Go SDK

The openlankapay-go-sdk package provides an idiomatic Go client for the Open Pay API with full error handling and context support.

Installation

go get github.com/openlankapay/openlankapay-go-sdk

Initialization

package main

import (
    "os"

    openpay "github.com/openlankapay/openlankapay-go-sdk"
)

func main() {
    client := openpay.NewClient(
        os.Getenv("OPENPAY_API_KEY"),
        os.Getenv("OPENPAY_API_SECRET"),
    )

    // Optionally override the base URL
    client.BaseURL = "https://olp-api.nipuntheekshana.com"
}

Create a Payment

ctx := context.Background()

payment, err := client.Payments.Create(ctx, &openpay.CreatePaymentRequest{
    Amount:      50.00,
    Currency:    "USD",
    Description: "Invoice #1234",
    Metadata: map[string]string{
        "orderId":    "order_abc123",
        "customerId": "cust_456",
    },
})
if err != nil {
    log.Fatalf("failed to create payment: %v", err)
}

fmt.Printf("Payment ID: %s\n", payment.ID)
fmt.Printf("Status: %s\n", payment.Status)
fmt.Printf("Wallet: %s\n", payment.WalletAddress)

Create a Checkout Session

session, err := client.Checkout.CreateSession(ctx, &openpay.CreateCheckoutSessionRequest{
    Amount:      25.00,
    Currency:    "USD",
    Description: "Premium Plan - Monthly",
    Metadata: map[string]string{
        "orderId":    "order_12345",
        "customerId": "cust_67890",
    },
    SuccessURL: "https://yoursite.com/payment/success",
    CancelURL:  "https://yoursite.com/payment/cancel",
})
if err != nil {
    log.Fatalf("failed to create checkout session: %v", err)
}

fmt.Printf("Redirect to: %s\n", session.CheckoutURL)

Verify Webhook Signature

package main

import (
    "io"
    "net/http"

    openpay "github.com/openlankapay/openlankapay-go-sdk"
)

func webhookHandler(w http.ResponseWriter, r *http.Request) {
    payload, err := io.ReadAll(r.Body)
    if err != nil {
        http.Error(w, "failed to read body", http.StatusBadRequest)
        return
    }

    signature := r.Header.Get("X-Webhook-Signature")
    timestamp := r.Header.Get("X-Webhook-Timestamp")

    valid, err := client.Webhooks.VerifySignature(payload, signature, timestamp)
    if err != nil || !valid {
        http.Error(w, "invalid signature", http.StatusUnauthorized)
        return
    }

    event, err := openpay.ParseWebhookEvent(payload)
    if err != nil {
        http.Error(w, "invalid payload", http.StatusBadRequest)
        return
    }

    switch event.Type {
    case "payment.completed":
        log.Printf("Payment completed: %s", event.Data.PaymentID)
        // Fulfill the order
    case "payment.failed":
        log.Printf("Payment failed: %s", event.Data.PaymentID)
    case "payment.expired":
        log.Printf("Payment expired: %s", event.Data.PaymentID)
    }

    w.WriteHeader(http.StatusOK)
    w.Write([]byte(`{"received": true}`))
}

List Payments

payments, err := client.Payments.List(ctx, &openpay.ListPaymentsRequest{
    Page:   1,
    Limit:  20,
    Status: "completed",
})
if err != nil {
    log.Fatalf("failed to list payments: %v", err)
}

for _, p := range payments.Data {
    fmt.Printf("%s: %.2f %s - %s\n", p.ID, p.Amount, p.Currency, p.Status)
}

Error Handling

The SDK returns typed errors that you can inspect for status codes and error details.

payment, err := client.Payments.Create(ctx, &openpay.CreatePaymentRequest{
    Amount:   50.00,
    Currency: "USD",
})
if err != nil {
    var apiErr *openpay.APIError
    if errors.As(err, &apiErr) {
        fmt.Printf("API Error %d: %s (code: %s)\n",
            apiErr.StatusCode, apiErr.Message, apiErr.Code)
    } else {
        fmt.Printf("Unexpected error: %v\n", err)
    }
    return
}

Error Field	Type	Description
`StatusCode`	`int`	HTTP status code
`Message`	`string`	Human-readable message
`Code`	`string`	Machine-readable code (e.g., `INVALID_AMOUNT`)

Context Support

All methods accept a context.Context for cancellation and timeouts:

ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
defer cancel()

payment, err := client.Payments.Create(ctx, &openpay.CreatePaymentRequest{
    Amount:   50.00,
    Currency: "USD",
})