I'm starting out with SignalR and I have a situation where I'm going to have a SignalR site that will be broadcasting messages to clients, but I also need an admin interface that will actually trigger those messages. The admin page will call server side methods that will, in turn, call client side Javascript methods for regular users. So I'm thinking I can either set up two separate hubs (one for admin, one for everybody else) or I can have methods in a single hub that can only be called by the admin that will check authorization.
But in addition to the authorization, I'd like to have SignalR not include admin methods or an admin hub in the generated Javascript proxy classes so that I'm not advertising their existence (again - this is NOT the only security, I will be checking authorization). Is there an attribute or property I can set on individual hubs or on methods within a hub that will suppress them from being included in the proxy (but still have them callable from Javascript)? I know you can set EnableJavaScriptProxies to false in your HubConfiguration, but that seems to be global and I'd like to keep the proxy for the stuff I do want the regular client to be using.
There is one trick using interfaces. As proxy will generate only public methods in proxy, you can create hub using interface like this:
public class MyHub : Hub, IMyHub
{
void IMyHub.NotGeneratedOnClient()
{
}
public void GeneratedOnClient()
{
}
}
NotGeneratedOnClient method will not be visible if you use object of type MyHub, you can access it only using interface. As method is not public proxy generator is not going to add it to client proxy
We don't have a way of excluding specific methods from the proxy today. You'd have to re-implement your own proxy generator that basically does what we do in our default impl but has knowledge of some attribute to skip generation of specific methods.
We can conceivable add this in a future version of SignalR. File an issue on github if you feel strongly about having this.
Here's the default implementation (it would have been easier if we made more methods virtual and non static).
https://github.com/SignalR/SignalR/blob/master/src/Microsoft.AspNet.SignalR.Core/Hubs/DefaultJavaScriptProxyGenerator.cs
Here is a modified DefaultJavaScriptProxyGenerator with the following changes:
It will exclude functions from Javascript proxy generation with a new [HubMethodExcludeFromProxy] attribute.
The private static functions have changed to protected virtual for future derivatives.
The GenerateProxy( ) function has an overload to include DocComments, but that was not caching the results like the non DocComments version. Now they both cache.
Two resources, Resources.DynamicComment_CallsMethodOnServerSideDeferredPromise and Resources.DynamicComment_ServerSideTypeIs were private to another assembly, so to get things to compile, I copied the text from the resource file directly. These two resources are only used if DocComments is true.
All of the DefaultJavaScriptProxyGenerator references were changed to CustomJavaScriptProxyGenerator except for one, which is used to locate the resource script Microsoft.AspNet.SignalR.Scripts.hubs.js, located in a different assembly.
First, you will need to update the dependency resolver to use the new CustomJavaScriptProxyGenerator for the IJavaScriptProxyGenerator interface. If you are using the default resolver, you can set up a custom resolver like this:
map.RunSignalR(
new HubConfiguration() {
Resolver = new CustomDependencyResolver()
}
);
And here is a custom resolver that derives from the DefaultDependecyResolver:
namespace Microsoft.AspNet.SignalR
{
public class CustomDependencyResolver : DefaultDependencyResolver
{
MyDependencyResolver() : base()
{
var proxyGenerator = new Lazy(() => new CustomJavaScriptProxyGenerator(this));
Register(typeof(IJavaScriptProxyGenerator), () => proxyGenerator.Value);
}
}
}
And finally, here is the new CustomJavaScriptProxyGenerator.cs file (the HubMethodExcludeFromProxyAttribute class is at the bottom):
// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
// Mods by Brain2000
using System;
using System.Collections;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Text;
using Microsoft.AspNet.SignalR.Json;
using Microsoft.AspNet.SignalR.Hubs;
using Newtonsoft.Json;
namespace Microsoft.AspNet.SignalR.Hubs
{
public class CustomJavaScriptProxyGenerator : IJavaScriptProxyGenerator
{
protected static readonly Lazy _templateFromResource = new Lazy(GetTemplateFromResource);
protected static readonly Type[] _numberTypes = new[] { typeof(byte), typeof(short), typeof(int), typeof(long), typeof(float), typeof(decimal), typeof(double) };
protected static readonly Type[] _dateTypes = new[] { typeof(DateTime), typeof(DateTimeOffset) };
protected const string ScriptResource = "Microsoft.AspNet.SignalR.Scripts.hubs.js";
protected readonly IHubManager _manager;
protected readonly IJavaScriptMinifier _javaScriptMinifier;
protected readonly Lazy _generatedTemplate;
protected readonly Lazy _generatedTemplateWithComments;
public CustomJavaScriptProxyGenerator(IDependencyResolver resolver) :
this(resolver.Resolve(),
resolver.Resolve())
{
}
public CustomJavaScriptProxyGenerator(IHubManager manager, IJavaScriptMinifier javaScriptMinifier)
{
_manager = manager;
_javaScriptMinifier = javaScriptMinifier ?? NullJavaScriptMinifier.Instance;
_generatedTemplate = new Lazy(() => GenerateProxy(_manager, _javaScriptMinifier, includeDocComments: false));
_generatedTemplateWithComments = new Lazy(() => GenerateProxy(_manager, _javaScriptMinifier, includeDocComments: true));
}
public string GenerateProxy(string serviceUrl)
{
serviceUrl = JavaScriptEncode(serviceUrl);
return _generatedTemplate.Value.Replace("{serviceUrl}", serviceUrl);
}
public string GenerateProxy(string serviceUrl, bool includeDocComments)
{
if (!includeDocComments) return GenerateProxy(serviceUrl); //use the includeDocComments: false cached version
serviceUrl = JavaScriptEncode(serviceUrl);
return _generatedTemplateWithComments.Value.Replace("{serviceUrl}", serviceUrl);
}
protected virtual string GenerateProxy(IHubManager hubManager, IJavaScriptMinifier javaScriptMinifier, bool includeDocComments)
{
string script = _templateFromResource.Value;
var hubs = new StringBuilder();
var first = true;
foreach (var descriptor in hubManager.GetHubs().OrderBy(h => h.Name))
{
if (!first)
{
hubs.AppendLine(";");
hubs.AppendLine();
hubs.Append(" ");
}
GenerateType(hubManager, hubs, descriptor, includeDocComments);
first = false;
}
if (hubs.Length > 0)
{
hubs.Append(";");
}
script = script.Replace("/*hubs*/", hubs.ToString());
return javaScriptMinifier.Minify(script);
}
protected virtual void GenerateType(IHubManager hubManager, StringBuilder sb, HubDescriptor descriptor, bool includeDocComments)
{
// Get only actions with minimum number of parameters.
var methods = GetMethods(hubManager, descriptor);
var hubName = GetDescriptorName(descriptor);
sb.AppendFormat(" proxies['{0}'] = this.createHubProxy('{1}'); ", hubName, hubName).AppendLine();
sb.AppendFormat(" proxies['{0}'].client = {{ }};", hubName).AppendLine();
sb.AppendFormat(" proxies['{0}'].server = {{", hubName);
bool first = true;
foreach (var method in methods)
{
if (!first)
{
sb.Append(",").AppendLine();
}
GenerateMethod(sb, method, includeDocComments, hubName);
first = false;
}
sb.AppendLine();
sb.Append(" }");
}
protected virtual string GetDescriptorName(Descriptor descriptor)
{
if (descriptor == null)
{
throw new ArgumentNullException("descriptor");
}
string name = descriptor.Name;
// If the name was not specified then do not camel case
if (!descriptor.NameSpecified)
{
name = JsonUtility.CamelCase(name);
}
return name;
}
protected virtual IEnumerable GetMethods(IHubManager manager, HubDescriptor descriptor)
{
return from method in manager.GetHubMethods(descriptor.Name).Where(md => md.Attributes.FirstOrDefault(a => (a.GetType() == typeof(HubMethodExcludeFromProxyAttribute))) == null)
group method by method.Name into overloads
let oload = (from overload in overloads
orderby overload.Parameters.Count
select overload).FirstOrDefault()
orderby oload.Name
select oload;
}
protected virtual void GenerateMethod(StringBuilder sb, MethodDescriptor method, bool includeDocComments, string hubName)
{
var parameterNames = method.Parameters.Select(p => p.Name).ToList();
sb.AppendLine();
sb.AppendFormat(" {0}: function ({1}) {{", GetDescriptorName(method), Commas(parameterNames)).AppendLine();
if (includeDocComments)
{
sb.AppendFormat(" /// Calls the {0} method on the server-side {1} hub.\nReturns a jQuery.Deferred() promise.", method.Name, method.Hub.Name).AppendLine();
var parameterDoc = method.Parameters.Select(p => String.Format(CultureInfo.CurrentCulture, " /// Server side type is {2}", p.Name, MapToJavaScriptType(p.ParameterType), p.ParameterType)).ToList();
if (parameterDoc.Any())
{
sb.AppendLine(String.Join(Environment.NewLine, parameterDoc));
}
}
sb.AppendFormat(" return proxies['{0}'].invoke.apply(proxies['{0}'], $.merge([\"{1}\"], $.makeArray(arguments)));", hubName, method.Name).AppendLine();
sb.Append(" }");
}
protected virtual string MapToJavaScriptType(Type type)
{
if (!type.IsPrimitive && !(type == typeof(string)))
{
return "Object";
}
if (type == typeof(string))
{
return "String";
}
if (_numberTypes.Contains(type))
{
return "Number";
}
if (typeof(IEnumerable).IsAssignableFrom(type))
{
return "Array";
}
if (_dateTypes.Contains(type))
{
return "Date";
}
return String.Empty;
}
protected virtual string Commas(IEnumerable values)
{
return Commas(values, v => v);
}
protected virtual string Commas(IEnumerable values, Func selector)
{
return String.Join(", ", values.Select(selector));
}
protected static string GetTemplateFromResource()
{
//this must remain "DefaultJavaScriptProxyGenerator" because the resource "Microsoft.AspNet.SignalR.Scripts.hubs.js" lives there
using (Stream resourceStream = typeof(DefaultJavaScriptProxyGenerator).Assembly.GetManifestResourceStream(ScriptResource))
{
var reader = new StreamReader(resourceStream);
return reader.ReadToEnd();
}
}
protected virtual string JavaScriptEncode(string value)
{
value = JsonConvert.SerializeObject(value);
// Remove the quotes
return value.Substring(1, value.Length - 2);
}
}
[AttributeUsage(AttributeTargets.Method, Inherited = false, AllowMultiple = false)]
public sealed class HubMethodExcludeFromProxyAttribute : Attribute
{
}
}
Now all you need to do is all a decorator to your hub methods, such as:
public class MyHub : Hub
{
[HubMethodExcludeFromProxy]
public void NotGeneratedOnClient()
{
}
public void GeneratedOnClient()
{
}
}
EDIT : There is an issue with dependency injection where if you have two different instances of a resolver, one in the GlobalHost.DependencyResolver and one in the Signalr configuration, it will cause remote methods to sometimes not work. Here is the fix:
//use only !ONE! instance of the resolver, or remote SignalR functions may not run!
var resolver = new CustomDependencyResolver();
GlobalHost.Configuration.DependencyResolver = resolver;
map.RunSignalR(
new HubConfiguration() {
Resolver = resolver;
}
);
Reference: https://github.com/SignalR/SignalR/issues/2807
Related
Is there any way to get the version_name based on the version_code of an android package?
For example:
'com.nianticlabs.pokemongo'
version_code: 2017121800
=> version_name: 0.87.5
all I want is something like:
function getVersionName(version_code) {
// do smt with version_code
return version_name;
}
But I don't think you can get one depending on the other, those are two separate things: only a string and an int
In native java you have:
public static int getVersionCode(Context context) {
try {
PackageInfo pInfo = context.getPackageManager().getPackageInfo(context.getPackageName(), 0);
return pInfo.versionCode;
} catch (PackageManager.NameNotFoundException e) {
return -1;
}
}
public static String getVersionName(Context context) {
try {
PackageInfo pInfo = context.getPackageManager().getPackageInfo(context.getPackageName(), 0);
return pInfo.versionName;
} catch (PackageManager.NameNotFoundException e) {
return "";
}
}
you could look for the equivalent in your javascript google API
Easiest way to get version name:
private String getVersionName() {
versionName = BuildConfig.VERSION_NAME;
return versionName;
}
No this is not possible in general. Every app is completely free to choose it's own version name (user readable string) and version code scheme. Many apps will have two APKs which have different version codes with exactly the same version name. See the docs.
(I'm new to Signalr)
I'm developing an web application which uses Signalr-core to update the page in realtime.
The problem i walk into is that when i run multiple clients the method i'm running wil run as many times at once as there are clients.
so i want to know if there is any way to make the first client call the hub method and then keep it running and broadcasting to all connected clients.
this is what i'm doing with my client:
connection.on('update', (id, Color) => {
var x = document.getElementById(id);
if (Color === "green" && x.classList.contains("red"))
{
//console.log("green");
x.classList.remove("red");
x.classList.add("green");
}
else if (Color === "red" && x.classList.contains("green"))
{
//console.log("Red");
x.classList.remove("green");
x.classList.add("red");
}});
connection.start()
.then(() => connection.invoke('updateclient', updating));
and this is what i'm doing with my hub:
public void UpdateClient(bool updating)//this must run only once
{
while (updating == true)
{
Thread.Sleep(2000);
foreach (var item in _context.Devices)
{
IPHostEntry hostEntry = Dns.GetHostEntry(item.DeviceName);
IPAddress[] ips = hostEntry.AddressList;
foreach (IPAddress Ip in ips)
{
Ping MyPing = new Ping();
PingReply reply = MyPing.Send(Ip, 500);
if (reply.Status == IPStatus.Success)
{
Color = "green";
Clients.All.InvokeAsync("update", item.DeviceID, Color);
break;
}
else
{
Color = "red";
Clients.All.InvokeAsync("update", item.DeviceID, Color);
}
}
}
}
}
please let me know if i'm unclear about something.
and thank you in advance.
As I mention in the comment, you can invoke UpdateClient method on first appearance of any client. The option I came up with is as follows;
It is quite common to use a static list for clients connected to hub
public static class UserHandler
{
public static List<string> UserList = new List<string>();
}
In your hub, override OnConnected and OnDisconnected methods to add/remove clients to/from the list and define the very first client connected to hub for your purpose.
public class MyHub : Hub
{
private static IHubContext context = GlobalHost.ConnectionManager.GetHubContext<MyHub>();
public override Task OnConnected()
{
//Here check the list if this is going to be our first client and if so call your method, next time because our list is filled your method won't be invoked.
if(UserHandler.UserList.Count==0)
UpdateClient(true);
UserHandler.UserList.Add(Context.ConnectionId)
return base.OnConnected();
}
public override Task OnDisconnected(bool stopCalled)
{
UserHandler.UserList.RemoveAll(u => u.ConnectionId == Context.ConnectionId);
return base.OnDisconnected(stopCalled);
}
}
I didn't take your business logic or your needings into consideration, this is just a general idea. For example, you might want to add some logic for when all the clients goes off, you should stop the loop inside UpdateClient with using updating flag.
Why I'm getting this error?
System.InvalidCastException was unhandled by user code
Message=Specified cast is not valid.
Source=System.Windows.Forms
StackTrace:
at System.Windows.Forms.UnsafeNativeMethods.IHTMLDocument2.GetLocation()
at System.Windows.Forms.WebBrowser.get_Document()
at System.Windows.Forms.WebBrowser.get_DocumentStream()
at System.Windows.Forms.WebBrowser.get_DocumentText()
at SiteBot.MainWindow.backgroundWorker1_DoWork(Object sender, DoWorkEventArgs e) in D:\Documents\Visual Studio 2010\Projects\SiteBot\MainWindow.cs:line 35
at System.ComponentModel.BackgroundWorker.OnDoWork(DoWorkEventArgs e)
at System.ComponentModel.BackgroundWorker.WorkerThreadStart(Object argument)
InnerException:
The following solves your cross thread issue.
public delegate string GetStringHandler();
public string GetDocumentText()
{
if (InvokeRequired)
return Invoke(new GetStringHandler(GetDocumentText)) as string;
else
return webBrowser.DocumentText;
}
if (regAddId.IsMatch(GetDocumentText()))
{
}
I get a threading exception with this test:
public class Test
{
private readonly WebBrowser wb;
public Test()
{
wb = new WebBrowser();
var bw = new BackgroundWorker();
bw.DoWork += DoWork;
bw.RunWorkerAsync();
while (bw.IsBusy)
{
Thread.Sleep(10);
Application.DoEvents();
}
}
private void DoWork(object sender, DoWorkEventArgs e)
{
wb.Navigate(#"www.clix-cents.com/pages/clickads");
Thread.Sleep(1000);
var regex = new Regex("onclick=\\'openad\\(\"([\\d\\w]+\"\\);");
regex.IsMatch(wb.DocumentText);
}
}
public class Program
{
[STAThread]
public static void Main(string[] args)
{
new Test();
}
}
The exception looks like this:
Since WebBrowser is really just a wrapper around IE's ActiveX control, you'll need to be careful about threading issues. I think what you really want to use here is a WebClient and not a WebBrowser, but I'm just guessing about your application.
[EDIT]
Like #Fun states you can just Invoke over to the GUI thread (assuming thats where the control was created. I'd still recommend using a WebClient.
I was allowed to run the zxcvbn.js (Javascript library) to Nashorn.
But there is one problem.
eval (pre-compile) is very slow. It takes about 3 minutes.
I want to move more quickly.
public class StrengthChecker {
private static final String ZXCVBN_PATH = "/META-INF/resources/webjars/zxcvbn/1.0/zxcvbn.js";
private final ScriptEngine engine;
public StrengthChecker() {
ScriptEngineManager manager = new ScriptEngineManager();
engine = manager.getEngineByName("nashorn");
Bindings engineScope = engine.getBindings(ScriptContext.ENGINE_SCOPE);
engineScope.put("window", engineScope);
try {
// -------------------------------------------
// Here is very slow definition of zxcvbn.js.
// -------------------------------------------
engine.eval(getResourceContents(ZXCVBN_PATH));
} catch (ScriptException e) {
throw new RuntimeException(e);
}
}
public Strength check(String pw) {
try {
Map<String, Object> result;
result = (Map<String, Object>) engine.eval("zxcvbn('" + pw + "');");
return new Strength(
((Double) result.get("entropy")).intValue(),
(int) result.get("score"),
((Double) result.get("crack_time")).intValue()
);
} catch (ScriptException e) {
throw new RuntimeException(e);
}
}
}
Please tell us something solution.
This is a known performance bug that has been fixed, see https://bugs.openjdk.java.net/browse/JDK-8137333. It should be released with Java 8u72, slated for January 2016. Pre-release builds of Java 9 available at https://jdk9.java.net/download/ also contain the fix (since JDK9 build b85).
What are the best practices to build an app's database schema on first execution?
In other words what I am trying to find out is:
SQLite does not support comma separated queries to be executed as a one statement batch. How to replace that so that the code stays future proof? (I don't see myself putting all the create statements in tx.executeSQL("") chained sequentially it would turn my code into a horrible piece of cr*p).
What I do, in native code as well as in Sencha/Phonegap is to use a DatabaseHelper Class that I refer to. In that class you can see the version of the Database with :
public DataBaseHelper(Context context) {
super(context, DB_NAME, null, 2);
this.myContext = context;
}
public void createDataBase() throws IOException {
boolean dbExist = checkDataBase();
if (dbExist) {
// do nothing - database already exist
openDataBase();
int cVersion = myDataBase.getVersion();
if(cVersion != 2){
onUpgrade(myDataBase, myDataBase.getVersion(), 2);}
close();
} ....}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
this.getReadableDatabase();
try{
db.execSQL("ADD SQL QUERY HERE TO ADD TABLE");
}
catch(Exception e){}
}
private boolean checkDataBase() {
SQLiteDatabase checkDB = null;
try {
String myPath = DB_PATH + DB_NAME;
checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READWRITE);
} catch (SQLiteException e) {
// database does't exist yet.
}
if (checkDB != null) {
checkDB.close();
}
return checkDB != null ? true : false;
}
Although this is tedious it keeps your database future proof and the query is called at run time. This covers both your needs.
I hope this helps :)