[ruby/net-http] Add ignore_eof access to HTTP and HTTPResponse

The ignore_eof setting on HTTPResponse makes it so an EOFError is
raised when reading bodies with a defined Content-Length, if the
body read was truncated due to the socket be closed.

The ignore_eof setting on HTTP sets the values used in responses
that are created by the object.

For backwards compatibility, the default is for both settings is
true.  However, unless you are specifically tested for and handling
truncated responses, it's a good idea to set ignore_eof to false so
that errors are raised for truncated responses, instead of those
errors silently being ignored.

Fixes [Bug #14972]

https://github.com/ruby/net-http/commit/4d47e34995

lib/net/http.rb

@@ -699,6 +699,7 @@ module Net   #:nodoc:
       @max_retries = 1
       @debug_output = nil
       @response_body_encoding = false
+      @ignore_eof = true
 
       @proxy_from_env = false
       @proxy_uri      = nil
@@ -839,6 +840,10 @@ module Net   #:nodoc:
     # The default value is 2 seconds.
     attr_accessor :keep_alive_timeout
 
+    # Whether to ignore EOF when reading response bodies with defined
+    # Content-Length headers. For backwards compatibility, the default is true.
+    attr_accessor :ignore_eof
+
     # Returns true if the HTTP session has been started.
     def started?
       @started
@@ -1606,6 +1611,7 @@ module Net   #:nodoc:
             res = HTTPResponse.read_new(@socket)
             res.decode_content = req.decode_content
             res.body_encoding = @response_body_encoding
+            res.ignore_eof = @ignore_eof
           end while res.kind_of?(HTTPInformation)
 
           res.uri = req.uri

lib/net/http/response.rb

@@ -85,6 +85,7 @@ class Net::HTTPResponse
     @uri  = nil
     @decode_content = false
     @body_encoding = false
+    @ignore_eof = true
   end
 
   # The HTTP version supported by the server.
@@ -119,6 +120,10 @@ class Net::HTTPResponse
     @body_encoding = value
   end
 
+  # Whether to ignore EOF when reading bodies with a specified Content-Length
+  # header.
+  attr_accessor :ignore_eof
+
   def inspect
     "#<#{self.class} #{@code} #{@message} readbody=#{@read}>"
   end
@@ -459,7 +464,7 @@ class Net::HTTPResponse
 
       clen = content_length()
       if clen
-        @socket.read clen, dest, true   # ignore EOF
+        @socket.read clen, dest, @ignore_eof
         return
       end
       clen = range_length()

test/net/http/test_http.rb

@@ -1348,3 +1348,33 @@ class TestNetHTTPForceEncoding < Test::Unit::TestCase
     assert_equal(Encoding::UTF_8, res.body.encoding)
   end
 end
+
+class TestNetHTTPPartialResponse < Test::Unit::TestCase
+  CONFIG = {
+    'host' => '127.0.0.1',
+    'proxy_host' => nil,
+    'proxy_port' => nil,
+  }
+
+  include TestNetHTTPUtils
+
+  def test_partial_response
+    str = "0123456789"
+    @server.mount_proc('/') do |req, res|
+      res.status = 200
+      res['Content-Type'] = 'text/plain'
+
+      res.body = str
+      res['Content-Length'] = str.length + 1
+    end
+    @server.mount_proc('/show_ip') { |req, res| res.body = req.remote_ip }
+
+    http = Net::HTTP.new(config('host'), config('port'))
+    res = http.get('/')
+    assert_equal(str, res.body)
+
+    http = Net::HTTP.new(config('host'), config('port'))
+    http.ignore_eof = false
+    assert_raise(EOFError) {http.get('/')}
+  end
+end