assert-headers

assert-headers-node

Assert HTTP headers

Usage

CLI

Global usage

npm i -g assert-headers
# Assume headersSchema.json in current working directory
assert-headers https://example.com

or with specified configuration

assert-headers --config ./customConfiguration.json https://example.com

or using npx

npx assert-headers https://example.com

in silent mode

npx assert-headers --silent --config ./customConfiguration.json https://example.com

to see what version you are running

assert-headers --version

Advanced CLI Usage

TODO: Add example of how to stream a column of a .csv into the tool

TODO: Show how the exit codes can be used in smoke tests

CLI Configuration

assert-headers currently accepts configuration in JSON or YAML formats. It allows specifying a schema for the headers, but also the outgoing origin and user-agent headers for the request. Below is an example configuration:

{
  "userAgent": "assert-headers-node",
  "origin": "https://example.com",
  "schema": {
    "cache-control": false,
    "strict-transport-security": true,
    "x-content-type-options": "nosniff",
    "x-frame-options": {
      "DENY": true,
      "SAMEORIGIN": false
    }
  }
}

userAgent: "assert-headers-py"
origin: "https://example.com"
schema:
  cache-control: False
  strict-transport-security: True
  x-content-type-options: "nosniff"
  x-frame-options:
    DENY: True
    SAMEORIGIN: False

Schema Explanation:

1. "disallowed-header-name": false - It is considered an error if this header is defined
2. "required-header-name": true - It is considered an error if this header is missing (or undefined)
3. "strict-header-name": "only good value" - It is considered an error if this header does not have this value
4. "enumerated-header-name": { "good header value": true, "another good value": true } - It is considered an error if this header contains a value other than one marked true.
5. "enumerated-header-name": { "bad header value": false, "another bad value": false } - It is considered an error if this header contains a value not marked true
6. If no enumerated header values are marked true, all listed values are considered invalid values. It is highly recommended to ONLY use true and false for enumerated values

assertHeader

const assertHeader = require('assert-header')

const headers = {
  'strict-transport-security': 'max-age=31536000; includeSubDomains',
  'x-content-type-options': 'nosniff',
  'x-frame-options': 'DENY'
}
const schema = {
  'cache-control': false,
  'strict-transport-security': true,
  'x-content-type-options': 'nosniff',
  'x-frame-options': {
    // if any are true, the header value must match a true schema value
    DENY: true
  }
}

try {
  assertHeaders(headers, schema)
} catch (err) {
  console.error('OOPS!', err.message)
  if (err.errors) {
    err.errors.forEach((assertionError) => {
      console.error(`The header ${assertionError.headerName} was bad!`)
    })
  }
}

This can also be used inside a test library for validating HTTP response headers.

assertHeader.fromUrl

const assertHeader = require('assert-header')

(async () => {
  const configuration {
    'userAgent': 'Custom User Agent name',
    origin: 'https://my-domain.com',
    schema: {
      'cache-control': false,
      'strict-transport-security': true,
      'x-content-type-options': 'nosniff',
      'x-frame-options': {
        // if any are true, the header value must match a true schema value
        DENY: true
      }
    }
  }

  await assertHeader.fromUrl('https://example.com/my-test-page', configuration)
})()

Changelog

[1.0.1] - 2021-05-24

Fixed

• YAML configuration example in readme