Add Stripe donation flow

2026-07-19 22:26:33 -05:00
parent f12904bf73
commit dec5e74aa7
30 changed files with 1053 additions and 1 deletions
@@ -0,0 +1,28 @@
+using QuestionsApi.Models;
+using Xunit;
+
+namespace QuestionsApi.Tests;
+
+public sealed class DonationTests
+{
+    [Theory]
+    [InlineData(499)]
+    [InlineData(1_000_001)]
+    public void RejectsAmountsOutsideConfiguredRange(long amountCents) =>
+        Assert.NotNull(DonationValidator.ValidateAmount(amountCents));
+
+    [Theory]
+    [InlineData(500)]
+    [InlineData(1_000)]
+    [InlineData(1_000_000)]
+    public void AcceptsAmountsInsideConfiguredRange(long amountCents) =>
+        Assert.Null(DonationValidator.ValidateAmount(amountCents));
+
+    [Fact]
+    public void PublicStatusDoesNotExposeStripeOrUserIdentifiers()
+    {
+        Assert.Null(typeof(DonationStatusResponse).GetProperty(nameof(Donation.UserId)));
+        Assert.Null(typeof(DonationStatusResponse).GetProperty(nameof(Donation.StripeCheckoutSessionId)));
+        Assert.Null(typeof(DonationStatusResponse).GetProperty(nameof(Donation.StripePaymentIntentId)));
+    }
+}
@@ -0,0 +1,86 @@
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using QuestionsApi.Models;
+using QuestionsApi.Services;
+using Stripe;
+using Stripe.Checkout;
+using System.Security.Claims;
+
+namespace QuestionsApi.Controllers;
+
+[ApiController, Route("api/donations")]
+public sealed class DonationsController(
+    DonationStore donations,
+    IStripeDonationGateway stripe,
+    IConfiguration configuration,
+    ILogger<DonationsController> logger) : ControllerBase
+{
+    [HttpPost("checkout"), Authorize(Roles = "USER,SUPER")]
+    public async Task<IActionResult> CreateCheckout(CreateDonationCheckoutRequest request, CancellationToken cancellationToken)
+    {
+        if (DonationValidator.ValidateAmount(request.AmountCents) is { } error) return BadRequest(error);
+        var donation = await donations.CreateAsync(UserId(), request.AmountCents);
+        try
+        {
+            var checkout = await stripe.CreateCheckoutAsync(donation.Id!, donation.AmountCents, cancellationToken);
+            await donations.AttachCheckoutSessionAsync(donation.Id!, checkout.SessionId);
+            return StatusCode(StatusCodes.Status201Created, new DonationCheckoutResponse
+            {
+                DonationId = donation.Id!, CheckoutUrl = checkout.CheckoutUrl, AmountCents = donation.AmountCents
+            });
+        }
+        catch (Exception exception)
+        {
+            await donations.MarkCheckoutCreationFailedAsync(donation.Id!, exception is StripeException ? "stripe_error" : "configuration_error");
+            logger.LogError(exception, "Unable to create Stripe Checkout Session for donation {DonationId}", donation.Id);
+            return Problem(statusCode: StatusCodes.Status502BadGateway, title: "Donation checkout unavailable",
+                detail: "The secure checkout could not be started. Please try again.");
+        }
+    }
+
+    [HttpGet("{id}"), Authorize(Roles = "USER,SUPER")]
+    public async Task<IActionResult> GetStatus(string id) =>
+        await donations.GetOwnedAsync(id.Trim(), UserId()) is { } donation
+            ? Ok(DonationStatusResponse.FromModel(donation))
+            : NotFound();
+
+    [HttpPost("stripe-webhook"), AllowAnonymous]
+    public async Task<IActionResult> StripeWebhook(CancellationToken cancellationToken)
+    {
+        var webhookSecret = configuration["Stripe:WebhookSecret"];
+        if (string.IsNullOrWhiteSpace(webhookSecret)) return Problem(statusCode: 503, title: "Stripe webhook is not configured");
+        using var reader = new StreamReader(Request.Body);
+        var json = await reader.ReadToEndAsync(cancellationToken);
+        Event stripeEvent;
+        try
+        {
+            stripeEvent = EventUtility.ConstructEvent(json, Request.Headers["Stripe-Signature"], webhookSecret);
+        }
+        catch (StripeException exception)
+        {
+            logger.LogWarning(exception, "Rejected Stripe webhook with an invalid signature");
+            return BadRequest("Invalid Stripe signature");
+        }
+
+        if (stripeEvent.Data.Object is not Session session) return Ok();
+        var status = stripeEvent.Type switch
+        {
+            "checkout.session.completed" when session.PaymentStatus == "paid" => DonationStatus.Paid,
+            "checkout.session.async_payment_succeeded" => DonationStatus.Paid,
+            "checkout.session.async_payment_failed" => DonationStatus.Failed,
+            "checkout.session.expired" => DonationStatus.Expired,
+            _ => ""
+        };
+        if (status.Length == 0) return Ok();
+        var donationId = session.ClientReferenceId;
+        if (string.IsNullOrWhiteSpace(donationId) && session.Metadata.TryGetValue("donation_id", out var metadataId)) donationId = metadataId;
+        var applied = await donations.ApplyStripeStatusAsync(
+            donationId ?? "", session.Id, session.AmountTotal ?? 0, session.Currency ?? "",
+            status, session.PaymentIntentId ?? "", stripeEvent.Id);
+        if (!applied) logger.LogWarning("Stripe event {EventId} did not match donation {DonationId}", stripeEvent.Id, donationId);
+        return Ok();
+    }
+
+    private string UserId() => User.FindFirstValue(ClaimTypes.NameIdentifier)
+        ?? User.FindFirstValue(ClaimTypes.Name) ?? User.Identity?.Name ?? "";
+}
@@ -0,0 +1,75 @@
+using MongoDB.Bson;
+using MongoDB.Bson.Serialization.Attributes;
+
+namespace QuestionsApi.Models;
+
+public static class DonationStatus
+{
+    public const string Pending = "pending";
+    public const string Paid = "paid";
+    public const string Failed = "failed";
+    public const string Expired = "expired";
+}
+
+public sealed class Donation
+{
+    [BsonId, BsonRepresentation(BsonType.ObjectId)] public string? Id { get; set; }
+    public string UserId { get; set; } = "";
+    public long AmountCents { get; set; }
+    public string Currency { get; set; } = "usd";
+    public string Status { get; set; } = DonationStatus.Pending;
+    [BsonIgnoreIfNull] public string? StripeCheckoutSessionId { get; set; }
+    public string StripePaymentIntentId { get; set; } = "";
+    public string LastStripeEventId { get; set; } = "";
+    public string FailureCode { get; set; } = "";
+    public DateTime CreatedUtc { get; set; } = DateTime.UtcNow;
+    public DateTime UpdatedUtc { get; set; } = DateTime.UtcNow;
+    public DateTime? PaidUtc { get; set; }
+}
+
+public sealed class CreateDonationCheckoutRequest
+{
+    public long AmountCents { get; set; }
+}
+
+public sealed class DonationCheckoutResponse
+{
+    public string DonationId { get; set; } = "";
+    public string CheckoutUrl { get; set; } = "";
+    public long AmountCents { get; set; }
+    public string Currency { get; set; } = "usd";
+    public string Status { get; set; } = DonationStatus.Pending;
+}
+
+public sealed class DonationStatusResponse
+{
+    public string DonationId { get; set; } = "";
+    public long AmountCents { get; set; }
+    public string Currency { get; set; } = "usd";
+    public string Status { get; set; } = DonationStatus.Pending;
+    public DateTime CreatedUtc { get; set; }
+    public DateTime? PaidUtc { get; set; }
+
+    public static DonationStatusResponse FromModel(Donation donation) => new()
+    {
+        DonationId = donation.Id ?? "",
+        AmountCents = donation.AmountCents,
+        Currency = donation.Currency,
+        Status = donation.Status,
+        CreatedUtc = donation.CreatedUtc,
+        PaidUtc = donation.PaidUtc
+    };
+}
+
+public static class DonationValidator
+{
+    public const long MinimumAmountCents = 500;
+    public const long MaximumAmountCents = 1_000_000;
+
+    public static string? ValidateAmount(long amountCents) => amountCents switch
+    {
+        < MinimumAmountCents => "amountCents must be at least 500",
+        > MaximumAmountCents => "amountCents must be no more than 1000000",
+        _ => null
+    };
+}
@@ -26,6 +26,8 @@ builder.Services.AddSingleton<QuestionBookmarkStore>();
 builder.Services.AddSingleton<ReviewQueueStore>();
 builder.Services.AddSingleton<DashboardStore>();
 builder.Services.AddSingleton<UserProfileStore>();
+builder.Services.AddSingleton<DonationStore>();
+builder.Services.AddSingleton<IStripeDonationGateway, StripeDonationGateway>();
 builder.Services.AddSingleton<ServiceMetrics>();
 builder.Services.AddHostedService<AnswerStatisticsMaintenanceService>();

@@ -10,6 +10,7 @@
    <PackageReference Include="Microsoft.AspNetCore.Authentication.JwtBearer" Version="8.0.8" />
    <PackageReference Include="Microsoft.AspNetCore.OpenApi" Version="8.0.8" />
    <PackageReference Include="MongoDB.Driver" Version="3.4.3" />
+    <PackageReference Include="Stripe.net" Version="52.1.1" />
    <PackageReference Include="Swashbuckle.AspNetCore" Version="6.5.0" />
  </ItemGroup>

@@ -0,0 +1,74 @@
+using MongoDB.Driver;
+using QuestionsApi.Models;
+
+namespace QuestionsApi.Services;
+
+public sealed class DonationStore
+{
+    private readonly IMongoCollection<Donation> _donations;
+
+    public DonationStore(MongoDatabaseProvider mongo)
+    {
+        _donations = mongo.Database.GetCollection<Donation>("Donations");
+        _donations.Indexes.CreateMany([
+            new CreateIndexModel<Donation>(Builders<Donation>.IndexKeys.Ascending(value => value.UserId).Descending(value => value.CreatedUtc)),
+            new CreateIndexModel<Donation>(Builders<Donation>.IndexKeys.Ascending(value => value.StripeCheckoutSessionId),
+                new CreateIndexOptions<Donation>
+                {
+                    Unique = true,
+                    PartialFilterExpression = Builders<Donation>.Filter.Type(value => value.StripeCheckoutSessionId, MongoDB.Bson.BsonType.String)
+                }),
+            new CreateIndexModel<Donation>(Builders<Donation>.IndexKeys.Ascending(value => value.Status).Descending(value => value.CreatedUtc))
+        ]);
+    }
+
+    public async Task<Donation> CreateAsync(string userId, long amountCents)
+    {
+        var donation = new Donation { UserId = userId, AmountCents = amountCents };
+        await _donations.InsertOneAsync(donation);
+        return donation;
+    }
+
+    public async Task<Donation?> GetOwnedAsync(string id, string userId) =>
+        await _donations.Find(value => value.Id == id && value.UserId == userId).FirstOrDefaultAsync();
+
+    public async Task AttachCheckoutSessionAsync(string id, string sessionId) =>
+        await _donations.UpdateOneAsync(
+            value => value.Id == id && value.Status == DonationStatus.Pending,
+            Builders<Donation>.Update.Set(value => value.StripeCheckoutSessionId, sessionId).Set(value => value.UpdatedUtc, DateTime.UtcNow));
+
+    public async Task MarkCheckoutCreationFailedAsync(string id, string failureCode) =>
+        await _donations.UpdateOneAsync(
+            value => value.Id == id && value.Status == DonationStatus.Pending,
+            Builders<Donation>.Update.Set(value => value.Status, DonationStatus.Failed)
+                .Set(value => value.FailureCode, failureCode).Set(value => value.UpdatedUtc, DateTime.UtcNow));
+
+    public async Task<bool> ApplyStripeStatusAsync(
+        string id,
+        string sessionId,
+        long amountCents,
+        string currency,
+        string status,
+        string paymentIntentId,
+        string eventId)
+    {
+        if (string.IsNullOrWhiteSpace(id) || string.IsNullOrWhiteSpace(sessionId)) return false;
+        var filter = Builders<Donation>.Filter.Eq(value => value.Id, id)
+            & Builders<Donation>.Filter.Eq(value => value.AmountCents, amountCents)
+            & Builders<Donation>.Filter.Eq(value => value.Currency, currency.ToLowerInvariant())
+            & (Builders<Donation>.Filter.Eq(value => value.StripeCheckoutSessionId, sessionId)
+                | Builders<Donation>.Filter.Eq(value => value.StripeCheckoutSessionId, null));
+
+        if (status != DonationStatus.Paid)
+            filter &= Builders<Donation>.Filter.Eq(value => value.Status, DonationStatus.Pending);
+
+        var now = DateTime.UtcNow;
+        var update = Builders<Donation>.Update.Set(value => value.Status, status)
+            .Set(value => value.StripeCheckoutSessionId, sessionId)
+            .Set(value => value.StripePaymentIntentId, paymentIntentId)
+            .Set(value => value.LastStripeEventId, eventId)
+            .Set(value => value.UpdatedUtc, now);
+        if (status == DonationStatus.Paid) update = update.Set(value => value.PaidUtc, now);
+        return (await _donations.UpdateOneAsync(filter, update)).ModifiedCount > 0;
+    }
+}
@@ -0,0 +1,57 @@
+using Stripe;
+using Stripe.Checkout;
+
+namespace QuestionsApi.Services;
+
+public sealed record StripeCheckoutResult(string SessionId, string CheckoutUrl);
+
+public interface IStripeDonationGateway
+{
+    Task<StripeCheckoutResult> CreateCheckoutAsync(string donationId, long amountCents, CancellationToken cancellationToken);
+}
+
+public sealed class StripeDonationGateway(IConfiguration configuration) : IStripeDonationGateway
+{
+    public async Task<StripeCheckoutResult> CreateCheckoutAsync(string donationId, long amountCents, CancellationToken cancellationToken)
+    {
+        var secretKey = configuration["Stripe:SecretKey"];
+        if (string.IsNullOrWhiteSpace(secretKey)) throw new InvalidOperationException("Stripe secret key is not configured.");
+        var successUrl = configuration["Stripe:SuccessUrl"]
+            ?? "https://doctor.ranaze.com/donation-complete.html?session_id={CHECKOUT_SESSION_ID}";
+        var cancelUrl = configuration["Stripe:CancelUrl"] ?? "https://doctor.ranaze.com/donation-canceled.html";
+        var client = new StripeClient(secretKey);
+        var service = new SessionService(client);
+        var metadata = new Dictionary<string, string> { ["donation_id"] = donationId };
+        var session = await service.CreateAsync(new SessionCreateOptions
+        {
+            Mode = "payment",
+            SuccessUrl = successUrl,
+            CancelUrl = cancelUrl,
+            ClientReferenceId = donationId,
+            CustomerCreation = "always",
+            BillingAddressCollection = "auto",
+            Metadata = metadata,
+            PaymentIntentData = new SessionPaymentIntentDataOptions { Metadata = metadata },
+            LineItems =
+            [
+                new SessionLineItemOptions
+                {
+                    Quantity = 1,
+                    PriceData = new SessionLineItemPriceDataOptions
+                    {
+                        Currency = "usd",
+                        UnitAmount = amountCents,
+                        ProductData = new SessionLineItemPriceDataProductDataOptions
+                        {
+                            Name = "Support MedMind",
+                            Description = "One-time contribution supporting MedMind development and medical education content."
+                        }
+                    }
+                }
+            ]
+        }, null, cancellationToken);
+        if (string.IsNullOrWhiteSpace(session.Id) || string.IsNullOrWhiteSpace(session.Url))
+            throw new InvalidOperationException("Stripe did not return a checkout URL.");
+        return new StripeCheckoutResult(session.Id, session.Url);
+    }
+}
@@ -2,6 +2,10 @@
  "Kestrel": { "Endpoints": { "Http": { "Url": "http://0.0.0.0:5008" } } },
  "MongoDB": { "ConnectionString": "mongodb://192.168.86.50:27017", "DatabaseName": "promiscuity" },
  "AnswerStatistics": { "ReconcileSeconds": 300 },
+  "Stripe": {
+    "SuccessUrl": "https://doctor.ranaze.com/donation-complete.html?session_id={CHECKOUT_SESSION_ID}",
+    "CancelUrl": "https://doctor.ranaze.com/donation-canceled.html"
+  },
  "Jwt": { "Key": "SuperUltraSecureJwtKeyWithAtLeast32Chars!!", "Issuer": "promiscuity", "Audience": "promiscuity-auth-api" },
  "Logging": { "LogLevel": { "Default": "Information" } }
 }
@@ -2,6 +2,10 @@
  "Kestrel": { "Endpoints": { "Http": { "Url": "http://0.0.0.0:5008" } } },
  "MongoDB": { "ConnectionString": "mongodb://192.168.86.50:27017", "DatabaseName": "promiscuity" },
  "AnswerStatistics": { "ReconcileSeconds": 300 },
+  "Stripe": {
+    "SuccessUrl": "https://doctor.ranaze.com/donation-complete.html?session_id={CHECKOUT_SESSION_ID}",
+    "CancelUrl": "https://doctor.ranaze.com/donation-canceled.html"
+  },
  "Jwt": { "Key": "SuperUltraSecureJwtKeyWithAtLeast32Chars!!", "Issuer": "promiscuity", "Audience": "promiscuity-auth-api" },
  "Logging": { "LogLevel": { "Default": "Information" } },
  "AllowedHosts": "*"
@@ -35,6 +35,16 @@ spec:
                secretKeyRef:
                  name: medmind-internal-api
                  key: purge-secret
+            - name: Stripe__SecretKey
+              valueFrom:
+                secretKeyRef:
+                  name: medmind-stripe
+                  key: secret-key
+            - name: Stripe__WebhookSecret
+              valueFrom:
+                secretKeyRef:
+                  name: medmind-stripe
+                  key: webhook-secret
          resources:
            requests:
              cpu: 250m