# cds-swagger-ui-express

An CAP plugin to serve OpenAPI definitions for [CAP](https://cap.cloud.sap) services in Swagger UI.
Builds on top of [swagger-ui-express](https://www.npmjs.com/package/swagger-ui-express).

![Preview](https://raw.githubusercontent.com/chgeo/cds-swagger-ui-express/main/assets/cds-swagger-ui.png)

## Setup

In your project, just add a dependency like so:
```sh
npm add --save-dev cds-swagger-ui-express
```

Once loaded by CAP, the package registers itself as a middleware with a default configuration.

## Run

After starting the app with `cds watch` or so, Swagger UI is served at `/$api-docs/<service-path>`, like http://localhost:4004/$api-docs/browse/

## Configuration

You can set the most prominent options in `package.json` or `.cdsrc.json`, as in other CAP apps:
```jsonc
"cds": {
  "swagger": {
    "basePath": "/$api-docs", // the root path to mount the middleware on
    "apiPath": "/", // the root path for the services (useful if behind a reverse proxy)
    "diagram": true, // whether to render the YUML diagram
    "odataVersion": "4.0" // the OData Version to compile the OpenAPI specs. Defaults to 4.01
  }
}
```

To disable the plugin, set this:
```jsonc
"cds": {
  "swagger": false
}
```

Note that you can also set environment variables for each option, like `CDS_SWAGGER=false`.  See the [`cds.env` docs](https://cap.cloud.sap/docs/node.js/cds-env#process-env) for more.


## Programmatic Usage (advanced)

If you need to register the plugin programmatically, e.g. in certain conditions only, you can do so in your [`server.js`](https://cap.cloud.sap/docs/node.js/cds-server#custom-server-js):

```js
const cds = require ('@sap/cds')
const cds_swagger = require ('cds-swagger-ui-express')
cds.on ('bootstrap', app =>
  app.use (cds_swagger ())
)
```

In this case, the default 'auto registration' as plugin is disabled automatically to avoid conflicts.

### Programmatic Configuration

If the middleware is registered programmatically, you need to pass in the options through the API as well. No configuration from `package.json` is used here.

Call `cds_swagger ({...})` with the following object as first parameter:
```jsonc
{
  "basePath": ...,
  // see section above for more
}
```

#### Swagger UI Options

Call `cds_swagger ({...}, {...})` with an additional object as <em>second</em> parameter. This object is passed to `swagger-ui-express` as [custom options](https://www.npmjs.com/package/swagger-ui-express#user-content-custom-swagger-options).

Example:

```jsonc
{
  "customSiteTitle": "My Custom Title",
  "swaggerOptions": {
    "requestInterceptor": ...
  }
}
```

See the [list of all options](https://github.com/swagger-api/swagger-ui/blob/master/docs/usage/configuration.md).
For questions to specific properties, contact the maintainers of [swagger-ui-express](https://www.npmjs.com/package/swagger-ui-express) or [swagger-ui](https://github.com/swagger-api/swagger-ui).

### Notes

If you call [`cds.serve`](https://cap.cloud.sap/docs/node.js/cds-serve#cds-serve) on your own in your `server.js`, make sure to install this middleware _before_, as it relies on CDS' [`serving` events](https://cap.cloud.sap/docs/node.js/cds-server#cdson--serving-service).