Apex Developer Guide

Apex Developer Guide
Getting Started with Apex
Writing Apex
Running 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
Named Credentials as Callout Endpoints
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
Debugging, Testing, and Deploying Apex
Apex Language Reference
Appendices
Glossary
PDF

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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, 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

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.

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.

  • 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 URL. A named credential URL contains the scheme callout:, the name of the named credential, and an optional path. For example: callout:My_Named_Credential/some_path. A named credential specifies the URL of a callout endpoint and its required authentication parameters in one definition. Salesforce manages all 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 callouts to external sites, for the site defined in the named credential. See Named Credentials as Callout Endpoints.

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.