support h2c with prior knowledge

[taoso]

Support both http/1.x and h2c over the same plain tcp port.

It is common to make h2c communication on the server side environment. However, the standard net/http library does not support this feature in box (more detail). It would be a great convenient for gin to support it.

This patch is extracted from William Chang's work.

[codecov]

Codecov Report

Merging #1398 into master will decrease coverage by 0.6%.
The diff coverage is 62.5%.

@@            Coverage Diff            @@
##           master   #1398      +/-   ##
=========================================
- Coverage   98.21%   97.6%   -0.61%     
=========================================
  Files          35      36       +1     
  Lines        1846    1878      +32     
=========================================
+ Hits         1813    1833      +20     
- Misses         26      32       +6     
- Partials        7      13       +6

Impacted Files	Coverage Δ
gin.go	93.96% <60%> (-4.11%)	⬇️
h2c.go	71.42% <71.42%> (ø)

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[steveum0105]

Do you have any plan to keep going this feature?
I need H2C to support HTTP2 with TLS offloading.

In addition, there is now "golang.org/x/net/http2/h2c" package. I think it is quite simple to complete this with the package.

[Mistic92]

Any update on this or maybe it's already implemented?

[taoso]

hi @thinkerou , it seems some people still need this feature. And I have reimplemented it based on the golang.org/x/net/http2/h2c package. A new UseH2c option has been introduced to minimize the influence to other feature.

[kishaningithub]

@appleboy @thinkerou You have any concerns? I also resonate with @epii1 on the usefulness of this feature.

[raptoria]

+1

[c3l3si4n]

+1, i need this feature also

[HowardTangHw]

+1, i need this feature also

[Cavdy]

+1

[xiekeyi98]

+1 , any update?

[appleboy]

need @thinkerou approval.

[thinkerou]

lgtm

[halegreen]

Is gin support h2c ? I don't got this work

[kishaningithub]

The support for this got released in version 1.8.0. What is the version of gin you are using @ZoeShaw101 ?

Release notes - https://github.com/gin-gonic/gin/releases/tag/v1.8.0

[halegreen]

The support for this got released in version 1.8.0. What is the version of gin you are using @ZoeShaw101 ?

Release notes - https://github.com/gin-gonic/gin/releases/tag/v1.8.0

I'm using gin v1.8.1

github.com/gin-gonic/gin => github.com/gin-gonic/gin v1.8.1

[vorishirne]

doesn't supports yet.

curl --http2-prior-knowledge -i --location --request GET 'http://ncx-auth.cradlepoint.com:8000/oauth2/authorize?client_id=nca_linux_client&redirect_uri=https://www.google.com&scope=readall&state=fresh&login_hint=pkv@google_2.com&code_challenge=kp3mXDziinTfUVfUwdZVKHIB4OqQIQOBdBg41aWco30&response_type=code&code_challenge_method=SHA256' -v
Note: Unnecessary use of -X or --request, GET is already inferred.
*   Trying 127.0.0.1:8000...
* Connected to ncx-auth.cradlepoint.com (127.0.0.1) port 8000 (#0)
* Using HTTP2, server supports multiplexing
* Connection state changed (HTTP/2 confirmed)
* Copying HTTP/2 data in stream buffer to connection buffer after upgrade: len=0
* Using Stream ID: 1 (easy handle 0x55a9f9d3ae80)
> GET /oauth2/authorize?client_id=nca_linux_client&redirect_uri=https://www.google.com&scope=readall&state=fresh&login_hint=pkv@google_2.com&code_challenge=kp3mXDziinTfUVfUwdZVKHIB4OqQIQOBdBg41aWco30&response_type=code&code_challenge_method=SHA256 HTTP/2
> Host: ncx-auth.cradlepoint.com:8000
> user-agent: curl/7.81.0
> accept: */*
> 
* Empty reply from server
* Closing connection 0
curl: (52) Empty reply from server

[vorishirne]

Oh needed to add these flags

	router := gin.Default()
	router.UseH2C = true

[appleboy]

Another example using http.Server package.

	r := gin.Default()
	r.POST(path+":name", giteaHandler(handler))
	r.POST(grpcPath+":name", giteaHandler(gHandler))
	r.POST(grpcAlphaPath+":name", giteaHandler(gAlphaHandler))
	r.POST(grpcHealthPath+":name", giteaHandler(gHealthHandler))

	srv := &http.Server{
		Addr: ":8080",
		Handler: h2c.NewHandler(
			r,
			&http2.Server{},
		),
		ReadHeaderTimeout: time.Second,
		ReadTimeout:       5 * time.Minute,
		WriteTimeout:      5 * time.Minute,
		MaxHeaderBytes:    8 * 1024, // 8KiB
	}

	if err := srv.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
		log.Fatalf("HTTP listen and serve: %v", err)
	}

[ecmap]

Can Gin support custom handler in H2C?

	func (engine *Engine) Handler(customHandler ...http.Handler) http.Handler

	gin.UseH2C = true
	httpServer := &http.Server{Handler: gin.Handler(customHandler)}

[kishaningithub]

@ecmap What is the use case you have in mind?

[ecmap]

@ecmap What is the use case you have in mind?

grpc & rest on the same port