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Is it possible to show me a sample http session with range requests. I mean what would be the request and response headers?
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An HTTP range request asks the server to send only a portion of an HTTP message back to a client. Range requests are useful for clients like media players that support random access, data tools that know they need only part of a large file, and download managers that let the user pause and resume the download.
To initiate a partial range request, the client must initiate a request to the server and will potentially receive two headers: Accept-Ranges and Content-Length . If the server supports partial range requests, the value for Accept-Ranges will be bytes ; otherwise, the value will be none .
The Range HTTP request header indicates the part of a document that the server should return. Several parts can be requested with one Range header at once, and the server may send back these ranges in a multipart document. If the server sends back ranges, it uses the 206 Partial Content for the response.
What are byte-range requests? # Byte-range requests occur when a client asks the server for only a portion of the requested file. The purpose of this is essentially to conserve bandwidth usage by avoiding the need to download a complete file when all that is required is a small section.
The following exchange is between Chrome and a static web server, retrieving an MP4 video.
Initial request - for the video. Note the Accept-Ranges response header to indicate the server has range header support:
GET /BigBuckBunny_320x180.mp4 Cache-Control: max-age=0 Connection: keep-alive Accept-Language: en-GB,en-US,en Host: localhost:8080 Range: Accept: text/html,application/xhtml+xml,application/xml,*/* User-Agent: Mozilla/5.0 (Windows NT 5.1) AppleWebKit/535.7 ... Accept-Encoding: gzip,deflate,sdch Accept-Charset: ISO-8859-1,utf-8,* 200 OK Content-Type: video/mp4 Connection: keep-alive Last-Modified: Wed,14 Dec 2011 15:50:59 GMT ETag: A023EF02BD589BC472A2D6774EAE3C58 Transfer-Encoding: Content-Length: 64657027 Accept-Ranges: bytes Server: Brisket/1.0.1 Date: Wed,14 Dec 2011 16:11:24 GMT Range header in previous response detected - subsequent request with open-ended range to confirm support. Response returns a 206 status and Content-Range header to indicate the bytes present in the response body:
GET /BigBuckBunny_320x180.mp4 Connection: keep-alive Accept-Language: en-GB,en-US,en Host: localhost:8080 Range: bytes=0- Accept: */* User-Agent: Mozilla/5.0 (Windows NT 5.1) AppleWebKit/535.7 ... Referer: http://localhost:8080/BigBuckBunny_320x180.mp4 Accept-Encoding: identity Accept-Charset: ISO-8859-1,utf-8,* 206 Partial Content Content-Type: video/mp4 Connection: keep-alive Last-Modified: Wed,14 Dec 2011 15:50:59 GMT ETag: A023EF02BD589BC472A2D6774EAE3C58 Transfer-Encoding: Content-Length: 64657027 Accept-Ranges: bytes Server: Brisket/1.0.1 Date: Wed,14 Dec 2011 16:11:25 GMT Content-Range: bytes 0-64657026/64657027 Subsequent range request to capture the end of the file (probably to capture trailing metadata):
GET /BigBuckBunny_320x180.mp4 Connection: keep-alive Accept-Language: en-GB,en-US,en Host: localhost:8080 Range: bytes=64312833-64657026 Accept: */* If-Range: A023EF02BD589BC472A2D6774EAE3C58 User-Agent: Mozilla/5.0 (Windows NT 5.1) AppleWebKit/535.7 ... Referer: http://localhost:8080/BigBuckBunny_320x180.mp4 Accept-Encoding: identity Accept-Charset: ISO-8859-1,utf-8,* 206 Partial Content Content-Type: video/mp4 Connection: keep-alive Last-Modified: Wed,14 Dec 2011 15:50:59 GMT ETag: A023EF02BD589BC472A2D6774EAE3C58 Transfer-Encoding: Content-Length: 344194 Accept-Ranges: bytes Server: Brisket/1.0.1 Date: Wed,14 Dec 2011 16:11:25 GMT Content-Range: bytes 64312833-64657026/64657027 User clicks in the video progress bar beyond the downloaded range - a range request is issued to begin playing from the selected position:
GET /BigBuckBunny_320x180.mp4 Connection: keep-alive Accept-Language: en-GB,en-US,en Host: localhost:8080 Range: bytes=1073152-64313343 Accept: */* If-Range: A023EF02BD589BC472A2D6774EAE3C58 User-Agent: Mozilla/5.0 (Windows NT 5.1) AppleWebKit/535.7 ... Referer: http://localhost:8080/BigBuckBunny_320x180.mp4 Accept-Encoding: identity Accept-Charset: ISO-8859-1,utf-8,* 206 Partial Content Content-Type: video/mp4 Connection: keep-alive Last-Modified: Wed,14 Dec 2011 15:50:59 GMT ETag: A023EF02BD589BC472A2D6774EAE3C58 Transfer-Encoding: Content-Length: 63240192 Accept-Ranges: bytes Server: Brisket/1.0.1 Date: Wed,14 Dec 2011 16:11:25 GMT Content-Range: bytes 1073152-64313343/64657027 If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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