2012/10/14 Angelo Di Iorio <diioangelo_at_gmail.com>:
> 2012/10/7 Daniel Stenberg <daniel_at_haxx.se>:
>>
>> You can get the HTTP traffic using many means, Wireshark being one but
>> LiveHTTPTraffic or the browsers own debugging tools are other ways. You
>> could focus on what exactly the differences are between what your browser
>> does and what your libcurl program does (or doesn't) do.
>>
>>
>> --
>>
>> / daniel.haxx.se
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>
> I've observed the behaviour of my code thanks to wireshark. With the
> following version of my code, where I'm trying to use a global CURL
> variable in order to perform a single connection to the server instead
> of multiple ones, I don't have any traffic at all (please note all the
> variable's names which starts with an underscore are global ones) :
>
> int simpleHttpRequest(char* url)
> {
> CURLcode res; //result of the request
>
> MemoryStruct chunk; //defined in HttpRequestSupport.h
>
> chunk.memory = malloc(1); // will be grown as needed by the
> realloc istruction in writeMemoryCallback
> chunk.size = 0; // no data at this point
>
> int result = 1;
>
> if(!_isInitialized)
> {
> initialize(_curl);
> _isInitialized = true;
> }
> if(!_isLogged)
> {
> result = login(_curl); //this function will return an error if
> the login phase fails
> if(result != 0) return result; //an error occoured during the
> login phase
> _isLogged = true;
> }
>
> if(_curl)
> {
> curl_easy_setopt(_curl, CURLOPT_URL, url);
>
> /* send all data to this function */
> curl_easy_setopt(_curl, CURLOPT_WRITEFUNCTION, writeMemoryCallback);
>
> /* we pass our 'chunk' struct to the callback function */
> curl_easy_setopt(_curl, CURLOPT_WRITEDATA, (void*) &chunk);
>
> /* some servers don't like requests that are made without a
> user-agent field, so we provide one */
> curl_easy_setopt(_curl, CURLOPT_USERAGENT, "libcurl-agent/1.0");
>
> /* Perform the request, res will get the return code */
> res = curl_easy_perform(_curl);
>
> /* Check for errors */
> result = check(res,chunk.memory);
> /* always cleanup */
> curl_easy_cleanup(_curl);
> if(chunk.memory) free(chunk.memory);
>
> return result;
> }
> else return -9;
> }
>
> this error shows up: curl_easy_perform() failed: A libcurl function
> was given a bad argument
>
> for the clarity's sake, here's the initialize() function:
>
> void initialize(CURL* curl)
> {
> curl_global_init(CURL_GLOBAL_ALL);
> curl = curl_easy_init();
> }
>
> I've already sent the login code in my very first email (and, after I
> had a look on wireshark, it seems to me the problem isn't in that
> portion of code. At least, not this one).
> With this version of my code, everything works fine (except the
> connections thing: I have multiple connections, obviously)
>
> int simpleHttpRequest(char* url)
> {
> CURL* curl; //curl handler
> CURLcode res; //result of the request
>
> MemoryStruct chunk; //defined in HttpRequestSupport.h
>
> chunk.memory = malloc(1); // will be grown as needed by the
> realloc istruction in writeMemoryCallback
> chunk.size = 0; // no data at this point
>
> int result = 1;
>
> curl = curl_easy_init();
>
> result = login(curl); //this function will return an error if the
> login phase fails
> if(result != 0) return result; //an error occoured during the login phase
>
> if(curl)
> {
> curl_easy_setopt(curl, CURLOPT_URL, url);
>
> /* send all data to this function */
> curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, writeMemoryCallback);
>
> /* we pass our 'chunk' struct to the callback function */
> curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void*) &chunk);
>
> /* some servers don't like requests that are made without a
> user-agent field, so we provide one */
> curl_easy_setopt(curl, CURLOPT_USERAGENT, "libcurl-agent/1.0");
>
> /* Perform the request, res will get the return code */
> res = curl_easy_perform(curl);
>
> /* Check for errors */
> result = check(res,chunk.memory);
> /* always cleanup */
> curl_easy_cleanup(curl);
> if(chunk.memory) free(chunk.memory);
>
> return result;
> }
> else return -9;
> }
>
> The difference between the two versions of my code is basically I
> don't have a global CURL variable (which I'd like to have).
> Excuse me for my poor english and 'noobness', I appreciate your help
> and suggestions.
> --
> Angelo Di Iorio

I solved it. I had to change the initialize() function, by making it
returning a CURL* pointer. Thanks for your support and patience.

-- 
Angelo Di Iorio
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