public static Cloud SetHooks(this Cloud cloud)
{
cloud.BeforeSave("Todo", todo =>
{
var title = todo.Get<string>("title");
// reset value for title
if (!string.IsNullOrEmpty(title))
if (title.Length > 20) todo["title"] = title.Substring(0, 20);
// returning any value will be ok.
return Task.FromResult(true);
}).BeforeSave("Review", review =>
{
var comment = review.Get<string>("comment");
if (comment.Length > 140) review["comment"] = comment.Substring(0, 137) + "...";
return Task.FromResult(comment);
}).AfterSave("Review", async review =>
{
var post = review.Get<AVObject>("post");
await post.FetchAsync();
post.Increment("comments");
await post.SaveAsync();
}).AfterSave("_User", async user =>
{
if (user is AVUser avUser)
{
avUser.Set("from", "LeanCloud");
await avUser.SaveAsync();
}
}).BeforeUpdate("Review", (EngineObjectHookContext context) =>
{
if (context.UpdatedKeys.Contains("comment"))
{
var comment = context.TheObject.Get<string>("comment");
if (comment.Length > 140) throw new EngineException(400, "comment 长度不得超过 140 字符");
}
return Task.FromResult(true);
}).AfterSave("Article", article =>
{
Console.WriteLine(article.ObjectId);
return Task.FromResult(true);
}).BeforeDelete("Album", async album =>
{
AVQuery<AVObject> query = new AVQuery<AVObject>("Photo");
query.WhereEqualTo("album", album);
int count = await query.CountAsync();
if (count > 0)
{
throw new Exception("无法删除非空相簿");
}
else
{
Console.WriteLine("deleted.");
}
}).AfterDelete("Album", async album =>
{
AVQuery<AVObject> query = new AVQuery<AVObject>("Photo");
query.WhereEqualTo("album", album);
var result = await query.FindAsync();
if (result != null && result.Count() != 0)
{
await AVObject.DeleteAllAsync(result);
}
}).OnVerifiedSMS((AVUser user) =>
{
Console.WriteLine("user verified by sms");
return Task.FromResult(true);
}).OnLogIn((AVUser user) =>
{
Console.WriteLine("user logged in.");
return Task.FromResult(true);
});
return cloud;
}
public static void UseLambda(this Cloud cloud)
{
// case 1. use EngineObjectHookContext
cloud.UseHook("Todo", EngineHookType.BeforeSave, (context) =>
{
var todo = context.TheObject;
var by = context.By;
return(Task.FromResult(context.TheObject));
});
cloud.BeforeSave("Todo", (context) =>
{
return(Task.FromResult(context.TheObject));
});
// case 2. use TheObject
cloud.UseHook("Todo", EngineHookType.BeforeSave, (AVObject todoObj) =>
{
return(Task.FromResult(todoObj));
});
cloud.BeforeSave("Todo", (AVObject todoObj) =>
{
return(Task.FromResult(todoObj));
});
// case 3. use TheObject and user
cloud.UseHook("Todo", EngineHookType.BeforeSave, (AVObject todoObj, AVUser by) =>
{
return(Task.FromResult(todoObj));
});
cloud.BeforeSave("Todo", (AVObject todoObj, AVUser by) =>
{
return(Task.FromResult(todoObj));
});
// case 3. use sub-class
AVObject.RegisterSubclass <Todo>();
cloud.UseHook <Todo>(EngineHookType.BeforeSave, (Todo theTodoObj) =>
{
// theTodoObj is an Todo instance.
return(Task.FromResult(theTodoObj));
});
cloud.UseHook <Todo>(EngineHookType.BeforeSave, (Todo theTodoObj, AVUser by) =>
{
return(Task.FromResult(theTodoObj));
});
cloud.BeforeSave <Todo>((todo) =>
{
// todo is an Todo instance.
return(Task.FromResult(todo));
});
cloud.BeforeSave <Todo>((todo, by) =>
{
// todo is an Todo instance.
return(Task.FromResult(todo));
});
cloud.BeforeUpdate("Todo", review =>
{
var updatedKeys = review.GetUpdatedKeys();
if (updatedKeys.Contains("comment"))
{
var comment = review.Get <string>("comment");
if (comment.Length > 140)
{
throw new EngineException(400, "comment 长度不得超过 140 字符");
}
}
return(Task.FromResult(true));
});
EngineHookDelegateSynchronous afterPostHook = (post) =>
{
};
cloud.AfterSave("Post", (EngineObjectHookDeltegateSynchronous)(async post =>
{
// 直接修改并保存对象不会再次触发 after update hook 函数
post["foo"] = "bar";
await post.SaveAsync();
// 如果有 FetchAsync 操作，则需要在新获得的对象上调用相关的 disable 方法
// 来确保不会再次触发 Hook 函数
await post.FetchAsync();
post.DisableAfterHook();
post["foo"] = "bar";
// 如果是其他方式构建对象，则需要在新构建的对象上调用相关的 disable 方法
// 来确保不会再次触发 Hook 函数
post = AVObject.CreateWithoutData <AVObject>(post.ObjectId);
post.DisableAfterHook();
await post.SaveAsync();
}));
}
public static Cloud SetHooks(this Cloud cloud)
{
cloud.BeforeSave("Todo", SampleHooks.Singleton.CheckTitle);
cloud.UseHookClass <TodoHook>();
return(cloud);
}
