Topic/209 connect to rds

coscine/issues#152

src/Project/Controllers/DataSourceController.cs

+using Coscine.Api.Project.Models;
+using Coscine.Api.Project.ReturnObjects;
+using Coscine.ApiCommons;
+using Coscine.ApiCommons.Utils;
+using Coscine.Configuration;
+using Coscine.Database.Model;
+using Microsoft.AspNetCore.Mvc;
+using Newtonsoft.Json.Linq;
+using System;
+using System.Collections.Generic;
+using System.IdentityModel.Tokens.Jwt;
+using System.Linq;
+using System.Net.Http;
+using System.Net.Http.Headers;
+using System.Threading.Tasks;
+
+namespace Coscine.Api.Project.Controllers
+{
+    public class DataSourceController : Controller
+    {
+        private readonly IConfiguration _configuration;
+        private readonly JWTHandler _jwtHandler;
+        private static readonly HttpClient _client = new HttpClient();
+        private readonly Authenticator _authenticator;
+        private readonly ResourceModel _resourceModel;
+
+        public DataSourceController()
+        {
+            _configuration = Program.Configuration;
+            _jwtHandler = new JWTHandler(_configuration);
+            _authenticator = new Authenticator(this, _configuration);
+            _resourceModel = new ResourceModel();
+        }
+
+
+        // inferring a ../ (urlencoded) can manipulate the url.
+        // However the constructed signature for s3 won't match and it will not be resolved.
+        // This may be a problem for other provider!
+        [HttpGet("[controller]/{resourceId}/{*path}")]
+        public async Task<IActionResult> Get(string resourceId, string path)
+        {
+
+            if (!Guid.TryParse(resourceId, out Guid resouceGuid))
+            {
+                return BadRequest($"{resourceId} is not a guid.");
+            }
+
+            Resource resource;
+            try
+            {
+                resource = _resourceModel.GetById(resouceGuid);
+                if (resource == null)
+                {
+                    return NotFound($"Could not find resource with id: {resourceId}");
+                }
+            }
+            catch (Exception)
+            {
+                return NotFound($"Could not find resource with id: {resourceId}");
+            }
+
+            // Temporary
+#if (!DEBUG)
+            var user = _authenticator.GetUserFromToken();
+            if (!_resourceModel.OwnsResource(user, resource))
+            {
+                return Forbid($"The user does not own the resource {resourceId}");
+            }
+#endif
+
+            if (resource.Type == null)
+            {
+                ResourceTypeModel resourceTypeModel = new ResourceTypeModel();
+                resource.Type = resourceTypeModel.GetById(resource.TypeId);
+            }
+
+            string authHeader = null;
+
+            if (resource.Type.DisplayName.ToLower() == "rds")
+            {
+                authHeader = BuildRdsAuthHeader(resource.ExternalId);
+            }
+            else if (resource.Type.DisplayName.ToLower() == "gitlab")
+            {
+                authHeader = BuildGitlabAuthHeader();
+            }
+
+            if (authHeader != null)
+            {
+                // If the path is null, an empty string is added.
+                string url = $"{_configuration.GetString("coscine/global/waterbutler_url")}{resource.Type.DisplayName.ToLower()}/{path}";
+
+                var request = new HttpRequestMessage(HttpMethod.Get, url);
+                request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", authHeader);
+
+                // Thread safe according to msdn and HttpCompletionOption sets it to get only headers first.
+                var response = await _client.SendAsync(request, HttpCompletionOption.ResponseHeadersRead);
+                if (response.IsSuccessStatusCode)
+                {
+                    if (response.Content.Headers.Contains("Content-Disposition"))
+                    {
+                        return File(await response.Content.ReadAsStreamAsync(),
+                            response.Content.Headers.GetValues("Content-Type").First());
+                    }
+                    else
+                    {
+                        var data = JObject.Parse(await response.Content.ReadAsStringAsync())["data"];
+                        return Ok(new WaterbutlerObject(path, data));
+                    }
+                }
+                else
+                {
+                    if (response.StatusCode == System.Net.HttpStatusCode.NotFound)
+                    {
+                        return NotFound($"Could not find object for: \"{path}\".");
+                    }
+                    else
+                    if (response.StatusCode == System.Net.HttpStatusCode.Forbidden)
+                    {
+                        return Forbid($"Not allowed to access the datasource.");
+                    }
+                    else
+                    {
+                        return BadRequest($"Error in communication with waterbutler: {response.StatusCode}");
+                    }
+                }
+            }
+            else
+            {
+                return BadRequest($"No provider for: \"{resource.Type.DisplayName}\".");
+            }
+        }
+
+        private string BuildRdsAuthHeader(string bucketname)
+        {
+            var auth = new Dictionary<string, object>();
+
+            var credentials = new Dictionary<string, object>
+                    {
+                        { "access_key", _configuration.GetString("coscine/global/rds_access_key") },
+                        { "secret_key", _configuration.GetString("coscine/global/rds_secret_key") }
+                    };
+
+            var settings = new Dictionary<string, object>
+                    {
+                        { "bucket", bucketname }
+                    };
+
+            var data = new Dictionary<string, object>
+                    {
+                        { "auth", auth },
+                        { "credentials", credentials },
+                        { "settings", settings },
+                        { "callback_url", "rwth-aachen.de" }
+                    };
+
+            var payload = new JwtPayload
+                    {
+                        { "data", data }
+                    };
+
+            return _jwtHandler.GenerateJwtToken(payload);
+        }
+
+        private string BuildGitlabAuthHeader()
+        {
+            return null;
+        }
+    }
+}