npm:@paypal/paypalhttp

README

PayPal HttpClient

PayPalHttp is a generic HTTP Client.

In it's simplest form, an HttpClient exposes an #execute method which takes an HttpRequest, executes it against the domain described in an Environment, and returns a Promise.

Environment

An Environment describes a domain that hosts a REST API, against which an HttpClient will make requests. Environment is a simple class that contains one property, baseUrl.

let env = new Environment('https://example.com');

Requests

HTTP requests contain all the information needed to make an HTTP request against the REST API. Specifically, one request describes a path, a verb, any path/query/form parameters, headers, attached files for upload, and body data. In Javascript, an HttpRequest is simply an object literal with path, verb, and optionally, requestBody, and headers populated.

Responses

HTTP responses contain information returned by a server in response to a request as described above. They are simple objects which contain a statusCode, headers, and a result, which represents any data returned by the server.

let req = {
  path: "/path/to/resource",
  verb: "GET",
  headers: {
    "X-Custom-Header": "custom value"
  }
}

client.execute(req)
  .then((resp) => {
    let statusCode = resp.statusCode;
    let headers = resp.headers;
    let responseData = resp.result;
  });

Injectors

Injectors are closures that can be used for executing arbitrary pre-flight logic, such as modifying a request or logging data. Injectors are attached to an HttpClient using the #addInjector method. They must take one argument (a request), and may return nothing, or a Promise.

The HttpClient executes its injectors in a first-in, first-out order, before each request.

let client = new HttpClient(env);
client.addInjector((req) => {
  console.log(req);
});

client.addInjector((req) => {
  req.headers['Request-Id'] = 'abcd';
});

...

Error Handling

The Promise returned by HttpClient#execute maybe be rejected if something went wrong during the course of execution. If the server returned a non-200 response, this error will be an object that contains a status code, headers, and any data that was returned for debugging.

client.execute(req)
  .then((resp) => {
    let statusCode = resp.statusCode;
    let headers = resp.headers;
    let responseData = resp.result;
  })
  .catch((err) => {
    if (err.statusCode) {
      let statusCode = err.statusCode;
      let headers = err.headers;
      let message = err.message;
    } else {
      // Something else went wrong
      console.err(err);
    }
  });

Serializer

(De)Serialization of request and response data is done by instances of Encoder. PayPalHttp currently supports json encoding out of the box.

License

PayPalHttp-Node is open source and available under the MIT license. See the LICENSE file for more info.

Contributing

Pull requests and issues are welcome. Please see CONTRIBUTING.md for more details.

Usage no npm install needed!