Apex Batch – Use of interface Database.AllowsCallouts in Batch Class

Hello guys,

Today, I will talk about interface named as Database.AllowsCallout in Batch helps in integrate Salesforce with an external server. To use a callout in batch Apex, we must use an interface Database.AllowsCallouts in the class definition of batch class.

Syntax-

global class SearchAndReplace implements Database.Batchable<sObject>, Database.AllowsCallouts{
}

Let see a simple example on Database.AllowCallouts -

global class BatchWithCallout implements Database.Batchable<sObject>,
Database.AllowsCallouts, Database.Stateful {
    private final String clientId = ‘xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx’;
    private final String clientSecret = ‘xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx’;
    private final String username = ‘xxxxxxxxxxxxxxxxxxxxx’;
    private final String password = ‘xxxxxxx’;
    public  Integer count=0;
    public String q = ‘Select ID, Name from Account LIMIT 10’;
    global Database.QueryLocator start(Database.BatchableContext BC) {
        return Database.getQueryLocator(q);
    }
    global void execute(Database.BatchableContext BC, List<Account> records) {
        count = count+1;
        String endpoint = ‘https://login.salesforce.com/services/oauth2/token’;
        for ( integer i = 0; i< records.size(); i++ ){
            try {
                String reqbody = ‘grant_type=password&client_id=’+
                clientId+’&client_secret=’+
                clientSecret+’&username=’+
                username+’&password=’+password;
                Http http = new Http();
                HttpRequest request = new HttpRequest();
                HttpResponse response = new HttpResponse();
                request .setBody(reqbody);
                request .setMethod(‘POST’);
                request .setEndpoint(‘https://login.salesforce.com/services/oauth2/token’);
                response = http.send(req);
                request .setHeader(‘Authorization’, ‘header’);
                request .setHeader(‘Content-Type’, ‘application/json’);
                request .setEndpoint(endpoint);
                request .setMethod(‘POST’);
                request .setBody(‘Information you wanna send’);
                request .setCompressed(true); // This is imp according to SF, but please check if
                // the web service accepts the info. Mine did not 😛
                // Had to set it to false
                if (!Test.isRunningTest()) {
                    response = http.send(request);
                    String sJson = response .getBody();
                    System.debug(‘@@@@Str:’ + response .getBody());
                }
                // now do what u want to with response
                System.debug(‘@@@@execute’+count);
            }
            catch (Exception err) {
                System.debug(‘@@@@Error:’ + err.getMessage() + ‘LN:’ + err.getLineNumber() );
            }
        }
    }
    global void finish(Database.BatchableContext BC){
        System.debug(‘@@@@finish’+count);
    } 
}

Note:- If you don’t know what is Database.Stateful, Kindly read this blog.

Thanks.

Happy Coding.