/// <summary>
/// If the current user-agent in the request is eligible for ES5 fallback, return true
/// </summary>
/// <param name="request"></param>
/// <returns></returns>
public static bool BrowserNeedES5Fallback(this HttpRequest request)
{
BlazorPolyfillOptions _options = BlazorPolyfillMiddlewareExtensions.GetOptions();
if (_options.ForceES5Fallback)
{
return(true);
}
//In this case, the user is responsible from any delegate crash.
//As it does have control over the delegate, the error will be visible for him.
//If this call does not return true, we must continue the regular checking workflow
if (_options.ES5FallbackValidation != null && _options.ES5FallbackValidation(request))
{
return(true);
}
string userAgent = request.Headers["User-Agent"];
if (userAgent == null)
{
return(false);
}
return(IsInternetExplorer(userAgent) ||
IsEdgeHTML(userAgent));
}
public static IApplicationBuilder UseBlazorPolyfill(
this IApplicationBuilder builder, Action <BlazorPolyfillOptions> configureOptions)
{
if (builder is null)
{
throw new ArgumentNullException(nameof(builder));
}
if (configureOptions is null)
{
throw new ArgumentNullException(nameof(configureOptions));
}
BlazorPolyfillOptions options = new BlazorPolyfillOptions();
//Let the user configure the options in it's delegate method
configureOptions(options);
return(UseBlazorPolyfill(builder, options));
}
private static FileContentReference GetPatchedBlazorServerFile()
{
if (_patchedBlazorServerFile == null)
{
BlazorPolyfillOptions option = GetOptions();
if (option.UsePackagedBlazorServerLibrary)
{
//Get packaged blazor.server.js
var assembly = GetBlazorPolyfillAssembly();
var resources = assembly.GetManifestResourceNames();
var resourceName = resources.Single(str => str.EndsWith("blazor.server.packaged.js"));
using (Stream stream = assembly.GetManifestResourceStream(resourceName))
{
using (StreamReader reader = new StreamReader(stream))
{
string js = reader.ReadToEnd();
string Etag = CryptographyHelper.CreateSHA256(js);
//We should rely on ETag and not on LastModifed informations
DateTime buildTime = GetAssemblyCreationDate(assembly);
_patchedBlazorServerFile = new FileContentReference()
{
Value = js,
ETag = Etag,
LastModified = buildTime,
ContentLength = System.Text.UTF8Encoding.UTF8.GetByteCount(js).ToString(CultureInfo.InvariantCulture)
};
}
}
}
else
{
var assembly = GetAspNetCoreComponentsServerAssembly();
var resources = assembly.GetManifestResourceNames();
var resourceName = resources.Single(str => str.EndsWith("blazor.server.js"));
using (Stream stream = assembly.GetManifestResourceStream(resourceName))
{
using (StreamReader reader = new StreamReader(stream))
{
string js = reader.ReadToEnd();
#region Patch Regex
//Patch Descriptor Regex as it make Babel crash during transform
js = js.Replace("/\\W*Blazor:[^{]*(?<descriptor>.*)$/;", @"/[\0-\/:-@\[-\^`\{-\uFFFF]*Blazor:(?:(?!\{)[\s\S])*(.*)$/;");
js = js.Replace("/^\\s*Blazor-Component-State:(?<state>[a-zA-Z0-9\\+\\/=]+)$/", @"/^[\t-\r \xA0\u1680\u2000-\u200A\u2028\u2029\u202F\u205F\u3000\uFEFF]*Blazor\x2DComponent\x2DState:([\+\/-9=A-Za-z]+)$/");
js = js.Replace("/^\\s*Blazor:[^{]*(?<descriptor>.*)$/", @"/^[\t-\r \xA0\u1680\u2000-\u200A\u2028\u2029\u202F\u205F\u3000\uFEFF]*Blazor:(?:(?!\{)[\s\S])*(.*)$/");
#endregion Patch Regex
//Transpile code to ES5 for IE11 before manual patching
js = BabelHelper.Transform(js, "blazor.server.js");
#region Regex named groups fix
//At this point, Babel has unminified the code, and fixed IE11 issues, like 'import' method calls.
//We still need to fix 'descriptor' regex evaluation code, as it was expecting a named capture group.
js = Regex.Replace(js, "([_a-zA-Z0-9]+)(.groups[ ]*&&[ ]*[_a-zA-Z0-9]+.groups.descriptor)", "$1[1]");
//We still need to fix 'state' regex evaluation code, as it was expecting a named capture group.
js = Regex.Replace(js, "([_a-zA-Z0-9]+)(.groups[ ]*&&[ ]*[_a-zA-Z0-9]+.groups.state)", "$1[1]");
//Here we fix invalids interopRequireWildcard(require(''.concat(n))) to _interopRequireWildcard(''.concat(n)) (works for '' or "")
//Warning: " is written "" here but must be read as " from the regex logic: We are in a verbatim string
js = Regex.Replace(js, @"(require\((['""]['""].concat\([a-zA-Z]+\))\))", "$2");
#endregion Regex named groups fix
//Minify with AjaxMin (we don't want an additional external tool with NPM or else for managing this
//kind of thing here...
js = Uglify.Js(js).Code;
//Computing ETag. Should be computed last !
string Etag = CryptographyHelper.CreateSHA256(js);
//Computing Build time for the Last-Modified Http Header
//We should rely on the creation date of the Microsoft API
//not the Blazor.Polyfill.Server one as the Microsoft.AspNetCore.Components.Server
//assembly may be updated in time. We will rely on the current creation/modification date on disk
DateTime buildTime = GetAssemblyCreationDate(assembly);
_patchedBlazorServerFile = new FileContentReference()
{
Value = js,
ETag = Etag,
LastModified = buildTime,
ContentLength = System.Text.UTF8Encoding.UTF8.GetByteCount(js).ToString(CultureInfo.InvariantCulture)
};
}
}
}
}
return(_patchedBlazorServerFile);
}
public static IApplicationBuilder UseBlazorPolyfill(
this IApplicationBuilder builder, BlazorPolyfillOptions options)
{
if (builder is null)
{
throw new ArgumentNullException(nameof(builder));
}
if (options is null)
{
throw new ArgumentNullException(nameof(options));
}
SetOptions(options);
InitReact(builder);
//This is a kind of hack for caching the data at boot
//It's better to prevent anything at first request by caching instead of
//making the user wait the file generation
builder.Use((context, next) =>
{
if (!IsBlazorPolyfillLibCached())
{
//Avoiding first client to await the file generation
CacheBlazorPolyfillLib();
}
//Normal behavior
return(next());
});
//This is used in order to transpile dynamically StaticFiles to ES5 when needed
builder.UseMiddleware <ECMAScript5Middleware>();
//BrowserNeedES5Fallback is written hiere and not in the builder
//because we only want to use MapWhen when we need ES5 fallback.
//If this is false, the request will be redirected to the Microsoft
//default request management for this file.
builder.MapWhen(ctx =>
ECMAScript5Middleware.RequestedFileIsBlazorServerJS(ctx.Request) &&
ctx.Request.BrowserNeedES5Fallback(),
subBuilder =>
{
subBuilder.Run(async(context) =>
{
var fileContent = GetPatchedBlazorServerFile();
await HttpRequestManager.ManageRequest(context, fileContent);
});
});
//As blazor.polyfill.js files does not exist really on theses path and
//does not have a real fallback request mangement (as for blazor.server.js)
//we should intercept them at any time with MapWhen, but change the result
//behavior lately in the builder. Otherwise this would return a 404 error.
builder.MapWhen(ctx =>
ECMAScript5Middleware.RequestedFileIsBlazorPolyfill(ctx.Request, out bool isMinified),
subBuilder =>
{
subBuilder.Run(async(context) =>
{
ECMAScript5Middleware.RequestedFileIsBlazorPolyfill(context.Request, out bool isMinified);
//Eval if the requested file is the minified version or not
var fileContent = GetBlazorPolyfillFile(context.Request.BrowserNeedES5Fallback(), isMinified);
await HttpRequestManager.ManageRequest(context, fileContent);
});
});
return(builder);
}
private static void SetOptions(BlazorPolyfillOptions options)
{
_options = options;
}
private static FileContentReference GetPatchedBlazorServerFile()
{
if (_patchedBlazorServerFile == null)
{
BlazorPolyfillOptions option = GetOptions();
if (option.UsePackagedBlazorServerLibrary)
{
//Get packaged blazor.server.js
var assembly = GetBlazorPolyfillAssembly();
var resources = assembly.GetManifestResourceNames();
var resourceName = resources.Single(str => str.EndsWith("blazor.server.packaged.js"));
using (Stream stream = assembly.GetManifestResourceStream(resourceName))
{
using (StreamReader reader = new StreamReader(stream))
{
string js = reader.ReadToEnd();
string Etag = EtagGenerator.GenerateEtagFromString(js);
//Computing Build time for the Last-Modified Http Header
//We should rely on the creation date of the Microsoft API
//not the Blazor.Polyfill.Server one as the Microsoft.AspNetCore.Components.Server
//assembly may be updated in time. We will rely on the current creation/modification date on disk
DateTime buildTime = GetAssemblyCreationDate(assembly);
_patchedBlazorServerFile = new FileContentReference()
{
Value = js,
ETag = Etag,
LastModified = buildTime,
ContentLength = System.Text.UTF8Encoding.UTF8.GetByteCount(js).ToString(CultureInfo.InvariantCulture)
};
}
}
}
else
{
var assembly = GetAspNetCoreComponentsServerAssembly();
var resources = assembly.GetManifestResourceNames();
var resourceName = resources.Single(str => str.EndsWith("blazor.server.js"));
using (Stream stream = assembly.GetManifestResourceStream(resourceName))
{
using (StreamReader reader = new StreamReader(stream))
{
string js = reader.ReadToEnd();
//Patch Descriptor Regex as it make Babel crash during transform
js = js.Replace("/\\W*Blazor:[^{]*(?<descriptor>.*)$/;", @"/[\0-\/:-@\[-\^`\{-\uFFFF]*Blazor:(?:(?!\{)[\s\S])*(.*)$/;");
//Transpile code to ES5 for IE11 before manual patching
js = Transform(js, "blazor.server.js", "{\"plugins\":[\"proposal-class-properties\",\"proposal-object-rest-spread\"],\"presets\":[[\"env\",{\"targets\":{\"browsers\":[\"ie 11\"]}}], \"es2015\",\"es2016\",\"es2017\",\"stage-3\"], \"sourceType\": \"script\"}");
//At this point, Babel has unminified the code, and fixed IE11 issues, like 'import' method calls.
//We still need to fix 'descriptor' regex evaluation code, as it was expecting a named capture group.
js = Regex.Replace(js, "([a-zA-Z]+)(.groups[ ]*&&[ ]*[a-zA-Z]+.groups.descriptor)", "$1[1]");
//Minify with AjaxMin (we don't want an additional external tool with NPM or else for managing this
//kind of thing here...
js = Uglify.Js(js).Code;
//Computing ETag. Should be computed last !
string Etag = EtagGenerator.GenerateEtagFromString(js);
//Computing Build time for the Last-Modified Http Header
//We should rely on the creation date of the Microsoft API
//not the Blazor.Polyfill.Server one as the Microsoft.AspNetCore.Components.Server
//assembly may be updated in time. We will rely on the current creation/modification date on disk
DateTime buildTime = GetAssemblyCreationDate(assembly);
_patchedBlazorServerFile = new FileContentReference()
{
Value = js,
ETag = Etag,
LastModified = buildTime,
ContentLength = System.Text.UTF8Encoding.UTF8.GetByteCount(js).ToString(CultureInfo.InvariantCulture)
};
}
}
}
}
return(_patchedBlazorServerFile);
}
