CODEWITHSUNDEEP
c++libcurl
amplifier
amplifier

Reputation: 1833

Libcurl - downloading and saving file with its real name

I develop C++ application. It downloads files. Typical url looks like https://mysite.com/download.php?fileid=xxx So the first problem - I need to get real filename. I do it like:

curl_easy_setopt(pCurl, CURLOPT_HEADERFUNCTION, readHeader);

And a callback

size_t NetworkHelper::readHeader(void *ptr, size_t size, size_t nmemb, void *data)
{
        std::string header;
        header.assign((char*)ptr, nmemb);
    size_t delimPos = header.find_first_of(':');
    std::string headerName;
    std::string headerContent;
    if (delimPos != std::string::npos)
    {
        headerName = header.substr(0, delimPos);
        headerContent = header.substr(delimPos + 1, header.length());
        m_headers[headerName] = headerContent;
    }
    return size*nmemb;
}

Here I insert headers and its values into map this callback is invoked many times for each http header. The header which I really need is "Location: url/realfilename.yyy".

And writing callback:

size_t NetworkHelper::writeFileCallback(void* ptr, size_t size, size_t nmemb, void* data)
{
    size_t count;
    Fetchdata* fetchdata;
    fetchdata = (Fetchdata*)data;
    std::string fileName = NetworkHelper::m_headers["Location"].c_str();
    fileName = "C:/" + fileName.substr(fileName.find_last_of('/') + 1, fileName.length());
    fetchdata->stream = fopen( fileName.c_str(),"w+b");
    if (fetchdata->stream!=NULL)
    {
        count = fwrite(ptr, size, nmemb, fetchdata->stream);
        if (count > 0) 
        {
            fetchdata->size += (count * size);
        }
    }
    return nmemb*size;
}

And here fopen fails (returns NULL). Is it wrong how I process files and how to do it better way? Thanks.

Upvotes: 1

Views: 455

Answers (1)

BetMora
BetMora

Reputation: 11

At first check what fileName actually contains. Use error() or GetLastError on windows to check what's the problem. I may be wrong, but according to your code fileName actually contains something like this: C:/http://somesimet.somedomain/file.extension upd: sorry, was really wrong about file name

Upvotes: 1

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