# operation-id-defined

Source: https://apigenie.pl/docs/linter/swagger/rules/operation-id-defined

This rule checks whether every operation of a Swagger 2.0 document has an
operation ID.

## Rule Details

The `operationId` property identifies an operation. Code generators use it to
name the methods of generated clients and servers, and documentation tools use
it to build links to operations.

The `operation-id-defined` rule reports `Operation ID is not defined` for every
operation whose `operationId` is missing or empty.

## Configuration

None.

## Examples

**Good**. The operation has an operation ID.

```yaml
swagger: '2.0'
info:
  title: Reservations
  version: 1.0.0
paths:
  /reservations/{reservationId}:
    delete:
      operationId: cancelReservation
      parameters:
        - name: reservationId
          in: path
          required: true
          type: string
      responses:
        '204':
          description: The reservation was cancelled.
```

**Bad**. The operation has no operation ID.

```yaml
swagger: '2.0'
info:
  title: Reservations
  version: 1.0.0
paths:
  /reservations/{reservationId}:
    delete:
      parameters:
        - name: reservationId
          in: path
          required: true
          type: string
      responses:
        '204':
          description: The reservation was cancelled.
```

## Automatic fixes

When invoked with `--fix`, this rule sets `operationId` to an ID generated from
the HTTP method and the path. Each literal path segment is appended in
PascalCase, and each path parameter is appended as `By` followed by its name in
PascalCase: `GET /users/{userId}` becomes `getUsersByUserId`, and `GET /`
becomes `getRoot`. IDs already used in the document are reserved, and a
generated ID that collides with a reserved one gets a numeric suffix starting
at 2 (`getUsers2`).

## When Not to Use It

You may disable this rule when no tooling relies on operation IDs.

## Compatibility

This rule is compatible with Swagger 2.0 documents. OpenAPI 3.x documents are
linted by the OpenAPI linter, which has a rule of the same name.