Go 1.8 新 联网 features

सैफी खानsaifi@ACM.org

New Networking

Warm up

package main

import "net/http"

func main() {

_, err := http.Get(`https://graph.facebook.com//v2.4/oauth/access_token`)

if err != nil {

panic(err.Error())

}

}

(22 hrs ago) https://github.com/golang/go/issues/19103

Warm up

package main

import "net/http"

func main() {

_, err := http.Get(`https://graph.facebook.com//v2.4/oauth/access_token`)

if err != nil {

panic(err.Error())

}

}

(22 hrs ago) https://github.com/golang/go/issues/19103

x/net/http2: requests with absolute URIs in URL.Opaque produce incorrect :path header #16847 (2016-08-16)

setup

SYN attack

tear-down

TLS exchange

socket

message

response

Server Client

Packets via intermediate device

A t

ale

of t

wo

prot

ocol

s

One TCP connection.

Request → StreamStreams are multiplexedStreams are prioritized

Binary Framing LayerPrioritizationFlow ControlServer Push

Header Compression

HTTP/2 Server Push

What does all this mean for Go ?

● You got to make “changes” in the library.● Lots of “small” changes

– Tools

– Libraries

–

● “Context” is critical.

Context

● A Context carries – a deadline

– a cancelation signal

– and other values across API boundaries.

● Context's methods may be called by multiple goroutines simultaneously.

Fix

● The fix tool has a new “context” fix to change imports from “golang.org/x/net/context” to

“context”.

Pprof

● The pprof tool can now profile TLS servers and skip certificate validation by using the “https+insecure” URL scheme.

Vet

● Vet now checks for copying an array of locks, duplicate JSON and XML struct field tags, non-space-separated struct tags, deferred calls to HTTP Response.Body.Close before checking errors, and indexed arguments in Printf.

HTTP Server Graceful Shutdown

● The HTTP Server now has support for – graceful shutdown using the new Server.Shutdown method

– abrupt shutdown using the new Server.Close method.

HTTP/2 Push

● The net/http package now includes a mechanism to send HTTP/2 server pushes from a Handler.

● Similar to the existing Flusher and Hijacker interfaces, an HTTP/2 ResponseWriter now implements the new Pusher interface.

Context is gonna be HUGE

● new Server.Shutdown takes a context argument.

● significant additions to the database/sql package with context support.

● All nine of the new Lookup methods on the new net.Resolver now take a context.

●

crypto/tls

● Conn.CloseWrite allows TLS connections to be half closed

● Config.Clone clones a TLS configuration.● Config.GetClientCertificate callback allows

selecting a client certificate based on the server's TLS CertificateRequest message, represented by the new CertificateRequestInfo

● Config.KeyLogWriter allows debugging TLS connections in WireShark

● … more

crypto/x509

● PSS signatures are now supported.● UnknownAuthorityError now has a Cert

field, reporting the untrusted certificate.● Certificate validation is more permissive in a few

cases and stricter in a few other cases.● Root certificates will now also be looked for at

/etc/pki/ca-trust/extracted/pem/tls-ca-bundle.pem on Linux, to support RHEL and CentOS.

expvar

● Package expvar provides a standardized interface to public variables

● operation counters in servers.● exposed via HTTP at /debug/vars in JSON

format.● new Handler function returns the package's

HTTP handler, to enable installing it in non-standard locations.

func Handler() http.Handler

net

● The new Buffers type permits writing to the network more efficiently from multiple discontiguous buffers in memory

● cf. writev● Scatter – gather

https://linux.die.net/man/2/writev●

net/http/httptrace

● support for tracing a client request's TLS handshakes– ClientTrace.TLSHandshakeStart

– ClientTrace.TLSHandshakeDone

net/http

● graceful shutdown support● Server adds configuration options

– ReadHeaderTimeout

– IdleTimeout

– and documents WriteTimeout

● FileServer and ServeContent now support HTTP If-Match conditional requests (RFC 7232)

net/http … server .. Handler

● Context returned by Request.Context is canceled if the underlying net.Conn closes. For instance, if the user closes their browser in the middle of a slow request

● Handler can now detect that the user is gone. This complements the existing CloseNotifier support.

● Handler can now abort a response by panicking with the error ErrAbortHandler.

net/http … server .. Handler

● To serve trailers produced after the header has already been written, see the new TrailerPrefix mechanism.

● Write of zero bytes to a ResponseWriter is now defined as a way to test whether a ResponseWriter has been hijacked

● If so, the Write returns ErrHijacked without printing an error to the server's error log.

net/http … Client

● Client now copies most request headers on redirect.

● Client now supports 301, 307, and 308 redirects.● Client.Post now follows 301 redirects, converting

them to GET requests without bodies● If the redirect requires resending the request

body, the request must have the new Request.GetBody field defined.

● NewRequest sets Request.GetBody automatically for common body types.

net/http … Transport

● Transport now supports international domain names.

● Get and other helpers.● Transport now rejects requests for URLs with

ports containing non-digit characters.● DefaultTransport.Dialer now enables DualStack● Transport no longer reads a byte of a non-nil

Request.Body when the Request.ContentLength is zero to determine whether the ContentLength is actually zero or just undefined.

empty interface

● interface {} may hold values of ANY type

References {URL}

● Go 1.8 release notes https://tip.golang.org/doc/go1.8

● HTTP/2 spec http://http2.github.io/http2-spec/index.html

● RSA PSS (Probabilistic Signature Scheme) https://www.emc.com/emc-plus/rsa-labs/historical/raising-standard-rsa-signatures-rsa-pss.htm

●

Legal { Attribution(s) }

● The usage of images is purely educational. The copyright for the images resides with their respective authros.

● Released under Creative Commons 4.0 Non-Commercial Share-Alike

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