I'm using Net::HTTP with Ruby to crawl an URL.
I don't want to crawl streaming audio such as: http://listen2.openstream.co/334
in fact i only want to crawl Html content, so no pdfs, video, txt..
Right now, I have both open_timeout and read_timeout set to 10, so even if I do crawl these streaming audio pages they will timeout.
url = 'http://listen2.openstream.co/334' path = uri.path req= Net::HTTP::Get.new(path, {'Accept' => '*/*', 'Content-Type' => 'text/plain; charset=utf-8', 'Connection' => 'keep-alive','Accept-Encoding' => 'Identity'}) uri = Addressable::URI.parse(url) resp = Net::HTTP.start(uri.host, uri.inferred_port) do |httpRequest| httpRequest.open_timeout = 10 httpRequest.read_timeout = 10 #how can I read the headers here before it's streaming the body and then exit b/c the content type is audio? httpRequest.request(req) end However, is there a way to check the header BEFORE I read the body of a http response to see if it's an audio? I want to do so without sending a separate HEAD request.
4 Answers
Answers 1
net/http supports streaming, you can use this to read the header before the body.
Code example,
url = URI('http://stackoverflow.com/questions/41306082/ruby-nethttp-read-the-header-before-the-body-without-head-request') Net::HTTP.start(url.host, url.port) do |http| request = Net::HTTP::Get.new(url) http.request(request) do |response| # check headers here, body has not yet been read # then call read_body or just body to read the body if true response.read_body do |chunk| # process body chunks here end end end end Answers 2
Since I did not find a way to properly do this in Net::HTTP, and I saw that you're using the addressable gem as an external dependency already, here's a solution using the wonderful http gem:
require 'http' response = HTTP.get('http://listen2.openstream.co/334') # Here are the headers puts response.headers # Everything ok? Start streaming the response body = response.body body.stream! # now just call `readpartial` on the body until it returns `nil` # or some other break condition is met Sorry if you're required to use Net::HTTP, hopefully someone else will find an answer. A separate HEAD request might indeed be the way to go in that case.
Answers 3
You can do a whole host of net related things without using a gem. Just use the net/http module.
require 'net/http' url = URI 'http://listen2.openstream.co/334' Net::HTTP.start(url.host, url.port){|conn| conn.request_get(url){|resp| resp.each{|k_header, v_header| # process headers puts "#{k_header}: #{v_header}" } # # resp.read_body{|body_chunk| # # process body # } } } Note: while processing headers, just make sure to check the content-type header. For audio related content it would normally contain audio/mpeg value.
Hope, it helped.
Answers 4
I will add a ruby example later tonight. However, for a quick response. There is a simple trick to do this.
You can use HTTP Range header to indicate if which range of bytes you want to receive from the server. Here is an example -
curl -XGET http://www.sample-videos.com/audio/mp3/crowd-cheering.mp3 -v -H "Range: bytes=0-1"
The above example means. The server will return data from 0 to 1 byte range.
FYI: https://developer.mozilla.org/en-US/docs/Web/HTTP/Range_requests
Hope that works for you.
Thanks
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