How to download Nginx configuration file in sections

This time I will bring you the configuration file of Nginx. How to download the Nginx configuration file in parts? one time.

to implement segmented downloading of files.

Header Tag Request Request Header: Download the file content after 3744

range: bytes=3744-

Return Response Header: Total file length 15522643 bytes

accept-ranges': 'bytes'
content-range': 'bytes */15522643'

Nginx configuration First, you need to configure Nginx to support range tag return. It is very simple to add add_header Accept-Ranges bytes; this line.

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 the node.js side sends

containing range header, nginx will return range-related information: This is a complete Response Header. Note that

here is not the total length of the file, but the length of the current range. <div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false">{ 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: '&quot;5a5deb8b-ecdb53&quot;',  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' }</pre><div class="contentsignin">Copy after login</div></div> 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-downloaded files locally, then creates a file stream in 'r' read-write mode, and writes the response stream to the 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, other status codes may be returned, such as 206 or 416, with the following meaning:

206 Partial Content

What is returned is part of the file content

416 Requested Range Not Satisfiable

The requested range exceeds the file size                                                            

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