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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,98 @@ | ||
| // Install NuGet packages `NATS.Net` and `Microsoft.Extensions.Logging.Console`. | ||
| using NATS.Client.Core; | ||
| using NATS.Client.JetStream; | ||
| using NATS.Client.JetStream.Models; | ||
|
|
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| // `NATS_URL` environment variable can be used to pass the locations of the NATS servers. | ||
| var url = Environment.GetEnvironmentVariable("NATS_URL") ?? "127.0.0.1:4222"; | ||
|
|
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| // Connect to NATS server. Since connection is disposable at the end of our scope we should flush | ||
| // our buffers and close connection cleanly. | ||
| var opts = new NatsOpts | ||
| { | ||
| Url = url, | ||
| Name = "NATS-by-Example", | ||
| }; | ||
| await using var nats = new NatsConnection(opts); | ||
| var js = new NatsJSContext(nats); | ||
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| // ### Stream Setup | ||
| var stream = "list-subjects"; | ||
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| // Remove the stream first!, so we have a clean starting point. | ||
| try | ||
| { | ||
| await js.DeleteStreamAsync(stream); | ||
| } | ||
| catch (NatsJSApiException e) when (e is { Error.Code: 404 }) | ||
| { | ||
| } | ||
|
|
||
| // Create the stream with a variety of subjects | ||
| var streamConfig = new StreamConfig(stream, ["plain", "greater.>", "star.*"]) | ||
| { | ||
| Storage = StreamConfigStorage.Memory, | ||
| }; | ||
| await js.CreateStreamAsync(streamConfig); | ||
|
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| // ### GetStreamAsync with StreamInfoRequest | ||
| // Get the subjects via the GetStreamAsync call. | ||
| // Since this is "state" there are no subjects in the state unless | ||
| // there are messages in the subject. | ||
| // To get the subjects map, you must provide a SubjectsFilter | ||
| // Use the > to filter for all subjects | ||
| var jsStream = await js.GetStreamAsync(stream, new StreamInfoRequest() { SubjectsFilter = ">" }); | ||
| Console.WriteLine($"Before publishing any messages, there are 0 subjects: {jsStream.Info.State.Subjects?.Count}"); | ||
|
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| // Publish a message | ||
| await js.PublishAsync("plain", "plain-data"); | ||
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| jsStream = await js.GetStreamAsync(stream, new StreamInfoRequest() { SubjectsFilter = ">" }); | ||
| Console.WriteLine("After publishing a message to a subject, it appears in state:"); | ||
| if (jsStream.Info.State.Subjects != null) | ||
| { | ||
| foreach (var (subject, count) in jsStream.Info.State.Subjects) | ||
| { | ||
| Console.WriteLine($" Subject '{subject}', Count {count}"); | ||
| } | ||
| } | ||
|
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||
| // Publish some more messages, this time against wildcard subjects | ||
| await js.PublishAsync("greater.A", "gtA"); | ||
| await js.PublishAsync("greater.A.B", "gtAB"); | ||
| await js.PublishAsync("greater.A.B.C", "gtABC"); | ||
| await js.PublishAsync("greater.B.B.B", "gtBBB"); | ||
| await js.PublishAsync("star.1", "star1"); | ||
| await js.PublishAsync("star.2", "star2"); | ||
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| jsStream = await js.GetStreamAsync(stream, new StreamInfoRequest() { SubjectsFilter = ">" }); | ||
| Console.WriteLine("Wildcard subjects show the actual subject, not the template:"); | ||
| if (jsStream.Info.State.Subjects != null) | ||
| { | ||
| foreach (var (subject, count) in jsStream.Info.State.Subjects) | ||
| { | ||
| Console.WriteLine($" Subject '{subject}', Count {count}"); | ||
| } | ||
| } | ||
|
|
||
| // ### Specific Subject Filtering | ||
| // You can filter for a more specific subject | ||
| jsStream = await js.GetStreamAsync(stream, new StreamInfoRequest() { SubjectsFilter = "greater.>" }); | ||
| Console.WriteLine("Filtering the subject returns only matching entries ['greater.>']"); | ||
| if (jsStream.Info.State.Subjects != null) | ||
| { | ||
| foreach (var (subject, count) in jsStream.Info.State.Subjects) | ||
| { | ||
| Console.WriteLine($" Subject '{subject}', Count {count}"); | ||
| } | ||
| } | ||
|
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| jsStream = await js.GetStreamAsync(stream, new StreamInfoRequest() { SubjectsFilter = "greater.A.>" }); | ||
| Console.WriteLine("Filtering the subject returns only matching entries ['greater.A.>']"); | ||
| if (jsStream.Info.State.Subjects != null) | ||
| { | ||
| foreach (var (subject, count) in jsStream.Info.State.Subjects) | ||
| { | ||
| Console.WriteLine($" Subject '{subject}', Count {count}"); | ||
| } | ||
| } |
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examples/jetstream/list-subjects/dotnet2/list-subjects.csproj
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,15 @@ | ||
| <Project Sdk="Microsoft.NET.Sdk"> | ||
|
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| <PropertyGroup> | ||
| <OutputType>Exe</OutputType> | ||
| <TargetFramework>net8.0</TargetFramework> | ||
| <ImplicitUsings>enable</ImplicitUsings> | ||
| </PropertyGroup> | ||
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| <ItemGroup> | ||
| <PackageReference Include="NATS.Net" Version="2.3.1"/> | ||
| <PackageReference Include="NATS.Client.Serializers.Json" Version="2.0.0"/> | ||
| <PackageReference Include="Microsoft.Extensions.Logging.Console" Version="8.0.0" /> | ||
| </ItemGroup> | ||
|
|
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| </Project> |
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