# 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

<div class="hurl-structure-schema">
  <div class="hurl-structure">
    <div class="hurl-structure-col-0">
        <div class="hurl-part-0">
            HTTP 200
        </div>
        <div class=" hurl-part-1">
            content-length: 206<br>accept-ranges: bytes<br>user-agent: Test
        </div>
        <div class="hurl-part-2">
            [Captures]<br>...
        </div>
        <div class="hurl-part-2">
            [Asserts]<br>...
        </div>
        <div class="hurl-part-3">
            {<br>
            &nbsp;&nbsp;"type": "FOO",<br>
            &nbsp;&nbsp;"value": 356789,<br>
            &nbsp;&nbsp;"ordered": true,<br>
            &nbsp;&nbsp;"index": 10<br>
            }
        </div>
    </div>
    <div class="hurl-structure-col-1">
        <div class="hurl-request-explanation-part-0">
            <a href="/docs/asserting-response.html#version-status">Version and status (mandatory if response present)</a>
        </div>
        <div class="hurl-request-explanation-part-1">
            <br><a href="/docs/asserting-response.html#headers">HTTP response headers</a> (optional)
        </div>
        <div class="hurl-request-explanation-part-2">
            <br>
            <br>
        </div>
        <div class="hurl-request-explanation-part-2">
            <a href="/docs/capturing-response.html">Captures</a> and <a href="/docs/asserting-response.html#asserts">asserts</a> (optional sections, unordered)
        </div>
        <div class="hurl-request-explanation-part-2">
          <br>
          <br>
          <br>
          <br>
        </div>
        <div class="hurl-request-explanation-part-3">
            <a href="/docs/asserting-response.html#body">HTTP response body</a> (optional)
        </div>
    </div>
</div>
</div>


## 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.

<div>
    <img class="light-img u-drop-shadow u-border u-mt-4" src="/docs/assets/img/timings-light.svg" width="100%" alt="Response timings explanation"/>
    <img class="dark-img u-drop-shadow u-border u-mt-4" src="/docs/assets/img/timings-dark.svg" width="100%" alt="Response timings explanation"/>
</div>

<a href="https://blog.cloudflare.com/a-question-of-timing/"><small>Courtesy of CloudFlare</small></a>


[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