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Topic template extension maintenance (#2022)

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* Topic templates: Ensure parameter values are checked for wildcard

* Topic templates: Complement extension methods

- add template.BuildMessage()
- add subscribeOptionsBuilder.WithTopicTemplate()

* Topic templates: switch some samples to use a topic template

The changes should be self-explanatory and are
intended to provide more examples.

* Topic templates: add README
This commit is contained in:
simonthum
2024-06-22 14:54:11 +02:00
committed by GitHub
parent 8650002523
commit c5f4cf1f9b
10 changed files with 264 additions and 54 deletions
Download Patch File Download Diff File Expand all files Collapse all files
Samples/Client/Client_Subscribe_Samples.cs
+13 -30
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@@ -8,6 +8,7 @@
// ReSharper disable UnusedMember.Local
using MQTTnet.Client;
using MQTTnet.Extensions.TopicTemplate;
using MQTTnet.Packets;
using MQTTnet.Protocol;
using MQTTnet.Samples.Helpers;
@@ -16,6 +17,8 @@ namespace MQTTnet.Samples.Client;
public static class Client_Subscribe_Samples
{
static MqttTopicTemplate sampleTemplate = new MqttTopicTemplate("mqttnet/samples/topic/{id}");
public static async Task Handle_Received_Application_Message()
{
/*
@@ -42,11 +45,7 @@ public static class Client_Subscribe_Samples
await mqttClient.ConnectAsync(mqttClientOptions, CancellationToken.None);
var mqttSubscribeOptions = mqttFactory.CreateSubscribeOptionsBuilder()
.WithTopicFilter(
f =>
{
f.WithTopic("mqttnet/samples/topic/2");
})
.WithTopicTemplate(sampleTemplate.WithParameter("id", "2"))
.Build();
await mqttClient.SubscribeAsync(mqttSubscribeOptions, CancellationToken.None);
@@ -88,11 +87,8 @@ public static class Client_Subscribe_Samples
await mqttClient.ConnectAsync(mqttClientOptions, CancellationToken.None);
var mqttSubscribeOptions = mqttFactory.CreateSubscribeOptionsBuilder()
.WithTopicFilter(
f =>
{
f.WithTopic("mqttnet/samples/topic/1");
})
.WithTopicTemplate(
sampleTemplate.WithParameter("id", "1"))
.Build();
var response = await mqttClient.SubscribeAsync(mqttSubscribeOptions, CancellationToken.None);
@@ -121,21 +117,12 @@ public static class Client_Subscribe_Samples
// Create the subscribe options including several topics with different options.
// It is also possible to all of these topics using a dedicated call of _SubscribeAsync_ per topic.
var mqttSubscribeOptions = mqttFactory.CreateSubscribeOptionsBuilder()
.WithTopicFilter(
f =>
{
f.WithTopic("mqttnet/samples/topic/1");
})
.WithTopicFilter(
f =>
{
f.WithTopic("mqttnet/samples/topic/2").WithNoLocal();
})
.WithTopicFilter(
f =>
{
f.WithTopic("mqttnet/samples/topic/3").WithRetainHandling(MqttRetainHandling.SendAtSubscribe);
})
.WithTopicTemplate(
sampleTemplate.WithParameter("id", "1"))
.WithTopicTemplate(
sampleTemplate.WithParameter("id", "2"), noLocal: true)
.WithTopicTemplate(
sampleTemplate.WithParameter("id", "3"), retainHandling: MqttRetainHandling.SendAtSubscribe)
.Build();
var response = await mqttClient.SubscribeAsync(mqttSubscribeOptions, CancellationToken.None);
@@ -162,11 +149,7 @@ public static class Client_Subscribe_Samples
await mqttClient.ConnectAsync(mqttClientOptions, CancellationToken.None);
var mqttSubscribeOptions = mqttFactory.CreateSubscribeOptionsBuilder()
.WithTopicFilter(
f =>
{
f.WithTopic("mqttnet/samples/topic/1");
})
.WithTopicTemplate(sampleTemplate.WithParameter("id", "1"))
.Build();
var response = await mqttClient.SubscribeAsync(mqttSubscribeOptions, CancellationToken.None);
Samples/MQTTnet.Samples.csproj
+1
View File
@@ -17,6 +17,7 @@
<ProjectReference Include="..\Source\MQTTnet.AspnetCore\MQTTnet.AspNetCore.csproj" />
<ProjectReference Include="..\Source\MQTTnet.Extensions.ManagedClient\MQTTnet.Extensions.ManagedClient.csproj" />
<ProjectReference Include="..\Source\MQTTnet.Extensions.Rpc\MQTTnet.Extensions.Rpc.csproj" />
<ProjectReference Include="..\Source\MQTTnet.Extensions.TopicTemplate\MQTTnet.Extensions.TopicTemplate.csproj" />
<ProjectReference Include="..\Source\MQTTnet.Extensions.WebSocket4Net\MQTTnet.Extensions.WebSocket4Net.csproj" />
<ProjectReference Include="..\Source\MQTTnet\MQTTnet.csproj" />
</ItemGroup>
Source/MQTTnet.Extensions.TopicTemplate/MQTTnet.Extensions.TopicTemplate.csproj
+7 -3
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@@ -11,10 +11,10 @@
<Company>The contributors of MQTTnet</Company>
<Product>MQTTnet</Product>
<Description>
This is an extension library which provides mqtt topic templating logic to support dispatch,
routing and similar functionality based on the well known moustache syntax, aka
AsyncAPI dynamic channel address.
Provides mqtt topic templating logic to support dispatch,
routing and similar functionality based on the well known moustache syntax (AsyncAPI compatible).
</Description>
<PackageReadmeFile>README.md</PackageReadmeFile>
<Authors>The contributors of MQTTnet</Authors>
<PackageId>MQTTnet.Extensions.TopicTemplate</PackageId>
<SignAssembly>false</SignAssembly>
@@ -51,6 +51,10 @@
</PropertyGroup>
<ItemGroup>
<None Include="README.md">
<Pack>True</Pack>
<PackagePath>\</PackagePath>
</None>
<None Include="..\..\Images\nuget.png">
<Pack>True</Pack>
<PackagePath>\</PackagePath>
Source/MQTTnet.Extensions.TopicTemplate/MqttTopicTemplate.cs
+18 -6
View File
@@ -16,8 +16,8 @@ namespace MQTTnet.Extensions.TopicTemplate
/// segments in curly braces called parameters. This well-known
/// 'moustache' syntax also matches AsyncAPI Channel Address Expressions.
/// The topic template is designed to support dynamic subscription/publication,
/// message-topic matching and routing. It is intended to be more convenient
/// than String.Format() for aforementioned purposes.
/// message-topic matching and routing. It is intended to be more safe and
/// convenient than String.Format() for aforementioned purposes.
/// </summary>
/// <example>
/// topic/subtopic/{parameter}/{otherParameter}
@@ -282,12 +282,17 @@ namespace MQTTnet.Extensions.TopicTemplate
/// <returns>the topic template (without the parameter)</returns>
public MqttTopicTemplate WithoutParameter(string parameter)
{
return WithParameter(parameter, MqttTopicFilterComparer.SingleLevelWildcard.ToString());
if (string.IsNullOrEmpty(parameter) || !_parameterSegments.Contains(parameter))
{
throw new ArgumentException("topic template parameter must exist.");
}
return ReplaceInternal(parameter, MqttTopicFilterComparer.SingleLevelWildcard.ToString());
}
/// <summary>
/// Substitute a parameter with a given value, thus removing the parameter. If the parameter is not present,
/// the method trows. The value must not contain slashes.
/// the method trows. The value must not contain slashes or wildcards.
/// </summary>
/// <param
/// name="parameter">
@@ -304,12 +309,19 @@ namespace MQTTnet.Extensions.TopicTemplate
/// <returns>the topic template (without the parameter)</returns>
public MqttTopicTemplate WithParameter(string parameter, string value)
{
if (value == null || string.IsNullOrEmpty(parameter) || !_parameterSegments.Contains(parameter) || value.Contains(MqttTopicFilterComparer.LevelSeparator) ||
if (value == null || string.IsNullOrEmpty(parameter) || !_parameterSegments.Contains(parameter) ||
value.Contains(MqttTopicFilterComparer.LevelSeparator) ||
value.Contains(MqttTopicFilterComparer.SingleLevelWildcard) ||
value.Contains(MqttTopicFilterComparer.MultiLevelWildcard))
{
throw new ArgumentException("parameter must exist and value must not contain slashes.");
throw new ArgumentException("parameter must exist and value must not contain slashes or wildcard.");
}
return ReplaceInternal(parameter, value);
}
private MqttTopicTemplate ReplaceInternal(string parameter, string value)
{
var moustache = "{" + parameter + "}";
return new MqttTopicTemplate(Template.Replace(moustache, value));
}
Source/MQTTnet.Extensions.TopicTemplate/README.md
+79
View File
@@ -0,0 +1,79 @@
# MQTTNet.Extensions.TopicTemplate
Provides mqtt topic templating logic to support dispatch, routing and
similar functionality based on the well known moustache syntax, aka
AsyncAPI dynamic channel address.
Generating and parsing MQTT topics and topic filters is often done in
an ad-hoc fashion, leading to error-prone code and subtly introduced
showstoppers like forgetting to strip a slash from a parameter. To
remedy, this extension aids you write safe, maintainable logic
for topic generation, routing and dispatch.
## How it works
The package lets you write MQTTNet code like:
```csharp
var template = new MqttTopicTemplate("App/v1/{sender}/message");
var filter = new MqttTopicFilterBuilder()
.WithTopicTemplate(template) // (1)
.WithAtLeastOnceQoS()
.WithNoLocal()
.Build();
// filter.Topic == "App/v1/+/message"
var myTopic = template
.WithParameter("sender", "me, myself & i"); // (2)
var message = new MqttApplicationMessageBuilder()
.WithTopicTemplate( // (3)
myTopic)
.WithPayload("Hello!")
.Build();
// message.Topic == "App/v1/me, myself & i/message"
Assert.IsTrue(message.MatchesTopicTemplate(template)); // (4)
```
At (1), the parameter "sender" was automatically replaced by a plus sign
(single level wildcard) because the caller is creating a topic filter.
Using the same template (they are immutable), you can send
a message. At (2), we replace the parameter with a known value.
If that value contained a level separator or topic filter only
characters, we'd get an ArgumentException. If we forgot to replace
the parameter "sender" (e.g. when placing template not myTopic),
we would be prevented from sending at (3).
On the receiving side, a message can be matched to a template
using code like at (4).
These daily tasks become much safer and easier to code than
string.Format() and Split() allow for. More elaborate computation is supported
too. You could extract the sender using the template or route
messages based on topic content.
## Features
- Safe handling of topic parameters in moustache syntax
- Simplifies topic generation and parsing logic
- Match topics and extract the values of their parameters
- Translate between topic templates to ease dynamic routing
- Derive a canonical topic filter from a bunch of templates
- Integrates with MQTTNet message, subscription and filter builders
- Extension method friendly (sealed class with one public ctor)
## Additional documentation
- Some of the [unit tests](https://github.com/dotnet/MQTTnet/blob/master/Source/MQTTnet.Tests/Extensions/MqttTopicTemplate_Tests.cs) are instructive
- Some examples feature the extension, e.g. TopicGenerator, Client_Subscribe_Samples
## Feedback
Report any issues with the main project on https://github.com/dotnet/MQTTnet/issues
Source/MQTTnet.Extensions.TopicTemplate/TopicTemplateExtensions.cs
+43
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@@ -4,6 +4,8 @@
using System;
using System.Linq;
using MQTTnet.Client;
using MQTTnet.Packets;
using MQTTnet.Protocol;
namespace MQTTnet.Extensions.TopicTemplate
@@ -55,6 +57,24 @@ namespace MQTTnet.Extensions.TopicTemplate
return new MqttTopicFilterBuilder().WithTopicTemplate(topicTemplate, subscribeTreeRoot);
}
/// <summary>
/// Create a message builder from this template. The template must not have
/// remaining parameters.
/// </summary>
/// <param
/// name="topicTemplate">
/// a parameterless topic template
/// </param>
/// <returns>a new message builder</returns>
/// <exception
/// cref="ArgumentException">
/// if the topic template has parameters
/// </exception>
public static MqttApplicationMessageBuilder BuildMessage(this MqttTopicTemplate topicTemplate)
{
return new MqttApplicationMessageBuilder().WithTopicTemplate(topicTemplate);
}
/// <summary>
/// Return a message builder to respond to this message. The
/// message's response topic and correlation data are included
@@ -116,6 +136,29 @@ namespace MQTTnet.Extensions.TopicTemplate
return builder.WithTopic(subscribeTreeRoot ? topicTemplate.TopicTreeRootFilter : topicTemplate.TopicFilter);
}
/// <summary>
/// Set the subscription to the template's topic filter.
/// </summary>
/// <returns>the builder</returns>
public static MqttClientSubscribeOptionsBuilder WithTopicTemplate(
this MqttClientSubscribeOptionsBuilder builder,
MqttTopicTemplate topicTemplate,
MqttQualityOfServiceLevel qualityOfServiceLevel = MqttQualityOfServiceLevel.AtMostOnce,
bool noLocal = false,
bool retainAsPublished = false,
MqttRetainHandling retainHandling = MqttRetainHandling.SendAtSubscribe)
{
return builder.WithTopicFilter(
new MqttTopicFilter
{
Topic = topicTemplate.TopicFilter,
QualityOfServiceLevel = qualityOfServiceLevel,
NoLocal = noLocal,
RetainAsPublished = retainAsPublished,
RetainHandling = retainHandling
});
}
/// <summary>
/// Set the publication topic according to the topic template. The template
/// must not have remaining (unset) parameters or contain wildcards.
Source/MQTTnet.TestApp/MQTTnet.TestApp.csproj
+1
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@@ -21,6 +21,7 @@
<ProjectReference Include="..\..\Source\MQTTnet.Extensions.ManagedClient\MQTTnet.Extensions.ManagedClient.csproj" />
<ProjectReference Include="..\..\Source\MQTTnet.Extensions.WebSocket4Net\MQTTnet.Extensions.WebSocket4Net.csproj" />
<ProjectReference Include="..\..\Source\MQTTnet\MQTTnet.csproj" />
<ProjectReference Include="..\MQTTnet.Extensions.TopicTemplate\MQTTnet.Extensions.TopicTemplate.csproj" />
</ItemGroup>
</Project>
Source/MQTTnet.TestApp/TopicGenerator.cs
+18 -4
View File
@@ -1,6 +1,6 @@
using System;
using System.Collections.Generic;
using System.Text;
using MQTTnet.Extensions.TopicTemplate;
namespace MQTTnet.TestApp
{
@@ -17,6 +17,8 @@ namespace MQTTnet.TestApp
singleWildcardTopicsByPublisher = new Dictionary<string, List<string>>();
multiWildcardTopicsByPublisher = new Dictionary<string, List<string>>();
MqttTopicTemplate baseTemplate = new MqttTopicTemplate("{publisher}/{building}/{level}/{sensor}");
// Find some reasonable distribution across three topic levels
var topicsPerLevel = (int)Math.Pow(numTopicsPerPublisher, (1.0 / 3.0));
@@ -40,25 +42,37 @@ namespace MQTTnet.TestApp
int publisherTopicCount = 0;
var publisherName = "pub" + p;
var publisherTemplate = baseTemplate
.WithParameter("publisher", publisherName);
for (var l1 = 0; l1 < numLevel1Topics; ++l1)
{
var l1Template = publisherTemplate
.WithParameter("building", "building" + (l1 + 1));
for (var l2 = 0; l2 < numLevel2Topics; ++l2)
{
var l2Template = l1Template
.WithParameter("level", "level" + (l2 + 1));
for (var l3 = 0; l3 < maxNumLevel3Topics; ++l3)
{
if (publisherTopicCount >= numTopicsPerPublisher)
break;
var topic = string.Format("{0}/building{1}/level{2}/sensor{3}", publisherName, l1 + 1, l2 + 1, l3 + 1);
var topic = l2Template
.WithParameter("sensor", "sensor" + (l3 + 1))
.TopicFilter;
AddPublisherTopic(publisherName, topic, topicsByPublisher);
if (l2 == 0)
{
var singleWildcardTopic = string.Format("{0}/building{1}/+/sensor{2}", publisherName, l1 + 1, l3 + 1);
var singleWildcardTopic = l1Template
.WithParameter("sensor", "sensor" + (l3 + 1))
.TopicFilter;
AddPublisherTopic(publisherName, singleWildcardTopic, singleWildcardTopicsByPublisher);
if (l1 == 0)
{
var multiWildcardTopic = string.Format("{0}/+/level{1}/+", publisherName, l3 + 1);
var multiWildcardTopic = publisherTemplate
.WithParameter("sensor", "sensor" + (l3 + 1))
.TopicFilter;
AddPublisherTopic(publisherName, multiWildcardTopic, multiWildcardTopicsByPublisher);
}
}
Source/MQTTnet.Tests/Extensions/MqttTopicTemplate_Tests.cs
+67 -7
View File
@@ -46,6 +46,29 @@ namespace MQTTnet.Tests.Extensions
template.WithParameter("foo", "a#");
}
[TestMethod]
[ExpectedException(typeof(ArgumentException))]
public void RejectsReservedChars2()
{
var template = new MqttTopicTemplate("A/B/{foo}/D");
template.WithParameter("foo", "a+b");
}
[TestMethod]
[ExpectedException(typeof(ArgumentException))]
public void RejectsReservedChars3()
{
var template = new MqttTopicTemplate("A/B/{foo}/D");
template.WithParameter("foo", "a/b");
}
[TestMethod]
public void AcceptsEmptyValue()
{
var template = new MqttTopicTemplate("A/B/{foo}/D");
template.WithParameter("foo", "");
}
[TestMethod]
[ExpectedException(typeof(MqttProtocolViolationException))]
public void RejectsEmptyTemplate()
@@ -60,13 +83,6 @@ namespace MQTTnet.Tests.Extensions
var _ = new MqttTopicTemplate(null);
}
[TestMethod]
[ExpectedException(typeof(ArgumentException))]
public void RejectsReservedChars2()
{
var template = new MqttTopicTemplate("A/B/{foo}/D");
template.WithParameter("foo", "e/f");
}
[TestMethod]
public void IgnoresEmptyParameters()
@@ -114,6 +130,50 @@ namespace MQTTnet.Tests.Extensions
Assert.AreEqual("A/v1/+/F", filter.Topic);
}
[TestMethod]
public void SubscriptionSupport2()
{
var template = new MqttTopicTemplate("A/v1/{param}/F");
var subscribeOptions = new MqttFactory().CreateSubscribeOptionsBuilder()
.WithTopicTemplate(template)
.WithSubscriptionIdentifier(5)
.Build();
Assert.AreEqual("A/v1/+/F", subscribeOptions.TopicFilters[0].Topic);
}
[TestMethod]
public void SendAndSubscribeSupport()
{
var template = new MqttTopicTemplate("App/v1/{sender}/message");
var filter = new MqttTopicFilterBuilder()
.WithTopicTemplate(template)
.WithAtLeastOnceQoS()
.WithNoLocal()
.Build();
Assert.AreEqual("App/v1/+/message", filter.Topic);
var myTopic = template.WithParameter("sender", "me, myself & i");
var message = new MqttApplicationMessageBuilder()
.WithTopicTemplate(
myTopic)
.WithPayload("Hello!")
.Build();
Assert.IsTrue(message.MatchesTopicTemplate(template));
}
[TestMethod]
public void SendAndSubscribeSupport2()
{
var template = new MqttTopicTemplate("App/v1/{sender}/message");
Assert.ThrowsException<ArgumentException>(() =>
template.BuildMessage());
}
[TestMethod]
public void CanonicalPrefixFilter()
{
Source/MQTTnet.Tests/TopicGenerator.cs
+17 -4
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@@ -1,5 +1,6 @@
using System;
using System.Collections.Generic;
using MQTTnet.Extensions.TopicTemplate;
namespace MQTTnet.Tests
{
@@ -32,30 +33,42 @@ namespace MQTTnet.Tests
maxNumLevel3Topics = 1;
}
MqttTopicTemplate baseTemplate = new MqttTopicTemplate("{publisher}/{building}/{level}/{sensor}");
for (var p = 0; p < numPublishers; ++p)
{
int publisherTopicCount = 0;
var publisherName = "pub" + p;
var publisherTemplate = baseTemplate
.WithParameter("publisher", publisherName);
for (var l1 = 0; l1 < numLevel1Topics; ++l1)
{
var l1Template = publisherTemplate.WithParameter("building", "building" + (l1 + 1));
for (var l2 = 0; l2 < numLevel2Topics; ++l2)
{
var l2Template = l1Template.WithParameter("level", "level" + (l2 + 1));
for (var l3 = 0; l3 < maxNumLevel3Topics; ++l3)
{
if (publisherTopicCount >= numTopicsPerPublisher)
break;
var topic = string.Format("{0}/building{1}/level{2}/sensor{3}", publisherName, l1 + 1, l2 + 1, l3 + 1);
AddPublisherTopic(publisherName, topic, topicsByPublisher);
var l3Template = l2Template
.WithParameter("sensor", "sensor" + (l3 + 1));
AddPublisherTopic(publisherName, l3Template.TopicFilter, topicsByPublisher);
if (l2 == 0)
{
var singleWildcardTopic = string.Format("{0}/building{1}/+/sensor{2}", publisherName, l1 + 1, l3 + 1);
var singleWildcardTopic = l1Template
.WithParameter("sensor", "sensor" + (l3 + 1))
.TopicFilter;
AddPublisherTopic(publisherName, singleWildcardTopic, singleWildcardTopicsByPublisher);
}
if ((l1 == 0) && (l3 == 0))
{
var multiWildcardTopic = string.Format("{0}/+/level{1}/+", publisherName, l2 + 1);
var multiWildcardTopic = publisherTemplate
.WithParameter("level", "level" + (l2 + 1))
.TopicFilter;
AddPublisherTopic(publisherName, multiWildcardTopic, multiWildcardTopicsByPublisher);
}