HTTP Classes

These classes expose the HTTP request and response functionality.

• Http Class. Use this class to initiate an HTTP request and response.
• HttpRequest Class: Use this class to programmatically create HTTP requests like GET, POST, PATCH, PUT, and DELETE.
• HttpResponse Class: Use this class to handle the HTTP response returned by HTTP.

This example makes an HTTP GET request to the external server passed to the getCalloutResponseContents method in the url parameter. This example also accesses the body of the returned response.

1public class HttpCalloutSample {
2
3  // Pass in the endpoint to be used using the string url
4  public String getCalloutResponseContents(String url) {
5
6    // Instantiate a new http object
7    Http h = new Http();
8
9     // Instantiate a new HTTP request, specify the method (GET) as well as the endpoint
10    HttpRequest req = new HttpRequest();
11    req.setEndpoint(url);
12    req.setMethod('GET');
13
14    // Send the request, and return a response
15    HttpResponse res = h.send(req);
16    return res.getBody();
17  }
18}

The previous example runs synchronously, meaning no further processing happens until the external web service returns a response. Alternatively, you can use the @future annotation to make the callout run asynchronously.

To access an external server from an endpoint or a redirect endpoint, add the remote site to a list of authorized remote sites. Log in to Salesforce and from Setup, enter Remote Site Settings in the Quick Find box, then select Remote Site Settings.

Use the XML classes or JSON classes to parse XML or JSON content in the body of a request created by HttpRequest, or a response accessed by HttpResponse.