Invoking callouts using apex


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Invoking callouts using apex

  1. 1. Invoking Callouts Using Apex Invoking Callouts Using Apex * An Apex callout enables you to tightly integrate your Apex with an external service by making a call to an external Web service or sending a HTTP request from an Apex script and then receiving the response. Tightly Couple Architecture * Apex provides integration with Web services that utilize SOAP and WSDL, or HTTP services (RESTful services). Note: Note:Before any Apex callout can call an external site, that site must be registered in the Remote Site Settings page, or the callout fails. * Salesforce prevents calls to unauthorized network addresses. * Callouts enable Apex to invoke external web or HTTP services. *Apex Web services allow an external application to invoke Apex methods through Web services. Adding Remote Site Settings
  2. 2. To add a remote site setting: 1. Click Your Name ➤ Setup ➤ Security Controls ➤ Remote Site Settings. 2. Click New Remote Site. 3. Enter a descriptive term for the Remote Site Name. 4. Enter the URL for the remote site. 5. Optionally, enter a description of the site. 6. Click Save. Types of WSDL's 1. Enterprise WSDL * It is a big WSDL which contains information about schema of organization. * Strictly Typed: For Integer if we give 3.19 like that then it will not accept and throw error. * When schema is modified then we have to recreate new enterprise WSDL. 2. Partner WSDL * Loosly Typed: For Integer if we give 3.19 like that then it will accept and not throw error. * When schema is modified then it will automatically updated. SOAP Services: Defining a Class from a WSDL Document * Classes can be automatically generated from a WSDL document that is stored on a local hard drive or network. * Creating a class by consuming a WSDL document allows developers to make callouts to the external Web service in their Apex scripts. Note: - Use Outbound Messaging to handle integration solutions when possible. - Use callouts to third-party Web services only when necessary. To generate an Apex class from a WSDL: 1. In the application, click Your Name ➤ Setup ➤ Develop ➤ Apex Classes. 2. Click Generate from WSDL. 3. Click Browse to navigate to a WSDL document on your local hard drive or network, or type in the full path. This WSDL document is the basis for the Apex class you are creating.
  3. 3. Note: - The WSDL document that you specify might contain a SOAP endpoint location that references an outbound port. - For security reasons, Salesforce restricts the outbound ports you may specify to one of the following: - 80: This port only accepts HTTP connections. - 443: This port only accepts HTTPS connections. - 1024–66535 (inclusive): These ports accept HTTP or HTTPS connections. 4. Click Parse WSDL to verify the WSDL document contents. - The application generates a default class name for each namespace in the WSDL document and reports any errors. - Parsing will fail if the WSDL contains schema types or schema constructs that are not supported by Apex classes, or if the resulting classes exceed 1 million character limit on Apex classes. - For example, the Salesforce SOAP API WSDL cannot be parsed. 5. Modify the class names as desired. - While you can save more than one WSDL namespace into a single class by using the same class name for each namespace, Apex classes can be no more than 1 million characters total. 6. Click Generate Apex. - The final page of the wizard shows which classes were successfully generated, along with any errors from other classes. - The page also provides a link to view successfully-generated code. * The successfully-generated Apex class includes stub and type classes for calling the third-party Web service represented by the WSDL document. * These classes allow you to call the external Web service from Apex. Note the following about the generated Apex: * If a WSDL document contains an Apex reserved word, the word is appended with _x when the Apex class is generated. * For example, limit in a WSDL document converts to limit_x in the generated Apex class.
  4. 4. * If an operation in the WSDL has an output message with more than one element, the generated Apex wraps the elements in an inner class. * The Apex method that represents the WSDL operation returns the inner class instead of the individual elements. * After you have generated a class from the WSDL, you can invoke the external service referenced by the WSDL. How to run generated class from WSDL BookrWs.BookWs stub = new BookrWs.BookWs();//Top level class name.Inner level class name stub.sessionHeader = new BookrWs.sessionHeader_Element(); stub.sessionHeader.sessionID = userInfo.getSessionID(); stub.insertBook('SOAP19','VASU',1000);