File size of web-based flv. Reading some bytes from a web-based file

Ruby
1

This is such a noobie question.

I have a file, http:// … /One-minute-commercial-027.flv (I can’t
enter the name because the email gets rejected with a 5.7.1 as spam,
apparently.

I want to do two simple things:

  1. I want to get the file size. Please note that File.size() does not
    seem to work for me for a web-based file but does work for a local file.

C:\Users\Ralph>irb
irb(main):001:0>
File.size(‘c:/RailsInstaller/Sites/ultradedup002/app/views/usage/VideoTutorials.html.haml’)
=> 32406
irb(main):002:0> File.size(‘http:// … /One-minute-commercial-027.flv’)
Errno::EINVAL: Invalid argument - http:// something
/One-minute-commercial-027.flv
from (irb):2:in size' from (irb):2 from C:/RailsInstaller/Ruby1.9.2/bin/irb:12:in’
irb(main):003:0>

  1. I want to read a few hundred bytes from the beginning of the file so
    as to pick up the flv’s time duration.

Are there Ruby facilities to do this?

Ralph S.

2

You should probably make a HEAD request and parse Content-Length header

curl --head ‘’ | grep ‘Content-Length’

http:// … /One-minute-commercial-027.flv’

3

Tuesday, January 3, 2012, 6:39:07 AM, you wrote:

VG> You should probably make a HEAD request and parse Content-Length
header

VG> curl --head ‘’ | grep ‘Content-Length’

VG> http:// … /One-minute-commercial-027.flv’

Could you beef up the example/explanation a bit, please.

Also, what about reading a few hundred bytes from the flv?

4

On Tue, Jan 3, 2012 at 6:03 AM, Ralph S. [email protected] wrote:

Also, what about reading a few hundred bytes from the flv?

using net/http – something like

ruby-1.9.2-p290 :035 > uri = URI(‘http://localhost/’)
=> #<URI::HTTP:0x00000101861f80 URL:http://localhost/>
ruby-1.9.2-p290 :036 > req = Net::HTTP::Get.new(uri.request_uri)
=> #<Net::HTTP::Get GET>
ruby-1.9.2-p290 :037 > req[‘Range’] = ‘bytes=0-99’
=> “bytes=0-99”
ruby-1.9.2-p290 :038 > Net::HTTP.start(uri.host, uri.port) {|http|
http.request(req) }.body
=> "

The above does assume that your web server supports the Range
header, so YMMV.