sap-cf-destination
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convenience utility for calling a URL via a SAP CF destination
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# SAP CP Cloud Foundry destination handler
[](https://travis-ci.com/vobu/sap-cf-destination)
[](https://www.npmjs.com/package/sap-cf-destination)
## Install
~~~
npm install --save sap-cf-destination
~~~
## Prerequisites
- `destination` and `destination` instance created
- `connectivity` instance created
- `xsuaa` instance created
- all of the above instances bound to the node app, e.g. via `manifest.yml`:
~~~ yaml
applications:
- name: my_app
path: my_app
memory: 128M
services:
- xsuaa-instance
- connectivity-instance
- destination-instance
~~~
## Usage
~~~ javascript
const callDestination = require('sap-cf-destination');
// Promise chain
callDestination({
url: '/api/json',
connectivity_instance: 'connectivity-lite',
uaa_instance: 'uaa-lite',
destination_instance: 'destination-lite',
destination_name: 'tbaas',
http_verb: 'POST',
payload: {
"me": "here"
}
})
.then(response => {
// do sth clever from the response
// of $server_behind_destination_'tbaas'/api/json
})
.catch(err => {
// oh no 💩
})
// async/await? 👏
// add the 'async' keyword to an outer function wrapping 'callDestination'
async function getIt() {
try {
const response = await callDestination({...});
// do sth clever w/ the response
} catch (err) {
// oh no 💩
}
}
~~~
## API
## sap-cf-destination(options) ⇒ <code>Promise.<(any\|never)></code>
| Param | Type | Description |
| --- | --- | --- |
| options | <code>Map</code> | configuration options for several CF service instances |
| options.url | <code>string</code> | the url to call in the destination, absolute path (including leading slash) e.g. /api/v1/json |
| options.connectivity_instance | <code>string</code> | name of the instance of the connectivity service |
| options.uaa_instance | <code>string</code> | name of the instance of the uaa service |
| options.destination_instance | <code>string</code> | name of the instance of the destination service |
| options.destination_name | <code>string</code> | name of the destination to use |
| options.http_verb | <code>'GET'</code> \| <code>'POST'</code> \| <code>'PUT'</code> \| <code>'PATCH'</code> \| <code>'DELETE'</code> \| <code>'HEAD'</code> \| <code>'OPTIONS'</code> | HTTP method to use |
| [options.payload] | <code>object</code> | payload for POST, PUT or PATCH |
| [options.formData] | <code>object</code> | mimic a browser for POSTing a form to the destination; implies http verb POST |
| [options.content_type] | <code>string</code> | value for "Content-Type" http header, e.g. "application/json" |
| [options.full_response] | <code>boolean</code> | whether to have the full response (including all headers etc) pass through to the caller (BE -> proxy -> client) |
| [options.tech_error_only] | <code>boolean</code> | get a rejection only if the request failed for technical reasons, so e.g. 404 is considered a valid response |
| [options.binary] | <code>boolean</code> | whether to expect (and deliver) a binary at @param url |
| [options.scc_name] | <code>string</code> | Location ID of the SAP Cloud Connector |
## Hints & Limitations
- all major HTTP verbs are supported (`GET`, `POST`, `PUT`,`PATCH`,`HEAD`, `DELETE`,`OPTIONS`) per se
**BUT**: if the proxy software decides to not let any of them pass through, the request originating from this module will of course fail
- ~~`POST`,~~ `PUT` and `PATCH` only support a JSON payload.
The payload itself can be a plain, deeply nested object; it will be stringified automatically
- `POST` now supports both a JSON payload and a form-style ("like a browser") submission:
~~~js
callDestination({
url: ...,
http_verb: 'POST',
formData: {
field1: "some value",
field2: JSON.stringify([ { "el1": "v1", "el2": "v2" } ]) // stringify deep nested objects and array structures
}
})
~~~
- use `scc_name: '<locID>'` as a parameter to specify location ID of the SAP Cloud Connector (default: _none_)
~~~js
callDestination({
//...
scc_name: '<locID of SCC>'
}).then(...).catch(...);
~~~
- use `full_response: true` as a parameter to obtain the full response payload, e.g. to get access to response headers
~~~js
callDestination({
//...
full_response: true
}).then(...).catch(...);
~~~
- use `tech_error_only: true` as a parameter to only get a rejection if the request failed for technial reasons ("as long as [it has a status code](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/418), it's a valid response")
~~~js
callDestination({
//...
tech_error_only: true
}).then( response => {
// even ☕️ ends up here
// add
// full_response: true (see above)
// to get response.statusCode
}).catch( err => {
// network layer problem or such
});
~~~
- do a download of a binary file by specifying the matching `Content-Type` of the file and setting `binary` to `true`;
this will deliver a `Buffer` useable in `writeStreams`
~~~js
callDestination({
//...
content_type: 'application/zip',
binary: true
}).then( buffer => {
// write Buffer
fs.createWriteStream('file.zip')
.write(buffer, 'binary')
.end();
// don't forget to listen to the error and finish event
// ...
}).catch(...);
~~~
## License
Apache License 2.0
## References
- code inspiration from https://github.com/bertdeterd/scc-connector
- ported `Java` reference code from https://help.sap.com/viewer/cca91383641e40ffbe03bdc78f00f681/Cloud/en-US/313b215066a8400db461b311e01bd99b.html