REQUEST

Performs an HTTP request and executes the callback on completion.

Description

The REQUEST function is for making external HTTP requests. It’s one of the most powerful data event functions and enables you to retrieve external data while filling out a form. It can be combined with the other functions to create very dynamic forms that populate information on-demand from external sources. It contains the necessary options to perform any HTTP request, including support for PUT, POST, etc and custom headers.

CORS and Web Browser Support

To work in the web browser, URLs fetched using REQUEST require HTTPS & CORS. This is not a limitation of Fulcrum - it’s just the way modern web browsers work. Since Fulcrum is hosted on a secure website, all requests made from the site must also be secure and respond with the proper headers required by the browser. If you encounter CORS errors when trying to use an API with the REQUEST function, we recommend contacting the API provider and asking them to add CORS support to their API. As a last resort, you can use a CORS proxy to proxy requests to URLs that don’t support it. https://crossorigin.me is a freely hosted CORS proxy. Note that crossorigin.me is not a Fulcrum service.

Parameters

options Object (required) - The options to pass for the request

options.url string (required) - The url for the request

options.method string (optional) [default = GET] - The HTTP method for the request (POST, PUT, DELETE, etc.)

options.followRedirect boolean (optional) [default = true] - Should the request follow any redirects

options.headers Object (optional) [default = {}] - An object containing keys and values for additional header items

options.qs Object (optional) - An object containing query string parameters (url parameters)

options.json Object (optional) - An object to be passed in the request body, must be JSON.stringifyable

options.body string (optional) - The request body to send with a POST or PUT request

callback function (required) - The function to call when the request is complete - The function is passed error, response, and body parameters

Examples

// This example looks up the place name from OpenStreetMap when the location changes and fills in a text
// field with the place name. Replace 'place_name' below with a text field on your form.

ON('change-geometry', function(event) {
  var options = {
    url: 'https://nominatim.openstreetmap.org/search/' + LATITUDE() + ',' + LONGITUDE() + '?format=json&polygon=1&addressdetails=1'
  }

  REQUEST(options, function(error, response, body) {
    if (error) {
      ALERT('Error with request: ' + error)
    } else {
      var data = JSON.parse(body)

      if (data.length) {
        SETVALUE('place_name', data[0].display_name)
      }
    }
  })
});