當無法訪問服務器時，curl_easy_perform返回-1

Question

當我嘗試對無法訪問的服務器執行一些HTTP_POST，HTTP_DELETE操作時，返回代碼有時為-1。因為我的應用程序崩潰了。

這是我的示例代碼。

我的應用程序代碼在C ++中，我也在其中讀取響應和響應頭。

  lCode = curl_easy_setopt(curlHandle, CURLOPT_HEADERFUNCTION,
                                      HttpClientImplCurl::recvFunctionHeader);

    if (lCode != CURLE_OK) {
        LOG(LOG_CRIT, "CURL failure: curl_easy_setopt CURLOPT_HEADERFUNCTION returned %d\n", lCode);
        curl_slist_free_all(lHeaders);
        errorBuff = curl_easy_strerror(lCode);
        return http_code;

    }


    lCode = curl_easy_setopt(curlHandle, CURLOPT_WRITEHEADER,
                                      &readResHeaderBuffer);

    if (lCode != CURLE_OK) {
        LOG(LOG_CRIT, "CURL failure: curl_easy_setopt CURLOPT_WRITEHEADER returned %d\n", lCode);
        curl_slist_free_all(lHeaders);
        errorBuff = curl_easy_strerror(lCode);
        return http_code;

    }

        lCode = curl_easy_setopt(curlHandle, CURLOPT_WRITEFUNCTION,
                             HttpClientImplCurl::recvFunction);

    if (lCode != CURLE_OK) {
        LOG(LOG_CRIT, "CURL failure: curl_easy_setopt WRITEFUNCTION returned %d\n", lCode);
        curl_slist_free_all(lHeaders);
        errorBuff = curl_easy_strerror(lCode);
        return http_code;

    }

    lCode = curl_easy_setopt(curlHandle, CURLOPT_WRITEDATA,
                             &readResBuffer);

    if (lCode != CURLE_OK) {
        LOG(LOG_CRIT, "CURL failure: curl_easy_setopt WRITEDATA returned %d\n", lCode);
        curl_slist_free_all(lHeaders);
        errorBuff = curl_easy_strerror(lCode);
        return http_code;

    }

    lCode = curl_easy_setopt(curlHandle, CURLOPT_CUSTOMREQUEST, "DELETE"); /* !!! */

    if (lCode != CURLE_OK) {
        LOG(LOG_CRIT, "CURL failure: curl_easy_setopt CURLOPT_CUSTOMREQUEST returned %d\n", lCode);
        curl_slist_free_all(lHeaders);
        errorBuff = curl_easy_strerror(lCode);
        return http_code;

    }

    lCode =  curl_easy_setopt(curlHandle, CURLOPT_POSTFIELDS, aInRemovedata.getBuffer()); /* data goes here */

    if (lCode != CURLE_OK) {
        LOG(LOG_CRIT, "CURL failure: curl_easy_setopt CURLOPT_POSTFIELDS  returned %d\n", lCode);
        curl_slist_free_all(lHeaders);
        errorBuff = curl_easy_strerror(lCode);
        return http_code;

    }

lCode = curl_easy_perform(curlHandle);


    if (lCode != CURLE_OK) {
        LOG(LOG_CRIT, "CURL failure: curl_easy_perform returned %d\n", lCode);
        curl_slist_free_all(lHeaders);
        errorBuff = curl_easy_strerror(lCode);---->my doubt is when i am geting "-1", this line is caused the crash.
        return http_code;
    }

我的回調如下

  size_t
HttpClientImplCurl::recvFunctionHeader(void *aInBuf, size_t aInSize,
                                size_t aInNmemb, void* aInUserp)
{
    fprintf(stderr, "curl error: too small buffer in recv2\n");
    ((std::string*)aInUserp)->append((char*)aInBuf, aInSize * aInNmemb);
    return aInSize * aInNmemb;
}


// Private static callback
size_t
HttpClientImplCurl::recvFunction(void *aInBuf, size_t aInSize,
                                size_t aInNmemb, void* aInUserp)
{
    fprintf(stderr, "curl error: too small buffer in recv1\n");
    ((std::string*)aInUserp)->append((char*)aInBuf, aInSize * aInNmemb);
    return aInSize * aInNmemb;
}

請幫助我，為什么我們偶爾會用“ -1”代替“ 28”。

這是函數簽名，其中errorBuf作為參數出現

 int
HttpClientImplCurl::put(const HttpClient& aInClient,const base::Buffer& aInPutdata,
                          base::Buffer& aOutRecvBuf,base::Buffer&  aOutRecvHeaderBuf,const char*& errorBuff)

Answer 1

您可以嘗試設置CURLOPT_ERRORBUFFER和CURLOPT_VERBOSE以獲取有關為什么curl_easy_perform返回的值為-1的更多信息。