Write up documentation on posthog-dotnet

contents/docs/experiments/adding-experiment-code.mdx

@@ -149,6 +149,14 @@ if feature_flag.enabled == "variant-name" do
 end
 ```
 
+```dotnet
+var featureFlag = await posthog.GetFeatureFlagAsync("experiment-feature-flag-key", "user_distinct_id");
+
+if (featureFlag is { VariantKey: "variant-name" })
+{
+    // Do something
+}
+```
 </MultiLanguage>
 
 > Since feature flags are not supported yet in our Java and Rust SDKs, to run an experiment using these SDKs see our docs on [how to run experiments without feature flags](/docs/experiments/running-experiments-without-feature-flags). This also applies to running experiments using our API.
@@ -230,6 +238,13 @@ posthog.capture(
 );
 ```
 
+```dotnet
+posthog.Capture(
+    "distinct_id",
+    "event_name_of_your_goal_metric",
+    properties: new() { ["$feature/experiment-feature-flag-key"] = "variant-name" }
+);
+```
 </MultiLanguage>
 
 import Tab from "components/Tab"
@@ -238,6 +253,7 @@ import NodeMethod2 from "../integrate/feature-flags-code/_snippets/feature-flags
 import GoMethod2 from "../integrate/feature-flags-code/_snippets/feature-flags-code-go-set-send-feature-flags-to-true.mdx"
 import PythonMethod2 from "../integrate/feature-flags-code/_snippets/feature-flags-code-python-set-send-feature-flags-to-true.mdx"
 import PHPMethod2 from "../integrate/feature-flags-code/_snippets/feature-flags-code-php-set-send-feature-flags-to-true.mdx"
+import DotNetMethod2 from "../integrate/feature-flags-code/_snippets/feature-flags-code-dotnet-set-send-feature-flags-to-true.mdx"
 
 ### Method 2: Set `send_feature_flags` to `true`
 
@@ -265,5 +281,8 @@ import PHPMethod2 from "../integrate/feature-flags-code/_snippets/feature-flags-
         <Tab.Panel>
             <GoMethod2 />
         </Tab.Panel>
+        <Tab.Panel>
+            <DotNetMethod2 />
+        </Tab.Panel>
     </Tab.Panels>
 </Tab.Group>

contents/docs/experiments/installation.mdx

@@ -30,9 +30,10 @@ import ReactNativeInstall from '../integrate/_snippets/install-react-native.mdx'
 import AndroidInstall from '../integrate/_snippets/install-android.mdx'
 import IOSInstall from '../integrate/_snippets/install-ios.mdx'
 import ElixirInstall from '../integrate/_snippets/install-elixir.mdx'
+import DotNetInstall from '../integrate/_snippets/install-dotnet.mdx'
 
 <!-- prettier-ignore -->
-<Tab.Group tabs={['Web', 'React', 'Node.js', 'Python', 'PHP', 'Ruby', 'Go', 'React Native', 'Android', 'iOS', 'Java', 'Rust', 'Elixir', 'api']}>
+<Tab.Group tabs={['Web', 'React', 'Node.js', 'Python', 'PHP', 'Ruby', 'Go', 'React Native', 'Android', 'iOS', 'Java', 'Rust', 'Elixir', '.NET', 'api']}>
     <Tab.List>
         <Tab>Web</Tab>
         <Tab>React</Tab>
@@ -47,6 +48,7 @@ import ElixirInstall from '../integrate/_snippets/install-elixir.mdx'
         <Tab>Java</Tab>
         <Tab>Rust</Tab>
         <Tab>Elixir</Tab>
+        <Tab>.NET</Tab>
         <Tab>API</Tab>
     </Tab.List>
     <Tab.Panels>
@@ -93,6 +95,9 @@ import ElixirInstall from '../integrate/_snippets/install-elixir.mdx'
         <Tab.Panel>
             <ElixirInstall />
         </Tab.Panel>
+        <Tab.Panel>
+            <DotNetInstall />
+        </Tab.Panel>
         <Tab.Panel>
             <blockquote class='warning-note'>
                 To run an experiment using the <a href="/docs/api">PostHog API</a>, see our docs on <a href="/docs/experiments/running-experiments-without-feature-flags">how to run experiments without feature flags</a>. 

contents/docs/experiments/running-experiments-without-feature-flags.mdx

@@ -123,6 +123,16 @@ posthog.capture(
 );
 ```
 
+```csharp
+posthog.Capture(
+  "distinct_id",
+  "event_name_of_your_goal_metric",
+  properties: new() {
+    ["$feature/experiment-feature-flag-key"] = "variant-name"
+  }
+);
+```
+
 </MultiLanguage>
 
 ## Step 4 (optional): Send the `$feature_flag_called` event
@@ -245,4 +255,15 @@ posthog.capture(
 );
 ```
 
+```csharp
+posthog.Capture(
+    "distinct_id",
+    "$feature_flag_called",
+    properties: new() {
+        ["$feature_flag_response"] = "variant-name",
+        ["feature_flag"] = "feature-flag-key"
+    }
+);
+```
+
 </MultiLanguage>

contents/docs/feature-flags/adding-feature-flag-code.mdx

@@ -25,9 +25,10 @@ import AndroidFeatureFlagsCode from '../integrate/feature-flags-code/_snippets/f
 import IOSFeatureFlagsCode from '../integrate/feature-flags-code/_snippets/feature-flags-code-ios.mdx'
 import FlutterFeatureFlagsCode from '../integrate/feature-flags-code/_snippets/feature-flags-code-flutter.mdx'
 import ElixirFeatureFlagsCode from '../integrate/feature-flags-code/_snippets/feature-flags-code-elixir.mdx'
+import DotNetFeatureFlagsCode from '../integrate/feature-flags-code/_snippets/feature-flags-code-dotnet.mdx'
 
 <!-- prettier-ignore -->
-<Tab.Group tabs={['Web', 'React', 'Node.js', 'Python', 'PHP', 'Ruby', 'Go', 'React Native', 'Android', 'iOS', 'Flutter', 'Java', 'Rust', 'Elixir', 'api']}>
+<Tab.Group tabs={['Web', 'React', 'Node.js', 'Python', 'PHP', 'Ruby', 'Go', 'React Native', 'Android', 'iOS', 'Flutter', 'Java', 'Rust', 'Elixir', '.NET', 'api']}>
     <Tab.List>
         <Tab>Web</Tab>
         <Tab>React</Tab>
@@ -43,6 +44,7 @@ import ElixirFeatureFlagsCode from '../integrate/feature-flags-code/_snippets/fe
         <Tab>Java</Tab>
         <Tab>Rust</Tab>
         <Tab>Elixir</Tab>
+        <Tab>.NET</Tab>
         <Tab>API</Tab>
     </Tab.List>
     <Tab.Panels>
@@ -92,6 +94,9 @@ import ElixirFeatureFlagsCode from '../integrate/feature-flags-code/_snippets/fe
         <Tab.Panel>
             <ElixirFeatureFlagsCode />
         </Tab.Panel>
+        <Tab.Panel>
+            <DotNetFeatureFlagsCode />
+        </Tab.Panel>
         <Tab.Panel>
             <APIFeatureFlagsCode />
         </Tab.Panel>

contents/docs/feature-flags/installation.mdx

@@ -31,9 +31,10 @@ import JavaInstall from '../integrate/_snippets/install-java.mdx'
 import RustInstall from '../integrate/_snippets/install-rust.mdx'
 import FlutterInstall from '../integrate/_snippets/install-flutter.mdx'
 import ElixirInstall from '../integrate/_snippets/install-elixir.mdx'
+import DotNetInstall from '../integrate/_snippets/install-dotnet.mdx'
 
 <!-- prettier-ignore -->
-<Tab.Group tabs={['Web', 'React', 'Node.js', 'Python', 'PHP', 'Ruby', 'Go', 'React Native', 'Android', 'iOS', 'Java', 'Rust', 'Flutter', 'Elixir', 'api']}>
+<Tab.Group tabs={['Web', 'React', 'Node.js', 'Python', 'PHP', 'Ruby', 'Go', 'React Native', 'Android', 'iOS', 'Java', 'Rust', 'Flutter', 'Elixir', '.NET', 'api']}>
     <Tab.List>
         <Tab>Web</Tab>
         <Tab>React</Tab>
@@ -49,6 +50,7 @@ import ElixirInstall from '../integrate/_snippets/install-elixir.mdx'
         <Tab>Rust</Tab>
         <Tab>Flutter</Tab>
         <Tab>Elixir</Tab>
+        <Tab>.NET</Tab>
         <Tab>API</Tab>
     </Tab.List>
     <Tab.Panels>
@@ -98,6 +100,9 @@ import ElixirInstall from '../integrate/_snippets/install-elixir.mdx'
         <Tab.Panel>
             <ElixirInstall />
         </Tab.Panel>
+        <Tab.Panel>
+            <DotNetInstall />
+        </Tab.Panel>
         <Tab.Panel>
             <APIInstall />
             <blockquote>

contents/docs/integrate/_snippets/install-dotnet.mdx

@@ -0,0 +1,55 @@
+<DotNetInstall />
+
+At the moment, ASP.NET Core is the only supported platform for the PostHog .NET SDK.
+
+```bash
+dotnet add package PostHog.AspNetCore
+```
+
+In your `Program.cs` file, add the following code:
+
+```csharp
+using PostHog.AspNetCore;
+
+var builder = WebApplication.CreateBuilder(args);
+
+builder.AddPostHog();
+```
+
+Make sure to configure PostHog with your project API key, instance address, and optional personal API key. For example, in appsettings.json:
+
+```json
+{
+  "PostHog": {
+    "ProjectApiKey": "phc_...",
+    "Host": "https://us.i.posthog.com"
+  }
+}
+```
+
+> **Note:** If the host is not specified, the default host `https://us.i.posthog.com` is used.
+
+Use a secrets manager to store your personal API key. For example, when developing locally you can use the `UserSecrets` feature of the `dotnet` CLI:
+
+```bash
+dotnet user-secrets init
+dotnet user-secrets set "PostHog:PersonalApiKey" "phc_..."
+```
+
+You can find your project API key and instance address in the [project settings](https://app.posthog.com/project/settings) page in PostHog.
+
+To see detailed logging, set the log level to `Debug` or `Trace` in `appsettings.json`:
+
+```json
+{
+  "DetailedErrors": true,
+  "Logging": {
+    "LogLevel": {
+      "Default": "Information",
+      "Microsoft.AspNetCore": "Warning",
+      "PostHog": "Trace"
+    }
+  },
+  ...
+}
+```

contents/docs/integrate/feature-flags-code/_snippets/feature-flags-code-dotnet-set-send-feature-flags-to-true.mdx

@@ -0,0 +1,13 @@
+The `Capture()` method has an optional argument `sendFeatureFlags`, which is set to `false` by default. By setting this to `true`, feature flag information will automatically be sent with the event.
+
+Note that by doing this, PostHog will make an additional request to fetch feature flag information before capturing the event. So this method is only recommended if you don't mind the extra API call and delay.
+
+```csharp
+posthog.Capture(
+    "distinct_id_of_your_user",
+    "event_name",
+    properties: null,
+    groups: null,
+    sendFeatureFlags: true
+);
+```

contents/docs/integrate/feature-flags-code/_snippets/feature-flags-code-dotnet.mdx

@@ -0,0 +1,119 @@
+There are 2 steps to implement feature flags in .NET:
+
+### Step 1: Evaluate the feature flag value
+
+#### Boolean feature flags
+
+```csharp
+var isMyFlagEnabled = await posthog.IsFeatureEnabledAsync(
+    "flag-key",
+    "distinct_id_of_your_user"
+);
+if (isMyFlagEnabled.GetValueOrDefault())
+{
+    // Feature is enabled
+}
+else
+{
+    // Feature is disabled    
+}
+```
+
+> **Note:** The `IsFeatureEnabledAsync` method returns a nullable boolean. If the flag is not found or evaluating it is inconclusive, it returns `null`.
+
+#### Multivariate feature flags
+
+```csharp
+var flag = await posthog.GetFeatureFlagAsync(
+    "flag-key",
+    "distinct_id_of_your_user"
+);
+
+// replace "variant-key" with the key of your variant
+if (flag is { VariantKey: "variant-key"} ) {
+    // Do something differently for this user
+    // Optional: fetch the payload
+    var matchedPayload = flag.Payload;
+}
+```
+
+The `GetFeatureFlagAsync` method returns a nullable `FeatureFlag` object. If the flag is not found or evaluating it is inconclusive, it returns `null`. However, there is an implicit conversion to bool to make comparisons easier.
+
+```csharp
+if (await posthog.GetFeatureFlagAsync(
+    "flag-key",
+    "distinct_id_of_your_user")
+)
+{
+    // Do something differently for this user
+}
+```
+
+import IncludePropertyInEvents from "./include-feature-flag-property-in-backend-events.mdx" 
+
+<IncludePropertyInEvents />
+
+There are two methods you can use to include feature flag information in your events:
+
+#### Method 1: Include the `$feature/feature_flag_name` property
+
+ In the event properties, include `$feature/feature_flag_name: variant_key`:
+
+```csharp
+posthog.Capture(
+    "distinct_id_of_your_user",
+    "event_name",
+    properties: new() {
+        // replace feature-flag-key with your flag key.
+        // Replace 'variant-key' with the key of your variant
+        ["$feature/feature-flag-key"] = "variant-key"
+    }
+);
+```
+
+#### Method 2: Set `send_feature_flags` to `true`
+
+import DotNetSetSendFeatureFlagsTrue from "./feature-flags-code-dotnet-set-send-feature-flags-to-true.mdx" 
+
+<DotNetSetSendFeatureFlagsTrue />
+
+### Fetching all flags for a user
+
+You can fetch all flag values for a single user by calling `GetAllFeatureFlagsAsync()`.
+
+This is useful when you need to fetch multiple flag values and don't want to make multiple requests.
+
+```csharp  
+var flags = await posthog.GetAllFeatureFlagsAsync(
+    "distinct_id_of_your_user"
+);
+```
+
+### Sending `$feature_flag_called` events
+
+Capturing `$feature_flag_called` events enable PostHog to know when a flag was accessed by a user and thus provide [analytics and insights](/docs/product-analytics/insights) on the flag. By default, we send a these event when:
+
+1. You call `posthog.GetFeatureFlagAsync()` or `posthog.IsFeatureEnabledAsync()`, AND 
+2. It's a new user, or the value of the flag has changed. 
+
+> *Note:* Tracking whether it's a new user or if a flag value has changed happens in a local cache. This means that if you reinitialize the PostHog client, the cache resets as well – causing `$feature_flag_called` events to be sent again when calling `GetFeatureFlagAsync` or `IsFeatureEnabledAsync`. PostHog is built to handle this, and so duplicate `$feature_flag_called` events won't affect your analytics.
+
+You can disable automatically the additional request to capture `$feature_flag_called` events. For example, when you don't need the analytics, or it's being called at such a high volume that sending events slows things down.
+
+To disable it, set the `sendFeatureFlagsEvent` option in your function call, like so:
+
+```csharp
+var isMyFlagEnabled = await posthog.IsFeatureEnabledAsync(
+    "flag-key", 
+    "distinct_id_of_your_user",
+    options: new FeatureFlagOptions
+    {
+        SendFeatureFlagEvents = true
+    }
+);
+// will not send `$feature_flag_called` events
+```
+
+import DotNetOverrideServerProperties from './override-server-properties/dotnet.mdx'
+
+<DotNetOverrideServerProperties />

contents/docs/integrate/feature-flags-code/_snippets/override-server-properties/dotnet.mdx

@@ -0,0 +1,31 @@
+import OverrideServerPropertiesIntro from './override-server-properties-intro.mdx'
+
+<OverrideServerPropertiesIntro />
+
+```csharp
+var flag = await posthog.GetFeatureFlagAsync(
+    "flag-key",
+    "distinct_id_of_the_user",
+    options: new FeatureFlagOptions
+    {
+        PersonProperties = new() { ["property_name"] = "value" },
+        Groups = [
+            new Group("your_group_type", "your_group_id")
+            {
+                ["group_property_name"] = "your group value"
+            },
+            new Group(
+                "another_group_type",
+                "another_group_id",
+                new Dictionary<string, object?>
+                {
+                    ["group_property_name"] = "another group value"
+                }
+            )
+        ]
+    });
+```
+
+import OverrideGeoIPPropertiesSDK from './override-geoip-properties-SDKs.mdx'
+
+<OverrideGeoIPPropertiesSDK />