Improve keep-alive check

Author: kleisauke

lib/resty/http.lua

@@ -685,8 +685,8 @@ function _M.read_response(self, params)
     -- keepalive is true by default. Determine if this is correct or not.
     local ok, connection = pcall(str_lower, res_headers["Connection"])
     if ok then
-        if  (version == 1.1 and connection == "close") or
-            (version == 1.0 and connection ~= "keep-alive") then
+        if (version == 1.1 and str_find(connection, "close", 1, true)) or
+           (version == 1.0 and not str_find(connection, "keep-alive", 1, true)) then
             self.keepalive = false
         end
     else

t/07-keepalive.t

@@ -311,3 +311,61 @@ keep-alive
 --- no_error_log
 [error]
 [warn]
+
+=== TEST 7: Generic interface, HTTP 1.1, Connection: Upgrade, close. Test we don't try to keepalive, but also that subsequent connections can keepalive.
+--- http_config eval: $::HttpConfig
+--- config
+    location = /a {
+        content_by_lua_block {
+            local http = require "resty.http"
+            local httpc = http.new()
+
+            -- Create a TCP connection and return an raw HTTP-response because
+            -- there is no way to set an "Connection: Upgrade, close" header in nginx.
+            assert(httpc:connect("127.0.0.1", 12345),
+                "connect should return positively")
+
+            local res = httpc:request({
+                version = 1.1,
+                path = "/b",
+            })
+
+            local body = res:read_body()
+            ngx.print(body)
+
+            ngx.say(res.headers["Connection"])
+
+            local r, e = httpc:set_keepalive()
+            ngx.say(r)
+            ngx.say(e)
+
+            httpc:connect("127.0.0.1", ngx.var.server_port)
+            ngx.say(httpc:get_reused_times())
+
+            httpc:set_keepalive()
+
+            httpc:connect("127.0.0.1", ngx.var.server_port)
+            ngx.say(httpc:get_reused_times())
+        }
+    }
+--- tcp_listen: 12345
+--- tcp_reply
+HTTP/1.1 200 OK
+Date: Wed, 08 Aug 2018 17:00:00 GMT
+Server: Apache/2
+Upgrade: h2,h2c
+Connection: Upgrade, close
+
+OK
+--- request
+GET /a
+--- response_body
+OK
+Upgrade, close
+2
+connection must be closed
+0
+1
+--- no_error_log
+[error]
+[warn]