Add token exchange update procedure.

[budzanowski]

Changes proposed in this Pull Request:

When the plugin gets updated the token exchange procedure should be triggered.

Closes #844 .

Relies on #840.

Detailed test instructions:

1. Install the current production version and connect.
2. Complete the setup and connection.
3. Switch to this branch. Update manually PINTEREST_FOR_WOOCOMMERCE_VERSION to 1.4.0
4. Add a breakpoint at the update method. Reload the plugin.
5. Observer the flow.

[message-dimke]

Hey, @budzanowski !
There is one more issue with the API call headers.

Here:

pinterest-for-woocommerce/src/API/Base.php

Lines 288 to 290 in 9aed51b

	if ( $request['auth_header'] ) {
	$request['headers']['Authorization'] = 'Bearer ' . self::get_token()['access_token'];
	}

self::get_token() uses Pinterest_For_Woocommerce()::get_access_token() which returns no token since is looking for v5 token keys not v3.

As a result of Authorization: Bearer I am getting 401 Reconnect to your Pinterest account., access token is not added to the header.

We can redo Base::get_token() to be something like you did recently

public static function get_token() {
	if ( is_null( self::$token ) ) {
		self::$token = Pinterest_For_Woocommerce()::get_data( 'token', true );
	}

	return self::$token;
}

[budzanowski]

Sorry for the hassle. I was too lazy to constantly change branches so I was injecting the v3 token manually for testing.

This latest change ae22258 should fix the issue.

[message-dimke]

Hey, @budzanowski

The last change.

We need to Pinterest/Crypto::decrypt() our [access_token].

Suggested change

	return Pinterest_For_Woocommerce()::get_data( 'token', true );
	$token = Pinterest_For_Woocommerce()::get_data( 'token', true );
	try {
	$token['access_token'] = empty( $token['access_token'] ) ? '' : Pinterest\Crypto::decrypt( $token['access_token'] );
	} catch ( \Exception $th ) {
	/* Translators: The error description */
	Pinterest\Logger::log( sprintf( esc_html__( 'Could not decrypt the Pinterest API access token. Try reconnecting to Pinterest. [%s]', 'pinterest-for-woocommerce' ), $th->getMessage() ), 'error' );
	}
	return $token;

[budzanowski]

Good catch. I had my access token in the DB in a plane text.

[message-dimke]

Works as expected. Token exchange endpoint succeeds and we get v5 token from it. Also it gets saved into a database.

Thank you, @budzanowski !