REST Variables

Reuse data across your REST queries

Variables are a useful way to reuse data across REST queries. Variables come in two forms; static and dynamic.

The blank variables section of a REST datasource

Static Variables

Static variables store data that does not change. These can range from constants used in the metadata of the request to information about the request itself that can be used in the URL such as API version or hostname.

Variables nested inside other variables will not be evaluated.

Example static variables

Dynamic Variables

Dynamic variables provide a way to chain data between queries.

• Response data from one query can be used to create a dynamic variable

  • Header

  • Body field

• The result of the variable will be cached for a short period of time

• A variable will be re-evaluated if a query using it fails, in which case the query will retry once

• A query will fail if a variable cannot be evaluated

Header Variables

Use the ... menu alongside response headers to select Create dynamic variable

Creating a header based dynamic variable

Give the variable a name.

• The name must be unique

• The name will be used to bind this variable in your query. e.g cookie can be used as {{cookie}}

The variable will appear in the Dynamic Variables tab

A header based dynamic variable

Body Variables

Use the ... menu alongside schema items to select Create dynamic variable

Creating a schema (body) based dynamic variable

Give the variable a name as above

The variable will appear in the Dynamic Variables tab

A body based dynamic variable

Editing Dynamic Variables

In the above example we can see the user_id variable is bound to {{ data.0.[user] }} which is an object. To access nested data in the response body we can update the variable expression to reference the nested fields using dot notation e.g. {{ data.0.[user._id] }} .

Alternatively a query transformer can be used to update the schema so that the desired field is exposed in the schema directly.

Dynamic variables can also be created manually using the Add variable button.

• Access header data using {{ info.headers.[header-name] }}

• Access body data using {{ data.0.[body-field] }}

Editing a dynamic variable

Using Variables

Once a variable has been defined it can be used in the exact same was as a binding.

• For example a variable named my-id can be referenced in the headers, params or body of a query using {{my-id}}

• For more details seeUsing a binding