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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using System.Diagnostics.CodeAnalysis;
using System.Linq;
using System.Net;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Http;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
namespace Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore;
/// <summary>
/// Processes requests to execute migrations operations. The middleware will listen for requests to the path configured in the supplied options.
/// </summary>
public class MigrationsEndPointMiddleware
{
private readonly RequestDelegate _next;
private readonly ILogger _logger;
private readonly MigrationsEndPointOptions _options;
/// <summary>
/// Initializes a new instance of the <see cref="MigrationsEndPointMiddleware"/> class
/// </summary>
/// <param name="next">Delegate to execute the next piece of middleware in the request pipeline.</param>
/// <param name="logger">The <see cref="Logger{T}"/> to write messages to.</param>
/// <param name="options">The options to control the behavior of the middleware.</param>
public MigrationsEndPointMiddleware(
RequestDelegate next,
ILogger<MigrationsEndPointMiddleware> logger,
IOptions<MigrationsEndPointOptions> options)
{
ArgumentNullException.ThrowIfNull(next);
ArgumentNullException.ThrowIfNull(logger);
ArgumentNullException.ThrowIfNull(options);
_next = next;
_logger = logger;
_options = options.Value;
}
/// <summary>
/// Process an individual request.
/// </summary>
/// <param name="context">The context for the current request.</param>
/// <returns>A task that represents the asynchronous operation.</returns>
[RequiresDynamicCode("DbContext migrations operations are not supported with NativeAOT")]
public virtual Task Invoke(HttpContext context)
{
ArgumentNullException.ThrowIfNull(context);
if (context.Request.Path.Equals(_options.Path))
{
return InvokeCore(context);
}
return _next(context);
}
[RequiresDynamicCode("DbContext migrations operations are not supported with NativeAOT")]
private async Task InvokeCore(HttpContext context)
{
_logger.RequestPathMatched(context.Request.Path);
var db = await GetDbContext(context, _logger);
if (db != null)
{
var dbName = db.GetType().FullName!;
try
{
_logger.ApplyingMigrations(dbName);
await db.Database.MigrateAsync();
context.Response.StatusCode = (int)HttpStatusCode.NoContent;
context.Response.Headers.Add("Pragma", new[] { "no-cache" });
context.Response.Headers.Add("Cache-Control", new[] { "no-cache,no-store" });
_logger.MigrationsApplied(dbName);
}
catch (Exception ex)
{
var message = Strings.FormatMigrationsEndPointMiddleware_Exception(dbName) + ex;
_logger.MigrationsEndPointMiddlewareException(dbName, ex);
throw new InvalidOperationException(message, ex);
}
}
}
private static async Task<DbContext?> GetDbContext(HttpContext context, ILogger logger)
{
var form = await context.Request.ReadFormAsync();
var contextTypeName = form["context"].ToString();
if (string.IsNullOrWhiteSpace(contextTypeName))
{
logger.NoContextType();
await WriteErrorToResponse(context.Response, Strings.MigrationsEndPointMiddleware_NoContextType);
return null;
}
// Look for DbContext classes registered in the service provider
var registeredContexts = context.RequestServices.GetServices<DbContextOptions>()
.Select(o => o.ContextType);
var contextType = registeredContexts.FirstOrDefault(c => string.Equals(contextTypeName, c.AssemblyQualifiedName, StringComparison.Ordinal));
if (contextType is null)
{
var message = Strings.FormatMigrationsEndPointMiddleware_ContextNotRegistered(contextTypeName);
logger.ContextNotRegistered(contextTypeName);
await WriteErrorToResponse(context.Response, message);
return null;
}
var db = (DbContext?)context.RequestServices.GetService(contextType);
return db;
}
private static async Task WriteErrorToResponse(HttpResponse response, string error)
{
response.StatusCode = (int)HttpStatusCode.BadRequest;
response.Headers.Add("Pragma", new[] { "no-cache" });
response.Headers.Add("Cache-Control", new[] { "no-cache,no-store" });
response.ContentType = "text/plain";
// Padding to >512 to ensure IE doesn't hide the message
// http://stackoverflow.com/questions/16741062/what-rules-does-ie-use-to-determine-whether-to-show-the-entity-body
await response.WriteAsync(error.PadRight(513));
}
}
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