# Response
## Definition
Responses can be used to capture values to perform subsequent requests, or add asserts to HTTP responses. Response on
requests are optional, a Hurl file can just consist of a sequence of [requests].
A response describes the expected HTTP response, with mandatory [version and status], followed by optional [headers],
[captures], [asserts] and [body]. Assertions in the expected HTTP response describe values of the received HTTP response.
Captures capture values from the received HTTP response and populate a set of named variables that can be used
in the following entries.
## Example
```hurl
GET https://example.org
HTTP 200
Last-Modified: Wed, 21 Oct 2015 07:28:00 GMT
[Asserts]
xpath "normalize-space(//head/title)" startsWith "Welcome"
xpath "//li" count == 18
```
## Structure
HTTP 200
content-length: 206
accept-ranges: bytes
user-agent: Test
[Captures]
...
[Asserts]
...
{
"type": "FOO",
"value": 356789,
"ordered": true,
"index": 10
}
## Capture and Assertion
With the response section, one can optionally [capture value from headers, body],
or [add assert on status code, body or headers].
### Body compression
Hurl outputs the raw HTTP body to stdout by default. If response body is compressed (using [br, gzip, deflate]),
the binary stream is output, without any modification. One can use [`--compressed` option]
to request a compressed response and automatically get the decompressed body.
Captures and asserts work automatically on the decompressed body, so you can request compressed data (using [`Accept-Encoding`]
header by example) and add assert and captures on the decoded body as if there weren't any compression.
## Timings
HTTP response timings are exposed through Hurl structured output (see [`--json`]) and HTML report (see [`--report-html`]).
On each response, libcurl response timings are available:
- __time_namelookup__: the time it took from the start until the name resolving was completed. You can use
[`--resolve`] to exclude DNS performance from the measure.
- __time_connect__: The time it took from the start until the TCP connect to the remote host (or proxy) was completed.
- __time_appconnect__: The time it took from the start until the SSL/SSH/etc connect/handshake to the remote host was
completed. The client is then ready to send its HTTP GET request.
- __time_starttransfer__: The time it took from the start until the first byte was just about to be transferred
(just before Hurl reads the first byte from the network). This includes time_pretransfer and also the time the server
needed to calculate the result.
- __time_total__: The total time that the full operation lasted.
All timings are in microsecond.
[requests]: /docs/request.md
[version and status]: /docs/asserting-response.md#version-status
[headers]: /docs/asserting-response.md#headers
[captures]: /docs/capturing-response.md#captures
[asserts]: /docs/asserting-response.md#asserts
[body]: /docs/asserting-response.md#body
[capture value from headers, body]: /docs/capturing-response.md
[add assert on status code, body or headers]: /docs/asserting-response.md
[br, gzip, deflate]: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Accept-Encoding
[`--compressed` option]: /docs/manual.md#compressed
[`Accept-Encoding`]: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Accept-Encoding
[`--json`]: /docs/manual.md#json
[`--report-html`]: /docs/manual.md#report-html
[`--resolve`]: /docs/manual.md#resolve