fix(connector): [CRYPTOPAY] Skip metadata serialization if none

[deepanshu-iiitu]

Type of Change

• Bugfix
• New feature
• Enhancement
• Refactoring
• Dependency updates
• Documentation
• CI/CD

Description

Serialization of the metadata field in the payments request for cryptopay is skipped if the metadata is set to none.

Additional Changes

• This PR modifies the API contract
• This PR modifies the database schema
• This PR modifies application configuration/environment variables

Motivation and Context

#4206

How did you test it?

Testing can be done by creating a payment on cryptopay without passing metadata.
Request:

curl --location 'http://localhost:8080/payments' \
--header 'Content-Type: application/json' \
--header 'Accept: application/json' \
--header 'api-key: API_KEY_HERE' \
--data-raw '{
    "amount": 120,
    "currency": "USD",
    "confirm": true,
    "capture_method": "automatic",
    "customer_id": "custo",
    "email": "guest@example.com",
    "name": "John Doe",
    "phone": "999999999",
    "phone_country_code": "+1",
    "description": "Its my first payment request",
    "authentication_type": "no_three_ds",
    "return_url": "https://google.com",
    "payment_method": "crypto",
    "payment_method_type": "crypto_currency",
    "payment_experience": "redirect_to_url",
    "payment_method_data": {
        "crypto": {
            "pay_currency": "XRP"
        }
    },
    "billing": {
        "address": {
            "country": "US",
            "first_name": "joseph",
            "last_name": "Doe"
        }
    },
    "statement_descriptor_name": "joseph",
    "statement_descriptor_suffix": "JS",
    "order_details": [
        {
            "product_name": "test",
            "quantity": 1,
            "amount": 10
        }
    ],
    "business_label": "food",
    "business_country": "US"
}'

Response:

{
    "payment_id": "pay_CGNbknmiHZpwFIpXxYEP",
    "merchant_id": "merchant_1711445841",
    "status": "requires_customer_action",
    "amount": 120,
    "net_amount": 120,
    "amount_capturable": 120,
    "amount_received": null,
    "connector": "cryptopay",
    "client_secret": "pay_CGNbknmiHZpwFIpXxYEP_secret_CHuPxEbvvxOHqZR4MffY",
    "created": "2024-03-26T13:10:16.409Z",
    "currency": "USD",
    "customer_id": "custo",
    "description": "Its my first payment request",
    "refunds": null,
    "disputes": null,
    "mandate_id": null,
    "mandate_data": null,
    "setup_future_usage": null,
    "off_session": null,
    "capture_on": null,
    "capture_method": "automatic",
    "payment_method": "crypto",
    "payment_method_data": {
        "crypto": {},
        "billing": null
    },
    "payment_token": null,
    "shipping": null,
    "billing": {
        "address": {
            "city": null,
            "country": "US",
            "line1": null,
            "line2": null,
            "line3": null,
            "zip": null,
            "state": null,
            "first_name": "joseph",
            "last_name": "Doe"
        },
        "phone": null,
        "email": null
    },
    "order_details": [
        {
            "brand": null,
            "amount": 10,
            "category": null,
            "quantity": 1,
            "product_id": null,
            "product_name": "test",
            "product_type": null,
            "product_img_link": null,
            "requires_shipping": null
        }
    ],
    "email": "guest@example.com",
    "name": "John Doe",
    "phone": "999999999",
    "return_url": "https://google.com/",
    "authentication_type": "no_three_ds",
    "statement_descriptor_name": "joseph",
    "statement_descriptor_suffix": "JS",
    "next_action": {
        "type": "redirect_to_url",
        "redirect_to_url": "http://localhost:8080/payments/redirect/pay_CGNbknmiHZpwFIpXxYEP/merchant_1711445841/pay_CGNbknmiHZpwFIpXxYEP_1"
    },
    "cancellation_reason": null,
    "error_code": null,
    "error_message": null,
    "unified_code": null,
    "unified_message": null,
    "payment_experience": "redirect_to_url",
    "payment_method_type": "crypto_currency",
    "connector_label": "cryptopay_US_food",
    "business_country": "US",
    "business_label": "food",
    "business_sub_label": null,
    "allowed_payment_method_types": null,
    "ephemeral_key": {
        "customer_id": "custo",
        "created_at": ******,
        "expires": ******,
        "secret": "******"
    },
    "manual_retry_allowed": null,
    "connector_transaction_id": "******",
    "frm_message": null,
    "metadata": null,
    "connector_metadata": null,
    "feature_metadata": null,
    "reference_id": "pay_CGNbknmiHZpwFIpXxYEP_1",
    "payment_link": null,
    "profile_id": "pro_lCUrUVlcPzzcxNNyiMyg",
    "surcharge_details": null,
    "attempt_count": 1,
    "merchant_decision": null,
    "merchant_connector_id": "mca_B5Na72Sn8INfhxPv1FIz",
    "incremental_authorization_allowed": null,
    "authorization_count": null,
    "incremental_authorizations": null,
    "external_authentication_details": null,
    "external_3ds_authentication_attempted": false,
    "expires_on": "2024-03-26T13:25:16.409Z",
    "fingerprint": null,
    "payment_method_id": null,
    "payment_method_status": null
}

Checklist

• I formatted the code cargo +nightly fmt --all
• I addressed lints thrown by cargo clippy
• I reviewed the submitted code
• I added unit tests for my changes where possible
• I added a CHANGELOG entry if applicable