feat(router): add accept language header middleware

[srujanchikke]

Type of Change

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

Description

add accept language header middleware .
Case 1 : when query parameter locale is present it should overwrite the Accept-Language headers in the middleware for api request.
Case 2: If query parameter is not present then if request have Accept-Language headers, do nothing.

Case 3 : Incase if both query param & header is not present we should add new header Accept-Language header with default value "en".

This feature is meant to be used by internal api's, We will not suggest merchant to send query parameter . SDK will pass this headers to backend to perform backend loaclization. Will consume this header input and perform backend localization in future.

Additional Changes

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

Motivation and Context

How did you test it?

create any api request to hyperswitch with query params locale this should add accept-language header in the request. you can check this in the logs.

curl --location 'http://localhost:8080/accounts?locale=en' \
--header 'Content-Type: application/json' \
--header 'Accept: application/json' \
--header 'api-key: test_admin' \
--data-raw '{
    "merchant_id": "merchant_1722496591",
    "locker_id": "m0010",
    "merchant_name": "NewAge Retailer",
    "merchant_details": {
        "primary_contact_person": "John Test",
        "primary_email": "JohnTest@test.com",
        "primary_phone": "sunt laborum",
        "secondary_contact_person": "John Test2",
        "secondary_email": "JohnTest2@test.com",
        "secondary_phone": "cillum do dolor id",
        "website": "www.example.com",
        "about_business": "Online Retail with a wide selection of organic products for North America",
        "address": {
            "line1": "1467",
            "line2": "Harrison Street",
            "line3": "Harrison Street",
            "city": "San Fransico",
            "state": "California",
            "zip": "94122",
            "country": "US"
        }
    },
    "return_url": "https://google.com/success",
    "webhook_details": {
        "webhook_url": "https://enz8u459xx5j.x.pipedream.net/",
        "webhook_version": "1.0.1",
        "webhook_username": "ekart_retail",
        "webhook_password": "password_ekart@123",
        "payment_created_enabled": true,
        "payment_succeeded_enabled": true,
        "payment_failed_enabled": true
    },
    "sub_merchants_enabled": false,
    "metadata": {
        "account_name": "transaction_processing",
        "city": "NY",
        "unit": "245"
    }
}'

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

[pixincreate]

Other than that, LGTM!