1 files changed, 79 insertions, 0 deletions
diff --git a/src/marlin.web/Services/AgentAuthenticationHandler.cs b/src/marlin.web/Services/AgentAuthenticationHandler.cs
new file mode 100644
index 0000000..519d109
--- /dev/null
+++ b/src/marlin.web/Services/AgentAuthenticationHandler.cs
@@ -0,0 +1,79 @@
+namespace marlin.web.Services;
+
+using System.Security.Claims;
+using System.Text.Encodings.Web;
+using Data;
+using Microsoft.AspNetCore.Authentication;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Options;
+using Microsoft.Extensions.Primitives;
+
+public class AgentSchemeOptions : AuthenticationSchemeOptions
+{
+    public const string Name = "Agent";
+    public string AgentHeader { get; set; } = "Agent";
+    public string JobHeader { get; set; } = "Job";
+}
+
+public class AgentAuthenticationHandler : AuthenticationHandler<AgentSchemeOptions>
+{
+    private readonly ApplicationDbContext _dbContext;
+
+    public AgentAuthenticationHandler(
+        IOptionsMonitor<AgentSchemeOptions> options,
+        ILoggerFactory logger,
+        UrlEncoder encoder,
+        ApplicationDbContext dbContext) : base(options, logger, encoder)
+    {
+        this._dbContext = dbContext;
+    }
+
+    private bool TryReadPair(string headerName, out Guid id, out string token)
+    {
+        id = Guid.Empty;
+        token = string.Empty;
+
+        if (!Request.Headers.TryGetValue(headerName, out StringValues header))
+            return false;
+
+        var parts = header.ToString().Split(' ', 2);
+        if (parts.Length != 2 || parts[1].Length == 0)
+            return false;
+
+        token = parts[1];
+        return Guid.TryParse(parts[0], out id);
+    }
+
+    protected override async Task<AuthenticateResult> HandleAuthenticateAsync()
+    {
+        var claims = new List<Claim>();
+        
+        if (!TryReadPair(Options.AgentHeader, out var agentId, out var agentToken))
+            return AuthenticateResult.NoResult();
+
+        var agent = await this._dbContext.Agents
+            .FirstOrDefaultAsync(x => x.Id == agentId && x.AuthToken == agentToken);
+
+        if (agent == null)
+            return AuthenticateResult.Fail("Invalid agent credentials.");
+        
+        claims.Add(new Claim("agent_id", agent.Id.ToString()));
+
+        if (TryReadPair(Options.JobHeader, out var jobId, out var jobToken))
+        {
+            var job = await this._dbContext.Jobs
+                .FirstOrDefaultAsync(x => x.Id == jobId && x.AgentId == agent.Id && x.ClaimToken == jobToken);
+
+            if (job == null)
+                return AuthenticateResult.Fail("Invalid job claim token.");
+
+            claims.Add(new Claim("job_id", job.Id.ToString()));
+        }
+
+        var identity = new ClaimsIdentity(claims, this.Scheme.Name);
+        var principal = new ClaimsPrincipal(identity);
+        var ticket = new AuthenticationTicket(principal, this.Scheme.Name);
+
+        return AuthenticateResult.Success(ticket);
+    }
+}