[ruby-core:84816] [Ruby trunk Bug#14349] Net::HTTP doesn't reuse connections when used via ::new

Issue #14349 has been updated by rohitpaulk (Paul Kuruvilla).


> This happens because when start is called without a block and a connection doesn't exist, it proxies to a call with a block.

Oops, this should've read: "When request is called and a connection doesn't exist, it proxies to a `start` call with a block."

----------------------------------------
Bug #14349: Net::HTTP doesn't reuse connections when used via ::new
https://bugs.ruby-lang.org/issues/14349#change-69529

* Author: rohitpaulk (Paul Kuruvilla)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: ruby 2.5.0p0 (2017-12-25 revision 61468) [x86_64-darwin17]
* Backport: 2.3: UNKNOWN, 2.4: UNKNOWN, 2.5: UNKNOWN
----------------------------------------
From [Net::HTTP's docs](http://ruby-doc.org/stdlib-2.5.0/libdoc/net/http/rdoc/Net/HTTP.html#class-Net::HTTP-label-How+to+use+Net-3A-3AHTTP): 

> ::start immediately creates a connection to an HTTP server which is kept open for the duration of the block. The connection will remain open for multiple requests in the block if the server indicates it supports persistent connections.

> If you wish to re-use a connection across multiple HTTP requests without automatically closing it you can use ::new instead of ::start. request will automatically open a connection to the server if one is not currently open. You can manually close the connection with finish.

According to the above, I'd expect the following scripts to reuse the underlying HTTP connection: 


~~~
Net::HTTP.start('httpbin.org', port=443, use_ssl: true) { |http|
  10.times { http.get("/") }
}
~~~

~~~
http = Net::HTTP.new('httpbin.org', 443)
http.use_ssl = true
10.times { http.get("/") }
http.finish
~~~

The first one does indeed reuse connections, but the second doesn't. From a debug script (attached): 

~~~
------------
Using #start
------------
Connection Alive? true
Connection Alive? true
Connection Alive? true
Connection Alive? true
Connection Alive? true
Connection Alive? true
Connection Alive? true
Connection Alive? true
Connection Alive? true
Connection Alive? true

Time taken: 4.11464

----------
Using #new
----------
Connection Alive? false
Connection Alive? false
Connection Alive? false
Connection Alive? false
Connection Alive? false
Connection Alive? false
Connection Alive? false
Connection Alive? false
Connection Alive? false
Connection Alive? false

Time taken: 12.337512
~~~

This happens because when `start` is called without a block and a connection doesn't exist, it proxies to a call **with** a block. And when a block is passed to `start`, it automatically calls `finish` at the end.

I've attached a patch that I think solves the issue. With the patch, sockets will still get closed after single requests through methods like `Net::HTTP.get`, since they use the block form for `start`.

Command to run the new test that was added: `make test-all TESTS='net/http/test_http.rb -n test_keep_alive_using_new'`


---Files--------------------------------
net-http-reuse-connections.patch (1.32 KB)
debug_script.rb (1.14 KB)


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