视频请求中缺少范围标头? [英] Range header missing from video request?

问题描述

有时我的 Node.js 服务器上会出现错误，告诉我 req.headers.range 在用户请求 .mp4 时未定义(我没有尝试提供任何其他视频文件类型，不确定 mp4 是否相关).我不明白为什么缺少这个标题.

I sometimes get an error on my Node.js server telling me req.headers.range is undefined when a user is requesting a .mp4 (I haven't tried serving any other video filetypes, not sure if mp4 is relevant). I don't understand why this header is missing.

视频的请求标头有时是否应该排除range?

我像这样发送流:

var videoReqHandler = function(req, res, pathname) {

    var file = dirPath + "/Client" + pathname;
    var range = req.headers.range;
    var positions = range.replace(/bytes=/, "").split("-");
    var start = parseInt(positions[0], 10);

    fs.stat(file, function(err, stats) {
        if (err) {
            throw err;
        } else {
            var total = stats.size;
            var end = positions[1] ? parseInt(positions[1], 10) : total - 1;
            var chunksize = (end - start) + 1;
            res.writeHead(206, {
                "Content-Range" : "bytes " + start + "-" + end + "/" + total,
                "Accept-Ranges" : "bytes",
                "Content-Length" : chunksize,
                "Content-Type" : "video/mp4"
            });
            var stream = fs.createReadStream(file, {
                start : start,
                end : end
            }).on("open", function() {
                stream.pipe(res);
            }).on("error", function(err) {
                res.end(err);
            });
        }
    });
};

错误:

/video_stream.js:21
        var positions = range.replace(/bytes=/, "").split("-");
        TypeError: Cannot call method 'replace' of undefined

推荐答案

Range 标题是可选的:

使用条件或无条件 GET 方法的 HTTP 检索请求可以使用 Range 请求标头请求实体的一个或多个子范围，而不是整个实体(http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.35.2)

HTTP retrieval requests using conditional or unconditional GET methods MAY request one or more sub-ranges of the entity, instead of the entire entity, using the Range request header (http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.35.2)

请求是否针对视频流并不重要.我假设浏览器(或视频播放器库)不会为初始请求发送 Range 标头，而仅在搜索过程中使用它.

It doesn't matter if the request is for a video stream or not. I would assume that a browser (or a video player library) doesn't send a Range header for the initial request and only uses it during seeking.

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