Metadata and Cookies

Metadata

Metadata is additional information about the data returned by the REST API. This information includes the request URL, method, headers, and response status code, headers, and body. The metadata can be accessed within queries and components using the {{queries.<queryname>.metadata}} syntax.

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While accessing the properties of the metadata object, which contains a hyphen, you can use the bracket notation. For example, to access the user-agent property, you can use {{queries.restapi1.metadata.request.headers["user-agent"]}} or {{queries.restapi1.metadata.request.headers."user-agent"}}.

Example Metadata

{
  "request": {
    "url": "https://dummyjson.com/users",
    "method": "GET",
    "headers": {
      "user-agent": "got (https://github.com/sindresorhus/got)",
      "tj-x-forwarded-for": "103.171.99.41",
      "accept-encoding": "gzip, deflate, br"
    },
    "params": {}
  },
  "response": {
    "statusCode": 200,
    "headers": {
      "server": "[REDACTED]",
      "report-to": "{"group":"heroku-nel","max_age":3600,"endpoints":[{"url":"https://nel.heroku.com/reports?ts=1726207652&sid=e11707d5-02a7-43ef-b45e-2cf4d2036f7d&s=1ICCahr5yl4s1cOLwZ5JI7Le2a5Hp57L8DugEP6oEZQ%3D"}]}",
      "reporting-endpoints": "heroku-nel=https://nel.heroku.com/reports?ts=1726207652&sid=e11707d5-02a7-43ef-b45e-2cf4d2036f7d&s=1ICCahr5yl4s1cOLwZ5JI7Le2a5Hp57L8DugEP6oEZQ%3D",
      "nel": "{"report_to":"heroku-nel","max_age":3600,"success_fraction":0.005,"failure_fraction":0.05,"response_headers":["Via"]}",
      "connection": "close",
      "access-control-allow-origin": "*",
      "x-dns-prefetch-control": "off",
      "x-frame-options": "SAMEORIGIN",
      "strict-transport-security": "max-age=15552000; includeSubDomains",
      "x-download-options": "noopen",
      "x-content-type-options": "nosniff",
      "x-xss-protection": "1; mode=block",
      "x-ratelimit-limit": "100",
      "x-ratelimit-remaining": "99",
      "date": "Fri, 13 Sep 2024 06:07:32 GMT",
      "x-ratelimit-reset": "1726207656",
      "content-type": "application/json; charset=utf-8",
      "etag": "W/"7d39-+rQ7kyHBCLIn9tjTeKVf4oegWkQ"",
      "vary": "Accept-Encoding",
      "content-encoding": "gzip",
      "transfer-encoding": "chunked",
      "via": "1.1 vegur"
    }
  }
}

Valid and Invalid Headers

Valid Headers

Header Key	Header Value	Notes
Content-Type	'application/json'	String values are valid and commonly used for specifying content type.
X-Number	42	Numeric values are valid (e.g., 42, 3.14, -7).
X-Boolean	true	Boolean values are valid (true or false).
X-Trim-Me	' needs trimming '	Valid after trimming.
X-Empty-String	''	Empty string values are valid.

Invalid Headers

Header Key	Header Value	Reason Invalid
X-Null	null	null is not a valid header value.
X-Undefined	undefined	undefined is not a valid header value.
X-NaN	NaN	Special numeric values like NaN are invalid.
X-Infinity	Infinity	Infinity is not a valid primitive.
X-NegativeInfinity	-Infinity	-Infinity is also invalid.
X-Object	{ key: 'value' }	Objects are not allowed as header values.
X-Array	[1, 2, 3]	Arrays are not valid as header values.
X-Function	( ) => console.log('test')	Functions cannot be serialized into headers.
X-Symbol	Symbol('sym')	Symbols are non-serializable and invalid.
(empty key)	'Empty key'	Header keys must not be empty.

Cookies

In addition to the data source level cookies, you can add query-specific cookies in the Query builder. These cookies will be sent only with the specific query created using this data source instance.

To add cookies:

1. In the Query builder, navigate to the Setup tab.
2. Find the Cookies section.
3. Add your cookies as key-value pairs.

You can use both static values and dynamic values for cookie values.

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Query-specific cookies will override data source level cookies with the same name for that particular query.