elsa-core/src/modules/Elsa.Http/Activities/WriteHttpResponse.cs
2023-03-24 20:57:27 +01:00

115 lines
4.2 KiB
C#

using System.Net;
using Elsa.Extensions;
using Elsa.Http.ContentWriters;
using Elsa.Http.Models;
using Elsa.Http.Providers;
using Elsa.Workflows.Core;
using Elsa.Workflows.Core.Attributes;
using Elsa.Workflows.Core.Models;
using Microsoft.AspNetCore.Http;
namespace Elsa.Http;
/// <summary>
/// Write a response to the current HTTP response object.
/// </summary>
[Activity("Elsa", "HTTP", "Write a response to the current HTTP response object.", DisplayName = "HTTP Response")]
public class WriteHttpResponse : CodeActivity
{
/// <summary>
/// The status code to return.
/// </summary>
[Input(DefaultValue = HttpStatusCode.OK, Description = "The status code to return.")]
public Input<HttpStatusCode> StatusCode { get; set; } = new(HttpStatusCode.OK);
/// <summary>
/// The content to write back.
/// </summary>
[Input(Description = "The content to write back. String values will be sent as-is, while objects will be serialized to a JSON string. Byte arrays and streams will be sent as files.")]
public Input<object?> Content { get; set; } = default!;
/// <summary>
/// The content type to use when returning the response.
/// </summary>
[Input(
Description = "The content type to use when returning the response.",
OptionsProvider = typeof(WriteHttpResponseContentTypeOptionsProvider),
UIHint = InputUIHints.Dropdown
)]
public Input<string?> ContentType { get; set; } = default!;
/// <summary>
/// The headers to return along with the response.
/// </summary>
[Input(Description = "The headers to return along with the response.", Category = "Advanced")]
public Input<HttpResponseHeaders?> ResponseHeaders { get; set; } = new(new HttpResponseHeaders());
/// <inheritdoc />
protected override async ValueTask ExecuteAsync(ActivityExecutionContext context)
{
var httpContextAccessor = context.GetRequiredService<IHttpContextAccessor>();
var httpContext = httpContextAccessor.HttpContext;
if (httpContext == null)
{
// We're executing in a non-HTTP context (e.g. in a virtual actor).
// Create a bookmark to allow the invoker to export the state and resume execution from there.
context.CreateBookmark(OnResumeAsync);
return;
}
await WriteResponseAsync(context, httpContext.Response);
}
private async ValueTask OnResumeAsync(ActivityExecutionContext context)
{
var httpContextAccessor = context.GetRequiredService<IHttpContextAccessor>();
var httpContext = httpContextAccessor.HttpContext;
if (httpContext == null)
{
// We're not in an HTTP context, so let's fail.
throw new Exception("Cannot execute in a non-HTTP context");
}
await WriteResponseAsync(context, httpContext.Response);
}
private async Task WriteResponseAsync(ActivityExecutionContext context, HttpResponse response)
{
// Set status code.
response.StatusCode = (int)context.Get(StatusCode);
// Add headers.
var headers = context.GetHeaders(ResponseHeaders);
foreach (var header in headers)
response.Headers.Add(header.Key, header.Value);
// Get content and content type.
var content = context.Get(Content);
if (content == null)
return;
var contentType = ContentType.GetOrDefault(context);
if (string.IsNullOrWhiteSpace(contentType))
contentType = DetermineContentType(content);
var contentWriter = context.GetServices<IHttpContentFactory>().FirstOrDefault(x => x.SupportsContentType(contentType)) ?? new TextContentFactory();
var httpContent = contentWriter.CreateHttpContent(content, contentType);
// Set content type.
response.ContentType = httpContent.Headers.ContentType?.ToString() ?? contentType;
// Write content.
await httpContent.CopyToAsync(response.Body);
}
private string DetermineContentType(object? content) => content is byte[] or Stream
? "application/octet-stream"
: content is string
? "text/plain"
: "application/json";
}