hurl/docs/capturing-response.md

Capturing Response

Captures

Captures are optional values that are extracted from the HTTP response and stored in a named variable. These captures may be the response status code, part of or the entire the body, and response headers.

Captured variables can be accessed through a run session; each new value of a given variable overrides the last value.

Captures can be useful for using data from one request in another request, such as when working with CSRF tokens. Variables in a Hurl file can be created from captures or injected into the session.

# An example to show how to pass a CSRF token
# from one request to another:

# First GET request to get CSRF token value:
GET https://example.org

HTTP 200
# Capture the CSRF token value from html body.
[Captures]
csrf_token: xpath "normalize-space(//meta[@name='_csrf_token']/@content)"


# Do the login !
POST https://acmecorp.net/login?user=toto&password=1234
X-CSRF-TOKEN: {{csrf_token}}
HTTP 302

Structure of a capture:

my_varvariable : xpath "string(//h1)"query

A capture consists of a variable name, followed by : and a query. Captures section starts with [Captures].

Query

Queries are used to extract data from an HTTP response.

A query can be of the following type:

• status
• header
• url
• cookie
• body
• bytes
• xpath
• jsonpath
• regex
• variable
• duration

Extracted data can then be further refined using filters.

Status capture

Capture the received HTTP response status code. Status capture consists of a variable name, followed by a :, and the keyword status.

GET https://example.org

HTTP 200
[Captures]
my_status: status

Header capture

Capture a header from the received HTTP response headers. Header capture consists of a variable name, followed by a :, then the keyword header and a header name.

POST https://example.org/login
[FormParams]
user: toto
password: 12345678

HTTP 302
[Captures]
next_url: header "Location"

URL capture

Capture the last fetched URL. This is most meaningful if you have told Hurl to follow redirection (see [Options]section or --location option). URL capture consists of a variable name, followed by a :, and the keyword url.

GET https://example.org/redirecting
[Options]
location: true

HTTP 200
[Captures]
landing_url: url

Cookie capture

Capture a Set-Cookie header from the received HTTP response headers. Cookie capture consists of a variable name, followed by a :, then the keyword cookie and a cookie name.

GET https://example.org/cookies/set

HTTP 200
[Captures]
session-id: cookie "LSID"

Cookie attributes value can also be captured by using the following format: <cookie-name>[cookie-attribute]. The following attributes are supported: Value, Expires, Max-Age, Domain, Path, Secure, HttpOnly and SameSite.

GET https://example.org/cookies/set

HTTP 200
[Captures]
value1: cookie "LSID"
value2: cookie "LSID[Value]"     # Equivalent to the previous capture
expires: cookie "LSID[Expires]"
max-age: cookie "LSID[Max-Age]"
domain: cookie "LSID[Domain]"
path: cookie "LSID[Path]"
secure: cookie "LSID[Secure]"
http-only: cookie "LSID[HttpOnly]"
same-site: cookie "LSID[SameSite]"

Body capture

Capture the entire body (decoded as text) from the received HTTP response

GET https://example.org/home

HTTP 200
[Captures]
my_body: body

Bytes capture

Capture the entire body (as a raw bytestream) from the received HTTP response

GET https://example.org/data.bin

HTTP 200
[Captures]
my_data: bytes

XPath capture

Capture a XPath query from the received HTTP body decoded as a string. Currently, only XPath 1.0 expression can be used.

GET https://example.org/home

# Capture the identifier from the dom node <div id="pet0">5646eaf23</div
HTTP 200
[Captures]
ped-id: xpath "normalize-space(//div[@id='pet0'])"

# Open the captured page.
GET https://example.org/home/pets/{{pet-id}}

HTTP 200

XPath captures are not limited to node values (like string, or boolean); any valid XPath can be captured and asserted with variable asserts.

# Test that the XML endpoint return 200 pets
GET https://example.org/api/pets

HTTP 200
[Captures]
pets: xpath "//pets"
[Asserts]
variable "pets" count == 200

JSONPath capture

Capture a JSONPath query from the received HTTP body.

POST https://example.org/api/contact
[FormParams]
token: {{token}}
email: toto@rookie.net

HTTP 200
[Captures]
contact-id: jsonpath "$['id']"

Explain that the value selected by the JSONPath is coerced to a string when only one node is selected.

As with XPath captures, JSONPath captures can be anything from string, number, to object and collections. For instance, if we have a JSON endpoint that returns the following JSON:

{
  "a_null": null,
  "an_object": {
    "id": "123"
  },
  "a_list": [
    1,
    2,
    3
  ],
  "an_integer": 1,
  "a float": 1.1,
  "a_bool": true,
  "a_string": "hello"
}

We can capture the following paths:

GET https://example.org/captures-json

HTTP 200
[Captures]
an_object:  jsonpath "$['an_object']"
a_list:     jsonpath "$['a_list']"
a_null:     jsonpath "$['a_null']"
an_integer: jsonpath "$['an_integer']"
a_float:    jsonpath "$['a_float']"
a_bool:     jsonpath "$['a_bool']"
a_string:   jsonpath "$['a_string']"
all:        jsonpath "$"

Regex capture

Capture a regex pattern from the HTTP received body, decoded as text.

GET https://example.org/helloworld

HTTP 200
[Captures]
id_a: regex "id_a:([0-9]+)"
id_b: regex "id_b:(\\d+)"   # pattern using double quote 
id_c: regex /id_c:(\d+)/    # pattern using forward slash
name: regex "Hello ([a-zA-Z]+)"

The regex pattern must have at least one capture group, otherwise the capture will fail. When the pattern is a double-quoted string, metacharacters beginning with a backslash in the pattern (like \d, \s) must be escaped; literal pattern enclosed by / can also be used to avoid metacharacters escaping.

Variable capture

Capture the value of a variable into another.

GET https://example.org/helloworld

HTTP 200
[Captures]
in: body
name: variable "in"

Duration capture

Capture the response time of the request in ms.

GET https://example.org/helloworld

HTTP 200
[Captures]
duration_in_ms: duration