Tag: ORDS

I was inspired by others when looking for this subject, but for me in very important to have a blog from a developer prospective and not only to show something which I not have test myself. I use my blog mostly as documentation for myself.

ORDS can be used to define database API’s. You can give third party “controlled” access to the database via REST-API’s. ORDS is a layer above your database, you can use it inside APEX or SQLDeveloper. I prefer using APEX because it has integrated ORDS GUI, which makes it easier developers to define API’s and also to secure it.
BASIC Authentication.

This part of security is not APEX related, it is ORDS related.
In this blog I will show how to define API’s in command line and also how to secure these API’s with OAuth2 method.  I have used Oracle documentation where this is described properly.
I assume your HR schema is enabled and the EMP table is there.
The first thing you need to do is enabling the ORDS for the HR schema.

DECLARE
 PRAGMA AUTONOMOUS_TRANSACTION;
BEGIN
ORDS.ENABLE_SCHEMA(p_enabled => TRUE,
 p_schema => 'HR',
 p_url_mapping_type => 'BASE_PATH',
 p_url_mapping_pattern => 'hr',
 p_auto_rest_auth => TRUE);
commit;
END;

Define a basic webservice we can use for the test.

BEGIN
ORDS.define_service(
p_module_name => 'hrmodule',
p_base_path => 'api/hrschema/',
p_pattern => 'emp?{empno}',
p_method => 'GET',
p_source_type => ORDS.source_type_query,
p_source => 'SELECT * FROM emp WHERE empno = :empno',
p_items_per_page => 0);
COMMIT;
END;

You can test the service in POSTMAN by using the URL as GET method.

http://localhost:8080/ords/hr/api/hrschema/emp?7788

Response will be a JSON

{
"items": [
{
   "empno": 7788,
   "ename": "SCOTT",
   "job": "ANALYST",
   "mgr": 7566,
   "hiredate": "1987-04-18T22:00:00Z",
   "sal": 3000,
   "comm": null,
   "deptno": 20
  }
 ]
}

Now we will secure the service, we will create a Role and privilege, them map these together.

– Create a ROLE

BEGIN
ORDS.create_role(
 p_role_name => 'hr_role' );
COMMIT;
END;

– Create a new privilege called “hr_priv”, which is associated with the role.

DECLARE
l_arr OWA.vc_arr;
BEGIN
l_arr(1) := 'hr_role';
ORDS.define_privilege (
p_privilege_name => 'hr_priv',
p_roles => l_arr,
p_label => 'HR Data',
p_description => 'Allow access to the HR data.');
COMMIT;
END;

To protect the web service, we associate the privilege directly to a URL pattern.

BEGIN
ORDS.create_privilege_mapping(
p_privilege_name => 'hr_priv',
p_pattern => '/hr/api/emp/*'
);

COMMIT;
END;

OAuth 2: Authorization Code

The authorization code flow is a three-egged process.

• The user accesses a URL in a browser, which prompts for credentials
•  The browser is redirected to a specified page with an authorization code as one of the parameters in the URL.
•  The authorization code is used in a call to generate an access token

Create a client using the grant type of “authorization_code”. The redirect and support URLs are not real

BEGIN
OAUTH.create_client(
p_name            => 'HR-client',
p_grant_type      => 'authorisation_code',
p_owner           => 'Tester',
p_description     => 'HR management client',
p_redirect_uri    => 'http://localhost:8080/ords/hr/redirect',
p_support_email   => 'mazin@example.com',
p_support_uri     => 'http://localhost:8080/ords/hr/support',
p_privilege_names => 'hr_priv');
COMMIT;
END;

You can get the client_id and client_secret

SELECT id, name, client_id, client_secret
FROM   user_ords_clients;

Associate the client with the role that holds the correct privileges for the resources it needs to access.

BEGIN
OAUTH.grant_client_role(
p_client_name => 'HR-client',
p_role_name   => 'hr_role'
);
COMMIT;
END;

Got to the browser with the below URL, replace endpoint and Client ID with yours.

http://localhost:8080/ords/hr/oauth/auth?response_type=code&client_id=enDQOlmhW1yhBk_0OBxt1w..&state=3668D7A713E93372E0406A38A8C02171

You will receive the below message, you need to sign in.

You can create a ORDS use and add this to the Role by running this command where orgs.war file is.

java -jar ords.war user api_user hr_role

Login with the hr_user you created before and the approve the access.

 

After log in you need to approve the access. you will receive the 404 Not Found. this because the redirect page does not exist. From this step we need the URL only.

You need the code from the URL

http://localhost:8080/ords/hr/redirect?code=J0GYiIew9ZLMB6HUkjlvrA..&state=3668D7A713E93372E0406A38A8C02171

With the code and Client ID plus the secret ID you can get a token. (You can use POSTMAN as well)

curl -i --user client_id:client_secret --data "grant_type=authorization_code&code=J0GYiIew9ZLMB6HUkjlvrA.." http://localhost:8080/ords/hr/oauth/token

The response will look like

{"access_token":"LP8uasNPzDqVpBRlfngc_g..","token_type":"bearer","expires_in":3600,"refresh_token":"8wnzi9WZ00CkkZnjzJLkug.."}

from this point you are done. You can use the refresh token get a new token inside your external application, this after the token is expired within 3600 seconds.

curl -i --user client_id:client_secret--data "grant_type=refresh_token&refresh_token=8wnzi9WZ00CkkZnjzJLkug.." http://localhost:8080/ords/hr/oauth/token

If you have any question, please leave comment..

reference:

ORDS secure restful service (with SSL and without SSL)

With thank to Tim Hall from whom I learn a lot.  here is his detailed blog in this regard. https://oracle-base.com/articles/misc/oracle-rest-data-services-ords-authentication#