Named Credentials as Callout Endpoints - Salesforce Developer Guide

A named credential specifies the URL of a callout endpoint and its required authentication parameters in one definition. To simplify the setup of authenticated callouts, specify a named credential as the callout endpoint. 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.

Named Credentials also include an Outbound Network Connection field that you can use to route callouts through a private connection. By separating the endpoint URL and authentication from the callout definition, named credentials make callouts easier to maintain. For example, if an endpoint URL changes, you update only the named credential. All callouts that reference the named credential simply continue to work.

If you have multiple orgs, you can create a named credential with the same name but with a different endpoint URL in each org. You can then package and deploy—on all the orgs—one callout definition that references the shared name of those named credentials. For example, the named credential in each org can have a different endpoint URL to accommodate differences in development and production environments. If an Apex callout specifies the shared name of those named credentials, the Apex class that defines the callout can be packaged and deployed on all those orgs without programmatically checking the environment.

To reference a named credential from a callout definition, use the 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.

Don't forget to check out: Integration Using Named Credentials | Salesforce Developer Guide

Code:

HttpRequest req = new HttpRequest(); 
req.setEndpoint('callout:My_Named_Credential/some_path'); 
req.setMethod('GET'); 
Http http = new Http(); 
HTTPResponse res = http.send(req); 
System.debug(res.getBody());

HTTPCalloutService service= new HTTPCalloutService('GoatOrg'); 
System.debug(service.getRequest()); 
String query ='SELECT+Name+From+Student__c'; 
service.setURlParameter('q',query); 
System.debug(service.getRequest()); 
HTTPResponse response=service.sendRequest(); 
//System.debug(response.getstatuscode()); 
//System.debug(response.getHeader('Location')); 
System.debug(response.getBody());

A named credential is a logical entity that can be thought of as a named connection to an external system. A developer can write Apex to make a callout to an external system. With named credentials, there’s no need to embed the physical URL into the Apex code and manage authentication tokens in unencrypted data stores. Instead, a variable in the code allows an administrator to provision the physical endpoint at deployment time and manage user credentials in the organization's encrypted credential store. The named credential URL is resolved at runtime to the configured physical endpoint, along with the credentials for the authorized user performing the callout.

Named credentials support different types, with a default of Secure Endpoint. Advanced use cases can benefit from storing custom parameters, which are also supported. A parameter is essentially a name-value pair to capture arbitrary metadata, and the parameter values are stored securely. See the API documentation for more details.

The named credential type can be one of the following.

SecuredEndpoint - The named credential includes an endpoint’s transport protocol as secured through transport layer security (TLS).

Legacy - A legacy named credential specifies the URL of a callout endpoint and its required authentication parameters in one definition.

Authentications:

Anonymous
Per User authentication provides access control at the individual user level
Named Principal applies the same credential or authentication configuration for the entire org

Authentication Protocols:

Password: A static username and password are used to directly authenticate into the external system.
OAuth 2.0: A user or the admin applies a credential for a specified OAuth 2.0 system that authenticates into the external system.
JWT: A JWT (rhymes with “hot”), or JSON Web Token, manages your org’s authentication into the external system.

Check out another amazing blog by Mohit Kumar here: Learn All About Salesforce Apex Programming Language

JWT Token Exchange: A JWT token is sent to an authorization provider, similar to OAuth 2.0, and receives a token in return that is used to authenticate into the external system.

- Users don’t need to manage their own credentials for the external system. When users view their authentication settings for external systems, they can’t edit options using this authentication protocol. However, users can delete their JWT Token Exchange settings to use a differently named credential.
- The subject is a string when the identity type is named principal, and it’s a formula when the identity type is per user.
- Signing certificates aren’t included in packages. If you’re using JWT or JWT Token Exchange as the authentication protocol for a packaged named credential, recreate the package’s referenced signing certificate in the subscriber org before installing the package.

AWS Signature Version 4: A protocol to authenticate callouts to resources in Amazon Web Services over HTTP.

- The identity type must be named principal.
- You can use it as an authentication protocol for Named Credentials.
- You can’t use it as an authentication protocol for external data sources.