I've created a simple server Java application using Gradle. As an embedded server , I am using Jetty . I am also using a Gretty plugin as it supports the latest Jetty version.
The project runs just fine . And I have tried to stress test it. As a part of my test I need to check the response time and therefore I am sending "Connection:Close"
header via curl
.
My response is a long JSON string , and I see only part of it , after which the connection hangs . I would like to know Why is it happening , and how can I work around it.
NOTE :
Connection:Keep-alive
header , everything is fine HOW TO TEST :
./gradlew appRun
curl -H "Connection:Close" -i "http://localhost:8080/Environment/example"
Seems like you are confusing the persistent connection modes between HTTP/1.0
and HTTP/1.1
.
Either that, or you are using a really old version of curl
that still defaults to HTTP/1.0
.
HTTP/1.0
has no persistent connections by default, so to use persistent connections we send Connection: keep-alive
.
HTTP/1.1
uses persistent connections by default, so to disable it we can send Connection: close
Using HTTP/1.0
, with Connection: close
is like sending this ...
GET /Environment/example HTTP/1.0
Host: localhost:8080
Connection: close
... which produces an invalid header value for Connection
per the HTTP/1.0
spec
Lets use the verbose features of curl to see what's really going on Connection wise...
HTTP/1.1
with normal operation: $ curl --verbose --http1.1 http://apache.org/ -so /dev/null
* Trying 88.198.26.2...
* Connected to apache.org (88.198.26.2) port 80 (#0)
> GET / HTTP/1.1
> Host: apache.org
> User-Agent: curl/7.43.0
> Accept: */*
>
< HTTP/1.1 200 OK
< Date: Fri, 06 May 2016 12:05:39 GMT
< Server: Apache/2.4.7 (Ubuntu)
< Last-Modified: Fri, 06 May 2016 11:10:20 GMT
< ETag: "cf64-5322a812896a8"
< Accept-Ranges: bytes
< Content-Length: 53092
< Vary: Accept-Encoding
< Cache-Control: max-age=3600
< Expires: Fri, 06 May 2016 13:05:39 GMT
< Content-Type: text/html
<
{ [1125 bytes data]
* Connection #0 to host apache.org left intact
Notice that it says it kept the connection intact?
HTTP/1.1
with manual Connection: close
operation: $ curl --verbose --http1.1 --header "Connection: close" http://apache.org/ -so /dev/null
* Trying 140.211.11.105...
* Connected to apache.org (140.211.11.105) port 80 (#0)
> GET / HTTP/1.1
> Host: apache.org
> User-Agent: curl/7.43.0
> Accept: */*
> Connection: close
>
< HTTP/1.1 200 OK
< Date: Fri, 06 May 2016 12:06:35 GMT
< Server: Apache/2.4.7 (Ubuntu)
< Last-Modified: Fri, 06 May 2016 11:10:20 GMT
< ETag: "cf64-5322a812896a8"
< Accept-Ranges: bytes
< Content-Length: 53092
< Vary: Accept-Encoding
< Cache-Control: max-age=3600
< Expires: Fri, 06 May 2016 13:06:35 GMT
< Connection: close
< Content-Type: text/html
<
{ [1106 bytes data]
* Closing connection 0
Ah, the HTTP response headers say that the server will close, and curl saw the connection being closed. What we wanted.
HTTP/1.0
with normal operation: $ curl --verbose --http1.0 http://apache.org/ -so /dev/null
* Trying 140.211.11.105...
* Connected to apache.org (140.211.11.105) port 80 (#0)
> GET / HTTP/1.0
> Host: apache.org
> User-Agent: curl/7.43.0
> Accept: */*
>
< HTTP/1.1 200 OK
< Date: Fri, 06 May 2016 12:08:27 GMT
< Server: Apache/2.4.7 (Ubuntu)
< Last-Modified: Fri, 06 May 2016 11:10:20 GMT
< ETag: "cf64-5322a812896a8"
< Accept-Ranges: bytes
< Content-Length: 53092
< Vary: Accept-Encoding
< Cache-Control: max-age=3600
< Expires: Fri, 06 May 2016 13:08:27 GMT
< Connection: close
< Content-Type: text/html
<
{ [4002 bytes data]
* Closing connection 0
See how the HTTP response headers say that the server will close?
Curl also saw the connection being closed.
That's what we expect with normal HTTP/1.0
operation.
HTTP/1.0
with persistent connection: $ curl --verbose --http1.0 --header "Connection: keep-alive" http://apache.org/ -so /dev/null
* Trying 88.198.26.2...
* Connected to apache.org (88.198.26.2) port 80 (#0)
> GET / HTTP/1.0
> Host: apache.org
> User-Agent: curl/7.43.0
> Accept: */*
> Connection: keep-alive
>
< HTTP/1.1 200 OK
< Date: Fri, 06 May 2016 12:08:37 GMT
< Server: Apache/2.4.7 (Ubuntu)
< Last-Modified: Fri, 06 May 2016 11:10:20 GMT
< ETag: "cf64-5322a812896a8"
< Accept-Ranges: bytes
< Content-Length: 53092
< Vary: Accept-Encoding
< Cache-Control: max-age=3600
< Expires: Fri, 06 May 2016 13:08:37 GMT
< Keep-Alive: timeout=30, max=100
< Connection: Keep-Alive
< Content-Type: text/html
<
{ [3964 bytes data]
* Connection #0 to host apache.org left intact
Yup, the server indicates that it will use Keep-Alive too (per HTTP/1.0 spec), and curl even concurs and says the connection is left intact.
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