m3u8handler.cpp

#include "m3u8handler.h"
#include "logger.h"

M3u8Handler::M3u8Handler(std::string uri) : webUri(uri) {
}

bool M3u8Handler::startsWith(const std::string& str, const std::string& prefix) {
    return str.size() >= prefix.size() && 0 == str.compare(0, prefix.size(), prefix);
}

std::vector<std::string> M3u8Handler::split(const std::string &s, char delim) {
    std::vector<std::string> result;
    std::stringstream ss (s);
    std::string item;

    while (getline (ss, item, delim)) {
        result.push_back (item);
    }

    return result;
}

m3u_stream M3u8Handler::parseM3u() {
    DEBUG("Load file " + webUri);

    auto uri = uri::parse_uri(webUri);

    httplib::Client cli(uri.scheme + "://" + uri.authority.host + (uri.authority.port > 0 ? std::to_string(uri.authority.port) : ""));
    auto res = cli.Get(uri.path);

    m3u_stream result;
    result.width = result.height = 0;

    if (res == nullptr) {
        return result;
    }

    if (res->status != 200) {
        return result;
    }

    std::string m3u = res->body;
    std::istringstream stream(m3u);
    std::string line;

    int maxW = 0, maxH = 0;
    std::string audioGroup;
    std::string m3uMax;

    std::string starterStream = "#EXT-X-STREAM-INF:";
    std::string starterMedia = "#EXT-X-MEDIA:";
    std::string starterIgnore = "#EXTINF:";

    while (std::getline(stream, line)) {
        if (startsWith(line, starterStream)) {
            auto splitted = split(line.substr(starterStream.length()), ',');

            for (const auto& t : splitted) {
                if (startsWith(t, "RESOLUTION=")) {
                    int w, h;
                    sscanf(t.c_str() + 11, "%dx%d", &w, &h);

                    if (w > maxW) {
                        maxW = w;
                        maxH = h;
                        std::getline(stream, m3uMax);

                        if (!startsWith(m3uMax, "http://") && !startsWith(m3uMax, "https://")) {
                            // this is a relative URL -> construct absolute URL
                            auto last = webUri.find_last_of('/');
                            m3uMax = webUri.substr(0, last+1).append(m3uMax);
                        }
                    }
                } else if (startsWith(t, "AUDIO=")) {
                    audioGroup = t.substr(7, t.length()-8);
                }
            }
        } else if (startsWith(line, starterMedia)) {
            auto splitted = split(line.substr(starterMedia.length()), ',');

            bool addThis = true;
            media m;

            for (const auto& t : splitted) {
                if (startsWith(t, "TYPE=")) {
                    m.type = t.substr(5);
                    if (m.type != "AUDIO") {
                        // no audio -> skip
                        addThis = false;
                        break;
                    }
                } else if (startsWith(t, "LANGUAGE=")) {
                    m.language = t.substr(10, t.length()-11);
                } else if (startsWith(t, "NAME=")) {
                    m.name = t.substr(6, t.length()-7);
                } else if (startsWith(t, "GROUP-ID=")) {
                    m.groupId = t.substr(10, t.length()-11);
                } else if (startsWith(t, "URI=")) {
                    m.uri = t.substr(5, t.length()-6);
                }
            }

            if (addThis) {
                if (!startsWith(m.uri, "http://") && !startsWith(m.uri, "https://")) {
                    // this is a relative URL -> construct absolute URL
                    auto last = webUri.find_last_of('/');
                    m.uri = webUri.substr(0, last+1).append(m.uri);
                }

                result.audio.push_back(m);
            }
        } else if (startsWith(line, starterIgnore)) {
            // this is already a usable m3u8. Don't process anymore but return a useful result
            result.width = 1920;
            result.height = 1080;
            result.url = webUri;
            return result;
        }
    }

    // remove all unwanted audio streams with wrong group-id
    if (!audioGroup.empty() && !result.audio.empty()) {
        auto it = result.audio.begin();
        while(it != result.audio.end()) {
            if(it->groupId != audioGroup) {
                it = result.audio.erase(it);
            } else {
                ++it;
            }
        }
    }

    result.width = maxW;
    result.height = maxH;
    result.url = m3uMax;

    return result;
}