[browser] Generate boot config as javascript module #112947

maraf · 2025-02-26T10:20:41Z

This is a first part of dotnet/aspnetcore#59456.
The goal is to still produce blazor.boot.json by default, but allow to opt-in for javascript module generation. The schema of the javascript module will change in future PR, for now just moving the JSON to JS.
The PR contains a temporal way (window["__DOTNET_INTERNAL_BOOT_CONFIG_SRC"] or <html data-DOTNET_INTERNAL_BOOT_CONFIG_SRC="">) to tweak default boot config location for feature opt-in in tests when the PR flows to other repos

…ral way to tweak default boot config location

maraf · 2025-02-26T13:17:22Z

/azp run runtime

azure-pipelines · 2025-02-26T13:17:55Z

Azure Pipelines successfully started running 1 pipeline(s).

maraf · 2025-02-26T18:52:30Z

/azp run runtime

azure-pipelines · 2025-02-26T18:52:44Z

Azure Pipelines successfully started running 1 pipeline(s).

Copilot

PR Overview

This PR enables an experimental opt‑in for generating the boot configuration as a JavaScript module while continuing to support the default JSON file. Key changes include:

Updating the config loading logic (loader/config.ts) to use a global boot config source and adding new functions to fetch or import the boot config.
Changing file and option names in several test and build files to switch from "blazor.boot.json" to "boot.js" and updating parsing logic accordingly.
Extending type definitions (types/index.ts) to accommodate the possibility of a JavaScript module returning a non‐Response promise.

Reviewed Changes

File	Description
src/mono/browser/runtime/loader/config.ts	Updated boot config source resolution and added boot config fetch/import functions for JS modules.
src/mono/wasm/Wasm.Build.Tests/ProjectProviderBase.cs	Adjusted boot config file name and parsing logic to support boot.js.
src/tasks/Microsoft.NET.Sdk.WebAssembly.Pack.Tasks/GenerateWasmBootJson.cs	Refactored WriteBootJson logic to output a JS module when appropriate.
src/mono/wasm/Wasm.Build.Tests/Templates/WasmTemplateTestsBase.cs	Added helper methods to update boot.js reference in HTML files for tests.
src/mono/wasm/Wasm.Build.Tests/BrowserStructures/*	Updated BootConfigFileName from "blazor.boot.json" to "boot.js" in various MSBuild options.
src/mono/wasm/Wasm.Build.Tests/WasmRunOutOfAppBundleTests.cs	Modified test HTML to include the new boot.js configuration.
src/mono/browser/runtime/types/index.ts	Extended LoadBootResourceCallback's return type signature to accept additional promise types.

Copilot reviewed 16 out of 16 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (1)

src/mono/browser/runtime/loader/config.ts:238

Ensure the attribute name used to override the boot config (data-dotnet_internal_boot_config_src) is consistent with the global variable usage and across test setups to avoid potential case-sensitive mismatches.

module.configSrc = (globalThis as any)["__DOTNET_INTERNAL_BOOT_CONFIG_SRC"] ?? globalThis.window?.document?.documentElement?.getAttribute("data-dotnet_internal_boot_config_src") ?? "./blazor.boot.json";

src/mono/browser/runtime/types/index.ts

src/mono/wasm/Wasm.Build.Tests/BrowserStructures/PublishOptions.cs

src/tasks/Microsoft.NET.Sdk.WebAssembly.Pack.Tasks/GenerateWasmBootJson.cs

src/mono/browser/runtime/loader/config.ts

pavelsavara

should we also change samples and templates ?
what about test-main.js ?

maraf · 2025-02-27T10:29:55Z

should we also change samples and templates ?
what about test-main.js ?

Templates are not affected and will benefit from it once it's opt-out.
Library tests are using WasmAppBuilder and thus it's not supported there yet. I'll come with something once it's opt-out.

PR Overview

This PR enables an opt-in mode for generating the boot configuration as a JavaScript module while still producing the traditional JSON file by default. Key changes include:

Updating the configuration loader to support both JSON and JS module formats.
Adjusting boot config file name references in multiple locations to handle the new JS module output.
Modifying test assets and build options to account for the new boot config file naming.

Reviewed Changes

File	Description
src/mono/browser/runtime/loader/config.ts	Adds support for JS module boot config and adapts boot config loading logic.
src/mono/wasm/Wasm.Build.Tests/ProjectProviderBase.cs	Updates boot config file name handling and parsing for JS modules.
src/tasks/Microsoft.NET.Sdk.WebAssembly.Pack.Tasks/GenerateWasmBootJson.cs	Renames and refactors the boot config generation method to support JS output.
src/mono/wasm/Wasm.Build.Tests/BrowserStructures/MSBuildOptions.cs	Changes boot config file name, though its value now differs from other parts of the PR.
src/mono/wasm/Wasm.Build.Tests/BrowserStructures/PublishOptions.cs	Updates boot config file name reference.
src/mono/wasm/Wasm.Build.Tests/Templates/WasmTemplateTestsBase.cs	Inserts boot config override script into HTML tests with the new file naming.
src/mono/browser/runtime/types/index.ts; src/mono/browser/runtime/loader/assets.ts	Update type signatures to support the new BootModule callback return type.
src/mono/wasm/Wasm.Build.Tests/WasmRunOutOfAppBundleTests.cs	Ensures that updated boot config references are used in the test HTML.

Copilot reviewed 17 out of 17 changed files in this pull request and generated no comments.

Comments suppressed due to low confidence (2)

src/mono/wasm/Wasm.Build.Tests/BrowserStructures/MSBuildOptions.cs:25

BootConfigFileName is set to "dotnet.boot.js" here, while other parts of the PR reference "boot.js"; please unify the boot config file name across the codebase.

string                          BootConfigFileName              = "dotnet.boot.js",

src/mono/wasm/Wasm.Build.Tests/BrowserStructures/PublishOptions.cs:29

The BootConfigFileName is set to "boot.js" in PublishOptions, which is inconsistent with the "dotnet.boot.js" used elsewhere; consider standardizing the boot config file name.

string BootConfigFileName                                   = "boot.js",

javiercn · 2025-02-27T11:06:43Z

src/mono/browser/runtime/loader/config.ts

+            loadedConfigResponse = await fetchBootConfig(appendUniqueQuery(defaultConfigSrc, "manifest"));
+            loadedConfig = await readBootConfigResponse(loadedConfigResponse);
+        } else {
+            loadedConfig = (await import(appendUniqueQuery(defaultConfigSrc, "manifest"))).config;


Is this because we are letting people control where blazor.boot.json was being loaded from?

@maraf is there a need for us to support that moving forward?

What scenario do we think still mandates we keep this around.

I'm saying this because the more we can simplify this process the better.

Caching and all those things we are handling through the importmap work we did, and I can't really see a reason for this being loaded from elsewhere

I think this could be in use by non-blazor customers, but I don't have anything specific

What was the original motivation? Modifying the URLs to point to some CDN or subpath on the server is still valid.
This callback processes all framework assets, not just JS modules

Yes, the original motivation was for letting people control the URLs of the deployed app, when we had issues with the anti-virus.

I think it's still fine for things that are "data" like the webcil, but is there a reason why we couldn't rely on relative paths for the module bits? After all, you can already change these urls during the build process modifying the relative paths of the respective assets.

I don't have a strong opinion. Since blazor users can configure .NET runtime through a callback on Blazor.start, they have all the flexibility to define the assets and their URLs in a defferent way than through the loadResource callback, on the other it's a breaking change.

src/mono/wasm/testassets/WasmBasicTestApp/App/wwwroot/index.html

src/tasks/Microsoft.NET.Sdk.WebAssembly.Pack.Tasks/GenerateWasmBootJson.cs

…Tests output

javiercn · 2025-02-28T11:05:47Z

src/mono/wasm/Wasm.Build.Tests/ProjectProviderBase.cs

+            var serializer = new DataContractJsonSerializer(
+                typeof(BootJsonData),
+                new DataContractJsonSerializerSettings { UseSimpleDictionaryFormat = true });
+
+            var config = (BootJsonData?)serializer.ReadObject(stream);
+            Assert.NotNull(config);
+            return config;


Is there a reason why you aren't using S.T.J?

I dunno. This code was probably inspired by the similar on SDK tests. I'll try to use S.T.J in follow up

javiercn

Looks great!

I have two open questions, but we can address them in a follow-up:

Getting rid of the old boot.json path in the runtime file(s). For 9.0 we should only use dotnet.boot.js
Doing a top-level import for the dotnet.config.js instead of it being updatable. You can already choose the URLs at build time specifying a relative path, and the import can also be relative to the root of the dotnet.js file.
Also, do we think we can get rid of the assets cache now? Or is that a separate item?

maraf · 2025-02-28T12:19:41Z

Getting rid of the old boot.json path in the runtime file(s). For 9.0 we should only use dotnet.boot.js

The goal is to have only dotnet.boot.js for .NET 10+.

Doing a top-level import for the dotnet.config.js instead of it being updatable. You can already choose the URLs at build time specifying a relative path, and the import can also be relative to the root of the dotnet.js file.

We had customers (non blazor) that were interested in not having a boot config as a separate file and configure it manually. I plan to experiment with defining all the modules as static imports to see how it plays with JS bundlers.

Also, do we think we can get rid of the assets cache now? Or is that a separate item?

Yes, I believe we can remove the cache in a separate task

Publish is not incremental and thus config file from first publish remain in the output after second publish. Caused by refactoring from dotnet#109069

maraf added 2 commits February 26, 2025 11:16

Generate JS module when boot config has .js extension

55f59bb

Load boot manifest as JS module when URL doesn't contain .json. Tempo…

35c4923

…ral way to tweak default boot config location

maraf added arch-wasm area-Build-mono os-browser labels Feb 26, 2025

maraf added this to the 10.0.0 milestone Feb 26, 2025

maraf self-assigned this Feb 26, 2025

maraf added 2 commits February 26, 2025 13:58

Tweak Wasm.Build.Tests to use boot.js

52115a3

Tweak Wasm.Build.Tests that create apps from templates to use boot.js

d76ef82

build-analysis bot mentioned this pull request Feb 26, 2025

[wasm][AOT] emcc : error - received SIGKILL (-9) #89402

Open

maraf added 3 commits February 26, 2025 17:02

Fix MiscTests

25534c9

Fix RunOutOfAppBundle

7a8e9dc

Fix method protection level

bab63ee

Fix missing head

6c8540a

This was referenced Feb 27, 2025

Error reported in diagnostic logs. Please examine the log for more details dotnet/dnceng#1928

Open

restarted. Azure DevOps can't recover from restarts. dotnet/dnceng#3879

Open

maraf marked this pull request as ready for review February 27, 2025 08:22

Copilot bot review requested due to automatic review settings February 27, 2025 08:22

maraf requested review from ilonatommy, lewing and pavelsavara as code owners February 27, 2025 08:22

maraf requested a review from javiercn February 27, 2025 08:22

Copilot AI reviewed Feb 27, 2025

View reviewed changes

src/mono/browser/runtime/types/index.ts Outdated Show resolved Hide resolved

pavelsavara reviewed Feb 27, 2025

View reviewed changes

src/mono/wasm/Wasm.Build.Tests/BrowserStructures/PublishOptions.cs Outdated Show resolved Hide resolved

pavelsavara reviewed Feb 27, 2025

View reviewed changes

src/tasks/Microsoft.NET.Sdk.WebAssembly.Pack.Tasks/GenerateWasmBootJson.cs Outdated Show resolved Hide resolved

pavelsavara reviewed Feb 27, 2025

View reviewed changes

src/mono/browser/runtime/loader/config.ts Show resolved Hide resolved

pavelsavara reviewed Feb 27, 2025

View reviewed changes

src/mono/browser/runtime/loader/config.ts Outdated Show resolved Hide resolved

pavelsavara reviewed Feb 27, 2025

View reviewed changes

Feedback

efdbb2a

maraf requested review from pavelsavara and Copilot February 27, 2025 10:31

Copilot AI reviewed Feb 27, 2025

View reviewed changes

javiercn reviewed Feb 27, 2025

View reviewed changes

maraf added 2 commits February 27, 2025 12:23

Update dotnet.boot.js in BuildOptions.cs

96b9807

Updatedotnet.boot.js in PublishOptions.cs

098e33f

pavelsavara reviewed Feb 27, 2025

View reviewed changes

src/mono/wasm/testassets/WasmBasicTestApp/App/wwwroot/index.html Outdated Show resolved Hide resolved

pavelsavara reviewed Feb 27, 2025

View reviewed changes

src/tasks/Microsoft.NET.Sdk.WebAssembly.Pack.Tasks/GenerateWasmBootJson.cs Show resolved Hide resolved

Fix remaining places after rename to dotnet.boot.js

273ebde

pavelsavara approved these changes Feb 27, 2025

View reviewed changes

Merge branch 'main' into BootJs

43b0d9a

build-analysis bot mentioned this pull request Feb 28, 2025

[wasm] at System.Net.Http.BrowserHttpInterop.CancellationHelper #112533

Open

maraf added 2 commits February 28, 2025 08:58

Now that boot.js starts with dotnet, we need to assert it Wasm.Build.…

4421059

…Tests output

Add missing return statement in method

361ba8d

javiercn reviewed Feb 28, 2025

View reviewed changes

javiercn approved these changes Feb 28, 2025

View reviewed changes

maraf added 4 commits February 28, 2025 14:13

Apply default environment name for boot.js

1bf96d3

Skip dotnet.boot.js from checking boot config files starting with dotnet

4f53191

Fix double publish in ModuleConfigTests.OverrideBootConfigName

9281240

Publish is not incremental and thus config file from first publish remain in the output after second publish. Caused by refactoring from dotnet#109069

Hotfix computing files to compare stats

1d078b0

build-analysis bot mentioned this pull request Mar 3, 2025

ManagedToNativeGenerator task fails: Microsoft.Build.Framework.BuildException.GenericBuildTransferredException: Unsupported parameter type in method 'PInvokeTests.StructureTests+CdeclSimpleExplStructDelegate.Invoke' #113025

Open

Merge branch 'main' into BootJs

695c95a

maraf merged commit bb146ad into dotnet:main Mar 4, 2025
30 of 33 checks passed

maraf deleted the BootJs branch March 4, 2025 13:55

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

[browser] Generate boot config as javascript module #112947

[browser] Generate boot config as javascript module #112947

maraf commented Feb 26, 2025 •

edited

Loading

maraf commented Feb 26, 2025

azure-pipelines bot commented Feb 26, 2025

maraf commented Feb 26, 2025

azure-pipelines bot commented Feb 26, 2025

Copilot AI left a comment

pavelsavara left a comment

maraf commented Feb 27, 2025

javiercn Feb 27, 2025

maraf Feb 27, 2025

javiercn Feb 27, 2025

pavelsavara Feb 27, 2025

maraf Feb 27, 2025 •

edited

Loading

javiercn Feb 28, 2025

maraf Feb 28, 2025

javiercn Feb 28, 2025

maraf Feb 28, 2025

javiercn left a comment •

edited

Loading

maraf commented Feb 28, 2025

[browser] Generate boot config as javascript module #112947

[browser] Generate boot config as javascript module #112947

Conversation

maraf commented Feb 26, 2025 • edited Loading

maraf commented Feb 26, 2025

azure-pipelines bot commented Feb 26, 2025

maraf commented Feb 26, 2025

azure-pipelines bot commented Feb 26, 2025

Copilot AI left a comment

Choose a reason for hiding this comment

PR Overview

Reviewed Changes

pavelsavara left a comment

Choose a reason for hiding this comment

maraf commented Feb 27, 2025

Choose a reason for hiding this comment

PR Overview

Reviewed Changes

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

maraf Feb 27, 2025 • edited Loading

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

javiercn left a comment • edited Loading

Choose a reason for hiding this comment

maraf commented Feb 28, 2025

maraf commented Feb 26, 2025 •

edited

Loading

maraf Feb 27, 2025 •

edited

Loading

javiercn left a comment •

edited

Loading