I'm making a PokemonGo-like game.
Simply, each player chooses which faction to belong (indicated by three different colors); The main purpose of the game is to capture the towers that the server creates close to the player's geographical position.
Much of what I've described above has already been implemented and almost functional, but I have many doubts about the database and communication with it. I have currently written a REST web service in php that allows me to check if the players are registered and if they are online. Basically, in the player client in Unity I created a simple login interface where, after writing username and password, these data are inserted into a WWWForm object and the following call, UnityWebRequest.Post (loginUrl, form) , I can understand if the data entered corresponds to a registered user or not.
LoginStatus logInStatus = new LoginStatus();
var form = new WWWForm();
form.AddField("username",id); //id,pass = textField
form.AddField("password",pass);
using (UnityWebRequest www = UnityWebRequest.Post(loginUrl, form))
{
yield return www.Send();
if (www.isNetworkError)
gui.activatePopUp("Connection error, retry!");
else
{
var postResponse = www.downloadHandler.text;
gui.activatePopUp(logInStatus.getMessage(postResponse));
if (logInStatus.Success)
{
infos.username = id;
infos.password = pass;
SceneManager.LoadSceneAsync("ClientScene");
}
}
}
The loginUrl is a string variable that contains the login REST service address. So far, it's all simple and acceptable. The problem is that in the future I will need to retrieve much more information from the database, ie a player will be represented, for example, by the attributes Username, Faction, Level and so on. so what is the most appropriate way to intelligently communicate such an application with a web service rest? How do I make a smart mapping between my business classes and the relational model? Currently, the REST service queries a remote MySQL database.
Can some ORM be used?
A first solution I thought about is to apply the DAO pattern, let me return the records from the database as JSON and use a parser that recreates the objects. Do you think it's smart enough and efficient as a solution?
Related
I don't know how to process, and when i search in the internet, there is so many solutions, I'm a bit lost.
My task is to create a leaderboard, the game is developed in C# with unity and my internship supervisor just told me "You have to put some PHP into the database server of our client and then make a "bridge" between our game and this PHP"
I never used C# before (Java is sooo cooler) any advice, source with commented code "easy" to understand?
You may want to write your API. You will then call it with C# using web requests.
A very simple way to get data from your database is to switch through given endpoints in your the URL.
For instance, the following URL: http://yourserver.com/api/v1/?leaderboard/top
You may explode the URL to get the endpoints with $endpoints = explode('/', rtrim($_SERVER['QUERY_STRING'], '/'));. In this case, $endpoints[0] would give leaderboard.
You could then use a switch statement to handle your request.
// ...
$endpoints = explode('/', rtrim($_SERVER['QUERY_STRING'], '/'));
switch ($endpoints[0])
{
case 'leaderboard':
{
switch ($endpoints[1])
{
case 'top':
// Ask your database
$result = get_top_leaderboard();
echo json_encode($result);
break;
// case ...
}
break;
// case...
}
}
// ...
Use the same method with $_POST to get user entries, and write them in your database. Do not forget to protect yourself from SQL injections.
In C#, perform a GET request on your API:
var responseString = await client.GetStringAsync("http://yourserver.com/api/v1/?leaderboard/top");
Keep in mind this exemple is not secured. If you want to get sensible data from your database, do not let your API unsecured with public access.
I have a Web API providing a backend to an Angular.JS web application. The backend API needs to track the state of user activities. (Example: it needs to note which content ID a user last retrieved from the API)
Most access to the API is authenticated via username/password. For these instances, it works fine for me to store the user state in our database.
However, we do need to allow "guest" access to the service. For guests, the state does need to be tracked but should not be persisted long-term (e.g. session-level tracking). I'd really like to not have to generate "pseudo users" in our user table just to store the state for guest users, which does not need to be maintained for a significant period of time.
My plan is to generate a random value and store it in the client as a cookie. (for guests only - we use bearer authentication for authenticated users.) I would then store whatever state is necessary in an in-memory object, such as a Dictionary, using the random value as a key. I could then expire items off the dictionary periodically. It is perfectly acceptable for this data to be lost if the Web API is ever relaunched, and it would even be acceptable for the dictionary to be reset say, every day at a certain time.
What I don't know how to do in WebAPI is create the dictionary object, so that it will persist across Web API calls. I basically need a singleton dictionary object that will maintain its contents for as long as the server is running the Web API (barring a scheduled clearing or programmatic flushing)
I had the idea of dumping the Dictionary off to disk every time an API call is made, and then reading it back in when it's needed, but this does not allow for multiple simultaneous in-flight requests. The only method I can think of right now is to add another database table (guest_state or something) and replicate the users table, and then setup some sort of manual method to regularly clean out the data in the guest table.
Summary: what I need is
a way to store some data persistently in a Web API backend without having to go off to a database
preferably store this data in a Dictionary object so I can use randomly-generated session IDs as the key, and an object to store the state
the data is OK to be cleared after a set period of time or on a regular basis (not too frequently, maybe a minimum of a 6 hour persistence)
I figured out a solution using the Singleton pattern:
public static class Services
{
private static Dictionary<string, string> cache;
private static object cacheLock = new object();
public static Dictionary<string,string> AppCache
{
get
{
lock (cacheLock)
{
if (cache == null)
{
cache = new Dictionary<string, string>();
}
return cache;
}
}
}
}
public class testController()
{
[HttpGet]
public HttpResponseMessage persist()
{
HttpResponseMessage hrm = Request.CreateResponse();
hrm.StatusCode = HttpStatusCode.OK;
Services.AppCache.Add(Guid.NewGuid().ToString(), DateTime.Now.ToString());
string resp = "";
foreach (string s in Services.AppCache.Keys)
{
resp += String.Format("{0}\t{1}\n", s, Services.AppCache[s]);
}
resp += String.Format("{0} records.", Services.AppCache.Keys.Count);
hrm.Content = new StringContent(resp, System.Text.Encoding.ASCII, "text/plain");
return hrm;
}
}
It seems the Services.AppCache object successfully holds onto data until either the idle timeout expires or the application pool recycles. Luckily I can control all of that in IIS, so I moved my app to its own AppPool and setup the idle timeout and recycling as appropriate, based on when I'm ok with the data being flushed.
Sadly, if you don't have control over IIS (or can't ask the admin to set the settings for you), this may not work if the default expirations are too soon for you... At that point using something like a LocalDB file or even a flat JSON file might be more useful.
I want to pull documents with username attribute
as user1 for user1 like that for each user only attribute with their name.
This is my replication code.
private void setupreplication(){
Console.WriteLine ("Setting up replication");
Uri Server = new Uri("http://192.168.1.213:4984/aussie-coins-syncgw/");
var pull = _db.CreatePullReplication (Server);
var push = _db.CreatePushReplication (Server);
pull.Filter = "byUser";
pull.FilterParams = new Dictionary<string, object> { {"type", "user1"} };
pull.Continuous = true;
push.Continuous = true;
pull.Start();
push.Start();
}
This is my set filter code
_couchBaseLiteLocal.SetFilter("byUser", (revision, filterParams) =>
{
var typeParam = filterParams["type"].ToString();
return (typeParam != null) && typeParam.Equals("user1");
});
With the above code generic pull itself not working.
I just tried to do as given in the documentation.
I do not understand how the setfilter function works to filter data from server. It would be great if someone help in understanding how setfilter works and to make the above code working
Thanks in advance.
The filter function in pull replications can indeed return the specific documents you are interested in. But it's not very efficient, the filter function will run on all the documents on the remote database to determine which ones to pull, every time a pull replication is started.
Instead Sync Gateway introduces the concept of a sync function that incrementally routes and computes access control rules on documents. That way, when starting the pull replication, it's fast and straightforward for Sync Gateway to return the specific documents the user has access to.
You can specify individual channels in a pull replication from Sync Gateway if needed. But the thing to remember is that filtered pull replication between Sync Gateway and Couchbase Lite is not based on filter functions. It's based on the sync function and channel based filtering if needed.
In a P2P scenario (replications between two Couchbase Lite instances), the filter function model is used.
I have a webshop running which contains parts of cars. The prices next to the parts are loaded from a webservice running else where. This webservice only contains one webmethod: GetArticleInformation.
In this webservice there is a link to another webservice WebshopServiceClient running elsewhere which contains the info about the cars and holds the prices.
Now when a user select a part of the vehicle he wants to buy the first webservice is called and the method GetArticleInformation is executed. In this method I want to create a session which hold the logon of the second webservice ( the database ). In this way I want to prevent that for every call a new logon is required.
[WebMethod(EnableSession = true)]
public GetBackItems GetArticleInformation(User user, Items items)
{
//Create session if needed
client = (WebshopServiceClient)Session["SphinxLogon"];
if (client == null)
{
client = new WebshopServiceClient();
bool done = client.Logon();
if (done)
{
Session["SphinxLogon"] = client;
}
}
//Get information and send it back
...
}
Now when the user in the webshop selects a part the session is created but the next time the user selects a part the session is null again.
What am I doing wrong or what am I missing?
I would consider 'talking' to the various web-services via an internal 'proxy'-procedure -- fired up on app-start for example -- which would handle all traffic etc with the services. That way the individual client sessions do not have to logon or maintain a session with the services but can still be managed via the proxy. Individual clients would get a 'ticket' from the proxy which then could be part of their session and could be used to manage it.
I have a webpage that uses ajax polling to get stock market updates from the server. I'd like to use SignalR instead, but I'm having trouble understanding how/if it would work.
ok, it's not really stock market updates, but the analogy works.
The SignalR examples I've seen send messages to either the current connection, all connections, or groups. In my example the stock updates happen outside of the current connection, so there's no such thing as the 'current connection'. And a user's account is associated with a few stocks, so sending a stock notification to all connections or to groups doesn't work either. I need to be able to find a connection associated with a certain userId.
Here's a fake code example:
foreach(var stock in StockService.GetStocksWithBigNews())
{
var userIds = UserService.GetUserIdsThatCareAboutStock(stock);
var connections = /* find connections associated with user ids */;
foreach(var connection in connections)
{
connection.Send(...);
}
}
In this question on filtering connections, they mention that I could keep current connections in memory but (1) it's bad for scaling and (2) it's bad for multi node websites. Both of these points are critically important to our current application. That makes me think I'd have to send a message out to all nodes to find users connected to each node >> my brain explodes in confusion.
THE QUESTION
How do I find a connection for a specific user that is scalable? Am I thinking about this the wrong way?
I created a little project last night to learn this also. I used 1.0 alpha and it was Straight forward. I created a Hub and from there on it just worked :)
I my project i have N Compute Units(some servers processing work), when they start up they invoke the ComputeUnitRegister.
await HubProxy.Invoke("ComputeUnitReqisted", _ComputeGuid);
and every time they do something they call
HubProxy.Invoke("Running", _ComputeGuid);
where HubProxy is :
HubConnection Hub = new HubConnection(RoleEnvironment.IsAvailable ?
RoleEnvironment.GetConfigurationSettingValue("SignalREndPoint"):
"http://taskqueue.cloudapp.net/");
IHubProxy HubProxy = Hub.CreateHubProxy("ComputeUnits");
I used RoleEnviroment.IsAvailable because i can now run this as a Azure Role , a Console App or what ever in .NET 4.5. The Hub is placed in a MVC4 Website project and is started like this:
GlobalHost.Configuration.ConnectionTimeout = TimeSpan.FromSeconds(50);
RouteTable.Routes.MapHubs();
public class ComputeUnits : Hub
{
public Task Running(Guid MyGuid)
{
return Clients.Group(MyGuid.ToString()).ComputeUnitHeartBeat(MyGuid,
DateTime.UtcNow.ToEpochMilliseconds());
}
public Task ComputeUnitReqister(Guid MyGuid)
{
Groups.Add(Context.ConnectionId, "ComputeUnits").Wait();
return Clients.Others.ComputeUnitCameOnline(new { Guid = MyGuid,
HeartBeat = DateTime.UtcNow.ToEpochMilliseconds() });
}
public void SubscribeToHeartBeats(Guid MyGuid)
{
Groups.Add(Context.ConnectionId, MyGuid.ToString());
}
}
My clients are Javascript clients, that have methods for(let me know if you need to see the code for this also). But basicly they listhen for the ComputeUnitCameOnline and when its run they call on the server SubscribeToHeartBeats. This means that whenever the server compute unit is doing some work it will call Running, which will trigger a ComputeUnitHeartBeat on javascript clients.
I hope you can use this to see how Groups and Connections can be used. And last, its also scaled out over multiply azure roles by adding a few lines of code:
GlobalHost.HubPipeline.EnableAutoRejoiningGroups();
GlobalHost.DependencyResolver.UseServiceBus(
serviceBusConnectionString,
2,
3,
GetRoleInstanceNumber(),
topicPathPrefix /* the prefix applied to the name of each topic used */
);
You can get the connection string on the servicebus on azure, remember the Provider=SharedSecret. But when adding the nuget packaged the connectionstring syntax is also pasted into your web.config.
2 is how many topics to split it about. Topics can contain 1Gb of data, so depending on performance you can increase it.
3 is the number of nodes to split it out on. I used 3 because i have 2 Azure Instances, and my localhost. You can get the RoleNumber like this (note that i hard coded my localhost to 2).
private static int GetRoleInstanceNumber()
{
if (!RoleEnvironment.IsAvailable)
return 2;
var roleInstanceId = RoleEnvironment.CurrentRoleInstance.Id;
var li1 = roleInstanceId.LastIndexOf(".");
var li2 = roleInstanceId.LastIndexOf("_");
var roleInstanceNo = roleInstanceId.Substring(Math.Max(li1, li2) + 1);
return Int32.Parse(roleInstanceNo);
}
You can see it all live at : http://taskqueue.cloudapp.net/#/compute-units
When using SignalR, after a client has connected to the server they are served up a Connection ID (this is essential to providing real time communication). Yes this is stored in memory but SignalR also can be used in multi-node environments. You can use the Redis or even Sql Server backplane (more to come) for example. So long story short, we take care of your scale-out scenarios for you via backplanes/service bus' without you having to worry about it.