cla/lwp - LWP User Agent

The LWP user agent is a powerful and resourceful alternative to the cla/web module, which is lightweight and simpler.

lwp.agent(options)

Returns a new web agent object. The web agent object is analogous to a browser or a curl command, in a way that it can be used to craft elaborate web requests.

In this example, we invoke a REST GET webservice that returns JSON content.

var lwp = require('cla/lwp');
var ua = lwp.agent();
var res = ua.request('GET', 'http://example.com');
print(res.content());

Posting JSON content to an endpoint:

var lwp = require('cla/lwp');
var ua = lwp.agent();
var json = JSON.stringify({
    foo: 1234,
    bar: 'hello'
});

var res = ua.request('GET', 'https://jsonplaceholder.typicode.com/todos/1', {
    content_type: 'application/json',
    content: json
});

print(res.content(), res.code());

var obj = JSON.parse(res.content());
print('UserID' + obj.userId);

Using digest authentication:

var lwp = require('cla/lwp');
var ua = lwp.agent();
ua.credentials('server:8080', 'MyRealm', 'myusername', 'mypassword');
var res = ua.request('GET', 'http://some.digest.example.com');

Attaching a file as POST in a form:

var lwp = require("cla/lwp");
var ua = lwp.agent();
var localFile = '/tmp/myfile.tar';

const res = ua.post( 'http://example.com/postfile',
    'Content-Type',
    'multipart/form-data',
    'Content',
    { file: [localFile] }
);

if( res.isSuccess() ) {
    print("Done!");
}

Downloading a file is now also possible, and is done automatically by the cla/lwp module by sending the full path to the file using the option toFile in the request:

var lwp = require("cla/lwp");
var ua = lwp.agent();

const res = ua.request('GET',
    'https://file-examples-com.github.io/uploads/2017/02/zip_10MB.zip',
    { toFile: '/tmp/localzip.zip' }
);

if( res.isSuccess() ) {
    print("Done!");
}

You can also set toPath to downloading files. In this case, the file name will be extracted from the last part of the URL and appended to toPath:

var lwp = require("cla/lwp");
var ua = lwp.agent();

// writes the file /tmp/zip_10MB.zip
const res = ua.request('GET',
    'https://file-examples-com.github.io/uploads/2017/02/zip_10MB.zip',
    { toPath: '/tmp' }
);

if( res.isSuccess() ) {
    print("Done!");
}

More info

For a complete description of methods available, this library mimicks Perl's LWP::UserAgent.

https://metacpan.org/pod/LWP::UserAgent