Add token-authenticated catalog import API endpoint

POST /PowderCatalog/ImportApi accepts the JSON scrape format in the request
body, authenticated by a shared secret in the X-Import-Token header (matched
constant-time against CatalogImport:Token), with the vendor in X-Vendor-Name.
Runs through the same ImportJsonAsync -> shared upsert as the manual upload, so
the offline PrismaticSync tool can push unattended.

ImportJsonAsync refactored to take a Stream (the form upload now passes
file.OpenReadStream()). Endpoint is AllowAnonymous + IgnoreAntiforgeryToken
(it's token-gated, not cookie-auth) and returns 401 until a token is configured,
so it's inert by default. README updated with the route + token wiring.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/PowderCoating.Web/Controllers/PowderCatalogController.cs

@@ -25,6 +25,7 @@ public class PowderCatalogController : Controller
     private readonly IColumbiaCatalogSyncService _columbiaSyncService;
     private readonly IPowderCatalogUpsertService _upsertService;
     private readonly IPlatformSettingsService _platformSettings;
+    private readonly IConfiguration _config;
     private readonly ILogger<PowderCatalogController> _logger;
 
     public PowderCatalogController(
@@ -33,6 +34,7 @@ public class PowderCatalogController : Controller
         IColumbiaCatalogSyncService columbiaSyncService,
         IPowderCatalogUpsertService upsertService,
         IPlatformSettingsService platformSettings,
+        IConfiguration config,
         ILogger<PowderCatalogController> logger)
     {
         _unitOfWork = unitOfWork;
@@ -40,6 +42,7 @@ public class PowderCatalogController : Controller
         _columbiaSyncService = columbiaSyncService;
         _upsertService = upsertService;
         _platformSettings = platformSettings;
+        _config = config;
         _logger = logger;
     }
 
@@ -372,7 +375,8 @@ public class PowderCatalogController : Controller
         PowderCatalogImportResult result;
         try
         {
-            result = await ImportJsonAsync(file, vendorName);
+            using var stream = file.OpenReadStream();
+            result = await ImportJsonAsync(stream, vendorName);
         }
         catch (Exception ex)
         {
@@ -393,6 +397,67 @@ public class PowderCatalogController : Controller
         return RedirectToAction(nameof(Index));
     }
 
+    /// <summary>
+    /// Unattended catalog import for the offline scraper tool (e.g. PrismaticSync). Accepts the same
+    /// JSON scrape format in the request body, authenticated by a shared secret in the
+    /// <c>X-Import-Token</c> header (matched against <c>CatalogImport:Token</c>). The vendor name
+    /// comes from the <c>X-Vendor-Name</c> header. Runs through the same upsert as the manual upload.
+    /// Inert (401) until a token is configured.
+    /// </summary>
+    [HttpPost]
+    [AllowAnonymous]
+    [IgnoreAntiforgeryToken]
+    [RequestSizeLimit(50 * 1024 * 1024)] // 50 MB
+    public async Task<IActionResult> ImportApi()
+    {
+        var configuredToken = _config["CatalogImport:Token"];
+        if (string.IsNullOrWhiteSpace(configuredToken))
+        {
+            _logger.LogWarning("ImportApi called but no CatalogImport:Token is configured — rejecting.");
+            return Unauthorized(new { success = false, errorMessage = "Import API is not enabled." });
+        }
+
+        var providedToken = Request.Headers["X-Import-Token"].ToString();
+        if (!FixedTimeEquals(providedToken, configuredToken))
+            return Unauthorized(new { success = false, errorMessage = "Invalid import token." });
+
+        var vendorName = Request.Headers["X-Vendor-Name"].ToString();
+        if (string.IsNullOrWhiteSpace(vendorName))
+            vendorName = "Prismatic Powders";
+
+        try
+        {
+            var result = await ImportJsonAsync(Request.Body, vendorName);
+            _logger.LogInformation(
+                "ImportApi ({Vendor}): {Inserted} inserted, {Updated} updated, {Skipped} skipped, {Errors} errors.",
+                vendorName, result.Inserted, result.Updated, result.Skipped, result.Errors);
+
+            return Json(new
+            {
+                success = result.Success,
+                vendorName,
+                result.Inserted,
+                result.Updated,
+                result.Skipped,
+                result.Errors,
+                result.ErrorMessage
+            });
+        }
+        catch (Exception ex)
+        {
+            _logger.LogError(ex, "ImportApi failed for vendor {Vendor}", vendorName);
+            return StatusCode(500, new { success = false, errorMessage = "Import failed." });
+        }
+    }
+
+    /// <summary>Constant-time string comparison so token checks don't leak length/contents via timing.</summary>
+    private static bool FixedTimeEquals(string a, string b)
+    {
+        var ba = System.Text.Encoding.UTF8.GetBytes(a ?? string.Empty);
+        var bb = System.Text.Encoding.UTF8.GetBytes(b ?? string.Empty);
+        return System.Security.Cryptography.CryptographicOperations.FixedTimeEquals(ba, bb);
+    }
+
     /// <summary>
     /// AJAX endpoint used by the inventory form to search the catalog by SKU or color name.
     /// SKU exact matches are ranked first; color name substring matches follow.
@@ -527,9 +592,8 @@ public class PowderCatalogController : Controller
         }
     }
 
-    private async Task<PowderCatalogImportResult> ImportJsonAsync(IFormFile file, string vendorName)
+    private async Task<PowderCatalogImportResult> ImportJsonAsync(Stream stream, string vendorName)
     {
-        using var stream = file.OpenReadStream();
         using var doc = await JsonDocument.ParseAsync(stream);
 
         if (!doc.RootElement.TryGetProperty("results", out var resultsEl) ||

src/PowderCoating.Web/appsettings.json

@@ -47,6 +47,9 @@
     "BaseUrl": "https://columbiacoatings.com",
     "ApiBasePath": "/wp-json/cca/v1"
   },
+  "CatalogImport": {
+    "Token": ""
+  },
   "SendGrid": {
     "ApiKey": "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",
     "FromEmail": "spouliot@scppowdercoating.com",