getinfo for curl_easy interface about curlcpp

[JosephP91]

@typedeph I will put a get_info method in the next commit. Thank you!

[JosephP91]

@typedeph I just pushed a commit with get_info method for curl_easy interface. You will find an example in the README.md and in tests/easy_info.cpp. Let me know if everything works.

[AlexGoico]

I just went from:

      long code;
      curl_easy_getinfo(easy.get_curl(), CURLINFO_RESPONSE_CODE, &code);

to:

      long code = easy.get_info<long>(CURLINFO_RESPONSE_CODE).get().second;

Will probably split it along two lines for better readibility. Thanks, great job with the wrapper.

[AlexGoico]

Seems I was either wrong or lucky. The code I used before ran but for some reason the same encapsulated function will no longer run. I'm still a newbie at c++ but I think the reason is because my get function is dereferencing a dangling pointer in curl_easy. Here is my method with cout's to trace the seg fault:

  // the default parameter is included for more specificity but it is declared in the corresponding header for this function
  std::string get(const std::string& url, 
                            const std::string& ua = "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) "
    "Chrome/48.0.2564.116 Safari/537.36")
  {
    using namespace curl;
    std::ostringstream str;
    curl_ios<std::ostringstream> writer{str};

    curl_easy easy{writer};
    easy.add<CURLOPT_URL>(url.c_str());
    easy.add<CURLOPT_ACCEPT_ENCODING>("");
    easy.add<CURLOPT_FOLLOWLOCATION>(1L);
    easy.add<CURLOPT_USERAGENT>(ua.c_str());
    try {
      easy.perform();
      std::cout << "Getting info..." << std::endl;
      auto c = easy.get_info<long>(CURLINFO_RESPONSE_CODE);
      std::cout << "Getting pair..." << std::endl;
      auto p = c.get();
      std::cout << "Getting code..." << std::endl;
      long code = p.second;
      std::cout << "Code: " << code << std::endl;
      if (code < 200 || code >= 300)
        throw RequestException(url + " returned status code " +
                               std::to_string(code));
    }
    catch (curl_easy_exception error) {
      error.print_traceback();
    }
    catch (...) {
      std::cerr << "An unexepcted exception occurred" << std::endl;
    }
    return str.str();
  }

My code seg faults for http://www.google.com/ and other urls after printing "Getting pair...".
I am thinking this is because the pointer on line 1017 of curl_easy points to stack allocated data assigned at line 1018 and then this is overridden when the function returns. The curl_easy_info object will then have a dangling pointer that will seg fault when I dereference it in an attempt try to create the pair at line 61.

[JosephP91]

@typedeph you're right. The bug should be fixed with the last commit. Do a git pull and let me know! You can remove the part where you obtain the pair object. Pair has been removed. You will get just the variable containing the code you are trying to print.

[JosephP91]

It should be fixed now.

[AlexGoico]

Sorry for the late response, I was not able to get on my Linux machine until now. I did want to confirm that it is fixed though.

[JosephP91]

Good! Thank you!

[ronny332]

Hi,

may be I do something wrong, but with the latest version from github a usage of

auto code = easy.get_info<long>(CURLINFO_RESPONSE_CODE);

ends in

error: no matching function for call to ‘curl::curl_easy::get_info(CURLINFO)’ note: candidate: template<CURLINFO Info> const curl::curl_easy_info<typename curl::detail_info::info_t<<anonymous> >::type> curl::curl_easy::get_info() template<CURLINFO Info> const curl_easy_info<detail_info::Info_type<Info>> get_info();

Were there any changes, which are making the usage of get_info impossible?

EDIT:
ok, this is working:
auto code = easy.get_info<CURLINFO_RESPONSE_CODE>();

[JosephP91]

Good @ronny332