🔥 feat: Support for SendEarlyHints

[pjebs]

Description

Please provide a clear and concise description of the changes you've made and the problem they address. Include the purpose of the change, any relevant issues it solves, and the benefits it brings to the project. If this change introduces new features or adjustments, highlight them here.

Fixes #3211

Changes introduced

List the new features or adjustments introduced in this pull request. Provide details on benchmarks, documentation updates, changelog entries, and if applicable, the migration guide.

• [ ] Benchmarks: Describe any performance benchmarks and improvements related to the changes.
• [ ] Documentation Update: Detail the updates made to the documentation and links to the changed files.
• [ ] Changelog/What's New: Include a summary of the additions for the upcoming release notes.
• [ ] Migration Guide: If necessary, provide a guide or steps for users to migrate their existing code to accommodate these changes.
• [ ] API Alignment with Express: Explain how the changes align with the Express API.
• [ ] API Longevity: Discuss the steps taken to ensure that the new or updated APIs are consistent and not prone to breaking changes.
• [ ] Examples: Provide examples demonstrating the new features or changes in action.

Type of change

Please delete options that are not relevant.

• [ ] New feature (non-breaking change which adds functionality)
• [ ] Enhancement (improvement to existing features and functionality)
• [ ] Documentation update (changes to documentation)
• [ ] Performance improvement (non-breaking change which improves efficiency)
• [ ] Code consistency (non-breaking change which improves code reliability and robustness)

Checklist

Before you submit your pull request, please make sure you meet these requirements:

• [ ] Followed the inspiration of the Express.js framework for new functionalities, making them similar in usage.
• [ ] Conducted a self-review of the code and provided comments for complex or critical parts.
• [ ] Updated the documentation in the /docs/ directory for Fiber's documentation.
• [ ] Added or updated unit tests to validate the effectiveness of the changes or new features.
• [ ] Ensured that new and existing unit tests pass locally with the changes.
• [ ] Verified that any new dependencies are essential and have been agreed upon by the maintainers/community.
• [ ] Aimed for optimal performance with minimal allocations in the new code.
• [ ] Provided benchmarks for the new code to analyze and improve upon.

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[coderabbitai[bot]]

[!NOTE]

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Walkthrough

Adds HTTP 103 Early Hints support: new Ctx.SendEarlyHints([]string) and Res.SendEarlyHints([]string) APIs and tests; updates SendFile signature to SendFile(file string, config ...SendFile); App.Test changed to parse/discard interim 1xx responses and use a testable httpReadResponse wrapper; tests added for early hints and App.Test edge cases.

Changes

Cohort / File(s)	Summary
Ctx API changes ctx_interface_gen.go	Adds SendEarlyHints(hints []string) error; changes SendFile(file string) error → SendFile(file string, config ...SendFile) error.
Res API & impl res_interface_gen.go, res.go	Adds SendEarlyHints(hints []string) error to Res and implements func (r *DefaultRes) SendEarlyHints(hints []string) error (appends Link headers and calls fasthttp EarlyHints()).
App test client app.go	App.Test now loops to read interim 1xx responses, discards interim bodies, returns final response; introduces httpReadResponse var for test overriding.
Tests & helpers ctx_test.go, app_test.go	Adds Test_Ctx_SendEarlyHints and three App.Test edge-case tests; adds test helpers errorReadCloser, doubleCloseBody, test errors; tests override httpReadResponse.

Sequence Diagram(s)

sequenceDiagram
  autonumber
  participant Client
  participant TestClient as App.Test
  participant App
  participant Handler
  participant Res
  participant Fasthttp

  Client->>TestClient: raw request (test harness)
  TestClient->>App: deliver request
  App->>Handler: invoke route
  Handler->>Res: SendEarlyHints([]Link)
  Res->>Fasthttp: append Link headers and call EarlyHints()
  Fasthttp-->>Client: 103 Early Hints (Link headers)  -- interim
  Note right of TestClient: loop reads interim 1xx, discards body, continues
  Handler->>Res: write final status & body
  Res->>Fasthttp: send final response
  Fasthttp-->>Client: final response (e.g., 200 OK)

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Assessment against linked issues

Objective	Addressed	Explanation
Add Early Hints (HTTP 103) capability in Fiber (#3211)	✅
Provide Ctx API to send Early Hints (#3211)	✅
Implement via connection hijacking and manual 103 construction (#3211)	❌	Implementation calls fasthttp EarlyHints() and appends Link headers; no explicit hijack/manual raw write present.
Ensure Early Hints are sent before final response (#3211)	✅

Assessment against linked issues: Out-of-scope changes

Code Change	Explanation
App.Test multi-response loop and httpReadResponse test wrapper (app.go)	Test-client read-loop and test wrapper are client-side test harness changes, not required by the proposal which targeted server-side Early Hints. (app.go)
Test helper types simulating read/close failures (app_test.go)	Added test scaffolding (errorReadCloser, doubleCloseBody) to simulate client-side errors; these are test utilities unrelated to the original server-side proposal. (app_test.go)

Possibly related PRs

• gofiber/fiber#3172 — Changes to SendFile signature overlapping with this PR's SendFile(file string, config ...SendFile) change.
• gofiber/fiber#3279 — Modifies App.Test response-reading and error handling; closely related to the App.Test loop changes here.
• gofiber/fiber#3533 — Also updates Res/Ctx/DefaultRes to use variadic SendFile config; relevant to API surface changes.

Suggested reviewers

• sixcolors
• grivera64
• ReneWerner87

Poem

I tapped my paw and sent a hint,
A tiny 103—so bright, a glint!
Links raced off, the browser ran,
Final bytes arrived to finish the plan.
🥕🐇

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[pjebs]

I can't figure out why the tests are failing. Something not quite right with Fasthttp

[gaby]

I can't figure out why the tests are failing. Something not quite right with Fasthttp

You have a race condition in the SendEarlyHints test:

=== Failed
=== FAIL: . Test_Ctx_SendEarlyHints (0.00s)
panic: runtime error: invalid memory address or nil pointer dereference [recovered]
	panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0xcfe6f4]

goroutine 186 [running]:
testing.tRunner.func1.2({0x1097120, 0x1812bc0})
	/opt/hostedtoolcache/go/1.23.9/x64/src/testing/testing.go:1632 +0x3fc
testing.tRunner.func1()
	/opt/hostedtoolcache/go/1.23.9/x64/src/testing/testing.go:1635 +0x6b6
panic({0x1097120?, 0x1812bc0?})
	/opt/hostedtoolcache/go/1.23.9/x64/src/runtime/panic.go:791 +0x132
github.com/valyala/fasthttp.acquireWriter(0xc0002e1208)
	/home/runner/go/pkg/mod/github.com/valyala/[email protected]/server.go:2736 +0x54
github.com/valyala/fasthttp.(*RequestCtx).EarlyHints(0xc0002e1208)
	/home/runner/go/pkg/mod/github.com/valyala/[email protected]/server.go:647 +0xab
github.com/gofiber/fiber/v3.(*DefaultCtx).SendEarlyHints(0xc0002f6308, {0xc000264370, 0x1, 0x4bdb1b?})
	/home/runner/work/fiber/fiber/ctx.go:1577 +0x1d6
github.com/gofiber/fiber/v3.Test_Ctx_SendEarlyHints(0xc0003bb380)
	/home/runner/work/fiber/fiber/ctx_test.go:3123 +0xf9
testing.tRunner(0xc0003bb380, 0x11a8b70)
	/opt/hostedtoolcache/go/1.23.9/x64/src/testing/testing.go:1690 +0x227
created by testing.(*T).Run in goroutine 1
	/opt/hostedtoolcache/go/1.23.9/x64/src/testing/testing.go:1743 +0x826

[pjebs]

How can I fix it? It's not obvious where the race-condition is.

[gaby]

How can I fix it? It's not obvious where the race-condition is.

Seems the failure comes from Fasthttp? It happens when you call return c.fasthttp.EarlyHints()

[grivera64]

How can I fix it? It's not obvious where the race-condition is.

I would recommend using the app.Test() function for this kind of unit test. I ran into a similar race condition when I was working on c.SendStreamWriter() and c.End(). (See Issue #3278, PR #3279, and the app.Test() docs)

[pjebs]

Something is wrong. I changed the code.

app.Get("/earlyhints", func(c Ctx) error {
		c.SendEarlyHints(hints)
		c.Status(StatusBadRequest)
		return nil
})

resp.StatusCode is not updating to last status code. It is retaining 103 Early Hints instead of 400 Bad Request

This is how the test should look like: https://github.com/valyala/fasthttp/blob/master/server_test.go#L1922

[codecov[bot]]

Codecov Report

:x: Patch coverage is 88.46154% with 3 lines in your changes missing coverage. Please review. :white_check_mark: Project coverage is 91.81%. Comparing base (ac909e8) to head (03a8a25). :warning: Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
res.go	62.50%	2 Missing and 1 partial :warning:

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3483      +/-   ##
==========================================
- Coverage   91.81%   91.81%   -0.01%     
==========================================
  Files         114      114              
  Lines       11498    11517      +19     
==========================================
+ Hits        10557    10574      +17     
- Misses        681      682       +1     
- Partials      260      261       +1     

Flag	Coverage Δ
unittests	91.81% <88.46%> (-0.01%)	:arrow_down:

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[grivera64]

Something is wrong. I changed the code.

app.Get("/earlyhints", func(c Ctx) error {
		c.SendEarlyHints(hints)
		c.Status(StatusBadRequest)
		return nil
})

resp.StatusCode is not updating to last status code. It is retaining 103 Early Hints instead of 400 Bad Request

This is how the test should look like: https://github.com/valyala/fasthttp/blob/master/server_test.go#L1922

Can you try c.SendStatus(StatusBadRequest)? Maybe that's causing an issue, though I would also expect c.Status() to also work.

[pjebs]

Didn't work

[grivera64]

I tested it locally, and I can confirm that c.SendStatus() doesn't report StatusBadRequest properly either.

My thoughts are that one of the following is happening:

1. The app.Test() method only parses the EarlyHint, but doesn't parse the rest of the response.

For example, the HTTP response:

HTTP/1.1 103 Early Hints
Link: <https://cdn.com>; rel=preload; as=script

HTTP/1.1 200 OK
Content-Length: 0
Link: <https://cdn.com>; rel=preload; as=script

Could be parsed as only:

HTTP/1.1 103 Early Hints
Link: <https://cdn.com>; rel=preload; as=script

Possibly ignoring the rest of the response, or

2. There is some bug with SendEarlyHints(), where it only sends the hints and closes the connection.

If this is working properly locally, I believe that it's #1.

[grivera64]

I did some local testing, and indeed it's case #1. I added a panic within app.Test() to test if this happens:

// Check if anything is left in buffer
if buffer.Buffered() > 0 {
    remainingBytes, _ := buffer.Peek(buffer.Buffered())
    panic("BUFFER NOT EMPTY, REMAINING BYTES:\n\n" + string(remainingBytes))
}

And we indeed got a panic when running the test:

--- FAIL: Test_Ctx_SendEarlyHints (0.00s)
panic: BUFFER NOT EMPTY, REMAINING BYTES:

        HTTP/1.1 400 Bad Request
        Date: Tue, 27 May 2025 05:49:16 GMT
        Content-Type: text/plain; charset=utf-8
        Content-Length: 11
        Link: <https://cdn.com>; rel=preload; as=script

        Bad Request [recovered]
        panic: BUFFER NOT EMPTY, REMAINING BYTES:

        HTTP/1.1 400 Bad Request
        Date: Tue, 27 May 2025 05:49:16 GMT
        Content-Type: text/plain; charset=utf-8
        Content-Length: 11
        Link: <https://cdn.com>; rel=preload; as=script

        Bad Request

To properly test this feature, we would need to modify the app.Test() method (once again 😂) to ensure that we read the entire response as a client would.

[pjebs]

I believe HTTP/1.1 clients are meant to ignore 1xx status codes.

Only HTTP/2+ clients know how to properly interpret it.

[grivera64]

I believe HTTP/1.1 clients are meant to ignore 1xx status codes.

Only HTTP/2+ clients know how to properly interpret it.

@pjebs Do you know how a HTTP/2+ client would read in the request?

For example, should:

HTTP/1.1 103 Early Hints
Link: <https://cdn.com>; rel=preload; as=script

HTTP/1.1 400 Bad Request
Content-Length: 0
Link: <https://cdn.com>; rel=preload; as=script

be read as:

HTTP/1.1 400 Bad Request
Content-Length: 0
Link: <https://cdn.com>; rel=preload; as=script

Or would the client read it in some sort of other way? If the above is valid, then I have an idea of a (hacky) solution to get this to work within app.Test().

As of for actual clients, I believe that some sort of proxy that upgrades HTTP/1.1 responses into HTTP/2+ responses is necessary for production uses of Early Hints. (We should include this detail in the docs/ for this feature).

[pjebs]

Fiber is a http 1.1 server (and client). It should simply ignore interpreting the early hints and associated headers etc until it encounters a 2xx,3xx, 4xx or 5xx I believe.

A http 2 client will properly interpret the early hints. But the final status code will not be the early hints.

But for testing the server, we still need to verify that a 103 was first sent and then the 400

[ReneWerner87]

@pjebs thx for the implementation , check my hints

[pjebs]

Implementation is stuck right now

[ReneWerner87]

because of the problem with http2? if fiber sits behind a reverse proxy and communicates via http2 then the feature should work if not, then only no speed is saved or ?

[pjebs]

The issue is with the Test function and it's population of Response object's status.

Also potentially fiber.Client object.

Also, a way to read the Conn data sequentially (only for unit test purposes)

[ReneWerner87]

is it not possible to test it like in fasthttp ? https://github.com/valyala/fasthttp/pull/1996/files#diff-53170cac6baf0bf02f3aaa3994259ea4cffaaf2498e768fb7e03cf9f752af96c

or with an inmemory listener ? https://github.com/valyala/fasthttp/blob/46ae933953a610c389f33c1058b8c2b901113e55/fasthttputil/inmemory_listener.go#L16-L30

[ReneWerner87]

maybe we should provide another test method that uses buffers so that streaming etc. can be tested

[grivera64]

maybe we should provide another test method that uses buffers so that streaming etc. can be tested

@ReneWerner87 c.SendStreamWriter() is already supported with the currentapp.Test() configuration.

From my own testing, it is possible to modify our existing app.Test() implementation to work with c.SendEarlyHints() by doing the following:

• In app.Test(), the entire response is located in the buffer buffer := bufio.NewReader(&conn.w). We currently read the first response inside of this buffer and discard the rest of the buffer.

• Based on how we want to implement support for EarlyHints, we can:

1. Use a loop to continue trying to read from buffer for: a. A non 1XX response code (if we get any 1XX code, discard that portion of the buffer and try reading the next response) b. A non 103 response code (if we get EarlyHints, discard this portion of the buffer and try reading the next non 103 response) c. The last HTTP response (if we have a non-empty buffer, discard the currently read response and get the next one)
2. Or, Track all HTTP responses in a slice ([]*http.Response) if there are multiple responses in the output of the handler.

I have tried 1.b, and it seems to work for the unit test with c.Status(StatusBadRequest) after calling c.SendEarlyHints() above, so any of the above should help unblock @pjebs for this PR.

[grivera64]

A similar update for the above could be made for fiber.Client, though since it's tightly coupled with fasthttp's client in execFunc(), changes might need to made upstream first if it doesn't already work. We should probably test what happens with the current implementation.

[ReneWerner87]

@pjebs any progress ?

[pjebs]

It's blocked by issues in Fiber

[ReneWerner87]

Ok, i will test @grivera64 way for the tests

[ReneWerner87]

@grivera64 you mean like this ?

Patch

diff --git a/app.go b/app.go
index 75d83fd2dcbe7e916067b65a1f1a279ea0f48662..4229cabd3a95bdadf62957613a06b0e9313418cc 100644
--- a/app.go
+++ b/app.go
@@ -1094,60 +1094,74 @@ func (app *App) Test(req *http.Request, config ...TestConfig) (*http.Response, e
 		channel <- app.server.ServeConn(conn)
 		returned = true
 	}()
 
 	// Wait for callback
 	if cfg.Timeout > 0 {
 		// With timeout
 		select {
 		case err = <-channel:
 		case <-time.After(cfg.Timeout):
 			conn.Close() //nolint:errcheck // It is fine to ignore the error here
 			if cfg.FailOnTimeout {
 				return nil, os.ErrDeadlineExceeded
 			}
 		}
 	} else {
 		// Without timeout
 		err = <-channel
 	}
 
 	// Check for errors
 	if err != nil && !errors.Is(err, fasthttp.ErrGetOnly) && !errors.Is(err, errTestConnClosed) {
 		return nil, err
 	}
 
-	// Read response
+	// Read response(s)
 	buffer := bufio.NewReader(&conn.w)
 
-	// Convert raw http response to *http.Response
-	res, err := http.ReadResponse(buffer, req)
-	if err != nil {
-		if errors.Is(err, io.ErrUnexpectedEOF) {
-			return nil, ErrTestGotEmptyResponse
+	var res *http.Response
+	for {
+		// Convert raw http response to *http.Response
+		res, err = http.ReadResponse(buffer, req)
+		if err != nil {
+			if errors.Is(err, io.ErrUnexpectedEOF) {
+				return nil, ErrTestGotEmptyResponse
+			}
+			return nil, fmt.Errorf("failed to read response: %w", err)
+		}
+
+		// Break if this response is non-1xx or there are no more responses
+		if res.StatusCode >= http.StatusOK || buffer.Buffered() == 0 {
+			break
+		}
+
+		// Discard interim response body before reading the next one
+		if res.Body != nil {
+			_, _ = io.Copy(io.Discard, res.Body)
+			res.Body.Close()
 		}
-		return nil, fmt.Errorf("failed to read response: %w", err)
 	}
 
 	return res, nil
 }
 
 type disableLogger struct{}
 
 func (*disableLogger) Printf(string, ...any) {
 }
 
 func (app *App) init() *App {
 	// lock application
 	app.mutex.Lock()
 
 	// Initialize Services when needed,
 	// panics if there is an error starting them.
 	app.initServices()
 
 	// Only load templates if a view engine is specified
 	if app.config.Views != nil {
 		if err := app.config.Views.Load(); err != nil {
 			log.Warnf("failed to load views: %v", err)
 		}
 	}
 
diff --git a/app_test.go b/app_test.go
index 60232160e029885bd1215ee53e3eb05dbf40ddce..9d887d90518d801d5169bddcae0cdd64db9f5243 100644
--- a/app_test.go
+++ b/app_test.go
@@ -1737,50 +1737,71 @@ func Test_App_Test_timeout_empty_response(t *testing.T) {
 		return nil
 	})
 
 	_, err := app.Test(httptest.NewRequest(MethodGet, "/", nil), TestConfig{
 		Timeout:       100 * time.Millisecond,
 		FailOnTimeout: false,
 	})
 	require.ErrorIs(t, err, ErrTestGotEmptyResponse)
 }
 
 func Test_App_Test_drop_empty_response(t *testing.T) {
 	t.Parallel()
 
 	app := New()
 	app.Get("/", func(c Ctx) error {
 		return c.Drop()
 	})
 
 	_, err := app.Test(httptest.NewRequest(MethodGet, "/", nil), TestConfig{
 		Timeout:       0,
 		FailOnTimeout: false,
 	})
 	require.ErrorIs(t, err, ErrTestGotEmptyResponse)
 }
 
+func Test_App_Test_EarlyHints(t *testing.T) {
+	t.Parallel()
+
+	app := New()
+	hints := []string{"<https://cdn.com>; rel=preload; as=script"}
+	app.Get("/early", func(c Ctx) error {
+		c.SendEarlyHints(hints)
+		return c.Status(StatusOK).SendString("done")
+	})
+
+	req := httptest.NewRequest(MethodGet, "/early", nil)
+	resp, err := app.Test(req)
+
+	require.NoError(t, err)
+	require.Equal(t, StatusOK, resp.StatusCode)
+	require.Equal(t, hints, resp.Header["Link"])
+	body, err := io.ReadAll(resp.Body)
+	require.NoError(t, err)
+	require.Equal(t, "done", string(body))
+}
+
 func Test_App_SetTLSHandler(t *testing.T) {
 	t.Parallel()
 	tlsHandler := &TLSHandler{clientHelloInfo: &tls.ClientHelloInfo{
 		ServerName: "example.golang",
 	}}
 
 	app := New()
 	app.SetTLSHandler(tlsHandler)
 
 	c := app.AcquireCtx(&fasthttp.RequestCtx{})
 	defer app.ReleaseCtx(c)
 
 	require.Equal(t, "example.golang", c.ClientHelloInfo().ServerName)
 }
 
 func Test_App_AddCustomRequestMethod(t *testing.T) {
 	t.Parallel()
 	methods := append(DefaultMethods, "TEST") //nolint:gocritic // We want a new slice here
 	app := New(Config{
 		RequestMethods: methods,
 	})
 	appMethods := app.config.RequestMethods
 
 	// method name is always uppercase - https://datatracker.ietf.org/doc/html/rfc7231#section-4.1
 	require.Equal(t, len(app.stack), len(appMethods))
diff --git a/ctx_test.go b/ctx_test.go
index 0510f7b47e27f241df7a16411e8447e8bf2b57a0..0de5eea8f4253e3961d8c8922b4b31480143286b 100644
--- a/ctx_test.go
+++ b/ctx_test.go
@@ -3467,62 +3467,62 @@ func Test_Ctx_Download(t *testing.T) {
 	}()
 
 	expect, err := io.ReadAll(f)
 	require.NoError(t, err)
 	require.Equal(t, expect, c.Response().Body())
 	require.Equal(t, `attachment; filename="Awesome+File%21"`, string(c.Response().Header.Peek(HeaderContentDisposition)))
 
 	require.NoError(t, c.Res().Download("ctx.go"))
 	require.Equal(t, `attachment; filename="ctx.go"`, string(c.Response().Header.Peek(HeaderContentDisposition)))
 
 	require.NoError(t, c.Download("ctx.go", "файл.txt"))
 	header := string(c.Response().Header.Peek(HeaderContentDisposition))
 	require.Contains(t, header, `filename="файл.txt"`)
 	require.Contains(t, header, `filename*=UTF-8''%D1%84%D0%B0%D0%B9%D0%BB.txt`)
 }
 
 // go test -race -run Test_Ctx_SendEarlyHints
 func Test_Ctx_SendEarlyHints(t *testing.T) {
 	t.Parallel()
 	app := New()
 
 	hints := []string{"<https://cdn.com>; rel=preload; as=script"}
 	app.Get("/earlyhints", func(c Ctx) error {
 		c.SendEarlyHints(hints)
 		c.Status(StatusBadRequest)
-		return nil
+		return c.SendString("fail")
 	})
 
 	req := httptest.NewRequest(MethodGet, "/earlyhints", nil)
 	resp, err := app.Test(req)
 
-	fmt.Println(resp.StatusCode)
-	fmt.Println(resp.Header)
-
 	require.NoError(t, err, "app.Test(req)")
-	require.Equal(t, StatusEarlyHints, resp.StatusCode, "Status code")
+	require.Equal(t, StatusBadRequest, resp.StatusCode, "Status code")
 	require.Equal(t, hints, resp.Header["Link"], "Link header")
+	body, err := io.ReadAll(resp.Body)
+	require.NoError(t, err)
+	require.Equal(t, "fail", string(body))
 }
 
 // go test -race -run Test_Ctx_SendFile
 func Test_Ctx_SendFile(t *testing.T) {
 	t.Parallel()
 	app := New()
 
 	// fetch file content
 	f, err := os.Open("./ctx.go")
 	require.NoError(t, err)
 	defer func() {
 		require.NoError(t, f.Close())
 	}()
 	expectFileContent, err := io.ReadAll(f)
 	require.NoError(t, err)
 	// fetch file info for the not modified test case
 	fI, err := os.Stat("./ctx.go")
 	require.NoError(t, err)
 
 	// simple test case
 	c := app.AcquireCtx(&fasthttp.RequestCtx{})
 	err = c.SendFile("ctx.go")
 	// check expectation
 	require.NoError(t, err)
 	require.Equal(t, expectFileContent, c.Response().Body())

[grivera64]

@grivera64 you mean like this ?

Patch

diff --git a/app.go b/app.go

index 75d83fd2dcbe7e916067b65a1f1a279ea0f48662..4229cabd3a95bdadf62957613a06b0e9313418cc 100644

--- a/app.go

+++ b/app.go

@@ -1094,60 +1094,74 @@ func (app *App) Test(req *http.Request, config ...TestConfig) (*http.Response, e

 		channel <- app.server.ServeConn(conn)

 		returned = true

 	}()

 

 	// Wait for callback

 	if cfg.Timeout > 0 {

 		// With timeout

 		select {

 		case err = <-channel:

 		case <-time.After(cfg.Timeout):

 			conn.Close() //nolint:errcheck // It is fine to ignore the error here

 			if cfg.FailOnTimeout {

 				return nil, os.ErrDeadlineExceeded

 			}

 		}

 	} else {

 		// Without timeout

 		err = <-channel

 	}

 

 	// Check for errors

 	if err != nil && !errors.Is(err, fasthttp.ErrGetOnly) && !errors.Is(err, errTestConnClosed) {

 		return nil, err

 	}

 

-	// Read response

+	// Read response(s)

 	buffer := bufio.NewReader(&conn.w)

 

-	// Convert raw http response to *http.Response

-	res, err := http.ReadResponse(buffer, req)

-	if err != nil {

-		if errors.Is(err, io.ErrUnexpectedEOF) {

-			return nil, ErrTestGotEmptyResponse

+	var res *http.Response

+	for {

+		// Convert raw http response to *http.Response

+		res, err = http.ReadResponse(buffer, req)

+		if err != nil {

+			if errors.Is(err, io.ErrUnexpectedEOF) {

+				return nil, ErrTestGotEmptyResponse

+			}

+			return nil, fmt.Errorf("failed to read response: %w", err)

+		}

+

+		// Break if this response is non-1xx or there are no more responses

+		if res.StatusCode >= http.StatusOK || buffer.Buffered() == 0 {

+			break

+		}

+

+		// Discard interim response body before reading the next one

+		if res.Body != nil {

+			_, _ = io.Copy(io.Discard, res.Body)

+			res.Body.Close()

 		}

-		return nil, fmt.Errorf("failed to read response: %w", err)

 	}

 

 	return res, nil

 }

 

 type disableLogger struct{}

 

 func (*disableLogger) Printf(string, ...any) {

 }

 

 func (app *App) init() *App {

 	// lock application

 	app.mutex.Lock()

 

 	// Initialize Services when needed,

 	// panics if there is an error starting them.

 	app.initServices()

 

 	// Only load templates if a view engine is specified

 	if app.config.Views != nil {

 		if err := app.config.Views.Load(); err != nil {

 			log.Warnf("failed to load views: %v", err)

 		}

 	}

 

diff --git a/app_test.go b/app_test.go

index 60232160e029885bd1215ee53e3eb05dbf40ddce..9d887d90518d801d5169bddcae0cdd64db9f5243 100644

--- a/app_test.go

+++ b/app_test.go

@@ -1737,50 +1737,71 @@ func Test_App_Test_timeout_empty_response(t *testing.T) {

 		return nil

 	})

 

 	_, err := app.Test(httptest.NewRequest(MethodGet, "/", nil), TestConfig{

 		Timeout:       100 * time.Millisecond,

 		FailOnTimeout: false,

 	})

 	require.ErrorIs(t, err, ErrTestGotEmptyResponse)

 }

 

 func Test_App_Test_drop_empty_response(t *testing.T) {

 	t.Parallel()

 

 	app := New()

 	app.Get("/", func(c Ctx) error {

 		return c.Drop()

 	})

 

 	_, err := app.Test(httptest.NewRequest(MethodGet, "/", nil), TestConfig{

 		Timeout:       0,

 		FailOnTimeout: false,

 	})

 	require.ErrorIs(t, err, ErrTestGotEmptyResponse)

 }

 

+func Test_App_Test_EarlyHints(t *testing.T) {

+	t.Parallel()

+

+	app := New()

+	hints := []string{"<https://cdn.com>; rel=preload; as=script"}

+	app.Get("/early", func(c Ctx) error {

+		c.SendEarlyHints(hints)

+		return c.Status(StatusOK).SendString("done")

+	})

+

+	req := httptest.NewRequest(MethodGet, "/early", nil)

+	resp, err := app.Test(req)

+

+	require.NoError(t, err)

+	require.Equal(t, StatusOK, resp.StatusCode)

+	require.Equal(t, hints, resp.Header["Link"])

+	body, err := io.ReadAll(resp.Body)

+	require.NoError(t, err)

+	require.Equal(t, "done", string(body))

+}

+

 func Test_App_SetTLSHandler(t *testing.T) {

 	t.Parallel()

 	tlsHandler := &TLSHandler{clientHelloInfo: &tls.ClientHelloInfo{

 		ServerName: "example.golang",

 	}}

 

 	app := New()

 	app.SetTLSHandler(tlsHandler)

 

 	c := app.AcquireCtx(&fasthttp.RequestCtx{})

 	defer app.ReleaseCtx(c)

 

 	require.Equal(t, "example.golang", c.ClientHelloInfo().ServerName)

 }

 

 func Test_App_AddCustomRequestMethod(t *testing.T) {

 	t.Parallel()

 	methods := append(DefaultMethods, "TEST") //nolint:gocritic // We want a new slice here

 	app := New(Config{

 		RequestMethods: methods,

 	})

 	appMethods := app.config.RequestMethods

 

 	// method name is always uppercase - https://datatracker.ietf.org/doc/html/rfc7231#section-4.1

 	require.Equal(t, len(app.stack), len(appMethods))

diff --git a/ctx_test.go b/ctx_test.go

index 0510f7b47e27f241df7a16411e8447e8bf2b57a0..0de5eea8f4253e3961d8c8922b4b31480143286b 100644

--- a/ctx_test.go

+++ b/ctx_test.go

@@ -3467,62 +3467,62 @@ func Test_Ctx_Download(t *testing.T) {

 	}()

 

 	expect, err := io.ReadAll(f)

 	require.NoError(t, err)

 	require.Equal(t, expect, c.Response().Body())

 	require.Equal(t, `attachment; filename="Awesome+File%21"`, string(c.Response().Header.Peek(HeaderContentDisposition)))

 

 	require.NoError(t, c.Res().Download("ctx.go"))

 	require.Equal(t, `attachment; filename="ctx.go"`, string(c.Response().Header.Peek(HeaderContentDisposition)))

 

 	require.NoError(t, c.Download("ctx.go", "файл.txt"))

 	header := string(c.Response().Header.Peek(HeaderContentDisposition))

 	require.Contains(t, header, `filename="файл.txt"`)

 	require.Contains(t, header, `filename*=UTF-8''%D1%84%D0%B0%D0%B9%D0%BB.txt`)

 }

 

 // go test -race -run Test_Ctx_SendEarlyHints

 func Test_Ctx_SendEarlyHints(t *testing.T) {

 	t.Parallel()

 	app := New()

 

 	hints := []string{"<https://cdn.com>; rel=preload; as=script"}

 	app.Get("/earlyhints", func(c Ctx) error {

 		c.SendEarlyHints(hints)

 		c.Status(StatusBadRequest)

-		return nil

+		return c.SendString("fail")

 	})

 

 	req := httptest.NewRequest(MethodGet, "/earlyhints", nil)

 	resp, err := app.Test(req)

 

-	fmt.Println(resp.StatusCode)

-	fmt.Println(resp.Header)

-

 	require.NoError(t, err, "app.Test(req)")

-	require.Equal(t, StatusEarlyHints, resp.StatusCode, "Status code")

+	require.Equal(t, StatusBadRequest, resp.StatusCode, "Status code")

 	require.Equal(t, hints, resp.Header["Link"], "Link header")

+	body, err := io.ReadAll(resp.Body)

+	require.NoError(t, err)

+	require.Equal(t, "fail", string(body))

 }

 

 // go test -race -run Test_Ctx_SendFile

 func Test_Ctx_SendFile(t *testing.T) {

 	t.Parallel()

 	app := New()

 

 	// fetch file content

 	f, err := os.Open("./ctx.go")

 	require.NoError(t, err)

 	defer func() {

 		require.NoError(t, f.Close())

 	}()

 	expectFileContent, err := io.ReadAll(f)

 	require.NoError(t, err)

 	// fetch file info for the not modified test case

 	fI, err := os.Stat("./ctx.go")

 	require.NoError(t, err)

 

 	// simple test case

 	c := app.AcquireCtx(&fasthttp.RequestCtx{})

 	err = c.SendFile("ctx.go")

 	// check expectation

 	require.NoError(t, err)

 	require.Equal(t, expectFileContent, c.Response().Body())

@ReneWerner87 Yes, the patch LGTM 🚀

We could also consider having a separate Test method that returns the full stream of responses as a slice, but I am not sure if this is necessary.

If that's not needed, then I believe this is all we need to merge the PR to main.

[ReneWerner87]

@pjebs can you check my patch

[pjebs]

Where is the patch?