HttpResponse Class in Salesforce for Handling HTTP Response returned by HTTP Class

Use the HttpResponse class to handle the HTTP response returned by the Http class.

Use the DOM Classes or JSON Classes  to parse XML or JSON content in the body of a response accessed by HttpResponse.


Methods in HTTPResponse Class: 

The HttpResponse class contains the following public methods:

Name	Arguments	Return Type	Description
getBody		String	Retrieves the body returned in the response. Limit3 MB. The HTTP request and response sizes count towards the total heap size.
getBodyAsBlob		Blob	Retrieves the body returned in the response as a Blob. Limit3 MB. The HTTP request and response sizes count towards the total heap size.
getBodyDocument		Dom.Document	Retrieves the body returned in the response as a DOM document. Use it as a shortcut for: String xml = httpResponse.getBody(); Dom.Document domDoc = new Dom.Document(xml);
getHeader	String key	String	Retrieves the contents of the response header.
getHeaderKeys		String[]	Retrieves an array of header keys returned in the response.
getStatus		String	Retrieves the status message returned for the response.
getStatusCode		Integer	Retrieves the value of the status code returned in the response.
getXmlStreamReader		XmlStreamReader	Returns an XmlStreamReader (XmlStreamReader Class) that parses the body of the callout response. Use it as a shortcut for: String xml = httpResponse.getBody(); XmlStreamReader xsr = new XmlStreamReader(xml); For a full example, see below Example.
setBody	String	Void	Specifies the body returned in the response.
setBodyAsBlob	Blob	Void	Specifies the body returned in the response using a Blob.
setHeader	String key, String value	Void	Specifies the contents of the response header.
setStatus	String	Void	Specifies the status message returned in the response.
setStatusCode	Integer	Void	Specifies the value of the status code returned in the response.
toString		String	Returns the status message and status code returned in the response, for example: Status=OK, StatusCode=200

Example

public class ReaderFromCalloutSample {

  public void getAndParse() {

    // Get the XML document from the external server
    Http http = new Http();
    HttpRequest req = new HttpRequest();
    req.setEndpoint('http://www.cheenath.com/tutorial/sample1/build.xml');
    req.setMethod('GET');
    HttpResponse res = http.send(req);

    // Log the XML content
    System.debug(res.getBody());

    // Generate the HTTP response as an XML stream
    XmlStreamReader reader = res.getXmlStreamReader();

    // Read through the XML
    while(reader.hasNext()) {
      System.debug('Event Type:' + reader.getEventType());
      if (reader.getEventType() == XmlTag.START_ELEMENT) {
        System.debug(reader.getLocalName());
      }
      reader.next();
    }
 
  }
}

In the above getXmlStreamReader example, content is retrieved from an external Web server, then the XML is parsed using the XmlStreamReader class.

Enjoy........Keep Smiling.....