我不确定在这种情况下使用什么。
我有一个基本上可以做到这一点的 asp.net web api 方法
- 从用户附近的foursquare 中查找兴趣点。
- 使用四方位置在我的数据库中进行查询，以查找有关用户附近兴趣点的唯一数据。
但是，由于我需要存储一些四方信息以将我的唯一数据链接到该位置，因此我决定将所有信息存储在我的数据库中，并让我的数据库充当我的缓存系统。
这意味着我必须将任何新的兴趣点插入到我的数据库中，检查它是否存在，如果存在则跳过它，或者如果它存在检查最后一次刷新日期（foursquare 政策规定所有数据必须在 30 天后刷新）如果它超过了刷新日期，我必须更新数据。
我想减慢用户的速度，并且必须等待上述情况发生。我希望我的代码执行第 1 步，然后在执行第 2 步的同时执行我刚才提到的操作。
一旦第 2 步完成，我想返回数据并让用户继续前进。如果我的缓存系统没有完成，那么它应该继续运行但不会让用户陷入困境。
我不会在第 2 步中使用这些新结果中的任何一个，就好像我正在插入它一样，那么此时我在该位置将没有任何数据。
不确定我是否需要创建一个线程或使用 async/await 来实现这一点。
编辑
这是我想要做的
public HttpResponseMessage Get()
{
// this will do a foursquare lookup to find all stores near the user
// I want to insert them into my database and link it to my unquie data.
// stores pulled from foursquare will
// a) Be new and not in my database
// b) exist in my database but have been refreshed lately
// c) have not been refreshed in timeframe of foursquare policy
// THIS SHOULD WORK IN THE BACKGROUND
storeService.PointsOfInterestNearUser(80, -130); //As you can see it is
//void. Not sure where to put the async/await stuff
// find this product. Should be happening at the same time as above line.
var product = productService.FindProduct("Noodles");
//This will get returned to the user.
// the new stores taht are being added in StoreNearUser
//won't effect this search as I will have not data on this new store
// if existing store is being refreshed it is possible old
//address might be picked up...
//I can live with that as I doubt the address will change much.
// this should happen after product
var allStores = storeService.FindStoresThatHaveItem(product);
// this should be returned as soon as above line is finished.
//If StoreNearUser is not done, it should keep going but not hold up user.
return allStores;
}
public void StoresNearUser(double latitude, double longitude)
{
// get all categories I can about in foursquare.
//First time from db otherwise cached.
List<StoreCategory> storeCategories = GetStoreCategories();
// do a request and get everything in near the user
//(provided it is also in a category I care about)
var request = CreateFoursquareStoreRequest
(latitude, longitude, storeCategories);
// do the actual call.
var response = client.Execute<VenueSearch>(request);
if (response.StatusCode == System.Net.HttpStatusCode.OK)
{
// start going through the results, add or update or skip of entry will happen
AddUpdateStores(storeCategories, response);
}
else
{
ErrorSignal.FromCurrentContext().Raise(response.ErrorException);
}
}
编辑 2
public async Task StoresNearUser(double latitude, double longitude)
{
// get all categories I can about in foursquare. First time from db otherwise cached.
List<StoreCategory> storeCategories = GetStoreCategories();
// do a request and get everything in near the user(provided it is also in a category I care about)
var request = CreateFoursquareStoreRequest(latitude, longitude, storeCategories);
await client.ExecuteAsync<VenueSearch>
( request
, response =>
{
if (response.StatusCode == System.Net.HttpStatusCode.OK)
{
AddUpdateStores(storeCategories, response);
}
else
{
ErrorSignal.FromCurrentContext()
.Raise(response.ErrorException);
}
}
);
}
给我这个错误
Cannot await 'RestSharp.RestRequestAsyncHandle'
我也不明白 和 之间的Task区别void。从我读到的，如果你只是使用Task它意味着你没有发送任何意义，那么为什么不直接使用void呢？
编辑 2 我发现这篇文章向我展示了如何为 Restsharp 制作包装器。这不是我想要的 100%，但这是一个单独的问题。
public async Task StoresNearUser(double latitude, double longitude)
{
List<StoreCategory> storeCategories = GetStoreCategories();
var request = CreateFoursquareStoreRequest
(latitude, longitude, maxRadius, returnLimit, storeCategories);
var response = await client.GetResponseAsync(request);
if (response.StatusCode == HttpStatusCode.OK)
{
// had to use json.net right now as the wrapper does not expose restsharps deserilizer
var venue = JsonConvert
.DeserializeObject<VenueSearch>(response.Content);
AddUpdateStores(storeCategories, venue);
}
else
{
ErrorSignal.FromCurrentContext()
.Raise(response.ErrorException);
}
}
public async Task<HttpResponseMessage>Get()
{
await storeService.PointsOfInterestNearUser(80, -130);
var product = productService.FindProduct("Noodles");
var allStores = storeService.FindStoresThatHaveItem(product);
return allStores;
}
当我从调试器中观察时，它看起来仍然一切正常。我认为product并且allStores需要，因为我需要产品才能找到商店，但PointsOfInterestNearUser应该与FindProduct.
编辑 3 这是我的 FindProduct 方法。不知道要做什么让我异步看起来一切都需要等待。
public ResponseResult<Product> FindProduct(string barcode)
{
ResponseResult<Product> responseResult = new ResponseResult<Product>();
Product product = null;
try
{
var findBarCode = context.Barcodes.Where(x => x.Code == barcode).Select(x => x.Product).FirstOrDefault();
responseResult.Response = product;
if (product == null)
{
responseResult.Status.Code = HttpStatusCode.NotFound;
}
else
{
responseResult.Status.Code = HttpStatusCode.OK;
}
}
catch (SqlException ex)
{
ErrorSignal.FromCurrentContext().Raise(ex);
responseResult.Status.Code = HttpStatusCode.InternalServerError;
responseResult.Status.Message = GenericErrors.InternalError;
}
return responseResult;
}
编辑 4
仍然不确定如何执行 Task.WhenAll()
public async Task<HttpResponseMessage>Get()
{
Task[] tasks = new Task[2];
tasks[0] = storeService.PointsOfInterestNearUser(80, -130);
tasks[1] = productService.FindProduct("Noodles");
await Task.WhenAll(tasks);
// not sure how to get product back out. I looked in the debugger and saw a "Result" that has it but when I do tasks[1].Result inetllisene cannot find .Result
var allStores = storeService.FindStoresThatHaveItem(product);
return allStores;
}