Force.com Apex Code Developer's Guide

Getting Started
Writing Apex
Ways to Invoke Apex
Invoking Apex
Apex Transactions and Governor Limits
Using Salesforce Features with Apex
Integration and Apex Utilities
Invoking Callouts Using Apex
Adding Remote Site Settings
SOAP Services: Defining a Class from a WSDL Document
Invoking HTTP Callouts
HTTP Classes
Testing HTTP Callouts
Using Certificates
Callout Limits and Limitations
Make Long-Running Callouts from a Visualforce Page
JSON Support
XML Support
Securing Your Data
Encoding Your Data
Using Patterns and Matchers
Finishing Touches
Reference
Appendices
Glossary
PDF

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HTTP Classes

These classes expose the general HTTP request/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, PUT, and DELETE.
  • HttpResponse Class: Use this class to handle the HTTP response returned by HTTP.
The HttpRequest and HttpResponse classes support the following elements:
  • HttpRequest:
    • HTTP request types such as GET, POST, PUT, DELETE, TRACE, CONNECT, HEAD, and OPTIONS.
    • Request headers if needed.
    • Read and connection timeouts.
    • Redirects if needed.
    • Content of the message body.
  • HttpResponse:
    • The HTTP status code.
    • Response headers if needed.
    • Content of the response body.

The following example shows an HTTP GET request made to the external server specified by the value of url that gets passed into the getContent method. This example also shows accessing the body of the returned response:

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.

Before you can access external servers from an endpoint or redirect endpoint using Apex or any other feature, you must add the remote site to a list of authorized remote sites in the Salesforce user interface. To do this, log in to Salesforce and from Setup, click Security Controls | Remote Site Settings.

  • The AJAX proxy handles redirects and authentication challenges (401/407 responses) automatically. For more information about the AJAX proxy, see AJAX Toolkit documentation.
  • You can set the endpoint as a named credential instead of a URL. A named credential specifies the URL of a callout endpoint and its required authentication parameters in one definition. Salesforce manages all the authentication for Apex callouts that specify a named credential as the callout endpoint, so that your code doesn’t have to. You can also skip remote site settings, which are otherwise required for Apex callouts to external sites. For an example, see setEndpoint(endpoint). To set up named credentials, see “Define a Named Credential” in the Salesforce Help.

Note

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.