I already have searched for my question on Stack Overflow and on the documentation (https://docs.soliditylang.org/en/develop/contracts.html#visibility-and-getters), but I am not sure of the answer.
To better explain my answer, I have created an example:
pragma solidity ^0.8.17;
contract A{
bool public dummy;
function setDummy (bool x) public{
dummy = x;
}
function getDummy () public view returns(bool){
return dummy;
}
}
contract B {
A public aContract;
function initialize () public{
aContract = new A();
}
}
If I deploy B and call initialize, I can see the address of aContract. This means that I can interact with the aContract(like calling setDummy) without passing by B.
I do not want this behavior!
I would like that only B can call aContract. Does make aContract private solve this problem? Or I need to make some restriction like onlyOwner on setDummy?
I do not know if making aContract private still leave some vulnerabilities.
Thank You!
Using the new keyword in Solidity will create a new instance of your contract just as if you had deployed it from your EOA. There is no solidity language feature to restrict visibility of the deployed contract. You will have to implement yourself the access control you need.
A typical pattern in Solidity is to make the contract have an "owner" which is the only address authorized to call certain functions. For example it can be implemented with the Ownable abstract contract from Openzeppelin.
With the code below the owner will be set by the Ownable constructor to the deployer address, which in your case will be your B contract instance. And the onlyOwner keyword restricts setDummy so that it can only be called by the owner
import "#openzeppelin/contracts/ownership/Ownable.sol";
contract A is Ownable {
bool public dummy;
function setDummy (bool x) public onlyOwner {
dummy = x;
}
function getDummy () public view returns (bool) {
return dummy;
}
}
Related
UPDATE 2: FIXED THE CODE at the end
I have the abp.io service below with 2 parameters in the constructor instantiated via DI.
One of them, IOutcomeWriter, has 2 implementations.
I'd like to define at runtime which of the implementations of IOutcomeWriter to use.
This is the main service:
public class UCManagerService
: DomainService, IUCManagerService, ITransientDependency {
private readonly IUCInputReader _inputReader;
// This field can have 2 or 3 implementations.
private readonly IOutcomeWriter _outcomeWriter;
public UCManagerService(
IUCInputReader inputReader, IOutcomeWriter outcomeWriter) {
_inputReader = inputReader;
_outcomeWriter = outcomeWriter;
}
public async Task ExecuteAsync() {
// start processing the input and generate the output
var input = _inputReader.GetInput());
// do something
// ...
_outcomeWriter.Write(something);
}
}
The main service is registered in the AbpModule together with with IUCInputReader and the 2 implementations of IOutcomeWriter:
[DependsOn(
typeof(SwiftConverterDomainModule),
typeof(AbpAutofacModule) // <= use Autofac in some way (I don't know how)
)]
public class ProgramAppModule : AbpModule {
public override void ConfigureServices(ServiceConfigurationContext context) {
context.Services.AddTransient<IUCManagerService, UCManagerService>();
context.Services.AddTransient<IUCInputReader, UCInputReader>();
// 2 implementations of IOutcomeWriter
context.Services.AddTransient<IOutcomeWriter, OutcomeWriter1>();
context.Services.AddTransient<IOutcomeWriter, OutcomeWriter2>();
}
}
What I would like is to instantiate UCManagerService sometimes with OutcomeWriter1 and sometimes with OutcomeWriter2, according to some values in appsettings.json:
IList<JobSetting> jobsToSet = _configuration.GetSection("Jobs")
.Get<List<JobSetting>>();
foreach (JobSetting jobToSet in jobsToSet) {
// If jobsToSet.SomeValue == 'MyValue1' following line should have to
// require a IUCManagerService using OutcomeWriter1. If it is
// 'MyValue2' it'd use OutcomeWriter2, and so on:
var service = abpApplication.ServiceProvider.GetRequiredService<IUCManagerService>(); // ???
// do something else with service
// ...
}
Finally, if a tomorrow I add an OutcomeWriter3 I would just like to register it in ProgramAppModule.ConfigureServices(...) and of course use a different key in appsettings.json.
If I understand correctly, you need the IOutcomeWriter to differ based on the currently executed job. In other words, that means that you need to dynamically switch the writer based on its context.
The fact that it you need to change it dynamically, it means that is not a problem that can be solved solely using your DI configuration, because DI configurations are best kept static.
Instead, you need to mix and match a few concepts. First of all, you need a way to set the used job in the context. For instance:
// DI configuration
services.AddScoped<JobContext>();
// Execution of a job
using (var scope = abpApplication.ServiceProvider.CreateScope())
{
var context = scope.GetRequiredService<JobContext>();
context.CurrentJob = typeof(MyFirstJob);
var job = scope.GetRequiredService<MyFirstJob>();
var job.Execute();
}
In this example, JobContext is a class that holds the data that is used during the execution of a certain job. It is registered as Scoped to allow this data to be available for multiple classes within the same scope.
Now using this new JobContext, you can build an adapter for IOutcomeWriter that can forward the incoming call to the right implementation based on its injected JobContext. This might look as follows:
public class JobSpecificOutcomeWriter : IOutcomeWriter
{
private readonly JobContext context;
private readonly IList<JobSetting> settings;
private readonly IEnumerable<IOutcomeWriter> writers;
public JobSpecificOutcomeWriter(
JobContext context,
IList<JobSetting> settings,
IEnumerable<IOutcomeWriter> writers)
{
this.context = context;
this.settings = settings;
this.writers = writers;
}
// Implement all IOutcomeWriter methods by forwarding them to the
// CurrentWriter.
object IOutcomeWriter.SomeMethod(object a) =>
this.CurrentWriter.SomeMethod(a);
private IOutcomeWriter CurrentWriter
{
get
{
// TODO: Based on the current context and the settings,
// select the proper outcome writer from the writers list.
}
}
}
When JobSpecificOutcomeWriter is injected into UCManagerService (or any component for that matter), it transparently allows the proper writer to be used, without the consuming class from knowing about this.
The tricky part, actually, is to now configure your DI container correctly using JobSpecificOutcomeWriter. Depending on which DI Container you use, your mileage might vary and with the MS.DI Container, this is actually quite complicated.
services.AddTransient<IOutcomeWriter>(c =>
new JobSpecificOutcomeWriter(
context: c.GetRequiredService<JobContext>(),
settings: jobsToSet,
writers: new IOutcomeWriter[]
{
c.GetRequiredService<MyFirstJob>(),
c.GetRequiredService<MySecondJob>(),
c.GetRequiredService<MyThirdJob>(),
});
services.AddTransient<MyFirstJob>();
services.AddTransient<MySecondJob>();
services.AddTransient<MyThirdJob>();
New to WebFlux, reactive, and handlers.
I am able to get a Mono<> from a ServerRequest and process the contained POJO to add a new tuple to a database. But, it seems like there should be a "better" or "more accepted" way to write this code.
Any help/input with the code in AccountRequestHandler would be appreciated, especially with explanations of the rationale behind the recommend change(s).
Router implementation (stripped down to only "POST")...
#Configuration
public class AccountRequestRouter {
#Bean
public RouterFunction<ServerResponse> route(AccountRequestHandler requestHandler) {
return nest(path("/v2"),
nest(accept(APPLICATION_JSON),
.andRoute(RequestPredicates.POST("/accounts"), requestHandler::addAccount)
));
}
}
Handler implementation...
The code where I'm actually doing the add, and then separately creating a ServerResponse, is what I'm focused on. It seems "clunky", especially since AccountService.addAccount() returns a Mono on completion.
#Component
public class AccountRequestHandler {
#Autowired
private mil.navy.ccop.service.accounts.account.AccountService accountService;
public Mono<ServerResponse> addAccount(ServerRequest request) {
return request.bodyToMono(Account.class).flatMap(account -> {
accountService.addAccount(account);
return ServerResponse.ok().build();
})
.switchIfEmpty(ServerResponse.badRequest()
.contentType(APPLICATION_JSON)
.build(Mono.empty()));
}
}
AccountService implementation (again, stripped down)...
#Service
class AccountService {
#Autowired
private AccountRepository accounts;
public AccountService() {
}
public Mono<Void> addAccount(Account account) {
Account proxy;
// make sure that accountId is set to support auto-generation of synthetic key value
proxy = new Account(-1, account.getShortName(), account.getLongName(), account.getDescription());
accounts.save(proxy);
return Mono.empty();
}
}
Appreciating all the help in ramping up on this style of programming....
well first of all, you have 2 addAccount, that can be a bit confusing.
Second of all, what kind of "repository" are you writing too? if its an sql repo you need to properly wrap it in a Mono.fromCallable() otherwise it will block the Reactive thread pool and you can have really bad performance.
Yes there are other ways of doing things. A lot of people tend to do things in flatmap or map and sure it is completely possible to do things here, but for the semantics i'd say it is less good.
map and flatmap are usually used to perform some sort of computation on the inner value of the mono and then return the same or a new value and or type inside the mono.
i would rewrite this like such.
return void here:
public void addAccount(Account account) {
Account proxy;
// make sure that accountId is set to support auto-generation of synthetic key value
proxy = new Account(-1, account.getShortName(), account.getLongName(), account.getDescription());
accounts.save(proxy);
}
And here:
public Mono<ServerResponse> addAccount(ServerRequest request) {
return request.bodyToMono(Account.class)
.doOnSuccess(account -> {
accountService.addAccount(account);
}).then(ServerResponse.ok().build())
.switchIfEmpty(ServerResponse.badRequest()
.contentType(APPLICATION_JSON)
.build());
}
there are a number of different doOn methods that are ment to be used to consume and do "side effects" on things. Like doOnSuccess, doOnError, doOnCancel etc. etc.
you also have then and thenReturn which will just return whatever you put in them. Then returns whatever Mono you put in it. thenReturn wraps whatever value you put into it into a Mono and returns it.
I have an aggregate root like this:
Aggregate root:
#NoArgsConstructor
#Aggregate(repository = "positionAggregateRepository")
#AggregateRoot
#XSlf4j
#Data
public class HopAggregate {
#AggregateIdentifier
private String hopId;
private FilteredPosition position;
private LocalDate positionDate;
#AggregateMember
private Security security;
#CommandHandler
public HopAggregate(NewHopCommand cmd) {
log.info("creating new position , {}", cmd.getDateId());
apply(new HopEvent(cmd.getHopId(), cmd.getDateId(), cmd.getFilteredPosition(), cmd.getSecurity(), false));
}
#CommandHandler
public void handle(UpdateHopCommand cmd) {
log.info("creating hop update event {}", cmd);
apply(new HopEvent(this.hopId, this.positionDate, cmd.getFilteredPosition(), this.security, true));
}
#CommandHandler
public void handle(SecurityUpdate cmd) {
log.info("updating security {}", cmd);
apply(new SecurityUpdateEvent(this.hopId, cmd.getFilteredSecurity()));
}
#EventSourcingHandler
public void on(HopEvent evt) {
if (evt.getIsUpdate()) {
log.info("updating position {}", evt);
this.position = evt.getFilteredPosition();
} else {
log.info("adding new position to date {}", evt);
this.hopId = evt.getHopId();
this.positionDate = evt.getDate();
this.position = evt.getFilteredPosition();
this.security= evt.getSecurity();
}
}
#EventSourcingHandler
public void on(SecurityUpdateEvent evt) {
log.info("hop id {}, security update {}", this.hopId, evt.getFilteredSecurity().getSecurityId());
}
}
Child entity:
#XSlf4j
#Data
#RequiredArgsConstructor
#NoArgsConstructor
public class IpaSecurity implements Serializable {
#EntityId
#NonNull
private String id;
#NonNull
private FilteredSecurity security;
}
My issue is that when i am pushing and update like this:
#EventHandler
public void handleSecurityEvent(SecurityUpdate securityUpdate) {
log.info("got security event {}", securityUpdate);
commandGateway.send(securityUpdate);
}
and my command being:
#Data
#RequiredArgsConstructor
#NoArgsConstructor
#ToString
public class SecurityUpdate {
#NonNull
#TargetAggregateIdentifier
private String id;
#NonNull
private FilteredSecurity filteredSecurity;
}
I am getting aggregate root not found exception:
Command 'com.hb.apps.ipa.events.SecurityUpdate' resulted in org.axonframework.modelling.command.AggregateNotFoundException(The aggregate was not found in the event store)
I am not sure how to handle this scenario. My requirement is that each aggregate should check whether it contains the security and then update it if the command was issued. What am i missing? let me know if you need any more info on the code.
Thanks for your help.
A Command is always targeted towards a single entity.
This entity can be an Aggregate, an entity contained in an Aggregate (what Axon Framework calls an Aggregate Member) or a simple singleton component.
Important to note though, is that there will only be one entity handling the command.
This is what requires you to set the #TargetAggregateIdentifier in your Command for Axon to be able to route it to a single Aggregate instance if the Command Handler in question is part of it.
The AggregateNotFoundException you're getting signals that the #TargetAggregateIdentifier annotated field in your SecurityUpdate command does no correspond to any existing Aggregate.
I'd thus suspect that the id field in the SecurityUpdate does not correspond to any #AggregateIdentifier annotated field in your HopAggregate aggregates.
A part from the above, I have a couple of other suggestions when looking at your snippets which I'd like to share with you:
#Aggregate is meta-annotated with #AggregateRoot. You're thus not required to specify both on an Aggregate class
For logging messages being handled, you can utilize LoggingInterceptor. You can configure this on any component capable of handling messages, thus providing a universal way of logging. This will omit the necessity to add log lines in your message handling functions
You're publishing a HopEvent on both the create and update commands. Doing so makes your HopEvent very generic. Ideally, your events clarify business operations occurring in your system. My rule of thumb typically is such: "If I tell my business manager/customer about the event class, he/she should know exactly what it does". I'd thus suggest to rename the event to something more specific
Just as with the HopEvent, the UpdateHopCommand is quite generic. Your commands should express the intent to perform an operation in your application. Users will typically not desire an update, they desire an address change for example. Your commands classes ideally reflect this
The suggested naming convention for commands is to start with verb in the present tense. Thus, it should no be SecurityUpdate, but UpdateSecurity. A command is a request expressing intent, the messages ideally reflect this
Hope this helps you out #juggernaut!
I'm pretty new to MVVM light world, and after searches I can't find what I want to do.
My WP7 application contains a pivot, each pivot item content is View1 and viewmodel is VM1.
When loading my application, I'd like to create every pivot item with the same view and view model but with different parameter.
example :
PivotItem 1 -> send param "car" to the view model
PivotItem 2 -> send param "truck" to the view model, etc.
Google told me to use messaging but if I send 2 messages from my MainViewModel, both PivotItem1 and PivotItem2 ViewModel will receive these messages.
Am I wrong with this approach ?
Is there another solution to succeed ?
Thank you in advance for your answer.
PS : be indulgent, english is not my native language, don't hesitate to ask for further information.
Regards,
Aymeric Lagier
To seperate the messages use the second constructor signature whereby you can pass a token. This token can be anything but I generally use an enum to store all my message types within the system.
Create a static class in a common library and reference this in all projects where you need to send or receive messages.
The following code hopefully shows this approach, notice I am sending a string as a value within the message but this can be anything, even a complex object such as one of your business objects.
namespace MyProject.Common
{
public static class AppMessages
{
enum MessageTypes
{
ViewmodelA,
ViewmodelB
}
public static class ViewModelAUpdate
{
public static void Send(string value)
{
Messenger.Default.Send(value, MessageTypes.ViewmodelA);
}
public static void Register(object recipient, Action<string> action)
{
Messenger.Default.Register(recipient, MessageTypes.ViewmodelA, action);
}
}
public static class ViewModelBUpdate
{
public static void Send(string value)
{
Messenger.Default.Send(value, MessageTypes.ViewmodelB);
}
public static void Register(object recipient, Action<string> action)
{
Messenger.Default.Register(recipient, MessageTypes.ViewmodelB, action);
}
}
}
}
How about using a method to set the message you want to receive. (this could be done as a parameter in the constructor or a property as well)
public void RegisterForAppMessage(AppMessages.MessageTypes messageType)
{
switch (messageType)
{
case AppMessages.MessageTypes.PivotViewItem1Message:
AppMessages.PivotViewItem1Message.Register(this,DoSomethingWhenIRecievePivotViewItem1Messages)
break;
case AppMessages.MessageTypes.PivotViewItem2Message:
AppMessages.PivotViewItem2Message.Register(this,DoSomethingWhenIRecievePivotViewItem2Messages)
break;
}
}
private void DoSomethingWhenIRecievePivotViewItem2Messages(string obj)
{
// TODO: Implement this method
throw new NotImplementedException();
}
private void DoSomethingWhenIRecievePivotViewItem1Messages(string obj)
{
// TODO: Implement this method
throw new NotImplementedException();
}
Messaging sounds a bit heavy for this purpose. Could you simply inject a parameter into your ViewModel. If you already have MVVMLight you also have support for SimpleIOC. Maybe let the view locate its ViewModel when the view is resolved and there decide which parameter to use on the view model?
You can see an example of it here
I begin studying Unit testing with "(NUnit)". I know that this type of testing is used to test "classes" , "functions" and the "interaction between those functions".
In my case I develop "asp.net web applications".
How can i use this testing to test my
pages(as it is considered as a class
and the methods used in)and in which sequence?, i have three layers:
Interface layer(the .cs of each page).
Data access layer(class for each entity)(DAL).
Database layer (which contains connection to the database,open connection,close connection,....etc).
Business layer(sometimes to make calculation or some separate logic).
How to test the methods that make connection to the database?
How to make sure that my testing not a waste of time?.
There are unit and integration tests. Unit testing is testing single components/classes/methods/functions and interaction between them but with only one real object (system under test-SUT) and test doubles. Test doubles can be divided to stubs and mocks. Stubs provide prepared test data to SUT. That way you isolate SUT from the environment. So You don't have to hit database, web or wcf services and so on and you have same input data every time. Mocks are used to verify that SUT works as expected. SUT calls methods on mock object not even knowing it is not real object. Then You verify that SUT works by asserting on mock object. You can write stubs and mocks by hand or use one of many mocking frameworks. One of which is http://code.google.com/p/moq/
If You want to test interaction w/database that's integration testing and generally is a lot harder. For integration testing You have to setup external resources in well known state.
Let's take your layers:
You won't be able to unit test it. Page is to tightly coupled to ASP.NET runtime. You should try to not have much code in code behind. Just call some objects from your code behind and test those objects. You can look at MVC design patters. If You must test Your page You should look at http://watin.org/. It automates Your internet browser, clicks buttons on page and verifies that page displays expected result's.
This is integration testing. You put data in database, then read it back and compare results. After test or before test You have to bring test database to well known state so that tests are repeatable. My advice is to setup database before test runs rather then after test runs. That way You will be able to check what's in database after test fails.
I don't really know how that differs from that in point no. 2.
And this is unit testing. Create object in test, call it's methods and verify results.
How to test methods that make connections to the database is addresed in point 2.
How to not waste time? That will come with experience. I don't have general advice other then don't test properties that don't have any logic in it.
For great info about unit testing look here:
http://artofunittesting.com/
http://www.amazon.com/Test-Driven-Development-Kent-Beck/dp/0321146530
http://www.amazon.com/Growing-Object-Oriented-Software-Guided-Tests/dp/0321503627/ref=sr_1_2?ie=UTF8&s=books&qid=1306787051&sr=1-2
http://www.amazon.com/xUnit-Test-Patterns-Refactoring-Code/dp/0131495054/ref=sr_1_1?ie=UTF8&s=books&qid=1306787051&sr=1-1
Edit:
SUT, CUT - System or Class under test. That's what You test.
Test doubles - comes from stunt doubles. They do dangerous scenes in movies so that real actors don't have to. Same here. Test doubles replace real objects in tests so that You can isolate SUT/CUT in tests from environment.
Let's look at this class
public class NotTestableParty
{
public bool ShouldStartPreparing()
{
if (DateTime.Now.Date == new DateTime(2011, 12, 31))
{
Console.WriteLine("Prepare for party!");
return true;
}
Console.WriteLine("Party is not today");
return false;
}
}
How will You test that this class does what it should on New Years Eve? You have to do it on New Years Eve :)
Now look at modified Party class
Example of stub:
public class Party
{
private IClock clock;
public Party(IClock clock)
{
this.clock = clock;
}
public bool ShouldStartPreparing()
{
if (clock.IsNewYearsEve())
{
Console.WriteLine("Prepare for party!");
return true;
}
Console.WriteLine("Party is not today");
return false;
}
}
public interface IClock
{
bool IsNewYearsEve();
}
public class AlwaysNewYearsEveClock : IClock
{
public bool IsNewYearsEve()
{
return true;
}
}
Now in test You can pass the fake clock to Party class
var party = new Party(new AlwaysNewYearsEveClock());
Assert.That(party.ShouldStartPreparing(), Is.True);
And now You know if Your Party class works on New Years Eve. AlwaysNewYearsEveClock is a stub.
Now look at this class:
public class UntestableCalculator
{
private Logger log = new Logger();
public decimal Divide(decimal x, decimal y)
{
if (y == 0m)
{
log.Log("Don't divide by 0");
}
return x / y;
}
}
public class Logger
{
public void Log(string message)
{
// .. do some logging
}
}
How will You test that Your class logs message. Depending on where You log it You have to check the file or database or some other place. That wouldn't be unit test but integration test. In order to unit test You do this.
public class TestableCalculator
{
private ILogger log;
public TestableCalculator(ILogger logger)
{
log = logger;
}
public decimal Divide(decimal x, decimal y)
{
if (y == 0m)
{
log.Log("Don't divide by 0");
}
return x / y;
}
}
public interface ILogger
{
void Log(string message);
}
public class FakeLogger : ILogger
{
public string LastLoggedMessage;
public void Log(string message)
{
LastLoggedMessage = message;
}
}
And in test You can
var logger = new FakeLogger();
var calculator = new TestableCalculator(logger);
try
{
calculator.Divide(10, 0);
}
catch (DivideByZeroException ex)
{
Assert.That(logger.LastLoggedMessage, Is.EqualTo("Don't divide by 0"));
}
Here You assert on fake logger. Fake logger is mock object.