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Author: craigshoemaker

articles/azure-functions/functions-bindings-signalr-service-input.md

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+---
+title: Azure Functions SignalR Service input binding
+description: Learn to return a SignalR service endpoint URL and access token in Azure Functions.
+author: craigshoemaker
+ms.topic: reference
+ms.date: 02/20/2020
+ms.author: cshoe
+---
+
+# SignalR Service input binding for Azure Functions
+
+Before a client can connect to Azure SignalR Service, it must retrieve the service endpoint URL and a valid access token. The *SignalRConnectionInfo* input binding produces the SignalR Service endpoint URL and a valid token that are used to connect to the service. Because the token is time-limited and can be used to authenticate a specific user to a connection, you should not cache the token or share it between clients. An HTTP trigger using this binding can be used by clients to retrieve the connection information.
+
+For more information on how this binding is used to create a "negotiate" function that can be consumed by a SignalR client SDK, see the [Azure Functions development and configuration article](../azure-signalr/signalr-concept-serverless-development-config.md) in the SignalR Service concepts documentation.
+
+For information on setup and configuration details, see the [overview](functions-bindings-signalr-service.md).
+
+# [C#](#tab/csharp)
+
+The following example shows a [C# function](functions-dotnet-class-library.md) that acquires SignalR connection information using the input binding and returns it over HTTP.
+
+```cs
+[FunctionName("negotiate")]
+public static SignalRConnectionInfo Negotiate(
+    [HttpTrigger(AuthorizationLevel.Anonymous)]HttpRequest req,
+    [SignalRConnectionInfo(HubName = "chat")]SignalRConnectionInfo connectionInfo)
+{
+    return connectionInfo;
+}
+```
+
+# [C# Script](#tab/csharp-script)
+
+The following example shows a SignalR connection info input binding in a *function.json* file and a [C# Script function](functions-reference-csharp.md) that uses the binding to return the connection information.
+
+Here's binding data in the *function.json* file:
+
+Example function.json:
+
+```json
+{
+    "type": "signalRConnectionInfo",
+    "name": "connectionInfo",
+    "hubName": "chat",
+    "connectionStringSetting": "<name of setting containing SignalR Service connection string>",
+    "direction": "in"
+}
+```
+
+Here's the C# Script code:
+
+```cs
+#r "Microsoft.Azure.WebJobs.Extensions.SignalRService"
+using Microsoft.Azure.WebJobs.Extensions.SignalRService;
+
+public static SignalRConnectionInfo Run(HttpRequest req, SignalRConnectionInfo connectionInfo)
+{
+    return connectionInfo;
+}
+```
+
+# [JavaScript](#tab/javascript)
+
+The following example shows a SignalR connection info input binding in a *function.json* file and a [JavaScript function](functions-reference-node.md) that uses the binding to return the connection information.
+
+Here's binding data in the *function.json* file:
+
+Example function.json:
+
+```json
+{
+    "type": "signalRConnectionInfo",
+    "name": "connectionInfo",
+    "hubName": "chat",
+    "connectionStringSetting": "<name of setting containing SignalR Service connection string>",
+    "direction": "in"
+}
+```
+
+Here's the JavaScript code:
+
+```javascript
+module.exports = async function (context, req, connectionInfo) {
+    context.res.body = connectionInfo;
+};
+```
+
+# [Python](#tab/python)
+
+The following example shows a SignalR connection info input binding in a *function.json* file and a [Python function](functions-reference-python.md) that uses the binding to return the connection information.
+
+Here's binding data in the *function.json* file:
+
+Example function.json:
+
+```json
+{
+    "type": "signalRConnectionInfo",
+    "name": "connectionInfo",
+    "hubName": "chat",
+    "connectionStringSetting": "<name of setting containing SignalR Service connection string>",
+    "direction": "in"
+}
+```
+
+Here's the Python code:
+
+```python
+def main(req: func.HttpRequest, connectionInfoJson: str) -> func.HttpResponse:
+    return func.HttpResponse(
+        connectionInfoJson,
+        status_code=200,
+        headers={
+            'Content-type': 'application/json'
+        }
+    )
+```
+
+# [Java](#tab/java)
+
+The following example shows a [Java function](functions-reference-java.md) that acquires SignalR connection information using the input binding and returns it over HTTP.
+
+```java
+@FunctionName("negotiate")
+public SignalRConnectionInfo negotiate(
+        @HttpTrigger(
+            name = "req",
+            methods = { HttpMethod.POST },
+            authLevel = AuthorizationLevel.ANONYMOUS) HttpRequestMessage<Optional<String>> req,
+        @SignalRConnectionInfoInput(
+            name = "connectionInfo",
+            hubName = "chat") SignalRConnectionInfo connectionInfo) {
+    return connectionInfo;
+}
+```
+
+---
+
+### Authenticated tokens
+
+If the function is triggered by an authenticated client, you can add a user ID claim to the generated token. You can easily add authentication to a function app using [App Service Authentication](../app-service/overview-authentication-authorization.md).
+
+App Service Authentication sets HTTP headers named `x-ms-client-principal-id` and `x-ms-client-principal-name` that contain the authenticated user's client principal ID and name, respectively.
+
+# [C#](#tab/csharp)
+
+You can set the `UserId` property of the binding to the value from either header using a [binding expression](./functions-bindings-expressions-patterns.md): `{headers.x-ms-client-principal-id}` or `{headers.x-ms-client-principal-name}`.
+
+```cs
+[FunctionName("negotiate")]
+public static SignalRConnectionInfo Negotiate(
+    [HttpTrigger(AuthorizationLevel.Anonymous)]HttpRequest req, 
+    [SignalRConnectionInfo
+        (HubName = "chat", UserId = "{headers.x-ms-client-principal-id}")]
+        SignalRConnectionInfo connectionInfo)
+{
+    // connectionInfo contains an access key token with a name identifier claim set to the authenticated user
+    return connectionInfo;
+}
+```
+
+# [C# Script](#tab/csharp-script)
+
+You can set the `userId` property of the binding to the value from either header using a [binding expression](./functions-bindings-expressions-patterns.md): `{headers.x-ms-client-principal-id}` or `{headers.x-ms-client-principal-name}`.
+
+Example function.json:
+
+```json
+{
+    "type": "signalRConnectionInfo",
+    "name": "connectionInfo",
+    "hubName": "chat",
+    "userId": "{headers.x-ms-client-principal-id}",
+    "connectionStringSetting": "<name of setting containing SignalR Service connection string>",
+    "direction": "in"
+}
+```
+
+Here's the C# Script code:
+
+```cs
+#r "Microsoft.Azure.WebJobs.Extensions.SignalRService"
+using Microsoft.Azure.WebJobs.Extensions.SignalRService;
+
+public static SignalRConnectionInfo Run(HttpRequest req, SignalRConnectionInfo connectionInfo)
+{
+    // connectionInfo contains an access key token with a name identifier
+    // claim set to the authenticated user
+    return connectionInfo;
+}
+```
+
+# [JavaScript](#tab/javascript)
+
+You can set the `userId` property of the binding to the value from either header using a [binding expression](./functions-bindings-expressions-patterns.md): `{headers.x-ms-client-principal-id}` or `{headers.x-ms-client-principal-name}`.
+
+Example function.json:
+
+```json
+{
+    "type": "signalRConnectionInfo",
+    "name": "connectionInfo",
+    "hubName": "chat",
+    "userId": "{headers.x-ms-client-principal-id}",
+    "connectionStringSetting": "<name of setting containing SignalR Service connection string>",
+    "direction": "in"
+}
+```
+
+Here's the JavaScript code:
+
+```javascript
+module.exports = async function (context, req, connectionInfo) {
+    // connectionInfo contains an access key token with a name identifier
+    // claim set to the authenticated user
+    context.res.body = connectionInfo;
+};
+```
+
+# [Python](#tab/python)
+
+You can set the `userId` property of the binding to the value from either header using a [binding expression](./functions-bindings-expressions-patterns.md): `{headers.x-ms-client-principal-id}` or `{headers.x-ms-client-principal-name}`.
+
+Example function.json:
+
+```json
+{
+    "type": "signalRConnectionInfo",
+    "name": "connectionInfo",
+    "hubName": "chat",
+    "userId": "{headers.x-ms-client-principal-id}",
+    "connectionStringSetting": "<name of setting containing SignalR Service connection string>",
+    "direction": "in"
+}
+```
+
+Here's the Python code:
+
+```python
+def main(req: func.HttpRequest, connectionInfoJson: str) -> func.HttpResponse:
+    # connectionInfo contains an access key token with a name identifier
+    # claim set to the authenticated user
+    return func.HttpResponse(
+        connectionInfoJson,
+        status_code=200,
+        headers={
+            'Content-type': 'application/json'
+        }
+    )
+```
+
+# [Java](#tab/java)
+
+You can set the `userId` property of the binding to the value from either header using a [binding expression](./functions-bindings-expressions-patterns.md): `{headers.x-ms-client-principal-id}` or `{headers.x-ms-client-principal-name}`.
+
+```java
+@FunctionName("negotiate")
+public SignalRConnectionInfo negotiate(
+        @HttpTrigger(
+            name = "req",
+            methods = { HttpMethod.POST },
+            authLevel = AuthorizationLevel.ANONYMOUS) HttpRequestMessage<Optional<String>> req,
+        @SignalRConnectionInfoInput(
+            name = "connectionInfo",
+            hubName = "chat",
+            userId = "{headers.x-ms-client-principal-id}") SignalRConnectionInfo connectionInfo) {
+    return connectionInfo;
+}
+```
+
+---
+
+## Next steps
+
+- [Send SignalR Service messages  (Output binding)](./functions-bindings-signalr-service-output.md)