PATCH section and other updates (#32007)
Luke Latham
GitHub
parent
c15c3aa8fa
commit
d9ab1c3233
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@ -5,7 +5,7 @@ description: Learn how to call a web API from Blazor apps.
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monikerRange: '>= aspnetcore-3.1'
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ms.author: riande
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ms.custom: mvc
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ms.date: 03/07/2024
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ms.date: 03/08/2024
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uid: blazor/call-web-api
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---
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# Call a web API from ASP.NET Core Blazor
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@ -136,7 +136,7 @@ else
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}
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@code {
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private IEnumerable<GitHubBranch>? branches = Array.Empty<GitHubBranch>();
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private IEnumerable<GitHubBranch>? branches = [];
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private bool getBranchesError;
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private bool shouldRender;
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@ -175,6 +175,8 @@ else
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}
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```
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In the preceding example for C# 12 or later, an empty array (`[]`) is created for the `branches` variable. For earlier versions of C#, create an empty array (`Array.Empty<GitHubBranch>()`).
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For an additional working example, see the server-side file upload example that uploads files to a web API controller in the <xref:blazor/file-uploads#upload-files-to-a-server-with-server-side-rendering> article.
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:::moniker range=">= aspnetcore-8.0"
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@ -297,28 +299,31 @@ Use the <xref:System.Net.Http.Json?displayProperty=fullName> namespace for acces
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@using System.Net.Http.Json
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```
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### GET from JSON (`GetFromJsonAsync`)
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The following sections cover JSON helpers:
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* [GET](#get-from-json-getfromjsonasync)
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* [POST](#post-as-json-postasjsonasync)
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* [PUT](#put-as-json-putasjsonasync)
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* [PATCH](#patch-as-json-patchasjsonasync)
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<xref:System.Net.Http> includes additional methods for sending HTTP requests and receiving HTTP responses, for example to send a DELETE request. For more information, see the [DELETE and additional extension methods](#delete-deleteasync-and-additional-extension-methods) section.
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## GET from JSON (`GetFromJsonAsync`)
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<xref:System.Net.Http.Json.HttpClientJsonExtensions.GetFromJsonAsync%2A> sends an HTTP GET request and parses the JSON response body to create an object.
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In the following component code, the `todoItems` are displayed by the component. <xref:System.Net.Http.Json.HttpClientJsonExtensions.GetFromJsonAsync%2A> is called when the component is finished initializing ([`OnInitializedAsync`](xref:blazor/components/lifecycle#component-initialization-oninitializedasync)).
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> [!NOTE]
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> When targeting ASP.NET Core 5.0 or earlier, add `@using` directives to the following component for <xref:System.Net.Http?displayProperty=fullName>, <xref:System.Net.Http.Json?displayProperty=fullName>, and <xref:System.Threading.Tasks?displayProperty=fullName>.
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```csharp
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todoItems = await Http.GetFromJsonAsync<TodoItem[]>("todoitems");
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```
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### POST as JSON (`PostAsJsonAsync`)
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## POST as JSON (`PostAsJsonAsync`)
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<xref:System.Net.Http.Json.HttpClientJsonExtensions.PostAsJsonAsync%2A> sends a POST request to the specified URI containing the value serialized as JSON in the request body.
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In the following component code, `newItemName` is provided by a bound element of the component. The `AddItem` method is triggered by selecting a `<button>` element.
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> [!NOTE]
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> When targeting ASP.NET Core 5.0 or earlier, add `@using` directives to the following component for <xref:System.Net.Http?displayProperty=fullName>, <xref:System.Net.Http.Json?displayProperty=fullName>, and <xref:System.Threading.Tasks?displayProperty=fullName>.
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```csharp
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await Http.PostAsJsonAsync("todoitems", addItem);
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```
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@ -326,20 +331,16 @@ await Http.PostAsJsonAsync("todoitems", addItem);
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<xref:System.Net.Http.Json.HttpClientJsonExtensions.PostAsJsonAsync%2A> returns an <xref:System.Net.Http.HttpResponseMessage>. To deserialize the JSON content from the response message, use the <xref:System.Net.Http.Json.HttpContentJsonExtensions.ReadFromJsonAsync%2A> extension method. The following example reads JSON weather data as an array:
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```csharp
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var content = await response.Content.ReadFromJsonAsync<WeatherForecast[]>() ?? [];
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var content = await response.Content.ReadFromJsonAsync<WeatherForecast[]>() ??
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Array.Empty<WeatherForecast>();
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```
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In the preceding example for C# 12 or later, an empty array (`[]`) is created if no weather data is returned by the method, so `content` isn't null after the statement executes but returns. In earlier versions of C#, create an empty array (`Array.Empty<WeatherForecast>()`).
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### PUT as JSON (`PutAsJsonAsync`)
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## PUT as JSON (`PutAsJsonAsync`)
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<xref:System.Net.Http.Json.HttpClientJsonExtensions.PutAsJsonAsync%2A> sends an HTTP PUT request with JSON-encoded content.
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In the following component code, `editItem` values for `Name` and `IsCompleted` are provided by bound elements of the component. The item's `Id` is set when the item is selected in another part of the UI (not shown) and `EditItem` is called. The `SaveItem` method is triggered by selecting the `<button>` element. The following example doesn't show loading `todoItems` for brevity. See the [GET from JSON (`GetFromJsonAsync`)](#get-from-json-getfromjsonasync) section for an example of loading items.
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> [!NOTE]
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> When targeting ASP.NET Core 5.0 or earlier, add `@using` directives to the following component for <xref:System.Net.Http?displayProperty=fullName>, <xref:System.Net.Http.Json?displayProperty=fullName>, and <xref:System.Threading.Tasks?displayProperty=fullName>.
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```csharp
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await Http.PutAsJsonAsync($"todoitems/{editItem.Id}", editItem);
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```
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@ -347,79 +348,36 @@ await Http.PutAsJsonAsync($"todoitems/{editItem.Id}", editItem);
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<xref:System.Net.Http.Json.HttpClientJsonExtensions.PutAsJsonAsync%2A> returns an <xref:System.Net.Http.HttpResponseMessage>. To deserialize the JSON content from the response message, use the <xref:System.Net.Http.Json.HttpContentJsonExtensions.ReadFromJsonAsync%2A> extension method. The following example reads JSON weather data as an array:
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```csharp
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var content = await response.Content.ReadFromJsonAsync<WeatherForecast[]>() ?? [];
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var content = await response.Content.ReadFromJsonAsync<WeatherForecast[]>() ??
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Array.Empty<WeatherForecast>();
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```
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In the preceding example for C# 12 or later, an empty array (`[]`) is created if no weather data is returned by the method, so `content` isn't null after the statement executes but returns. In earlier versions of C#, create an empty array (`Array.Empty<WeatherForecast>()`).
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:::moniker range=">= aspnetcore-7.0"
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### PATCH as JSON (`PatchAsJsonAsync`)
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> [!NOTE]
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> This section's example isn't currently demonstrated in the sample apps (`BlazorWebAppCallWebApi`/`BlazorWebAssemblyCallWebApi`, .NET 8 or later).
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## PATCH as JSON (`PatchAsJsonAsync`)
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<xref:System.Net.Http.Json.HttpClientJsonExtensions.PatchAsJsonAsync%2A> sends an HTTP PATCH request with JSON-encoded content.
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This section's examples are based on a `TodoItem` class that stores the following todo item data:
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> [!NOTE]
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> For more information, see <xref:web-api/jsonpatch>.
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* ID (`Id`, `long`): Unique ID of the item.
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* Name (`Name`, `string`): Name of the item.
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* Status (`IsComplete`, `bool`): Indication if the todo item is finished.
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`TodoItem` class:
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In the following example, <xref:System.Net.Http.Json.HttpClientJsonExtensions.PatchAsJsonAsync%2A> receives a JSON PATCH document as a plain text string with escaped quotes:
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```csharp
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public class TodoItem
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{
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public long Id { get; set; }
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public string? Name { get; set; }
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public bool IsComplete { get; set; }
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}
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```
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In the following component code:
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* `incompleteTodoItems` is an array of incomplete `TodoItem`. The following example doesn't show loading `incompleteTodoItems` for brevity. Loading items is covered in the [GET from JSON (`GetFromJsonAsync`)](#get-from-json-getfromjsonasync) section.
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* The `UpdateItem` method is triggered by selecting the `<button>` element.
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* The PATCH document is provided as a plain text string. The web API described in the <xref:tutorials/first-web-api> article doesn't handle PATCH requests by default. To make the PATCH example in this section work with the tutorial's web API, implement a PATCH controller action in the web API following the guidance in <xref:web-api/jsonpatch>. Later, this section demonstrates an example controller action and shows how to compose PATCH documents for ASP.NET Core web API apps that use .NET JSON PATCH support.
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> [!NOTE]
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> When targeting ASP.NET Core 5.0 or earlier, add `@using` directives to the following component for <xref:System.Net.Http?displayProperty=fullName>, <xref:System.Net.Http.Json?displayProperty=fullName>, and <xref:System.Threading.Tasks?displayProperty=fullName>.
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```razor
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@using System.Text.Json
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@using System.Text.Json.Serialization
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@inject HttpClient Http
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<ul>
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@foreach (var item in incompleteTodoItems)
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{
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<li>
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@item.Name
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<button @onclick="_ => UpdateItem(item.Id)">
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Mark 'Complete'
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</button>
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</li>
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}
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</ul>
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@code {
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private async Task UpdateItem(long id) =>
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await Http.PatchAsJsonAsync(
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$"todoitems/{id}",
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"[{\"operationType\":2,\"path\":\"/IsComplete\",\"op\":\"replace\",\"value\":true}]");
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}
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await Http.PatchAsJsonAsync(
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$"todoitems/{id}",
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"[{\"operationType\":2,\"path\":\"/IsComplete\",\"op\":\"replace\",\"value\":true}]");
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```
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<xref:System.Net.Http.Json.HttpClientJsonExtensions.PatchAsJsonAsync%2A> returns an <xref:System.Net.Http.HttpResponseMessage>. To deserialize the JSON content from the response message, use the <xref:System.Net.Http.Json.HttpContentJsonExtensions.ReadFromJsonAsync%2A> extension method. The following example reads JSON todo item data as an array. An empty array is created if no item data is returned by the method, so `content` isn't null after the statement executes:
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```csharp
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var response = await Http.PatchAsJsonAsync(...);
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var content = await response.Content.ReadFromJsonAsync<TodoItem[]>() ??
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Array.Empty<TodoItem>();
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```
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<xref:System.Net.Http.Json.HttpClientJsonExtensions.PatchAsJsonAsync%2A> receives a JSON PATCH document for the PATCH request. The preceding `UpdateItem` method called <xref:System.Net.Http.Json.HttpClientJsonExtensions.PatchAsJsonAsync%2A> with a PATCH document as a string with escaped quotes. Laid out with indentation, spacing, and non-escaped quotes, the unencoded PATCH document appears as the following JSON:
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Laid out with indentation, spacing, and unescaped quotes, the unencoded PATCH document appears as the following JSON:
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```json
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[
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@ -438,9 +396,11 @@ Install the [`Microsoft.AspNetCore.JsonPatch`](https://www.nuget.org/packages/Mi
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[!INCLUDE[](~/includes/package-reference.md)]
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Add an `@using` directive for the <xref:Microsoft.AspNetCore.JsonPatch?displayProperty=fullName> namespace to the top of the Razor component:
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Add `@using` directives for the <xref:System.Text.Json?displayProperty=fullName>, <xref:System.Text.Json.Serialization?displayProperty=fullName>, and <xref:Microsoft.AspNetCore.JsonPatch?displayProperty=fullName> namespaces to the top of the Razor component:
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```razor
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@using System.Text.Json
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@using System.Text.Json.Serialization
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@using Microsoft.AspNetCore.JsonPatch
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```
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@ -451,7 +411,7 @@ var patchDocument = new JsonPatchDocument<TodoItem>()
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.Replace(p => p.IsComplete, true);
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```
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Pass the document's operations (`patchDocument.Operations`) to the <xref:System.Net.Http.Json.HttpClientJsonExtensions.PatchAsJsonAsync%2A> call. The following example shows how to make the call:
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Pass the document's operations (`patchDocument.Operations`) to the <xref:System.Net.Http.Json.HttpClientJsonExtensions.PatchAsJsonAsync%2A> call:
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```csharp
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private async Task UpdateItem(long id)
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@ -461,119 +421,60 @@ private async Task UpdateItem(long id)
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patchDocument.Operations,
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new JsonSerializerOptions()
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{
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DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingDefault,
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WriteIndented = true
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DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingDefault
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});
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}
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```
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<xref:System.Text.Json.JsonSerializerOptions.DefaultIgnoreCondition?displayProperty=nameWithType> is set to <xref:System.Text.Json.Serialization.JsonIgnoreCondition.WhenWritingDefault?displayProperty=nameWithType> to ignore a property only if it equals the default value for its type.
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<xref:System.Text.Json.JsonSerializerOptions.WriteIndented?displayProperty=nameWithType> is used merely to present the JSON payload in a pleasant format for this article. Writing indented JSON has no bearing on processing PATCH requests and isn't typically performed in production apps for web API requests.
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Add <xref:System.Text.Json.JsonSerializerOptions.WriteIndented?displayProperty=nameWithType> set to `true` if you want to present the JSON payload in a pleasant format for display. Writing indented JSON has no bearing on processing PATCH requests and isn't typically performed in production apps for web API requests.
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Next, follow the guidance in the <xref:web-api/jsonpatch> article to add a PATCH controller action to the web API, which is reproduced here in the following steps.
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Follow the guidance in the <xref:web-api/jsonpatch> article to add a PATCH controller action to the web API. Alternatively, PATCH request processing can be implemented as a [Minimal API](xref:fundamentals/minimal-apis) with the following steps.
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Add a package reference for the [`Microsoft.AspNetCore.Mvc.NewtonsoftJson`](https://www.nuget.org/packages/Microsoft.AspNetCore.Mvc.NewtonsoftJson) NuGet package to the web API app.
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> [!NOTE]
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> There's no need to add a package reference for the [`Microsoft.AspNetCore.JsonPatch`](https://www.nuget.org/packages/Microsoft.AspNetCore.JsonPatch) package to the app because the reference to the `Microsoft.AspNetCore.Mvc.NewtonsoftJson` package automatically transitively adds a package reference for `Microsoft.AspNetCore.JsonPatch`.
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Add a custom JSON PATCH input formatter to the web API app.
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`JSONPatchInputFormatter.cs`:
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```csharp
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using Microsoft.AspNetCore.Mvc;
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using Microsoft.AspNetCore.Mvc.Formatters;
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using Microsoft.Extensions.Options;
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public static class JSONPatchInputFormatter
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{
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public static NewtonsoftJsonPatchInputFormatter Get()
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{
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var builder = new ServiceCollection()
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.AddLogging()
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.AddMvc()
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.AddNewtonsoftJson()
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.Services.BuildServiceProvider();
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return builder
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.GetRequiredService<IOptions<MvcOptions>>()
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.Value
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.InputFormatters
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.OfType<NewtonsoftJsonPatchInputFormatter>()
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.First();
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}
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}
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```
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Configure the web API's controllers to use the `Microsoft.AspNetCore.Mvc.NewtonsoftJson` package and process PATCH requests with the JSON PATCH input formatter. Insert the `JSONPatchInputFormatter` in the first position of MVC's input formatter collection so that it processes requests prior to any other input formatter.
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In the `Program` file modify the call to <xref:Microsoft.Extensions.DependencyInjection.MvcServiceCollectionExtensions.AddControllers%2A>:
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```csharp
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builder.Services.AddControllers(options =>
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{
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options.InputFormatters.Insert(0, JSONPatchInputFormatter.Get());
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}).AddNewtonsoftJson();
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```
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In `Controllers/TodoItemsController.cs`, add a `using` statement for the <xref:Microsoft.AspNetCore.JsonPatch?displayProperty=fullName> namespace:
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In the `Program` file add an `@using` directive for the <xref:Microsoft.AspNetCore.JsonPatch?displayProperty=fullName> namespace:
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```csharp
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using Microsoft.AspNetCore.JsonPatch;
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```
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In `Controllers/TodoItemsController.cs`, add the following `PatchTodoItem` action method:
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Provide the endpoint to the request processing pipeline of the web API:
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```csharp
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[HttpPatch("{id}")]
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public async Task<IActionResult> PatchTodoItem(long id,
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JsonPatchDocument<TodoItem> patchDoc)
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app.MapPatch("/todoitems/{id}", async (long id, TodoContext db) =>
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{
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if (patchDoc == null)
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if (await db.TodoItems.FindAsync(id) is TodoItem todo)
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{
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return BadRequest();
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}
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var todoItem = await _context.TodoItems.FindAsync(id);
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var patchDocument =
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new JsonPatchDocument<TodoItem>().Replace(p => p.IsComplete, true);
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patchDocument.ApplyTo(todo);
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await db.SaveChangesAsync();
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if (todoItem == null)
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{
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return NotFound();
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return TypedResults.Ok(todo);
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}
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patchDoc.ApplyTo(todoItem);
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_context.Entry(todoItem).State = EntityState.Modified;
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try
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{
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await _context.SaveChangesAsync();
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}
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catch (DbUpdateConcurrencyException) when (!TodoItemExists(id))
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{
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return NotFound();
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}
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return NoContent();
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}
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return TypedResults.NoContent();
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});
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```
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> [!WARNING]
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> As with the other examples in the <xref:web-api/jsonpatch> article, the preceding PATCH controller action doesn't protect the web API from over-posting attacks. For more information, see <xref:tutorials/first-web-api#prevent-over-posting>.
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> As with the other examples in the <xref:web-api/jsonpatch> article, the preceding PATCH API doesn't protect the web API from over-posting attacks. For more information, see <xref:tutorials/first-web-api#prevent-over-posting>.
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For a fully working PATCH experience, see the `BlazorWebAppCallWebApi` [sample app](#sample-apps).
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:::moniker-end
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### Additional extension methods
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## DELETE (`DeleteAsync`) and additional extension methods
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<xref:System.Net.Http> includes additional extension methods for sending HTTP requests and receiving HTTP responses. <xref:System.Net.Http.HttpClient.DeleteAsync%2A?displayProperty=nameWithType> is used to send an HTTP DELETE request to a web API.
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In the following component code, the `<button>` element calls the `DeleteItem` method. The bound `<input>` element supplies the `id` of the item to delete.
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> [!NOTE]
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> When targeting ASP.NET Core 5.0 or earlier, add `@using` directives to the following component for <xref:System.Net.Http?displayProperty=fullName> and <xref:System.Threading.Tasks?displayProperty=fullName>.
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```csharp
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await Http.DeleteAsync($"todoitems/{id}");
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```
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@ -631,9 +532,6 @@ In the following component code:
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* An instance of <xref:System.Net.Http.IHttpClientFactory> creates a named <xref:System.Net.Http.HttpClient>.
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* The named <xref:System.Net.Http.HttpClient> is used to issue a GET request for JSON weather forecast data from the web API at `/forecast`.
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> [!NOTE]
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> When targeting ASP.NET Core 5.0 or earlier, add `@using` directives to the following component for <xref:System.Net.Http?displayProperty=fullName>, <xref:System.Net.Http.Json?displayProperty=fullName>, and <xref:System.Threading.Tasks?displayProperty=fullName>.
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```razor
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@inject IHttpClientFactory ClientFactory
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@ -736,9 +634,6 @@ In the following component code:
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* An instance of the preceding `ForecastHttpClient` is injected, which creates a typed <xref:System.Net.Http.HttpClient>.
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* The typed <xref:System.Net.Http.HttpClient> is used to issue a GET request for JSON weather forecast data from the web API.
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> [!NOTE]
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> When targeting ASP.NET Core 5.0 or earlier, add an `@using` directive to the following component for <xref:System.Threading.Tasks?displayProperty=fullName>.
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```razor
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@inject ForecastHttpClient Http
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@ -766,9 +661,6 @@ The `BlazorWebAppCallWebApi` [sample app](#sample-apps) demonstrates calling a w
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[`HttpClient`](xref:fundamentals/http-requests) ([API documentation](xref:System.Net.Http.HttpClient)) and <xref:System.Net.Http.HttpRequestMessage> can be used to customize requests. For example, you can specify the HTTP method and request headers. The following component makes a `POST` request to a web API endpoint and shows the response body.
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> [!NOTE]
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||||
> When targeting ASP.NET Core 5.0 or earlier, add `@using` directives to the following component for <xref:System.Net.Http?displayProperty=fullName> and <xref:System.Net.Http.Json?displayProperty=fullName>.
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`TodoRequest.razor`:
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||||
```razor
|
||||
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@ -853,9 +745,6 @@ The <xref:System.Net.Http.Json.HttpClientJsonExtensions.GetFromJsonAsync%2A> cal
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In <xref:Microsoft.AspNetCore.Components.ComponentBase.OnInitializedAsync%2A> on the client, <xref:System.NotSupportedException> is thrown when the response content is validated as non-JSON. The exception is caught in the `catch` block, where custom logic could log the error or present a friendly error message to the user.
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||||
|
||||
> [!NOTE]
|
||||
> When targeting ASP.NET Core 5.0 or earlier, add `@using` directives to the following component for <xref:System.Net.Http?displayProperty=fullName>, <xref:System.Net.Http.Json?displayProperty=fullName>, and <xref:System.Threading.Tasks?displayProperty=fullName>.
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||||
|
||||
`ReturnHTMLOnException.razor`:
|
||||
|
||||
```razor
|
||||
|
|
|
|||
Loading…
Reference in New Issue