This tag can be configured in Node.JS to implement segmented downloading of files. This article introduces you to Node.JS segmented downloading: how to implement the segmented download function of Nginx configuration files. Friends who need it can refer to it
Html5 provides a new Range tag to implement the file. Download in parts. This tag can be configured in Node.JS to implement segmented downloading of files.
Header tag
Request Request Header: Download the file content after 3744
range: bytes=3744-
Return Response Header: The total file length is 15522643 bytes
accept-ranges': 'bytes' content-range': 'bytes */15522643'
Nginx configuration
First of all, you need to configure Nginx to support range tag return. It is very simple to add add_header Accept-Ranges bytes; this line can
server { listen 80; server_name adksdf.com; location ~ ^/(img/|js/|css/|upload/|font/|fonts/|res/|icon) { add_header Access-Control-Allow-Origin *; add_header Accept-Ranges bytes; root /var/www/...; access_log off; expires max; } ... }
After enabling, if node The .js side sends request information containing range header, then nginx will return range-related information:
This is a complete Response Header. Note that content-length
here is not a file. The total length, but the length of the current range.
{ server: 'nginx', date: 'Wed, 24 Jan 2018 02:43:20 GMT', 'content-type': 'application/zip', 'content-length': '12420187', 'last-modified': 'Tue, 16 Jan 2018 12:09:47 GMT', connection: 'close', etag: '"5a5deb8b-ecdb53"', expires: 'Thu, 31 Dec 2037 23:55:55 GMT', 'cache-control': 'max-age=315360000', 'access-control-allow-origin': '*', 'accept-ranges': 'bytes', 'content-range': 'bytes 3102456-15522642/15522643' }
The total size of the file can be obtained based on the content-range in this header.
Node.JS implementation
This example first detects half of the files downloaded locally, and then creates the file in 'r' read-write mode stream and write the response stream to a file.
Here, range support will be added to the statement file.
var reqOptions = { url: packageUrl, headers: {} } var filepath = '/path/to/your/part/file' var fileOptions = {} fs.stat(filepath, function(err, states) { if (states) { //Range: bytes=3744- reqOptions.headers['range'] = 'bytes=' + states.size + '-' fileOptions = { start: states.size, flags: 'r+' } } //创建 http 对象方法 var reqUrl = reqOptions.url var urlObj = url.parse(reqUrl) var options = { hostname : urlObj.hostname , port : urlObj.port , path : urlObj.pathname , headers : reqOptions.headers || {} } var req = http.request(options, function(res) { var receives = [] var err = null var statusCode = res.statusCode var headers = res.headers var ws = fs.createWriteStream(filepath, fileOptions) ws.on('error', function(e) { console.log('ws error', e) }) res.on('data', function(chrunk) { ws.write(chrunk) }) res.on('error', function(err) { ws.end() }) res.on('end', function() { ws.end() }) }) req.on('error', function(e) { cb && cb(e, null, {}) }) req.end() ... })
Return Header
When requesting nginx may return other status codes, such as Say 206 or 416, the meaning is as follows:
206 Partial Content
Returns part of the file content
416 Requested Range Not Satisfiable
The requested range exceeds File size
The above is what I compiled for everyone. I hope it will be helpful to everyone in the future.
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