npm package: @kth/api-call
Description: Node.js module to make JSON calls against APIs.
Author: KTH
Latest version: 4.4.0

# KTH API Call for Node

Node module used to make JSON calls against APIs. (Previously published as `kth-node-api-call`, now `@kth/api-call`.)

To use in your node project, run:

```sh
npm i @kth/api-call
```

## Setup

In your init callback to the Express web server, this should happen:

```javascript
const connections = require('@kth/api-call').Connections

const nodeApi = {
  namedApi: {
    host: 'localhost', // api hostname
    https: false, // use ssl?
    port: 3001, // api port
    proxyBasePath: '/api/applicationName', // api base path
    required: true, // is the api required? Optional, defaults to false
    defaultTimeout: 2000, // milliseconds. Optional, defaults to 2000
  },
}

const cacheConfig = {
  namedApi: {
    redis: {
      host: 'localhost',
      port: 6379,
    },
  },
}

const apiKey = {
  namedApi: '1234',
}

const options = {
  timeout: 5000, // milliseconds, retry interval if getting API-paths fails
  log: myLogger, // your logger instance
  redis: myRedis, // optional kth-node-redis instance
  cache: cacheConfig, // your api cache options
  checkAPIs: true,
}
// either
module.exports = connections.setup(nodeApi, apiKey, options)
// or
const api = connections.setup(nodeApi, apiKey, options)
```

### Note

The checkAPIs option requires that the API implements a checkAPIkey route, see [node-api](https://www.github.com/KTH/node-api.git)
The endpoint can be overridden by setting the `statusCheckPath` property on the api config object

## Usage

Wherever you need to call your api, use something on the form of:

```javascript
const paths = api.namedApi.paths
const client = api.namedApi.client

// user is a uri parameter
client.getAsync(client.resolve(paths.[YOUR_ENDPOINT], {user: username, etc...}))
.then(response => {
  // do something with result
})

```

if you want to use a cached api, add the option `{useCache: true}` to the `getAsync` call like this:

```javascript
client.getAsync([FULL_PATH], { useCache: true }).then(response => {
  // etc.
})
```

## BasicAPI

This used to be a straightforward wrapper around [request][request]. Since version 4, `request` is replaced by [node-fetch][node-fetch], with efforts made to keep the same methods.

`BasicAPI` will allow more control but also encourage more code re-use. It allows the use of Promises and caching (via redis) of successful responses (status >= 200 and status < 400).

For more details see the examples below and [the source code][basicjs].

```javascript
// configure this and re-use throughout your app

const api = new BasicAPI({
  hostname: 'localhost',
  port: 3001,
  json: true,
  https: false,
  headers: {
    api_key: 'abcd',
  },
  // optionally enable redis for response caching
  // redis: {
  //   client: redisClient,
  //   prefix: 'node-api',
  //   expire: 120
  // }
})

// usage example:

const params = { id: 123 }
const uri = api.resolve('/value/:id', params)

// promise
api
  .getAsync(uri)
  .then(response => {
    if (response.statusCode >= 200 && response.statusCode < 400) {
      // do something with response.body
    } else {
      // bad/unexpected status code, delegate error
    }
  })
  .catch(err => {
    // handle/delegate err
  })

// or callback
api.get(uri, (err, response, body) => {
  if (err) {
    // handle/delegate err
    return
  }

  if (response.statusCode >= 200 && response.statusCode < 400) {
    // do something with response.body
  } else {
    // bad/unexpected status code, delegate error
  }
})
```

### HTTP Request Methods

Each of the following sends a corresponding HTTP request. Append `Async` (e.g. `getAsync`) to use Promise instead of callback. The first parameter should be either a uri (as a string) or an options object which is passed to [node-fetch][node-fetch]. For non-async methods the second parameter should be a function with the following signature: `function (error, response, body) { ... }`. The callback parameters are the same as for the request library.

Note that if you use Redis and/or the async methods you might lose some functionality. For details about this, read the source code!

- `get`/`getAsync`
- `post`/`postAsync`
- `put`/`putAsync`
- `del`/`delAsync`
- `head`/`headAsync`
- `patch`/`patchAsync`

### Utility Methods

- `resolve` takes two parameters. The first is a uri template, e.g. `/value/:name`, and the second is a plain object, e.g. `{ name: 'foo' }`. It will then replace `:name` with the matching values in the object, resolving the uri `/value/foo`.
- `defaults` re-uses the same config and applies another configuration set on top. Basically it does the same as `request.defaults()` but returns a valid `BasicAPI` instance.

### Migration from version 3 to 4

- `jar` and `cookie` were basic wrappers to the corresponding [request][request] methods. They were removed in version 4.
- `defaults` was deprecated in version 4. Use `new BasicAPI(options)` instead.

[request]: https://github.com/request/request
[node-fetch]: https://github.com/node-fetch/node-fetch
[basicjs]: ./basic.js