Use Mustangserver with Javascript

If you can not, or do not want to generate a custom client (e.g. like for PHP), e.g. because you target low code platforms like Node Red, you can actually get quite far with the following node.js’s / npm packages in your package.json

{
  "dependencies": {
    "axios": "^1.7.9",
    "file-saver": "^2.0.5",
    "string-to-file-stream": "^2.0.0"
  }
}

After a “npm install” and obtaining an access token for client_credentials as described via

axios.post('https://gw.usegroup.de:9443/oauth2/token',
    null,
    {
	    params: {'grant_type':'client_credentials'},
        auth: {
            username: '<client id/>',
            password: '<client secret/>'
        }
    }
).then(function (response) {
        // handle success
        const msg={};
        msg.payload =response.data.access_token;

        console.log("done", msg.payload);
    })
    .catch(function (error) {
        // handle error
        console.warn(error);
    })
    .finally(function () {
        // always executed
        console.log("finished");
    });

A simple request will then work as follows after inserting the obtained access_token below:

const axios = require('axios');
axios.get('https://gw.usegroup.de:8243/mustang/1.5.1/mustang/ping',
    {
         headers: {
            'accept': '*/*',
            'Authorization': 'Bearer <access_token/>'
        }
    }
).then(function (response) {
        // handle success
	
        console.log("done: ",response.data);
    })
    .catch(function (error) {
        // handle error
        console.warn(error);
    })
    .finally(function () {
        // always executed
        console.log("finished");
    });

And a more complex operation with a file request and a file response may work like

const stringToFileStream = require('string-to-file-stream');
const axios = require('axios');
const bufStr='<rsm:CrossIndustryInvoice...';// rest of XML goes in here!
const stream=stringToFileStream(bufStr);
const FormData = require('form-data');
const fsPromises = require('fs').promises;

const form = new FormData();
form.append("file",  stream);

axios.post('https://gw.usegroup.de:8243/mustang/1.5.1/mustang/xmltopdf',
    form,
    {
	  responseType: 'arraybuffer',
         headers: {
            'accept': '*/*',
            'Content-Type': 'multipart/form-data',
            'Authorization': 'Bearer <access_token/>'
        }
    }
).then(function (response) {
        // handle success
        fsPromises.writeFile('response.pdf', response.data, { encoding: 'binary' });

        console.log("done");
    })
    .catch(function (error) {
        // handle error
        console.warn(error);
    })
    .finally(function () {
        // always executed
        console.log("finished");
    });

Node Red

This is a Node Red flow which watches a directory (/tmp/incoming), converts newly placed UBL files into CII, additionally converts them into PDF and adds the CII contents to create a Factur-X file from a XRechnung:

The custom function UBL2CII has the setup

and is defined as

axios.post('https://gw.usegroup.de:8243/eigor/v1.6.0/eeisi/eigor?sourceFormat=ubl&destFormat=cii',
msg.payload,
{

"responseType": 'arraybuffer',
headers: {
'Content-Type': 'text/plain',
'accept': '*/*',
            'apikey': 'eyJ4N...=='
}
}
).then(function (response) {
msg.payload=response.data;
node.send(msg);
})

XML2PDF is defined as

flow.set("read",msg.payload);
const form=new FormData();
form.append("file", stringToFileStream(msg.payload))

axios.post('https://gw.usegroup.de:8243/mustang/1.6.1/mustang/xmltopdf?returnJSON=false',
form,
{
"responseType": 'arraybuffer',
headers: {
'Content-Type': 'multipart/form-data',
'accept': '*/*',
            'apikey': 'eyJ4N...=='
}
}
).then(function (response) {
msg.payload=response.data;
flow.set("pdf",response.data);
node.send(msg);
})

and PDF2FX is defined as

const form=new FormData();
form.append("file", stringToFileStream(flow.get('pdf')))
form.append("XML", flow.get('read'))

axios.post('https://gw.usegroup.de:8243/mustang/1.6.1/mustang/combineXML?format=fx&version=2&profile=EN16931',
form,
{
"responseType": 'arraybuffer',
headers: {
'Content-Type': 'multipart/form-data',
'accept': '*/*',
            'apikey': 'eyJ4N...=='
}
}
).then(function (response) {
msg.payload=response.data;
node.send(msg);
})

Have fun!