Ranges that are not in the form 0-n do not work.

[NikkiOfTheValley]

The library makes several bad assumptions in range_error and in a few other places that I haven't been able to track down that ranges are always from zero and that the body field of the response contains the entire file (this makes no sense. Why would you want to waste disk space and time getting the entire file rather than just a smaller chunk of it?), as ranges that are not formatted like that cause range errors. If I comment out the range_error call in the library, it still doesn't work.
The reason why this needs to be implemented is that video streaming needs the ability to get an arbitrary range of bytes.

This is my code for handling range requests:

std::ostringstream sstr;
std::string data = "";

if (req.ranges.size() != 0)
{
    Range range = req.ranges[0];

    ssize_t numBytes = range.second == -1 ? 1024 : range.second - range.first;
    ssize_t offset = range.first;

    data.resize(numBytes + 1);

    inputFile.seekg(offset);
    numBytes = inputFile.readsome(data.data(), numBytes);

    res.set_content(data.data(), numBytes, "video/webm");
    res.content_length_ = numBytes;
    logger->log("numbytes:" + std::to_string(numBytes));

    inputFile.close();
}
else
{
    sstr << inputFile.rdbuf();
    data = sstr.str();
    inputFile.close();
}

[yhirose]

@NikkiOfTheValley thank you for the feedback and suggested implementation. Could you please send a pull request and some unit tests? Thanks a lot!

[NikkiOfTheValley]

@yhirose Oh, I should've clarified. That is my current implementation using the library itself. It's actually impossible as far as I can tell to use the library to handle range requests properly. I have no idea where exactly the bad assumption in the rest of the library code outside of range_error() is.

Even if I remove the call to range_error on the server, it seems like the library tries to truncate the data (which, again, is a really wonky way of doing that), gets nonsense results, and corrupts the data. In some situations it even fails to send all the data, causing a timeout on the request.

[yhirose]

@NikkiOfTheValley thanks for the additional information. But I still don't fully understand what you mean and what I should do for it. Could you please show me your calling example of cpp-httplib with your HTTP request, and expected result? Then, I'll try to reproduce the problem on my machine. Thanks!

[NikkiOfTheValley]

@yhirose I'm not actually sending the requests from the client using cpp-httplib, I'm using it for a simple web server. The actual thing that's doing the requests is DASH, which is a browser-side video streaming library. It would require a lot of setup on your end to get it to work, and it's way overcomplicated to replicate exactly what I'm trying to do on your machine. Just send a request that has a range that doesn't start with zero using curl or something, and then you should be able to replicate the issue.

[yhirose]

@NikkiOfTheValley do you mean that you create a simple web server based on the cpp-httplib server and send HTTP requests with a '0-n range' header from your system, but you don't get responses that you expect?

Could you please show me your HTTP requests and actual responses from the cpp-httplib based server?
Also I am not familiar to DASH. How does it work?

Thanks for your help and sorry for my slow understanding...