`Connection` header is inconsistently set to `close`

[mattbearman]

Depending on how you start a connection, the Connection header may be unexpectedly set to close

Creating a new instance of Net::HTTP and then calling its request method (or any of its methods that call request, eg: get) will first set the Connection header to close (if it's not already set), then start the connection, and re-call itself

Where as initiating a request with class methods, or by manually starting a connection before calling request will not set the Connection header

As the default connection in HTTP 1.1 is keep-alive, having the Connection header silently set to close is unexpected

Examples:

uri = URI('https://example.com/test')

http = Net::HTTP.new(uri.host, uri.port)
http.use_ssl = true
req = Net::HTTP::Get.new(uri.path)
req['connection'] # => nil
res = http.request(req)
req['connection'] # => 'close'

http = Net::HTTP.new(uri.host, uri.port)
http.use_ssl = true
http.start
req = Net::HTTP::Get.new(uri.path)
req['connection'] # => nil
res = http.request(req)
req['connection'] # => nil

I've created a PR to fix this issue - #179

[aeuillot]

I have encountered the same problem today with a public API.

Examples:

uri = URI("https://ec.europa.eu/taxation_customs/vies/rest-api/check-status")

http = Net::HTTP.new(uri.host, uri.port)
http.use_ssl = true

req = Net::HTTP::Get.new(uri.path)
http.request(req) # => SSL_read: unexpected eof while reading (OpenSSL::SSL::SSLError)

req = Net::HTTP::Get.new(uri.path, connection: "keep-alive")
http.request(req) # => #<Net::HTTPOK 200 OK readbody=true>

Additional information about HTTP/2 : https://datatracker.ietf.org/doc/html/rfc7540#section-8.1.2.2

[mattbearman]

That's the exact same error I saw that lead me to dig into this and find a fix. Unfortunately the PR has been open for almost exactly a year with no acknowledgment, so it could be a while before it gets merged 😅