);
}