LI-HAR config format

The specification describes a JSON config format to act as a static representation of a K6 script.
The proposed format is an extension of HAR 1.2
Items deviating from the HAR spec are:

options
entries list order is significant.
checks
variables

Log

This object represents the root of exported data.

type Log = {
  version: String // Version number of the format
  creator: String // Name and version info of the log creator application
  options?: JSONObject // K6 configuration object
  pages?: Array // List of exported pages
  entries?: Array // List of exported requests
  comment?: Check // A comment provided by the user or the application
}

Options

Options allow you to configure how K6 will behave during test execution, duration, execution mode etc.
If any (embedded in log object).

type Options = {
  // ... see K6 docs
}

K6 options docs

Pages

This object represents list of pages/groups.
Pages are a way to couple entries together. Pages can be referenced from an entry via the pageref property and need to match the page objects id.

{
  pages: [
    {
      id: "group_0",
      title: "Group 0"
    }
  ]
}

type Page = {
  id: String, // Unique identifier referenceable from entry.pageref
  title: String // Name or description of the page/group
}

Entries

This object represents an array with all HTTP requests that should be executed, presented in execution order.

Entries and groups are executed in the order presented in the entries list. An entry without a pageref is executed outside any group in list order. Groups are ordered to the location of their first entry. If the entries of a group are split they're moved to the location of the first entry in list order.

{
  entries: [
    {
      request: {},
      comment: "",
      pageref: "page_0",
      checks: [],
      variables: []
    }
  ]
}

Optional properties are denoted with "?"

type Entry = {
  request: Array, // Detailed info about the request
  comment?: String, // Used as a name or description of the request
  pageref?: String, // Reference to a page/group
  checks?: Check, // List of check objects
  variables?: Variable // List of variable objects
}

Pageref

pageref is a property that specified which page a given entry belongs to. Two entries specifying the same pageref should always end up in the same K6 group.

The same order criterion applies in the case of not specifying a pageref or specifying a pageref that does not match any of the page objects ids will

Example

// HAR configuration

{
  pages: [
    {
      id: "group_0",
      title: "Group 0",
    },
    {
      id: "group_1",
      title: "Group 1",
    } 
  ],
  entries: [
    {
      pageref: "group_0",
      request: {
        method: "POST",
        url: "http://test.loadimpact.com/login",
      }
    },
    {
      pageref: "group_0",
      request: {
        method: "GET",
        url: "http://test.loadimpact.com/users",
      }
    }
    },
    {
      pageref: "group_1",
      request: {
        method: "GET",
        url: "http://test.loadimpact.com/items",
      }
    }
    },
    {
      pageref: "group_1",
      request: {
        method: "POST",
        url: "http://test.loadimpact.com/checkout",
      }
    }
  ]
}


// K6 script equivalent

import { group } from "k6";

export default function() {
  group("Group 0", function() {
    http.post("http://test.loadimpact.com/login");
    http.get("http://test.loadimpact.com/users");
  });

  group("Group 1", function() {
    http.get("http://test.loadimpact.com/items");
    http.post("http://test.loadimpact.com/checkout");
  });
};

Request

This object contains detailed info about performed request.

{
  request: {
    method: "GET",
    url: "http://test.loadimpact.com/path/?param=value",
    httpVersion: "HTTP/1.1",
    headers: [],
    queryString: [],
    postData : {}
  }
}

Optional properties are denoted with "?"

type Request = {
  method: String, // Request method (GET, POST, ...)
  url: String, // Absolute URL of the request (fragments are not included)
  headers?: Array, // List of header objects.
  queryString?: Array, // List of query parameter objects.
  postData?: PostDataType, // Posted data info.
  httpVersion?: String, // Request HTTP Version.
}

URL

Url of the request to be performed. The url must include a valid protocol e.g. http://.
Variables can be referenced in the URL like:
http://test.loadimpact.com/?someParam=${variableName}
http://test.loadimpact.com/users/${userId}/profile

Headers

List of request headers, if any (embedded in request object).
If the value property includes a variable notation like ${accessToken}, this means that the header tries to access a variable defined by another entry and should be replaced with the variables assigned value.

[
  {
    name: "Content-Type",
    value: "application/json"
  },
  {
    name: "Authorization",
    value: "Bearer ${accessToken}"
  }
]

QueryString

This object contains list of all parameters & values parsed from a query string, if any (embedded in request object).

[
  {
    name: "utm_source",
    value: "loadimpact.com"
  },
  {
    name: "color",
    value: "red"
  },
  {
    name: "token",
    value: "${accessToken}"
  }
]

PostData

This object describes posted data, if any (embedded in request object).

{
  postData: {
    mimeType: "application/json",
    text : "plain posted data",
    params: []
  }
}

type PostData = {
  mimeType: String, // Mime type of posted data
  params?: Array, // List of posted parameters (in case of URL encoded parameters)
  text: Array, // Plain text posted data. Can be stringified JSON, XML, HTML, base64encoded data etc.
}

Referencing variables

Just like headers, variables can also be used in the request body.

{
  postData: {
    mimeType: "application/json",
    text: "{\"user\":\"${user_uuid}\",\"email\":\"email@email.email\"}"
  }
}

Examples with different payload types

application/json

{
  postData: {
    "mimeType": "application/json",
    "text": "{\"foo\":\"bar\",\"hello\":\"world!\"}"
  }
}

application/x-www-form-urlencoded

{
  postData: {
    mimeType: "application/x-www-form-urlencoded",
    text: "login=admin&password=123",
    params: [
      {
        name: "login",
        value: "admin"
      },
      {
        name: "password",
        value: "123"
      }
    ]
  }
}

text/plain

{
  postData: {
    "mimeType": "text/plain",
    "text": "Hello world"
  }
}

text/xml

{
  postData: {
    "mimeType": "text/xml",
    "text": "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\r\n<note>\r\n  <to>Foo</to>\r\n  <from>Bar</Ffrom>\r\n  <heading>Reminder</heading>\r\n  <body>Hello world!</body>\r\n</note>\r\n"
  }
}

image/png

// HAR configuration
{
  postData: {
    "mimeType": "image/png",
    "text": "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAKz2lDQ1BJQ0MgUHJvZmlsZQAASImVlwdUU2k"
  }
}


// Generated K6 script
import http from "k6/http";

let binFile = open("./mypicture.png", "b");

export default function() {
  var res = http.post("https://api.example.com/upload", {
    file: http.file(binFile, "mypicture.png")
  });
}

Checks

This property represents an array with checks (assertions) to be done, if any (embedded in entry object).
The properties present in the check object will differ depending on the type of the check.
Here is a mapping of the type - fields relation:

type === CheckTypeVariant.Text
  subject
  condition
  value

// CheckSubjectVariant.ResponseBody should be assumed.
type === CheckTypeVariant.JSONPathValue
  expression
  condition
  value

// CheckSubjectVariant.ResponseBody should be assumed.
type === CheckTypeVariant.JSONPath
  expression

type === CheckTypeVariant.Regex
  subject
  expression

type Check = {
  type: CheckTypeVariant,
  subject?: CheckSubjectVariant,
  condition?: CheckConditionVariant,
  expression?: String,
  value?: String
}

type CheckTypeVariant =
  | Text = 0
  | JSONPathValue = 1
  | JSONPath = 2
  | Regex = 3;

type CheckSubjectVariant =
  | ResponseBody = 0
  | ResponseHeaders = 1
  | HttpStatusCode = 2;

type CheckConditionVariant =
  | Contains = 0
  | NotContains = 1
  | Equals = 2
  | StartsWith = 3
  | EndsWith = 4;

HAR example

Some fields wont always be present, for example condition and value does not make sense when check is of type Regex.
Check type JSONPathValue and JSONPath should assume CheckSubjectVariant.ResponseBody.

NOTE: Consider adding a property name or description that can be used as the K6 check name.

{
  checks: [
    {
      type: 1,
      expression: "user.name",
      condition: 2,
      value: "Batman"
    },
    {
      type: 0,
      subject: 1,
      condition: 0,
      value: "Hello world"
    },
    {
      type: 0,
      subject: 2,
      condition: 2,
      value: 200
    },
    {
      type: 3,
      subject: 0,
      expression: "[0-9]+(\s{1})?%"
    }
  ]
}

Generated K6 script

The above config would generate

check(res, {
  "user.name equals Batman": (r) => r.body.user.name === "Batman"
});

check(res, {
  "body contains Hello world": (r) => r.body.includes("Hello world")
});

check(res, {
  "HTTP status code equals 200": (r) => r.status === 200
});

check(res, {
  "body matches [0-9]+(\s{1})?%": (r) => /[0-9]+(\s{1})?%/.test(r.body)
});

variables

List of variables, if any (embedded in entry object).
The object defines instructions for data that should be extracted from the responseBody and be reusable in subsequent requests.
The variable should be referenceable in subsequent entries. Properties that can reference variables are headers, postData, url and queryString.
A variable named access_token is referenced as ${access_token}.

Type definition

type Variable = {
  name: String,
  type: VariableTypeVariant,
  expression: String
}

type VariableTypeVariant =
  | JSONPath = 0
  | Regex = 1;

Expression match, variable initialization

If the variables JSONPath or RegEx expression cannot be resolved with the returned response, the variable should still be declared and initialized. When there are multiple matches for a Regex expression then $1 will be the assigned value.

Variable overrides

If multilple entries define the same variable names then the variable will be overridden according to the execution order of the entries.

HAR example

{
  "log": {
    "entries": [
      {
        "variables": [
          {
            name: "accessToken",
            type: 0,
            expression: "user.token"
          }
        ],
        "request": {
          "url": "http://api.test.com/authenticate",
          "method": "POST",
          "headers": [
            {
              "name": "Content-Type",
              "value": "application/json"
            }
          ]
          "postData": {
            "mimeType": "application/json",
            "text": "{\"username\":\"admin\",\"password\":\"123\"}"
          }
        }
      },
      {
        "request": {
          "url": "http://api.test.com/users",
          "method": "GET",
          "headers": [
            {
              "name": "Autorization",
              "value": "Bearer ${accessToken}"
            }
          ]
        }
      }
    ]
  }
}

Generated K6 script

The above config would generate

export default function() {
  let accessToken;
  var r = http.post("http://api.test.com/authenticate",
    JSON.stringify({
      username: "admin",
      password: "123"
    }),
    {
      headers: {
        "Content-Type": "application/json"
      }
    }
  );
  accessToken = r.body.user.token;

  http.get("http://api.test.com/users", {
    headers: {
      "Authorization": `Bearer ${accessToken}`
    }
  })
}

Examples

Post JSON data to api

// Config
{
  log: {
    entries: [
      {
        request: {
          method: "POST",
          url: "http://test.loadimpact.com/login",
          headers: [
            {
              "name": "Content-Type",
              "value": "application/json"
            }
          ],
          postData: {
            "mimeType": "application/json",
            "text": "{\"user\":\"admin\",\"password\":\"123\"}"
          },
        },
      }
    ],
  }
};

// Generated K6 script
import http from "k6/http";

export default function() {
  var payload = JSON.stringify({ email: "aaa", password: "bbb" });
  http.post("http://test.loadimpact.com/login", payload, {
    headers: { "Content-Type": "application/json" }
  });
}

Post JSON data with check

// Config
{
  log: {
    entries: [
      {
        checks: [
          {
            type: 0,
            subject: 2,
            condition: 2,
            value: 200
          }
        ],
        request: {
          method: "POST",
          url: "http://test.loadimpact.com/login",
          headers: [
            {
              "name": "Content-Type",
              "value": "application/json"
            }
          ],
          postData: {
            "mimeType": "application/json",
            "text": "{\"user\":\"admin\",\"password\":\"123\"}"
          },
        },
      }
    ],
  }
};

// Generated K6 script
import http from "k6/http";

export default function() {
  let payload = JSON.stringify({ email: "admin", password: "123" });

  let res = http.post("http://test.loadimpact.com/login", payload, {
    headers: { "Content-Type": "application/json" }
  });

  check(res, {
    "HTTP status code equals 200": r => r.status === 200
  });
}

Set reusable variable based on request response

// Config
{
  log: {
    entries: [
      {
        variables: [
          {
            type: 0,
            name: "accessToken",
            expression: "user.token"
          }
        ],
        request: {
          method: "POST",
          url: "http://test.loadimpact.com/login",
          headers: [
            {
              "name": "Content-Type",
              "value": "application/json"
            }
          ],
          postData: {
            "mimeType": "application/json",
            "text": "{\"user\":\"admin\",\"password\":\"123\"}"
          },
        },
      },
      {
        request: {
          method: "GET",
          url: "http://test.loadimpact.com/users",
          headers: [
            {
              "name": "Authorization",
              "value": "Bearer ${accessToken}"
            }
          ]
        },
      }
    ],
  }
};

// Generated K6 script
import http from "k6/http";

export default function() {
  let accessToken;

  let payload = JSON.stringify({ email: "admin", password: "123" });
  let res = http.post("http://test.loadimpact.com/login", payload, {
    headers: { "Content-Type": "application/json" }
  });

  accessToken = res.body.accessToken;

  http.get("http://test.loadimpact.com/my_messages", {
    headers: { Authorization: `Bearer ${accessToken}` }
  });
}

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li-har.spec.md

li-har.spec.md

LI-HAR config format

Table of Contents

Log

Options

Pages

Entries

Pageref

Example

Request

URL

Headers

QueryString

PostData

Referencing variables

Examples with different payload types

application/json

application/x-www-form-urlencoded

text/plain

text/xml

image/png

Checks

HAR example

Generated K6 script

variables

Type definition

Expression match, variable initialization

Variable overrides

HAR example

Generated K6 script

Examples

Post JSON data to api

Post JSON data with check

Set reusable variable based on request response

Files

li-har.spec.md

Latest commit

History

li-har.spec.md

File metadata and controls

LI-HAR config format

Table of Contents

Log

Options

Pages

Entries

Pageref

Example

Request

URL

Headers

QueryString

PostData

Referencing variables

Examples with different payload types

application/json

application/x-www-form-urlencoded

text/plain

text/xml

image/png

Checks

HAR example

Generated K6 script

variables

Type definition

Expression match, variable initialization

Variable overrides

HAR example

Generated K6 script

Examples

Post JSON data to api

Post JSON data with check

Set reusable variable based on request response