http2及server push

 

本文主要研究下java9+springboot2+undertow2啟用http2及server push

maven

    <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.0.0.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>9</java.version> </properties> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-undertow</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> <exclusions> <exclusion> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-tomcat</artifactId> </exclusion> </exclusions> </dependency>

注意這里使用undertow，移除掉了starter-web中的tomcat依賴

配置

application.yml

server:  port: 8443  ssl: key-store: classpath:keystore.jks key-store-password: xxx key-password: xxx  protocol: TLSv1.2  http2:  enabled: true use-forward-headers: true

keystore生成實例

keytool -genkey -keyalg RSA -alias selfsigned -keystore src/main/resources/keystore.jks -storepass xxx -validity 360 -keysize 2048

ENABLE_HTTP2及ENABLE_PUSH

@Configuration public class Http2Config { @Bean UndertowServletWebServerFactory undertowServletWebServerFactory() { UndertowServletWebServerFactory factory = new UndertowServletWebServerFactory(); factory.addBuilderCustomizers( builder -> { builder.setServerOption(UndertowOptions.ENABLE_HTTP2, true) .setServerOption(UndertowOptions.HTTP2_SETTINGS_ENABLE_PUSH,true); }); return factory; } }

這里開啟了HTTP2以及server push功能

HTTP2實例

controller

@RestController public class IndexController { /** * curl -Ik --http2 https://localhost:8443/hello * @return */ @GetMapping("/hello") public String hello(){ return "hello"; } } 

運行

curl -Ivk --http2 https://localhost:8443/hello
* Trying ::1... * Connected to localhost (::1) port 8443 (#0) * ALPN, offering h2 * ALPN, offering http/1.1 * Cipher selection: ALL:!EXPORT:!EXPORT40:!EXPORT56:!aNULL:!LOW:!RC4:@STRENGTH * successfully set certificate verify locations: * CAfile: /usr/local/etc/openssl/cert.pem CApath: none * TLSv1.2 (OUT), TLS header, Certificate Status (22): * TLSv1.2 (OUT), TLS handshake, Client hello (1): * TLSv1.2 (IN), TLS handshake, Server hello (2): * TLSv1.2 (IN), TLS handshake, Certificate (11): * TLSv1.2 (IN), TLS handshake, Server key exchange (12): * TLSv1.2 (IN), TLS handshake, Server finished (14): * TLSv1.2 (OUT), TLS handshake, Client key exchange (16): * TLSv1.2 (OUT), TLS change cipher, Client hello (1): * TLSv1.2 (OUT), TLS handshake, Finished (20): * TLSv1.2 (IN), TLS change cipher, Client hello (1): * TLSv1.2 (IN), TLS handshake, Finished (20): * SSL connection using TLSv1.2 / ECDHE-RSA-AES256-GCM-SHA384 * ALPN, server accepted to use h2 * Server certificate: * subject: C=ZH; ST=guangdong; L=shenzhen; O=spring; OU=springboot; CN=localhost * start date: Mar 9 14:10:54 2018 GMT * expire date: Mar 4 14:10:54 2019 GMT * issuer: C=ZH; ST=guangdong; L=shenzhen; O=spring; OU=springboot; CN=localhost * SSL certificate verify result: self signed certificate (18), continuing anyway. * Using HTTP2, server supports multi-use * Connection state changed (HTTP/2 confirmed) * TCP_NODELAY set * Copying HTTP/2 data in stream buffer to connection buffer after upgrade: len=0 * Using Stream ID: 1 (easy handle 0x7f8a5280ea00) > HEAD /hello HTTP/1.1 > Host: localhost:8443 > User-Agent: curl/7.46.0 > Accept: */* > < HTTP/2.0 200 HTTP/2.0 200 < content-type:text/plain;charset=UTF-8 content-type:text/plain;charset=UTF-8 < content-length:5 content-length:5 < date:Fri, 09 Mar 2018 15:18:36 GMT date:Fri, 09 Mar 2018 15:18:36 GMT < * Connection #0 to host localhost left intact

注意，這里curl命令使用-k參數忽略校驗https，否則報錯

curl -I --http2 https://localhost:8443/hello curl: (60) SSL certificate problem: self signed certificate More details here: http://curl.haxx.se/docs/sslcerts.html curl performs SSL certificate verification by default, using a "bundle" of Certificate Authority (CA) public keys (CA certs). If the default bundle file isn't adequate, you can specify an alternate file using the --cacert option. If this HTTPS server uses a certificate signed by a CA represented in the bundle, the certificate verification probably failed due to a problem with the certificate (it might be expired, or the name might not match the domain name in the URL). If you'd like to turn off curl's verification of the certificate, use the -k (or --insecure) option.

server push實例

maven改動

    <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>9</java.version> <servlet-api.version>4.0.0</servlet-api.version> </properties> <dependencies> <dependency> <groupId>io.undertow</groupId> <artifactId>undertow-core</artifactId> <version>2.0.1.Final</version> </dependency> <dependency> <groupId>io.undertow</groupId> <artifactId>undertow-servlet</artifactId> <version>2.0.1.Final</version> </dependency> <dependency> <groupId>io.undertow</groupId> <artifactId>undertow-websockets-jsr</artifactId> <version>2.0.1.Final</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-undertow</artifactId> <exclusions> <exclusion> <groupId>io.undertow</groupId> <artifactId>undertow-core</artifactId> </exclusion> <exclusion> <groupId>io.undertow</groupId> <artifactId>undertow-servlet</artifactId> </exclusion> <exclusion> <groupId>io.undertow</groupId> <artifactId>undertow-websockets-jsr</artifactId> </exclusion> </exclusions> </dependency>

由於server push需要servlet4版本，目前springboot2依賴的undertow還是1.4版本的還只是servlet3，因此這里需要額外exclude掉再引入undertow2版本以支持servelt4

controller

    @GetMapping("/demo") public void http2ServerPush(HttpServletRequest request, HttpServletResponse response) throws IOException { PushBuilder pushBuilder = request.newPushBuilder(); pushBuilder .path("/demo.png") .addHeader("content-type", "image/png") .push(); try(PrintWriter respWriter = response.getWriter()){ respWriter.write("<html>" + "<img src='/demo.png'>" + "</html>"); } } @GetMapping(value = "/demo.png") public void download(HttpServletResponse response) throws IOException { InputStream data = getClass().getClassLoader().getResourceAsStream("demo.png"); response.setHeader("content-type", "image/png"); FileCopyUtils.copy(data,response.getOutputStream()); } 

運行

• 不啟用server push

沒有用server push，在在Initiator那欄，看到的是/demo這個觸發的。點開waterfall，會看到Content Download的耗時。

• 啟用server push

可以看到如果是用server push的，在Initiator那欄，有個Push標識，點開waterfall，會看到reading push的耗時。

小結

隨着java9支持HTTP2，servlet4引入PushBuilder支持server push，使用java作為服務端開發語言的開發者可以更方便地將HTTP2實踐起來。

截止到寫這篇文章之時，幾大servlet容器的servlet4支持情況：

• jetty尚且沒有看到支持servlet4的實現版本發布；
• tomcat有9.x版本支持servlet4，但是在springboot2上替換依賴報錯，整體實踐起來稍稍麻煩；
• undertow2.0.1.Final版本支持servlet4，在springboot2上替換依賴，非常簡單，沒有報錯，這也是本文選擇undertow的原因。

doc

• HTTP/2 服務器推送（Server Push）教程
• HTTP/2 PUSH(推送)與HTTP Preload(預加載)大比拼| Dexecure
• tomcat-9.0-doc
• Undertow provides support for Servlet 4.0, including support for embedded servlet