Libcurl笔记三

一，post请求和回报处理

//"host/path?extra"
//strHttp=" http://portal.liuhan.com:/web/getConfig?userName=liuhan01 &clientVersion=1.5.0.0";
Curl    m_objUrlParser;//ATL的处理类。
m_objUrlParser.CrackUrl(strHttp);

// "portal.liuhan.com" + "/web/getConfig"
std::string    strUrl = std::string(m_objUrlParser.GetHostName()) + std::string(m_objUrlParser.GetUrlPath());
// "?userName=liuhan01 &clientVersion=1.5.0.0"
std::string    strObject = std::string(m_objUrlParser.GetExtraInfo());
if (strObject.at() == '?')
{
    strObject.erase(, );
}

curl_easy_setopt(m_easyHandle, CURLOPT_URL, strUrl.str());
curl_easy_setopt(m_easyHandle, CURLOPT_POST, 1L);
curl_easy_setopt(m_easyHandle, CURLOPT_VERBOSE, 1L);

curl_easy_setopt(m_easyHandle, CURLOPT_POSTFIELDS, strObject.c_str());
curl_easy_setopt(m_easyHandle, CURLOPT_POSTFIELDSIZE, strObject.size());

curl_easy_setopt(m_easyHandle, CURLOPT_WRITEFUNCTION, write_data);
curl_easy_setopt(m_easyHandle, CURLOPT_WRITEDATA, pagefile);

    二，upload上传内存中的数据

网查了好久read_callback全是FILE*的处理，需要研究下。
1：CURLOPT_READFUNCTION设置后read_callback会一直被调用直到read_callback返回值为0为止；
2：第三个参数nitems表示buffer的最大缓冲长度。

static size_t read_callback(void *ptr, size_t size, size_t nmemb, void *stream)
{
    size_t retcode = fread(ptr, size, nmemb, stream);
    return retcode;
}

会一直回调读取文件流stream的内容，直到读到末尾返回读取长度为0时才结束。

typedef struct UploadBuffer
{
    char* pBuffs;
    unsigned int uOverallLength;
    unsigned int uCurrentPos;
} UPLOAD_BUFFER;

static size_t read_callback(void *ptr, size_t size, size_t nmemb, void *stream)
{
    UPLOAD_BUFFER* pBuffer = (UPLOAD_BUFFER*)stream;
    size_t len = pBuffer->uOverallLength- pBuffer->uCurrentPos;
    len = len < nmemb ? len : nmemb - ;
    memcpy_s(ptr, nmemb, pBuffer->pBuffs+ pBuffer->uCurrentPos, len);
    pBuffer->uCurrentPos += len;

    return len;
}

curl_easy_setopt(m_easyHandle, CURLOPT_UPLOAD, 1L);
curl_easy_setopt(m_easyHandle, CURLOPT_READFUNCTION, read_callback);
curl_easy_setopt(m_easyHandle, CURLOPT_URL, UPLOAD_URL);
curl_easy_setopt(m_easyHandle, CURLOPT_READDATA, pUpBuffer);