Spring Boot Web and Webflux Helpers/Binding for CloudEvents

.gitignore

@@ -40,3 +40,4 @@ _site/
 .sass-cache/
 .jekyll-cache/
 .jekyll-metadata
+.DS_Store

http/spring-boot-starter-web-cloudevents/README.md

@@ -0,0 +1,46 @@
+# HTTP Protocol Binding for Spring Boot Web (Reactive Stack)
+
+For Maven based projects, use the following to configure the CloudEvents Spring Boot Binding:
+
+```xml
+<dependency>
+    <groupId>io.cloudevents</groupId>
+    <artifactId>spring-boot-starter-web-cloudevents</artifactId>
+    <version>2.0.0-milestone1</version>
+</dependency>
+```
+
+## Receiving CloudEvents
+Below is a sample on how to read and write CloudEvents from a Post Request Headers and Body:
+
+```java
+    @PostMapping
+    public String recieveCloudEvent(@RequestHeader Map<String, String> headers, @RequestBody Object body) {
+      // Create a CloudEvent from Header and Body coming in the request
+      CloudEvent cloudEvent = CloudEventsHelper.parseFromRequest(headers, body);
+
+
+    }
+```
+
+
+## Sending CloudEvents
+
+
+Below is a sample on how to use the client to send a CloudEvent:
+
+```java
+  // Create the CloudEvent with the builder
+  final CloudEvent myCloudEvent = CloudEventBuilder.v03()
+                .withId("ABC-123")
+                .withType("my-first-cloud-event")
+                .withSource(URI.create("knative-event-producer.default.svc.cluster.local"))
+                .withData(SerializationUtils.serialize("{\"name\" : \"" + name + "-" + UUID.randomUUID().toString() + "\" }"))
+                .withDataContentType("application/json")
+                .build();
+
+  // Using RestTemplate
+  RestTemplate restTemplate = new RestTemplate();
+  ResponseEntity<String> response = CloudEventsHelper.createPostCloudEvent(restemplate, <HOST>, cloudEvent);
+
+```

http/spring-boot-starter-web-cloudevents/pom.xml

@@ -0,0 +1,52 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>io.cloudevents</groupId>
+        <artifactId>cloudevents-parent</artifactId>
+        <version>2.0.0-SNAPSHOT</version>
+        <relativePath>../../</relativePath>
+    </parent>
+
+	<artifactId>spring-boot-starter-web-cloudevents</artifactId>
+    <name>CloudEvents - Spring Boot Web Http Binding</name>
+	<description>Simple Helper for Cloud Events in Spring Boot Web</description>
+
+	<properties>
+		<java.version>11</java.version>
+		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
+		<maven.compiler.source>${java.version}</maven.compiler.source>
+		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+		<maven.compiler.target>${java.version}</maven.compiler.target>
+	</properties>
+
+    <dependencyManagement>
+		<dependencies>
+			<dependency>
+				<!-- Import dependency management from Spring Boot -->
+				<groupId>org.springframework.boot</groupId>
+				<artifactId>spring-boot-dependencies</artifactId>
+				<version>2.2.4.RELEASE</version>
+				<type>pom</type>
+				<scope>import</scope>
+			</dependency>
+		</dependencies>
+    </dependencyManagement>
+
+	<dependencies>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-web</artifactId>
+            <scope>provided</scope>
+		</dependency>
+		<dependency>
+			<groupId>io.cloudevents</groupId>
+			<artifactId>cloudevents-core</artifactId>
+			<version>${project.version}</version>
+		</dependency>
+
+	</dependencies>
+
+</project>

http/spring-boot-starter-web-cloudevents/src/main/java/io/cloudevents/http/springboot/web/helper/CloudEventsHelper.java

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+package io.cloudevents.http.springboot.web.helper;
+
+import io.cloudevents.CloudEvent;
+import io.cloudevents.core.builder.CloudEventBuilder;
+
+import org.springframework.http.HttpEntity;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.ResponseEntity;
+import org.springframework.util.SerializationUtils;
+import org.springframework.web.client.RestTemplate;
+
+import java.net.URI;
+import java.time.ZonedDateTime;
+import java.util.Map;
+
+public class CloudEventsHelper {
+
+    public static final String CE_ID = "Ce-Id";
+    public static final String CE_TYPE = "Ce-Type";
+    public static final String CE_SOURCE = "Ce-Source";
+    public static final String CE_SPECVERSION = "Ce-Specversion";
+    public static final String CE_TIME = "Ce-Time";
+
+    public static final String APPLICATION_JSON = "application/json";
+    public static final String CONTENT_TYPE = "Content-Type";
+
+
+    public static CloudEvent parseFromRequest(Map<String, String> headers, Object body) throws IllegalStateException {
+        if (headers.get(CE_ID) == null || (headers.get(CE_SOURCE) == null || headers.get(CE_TYPE) == null)) {
+            throw new IllegalStateException("Cloud Event required fields are not present.");
+        }
+
+        return CloudEventBuilder.v03()
+                .withId(headers.get(CE_ID))
+                .withType(headers.get(CE_TYPE))
+                .withSource((headers.get(CE_SOURCE) != null) ? URI.create(headers.get(CE_SOURCE)) : null)
+                .withTime((headers.get(CE_TIME) != null) ? ZonedDateTime.parse(headers.get(CE_TIME)) : null)
+                .withData(SerializationUtils.serialize(body))
+                .withDataContentType((headers.get(CONTENT_TYPE) != null) ? headers.get(CONTENT_TYPE) : APPLICATION_JSON)
+                .build();
+    }
+
+
+    public static ResponseEntity<String> createPostCloudEvent(RestTemplate restTemplate, String host, CloudEvent cloudEvent) {
+
+        HttpHeaders headers = new HttpHeaders();
+        headers.add(CE_ID, cloudEvent.getId());
+        headers.add(CE_SPECVERSION, cloudEvent.getSpecVersion().name());
+        headers.add(CONTENT_TYPE, APPLICATION_JSON);
+        headers.add(CE_TYPE, cloudEvent.getType());
+        headers.add(CE_TIME, cloudEvent.getTime().toString());
+        headers.add(CE_SOURCE, cloudEvent.getSource().toString());
+
+        for(String key : cloudEvent.getExtensionNames()) {
+            headers.add(key, cloudEvent.getExtension(key).toString());
+        }
+
+        HttpEntity<String> request = new HttpEntity<String>(SerializationUtils.deserialize(cloudEvent.getData()).toString(), headers);
+
+        return restTemplate.postForEntity(host, request, String.class);
+    }
+
+
+}

http/spring-boot-starter-webflux-cloudevents/README.md

@@ -0,0 +1,49 @@
+# HTTP Protocol Binding for Spring Boot Webflux (Reactive Stack)
+
+For Maven based projects, use the following to configure the CloudEvents Spring Boot Binding:
+
+```xml
+<dependency>
+    <groupId>io.cloudevents</groupId>
+    <artifactId>spring-boot-starter-web-cloudevents</artifactId>
+    <version>2.0.0-milestone1</version>
+</dependency>
+```
+
+## Receiving CloudEvents
+Below is a sample on how to read and write CloudEvents from a Post Request Headers and Body:
+
+```java
+    @PostMapping
+    public String recieveCloudEvent(@RequestHeader Map<String, String> headers, @RequestBody Object body) {
+      // Create a CloudEvent from Header and Body coming in the request
+      CloudEvent cloudEvent = CloudEventsHelper.parseFromRequest(headers, body);
+
+
+    }
+```
+
+
+## Sending CloudEvents
+
+
+Below is a sample on how to use the client to send a CloudEvent:
+
+```java
+  // Create the CloudEvent with the builder
+  final CloudEvent myCloudEvent = CloudEventBuilder.v03()
+                .withId("ABC-123")
+                .withType("my-first-cloud-event")
+                .withSource(URI.create("knative-event-producer.default.svc.cluster.local"))
+                .withData(SerializationUtils.serialize("{\"name\" : \"" + name + "-" + UUID.randomUUID().toString() + "\" }"))
+                .withDataContentType("application/json")
+                .build();
+
+  // Use Reactive WebClient
+  WebClient webClient = WebClient.builder().baseUrl(HOST).filter(logRequest()).build();
+  // Use the Helper to Create the Post Request with your CloudEvent in it
+  WebClient.ResponseSpec postCloudEvent = CloudEventsHelper.createPostCloudEvent(webClient, myCloudEvent);
+
+  postCloudEvent.bodyToMono(String.class).doOnError(t -> t.printStackTrace())
+                .doOnSuccess(s -> System.out.println("Result -> " + s)).subscribe();
+```

http/spring-boot-starter-webflux-cloudevents/pom.xml

@@ -0,0 +1,52 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>io.cloudevents</groupId>
+        <artifactId>cloudevents-parent</artifactId>
+        <version>2.0.0-SNAPSHOT</version>
+        <relativePath>../../</relativePath>
+    </parent>
+
+	<artifactId>spring-boot-starter-webflux-cloudevents</artifactId>
+    <name>CloudEvents - Spring Boot Webflux (Reactive) Http Binding</name>
+	<description>Simple Helper for Cloud Events in Spring Boot Webflux</description>
+
+	<properties>
+		<java.version>11</java.version>
+		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
+		<maven.compiler.source>${java.version}</maven.compiler.source>
+		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+		<maven.compiler.target>${java.version}</maven.compiler.target>
+	</properties>
+
+    <dependencyManagement>
+		<dependencies>
+			<dependency>
+				<!-- Import dependency management from Spring Boot -->
+				<groupId>org.springframework.boot</groupId>
+				<artifactId>spring-boot-dependencies</artifactId>
+				<version>2.2.4.RELEASE</version>
+				<type>pom</type>
+				<scope>import</scope>
+			</dependency>
+		</dependencies>
+    </dependencyManagement>
+
+	<dependencies>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-webflux</artifactId>
+            <scope>provided</scope>
+		</dependency>
+		<dependency>
+			<groupId>io.cloudevents</groupId>
+			<artifactId>cloudevents-core</artifactId>
+			<version>${project.version}</version>
+		</dependency>
+
+	</dependencies>
+
+</project>

http/spring-boot-starter-webflux-cloudevents/src/main/java/io/cloudevents/http/springboot/webflux/helper/CloudEventsHelper.java

@@ -0,0 +1,79 @@
+package io.cloudevents.http.springboot.webflux.helper;
+
+import io.cloudevents.CloudEvent;
+import io.cloudevents.Extension;
+import io.cloudevents.core.builder.CloudEventBuilder;
+import org.springframework.util.SerializationUtils;
+import org.springframework.web.reactive.function.BodyInserters;
+import org.springframework.web.reactive.function.client.WebClient;
+
+import java.net.URI;
+import java.time.ZonedDateTime;
+import java.util.Map;
+
+public class CloudEventsHelper {
+
+    public static final String CE_ID = "Ce-Id";
+    public static final String CE_TYPE = "Ce-Type";
+    public static final String CE_SOURCE = "Ce-Source";
+    public static final String CE_SPECVERSION = "Ce-Specversion";
+    public static final String CE_TIME = "Ce-Time";
+    public static final String CE_SUBJECT = "Ce-Subject";
+
+    public static final String APPLICATION_JSON = "application/json";
+    public static final String CONTENT_TYPE = "Content-Type";
+
+
+    public static CloudEvent parseFromRequest(Map<String, String> headers, Object body) throws IllegalStateException {
+        return parseFromRequestWithExtension(headers, body, null);
+    }
+
+
+    public static CloudEvent parseFromRequestWithExtension(Map<String, String> headers, Object body, Extension extension) {
+        if (headers.get(CE_ID) == null || (headers.get(CE_SOURCE) == null || headers.get(CE_TYPE) == null)) {
+            throw new IllegalStateException("Cloud Event required fields are not present.");
+        }
+
+        CloudEventBuilder builder = CloudEventBuilder.v03()
+            .withId(headers.get(CE_ID))
+            .withType(headers.get(CE_TYPE))
+            .withSource((headers.get(CE_SOURCE) != null) ? URI.create(headers.get(CE_SOURCE)) : null)
+            .withTime((headers.get(CE_TIME) != null) ? ZonedDateTime.parse(headers.get(CE_TIME)) : null)
+            .withData(SerializationUtils.serialize(body))
+            .withSubject(headers.get(CE_SUBJECT))
+            .withDataContentType((headers.get(CONTENT_TYPE) != null) ? headers.get(CONTENT_TYPE) : APPLICATION_JSON);
+
+        if (extension != null) {
+            builder = builder.withExtension(extension);
+        }
+        return builder.build();
+    }
+
+    public static WebClient.ResponseSpec createPostCloudEvent(WebClient webClient, CloudEvent cloudEvent) {
+        return createPostCloudEvent(webClient, "", cloudEvent);
+    }
+
+    public static WebClient.ResponseSpec createPostCloudEvent(WebClient webClient, String uriString, CloudEvent cloudEvent) {
+        WebClient.RequestBodySpec uri = webClient.post().uri(uriString);
+        WebClient.RequestHeadersSpec<?> headersSpec = uri.body(BodyInserters.fromValue(cloudEvent.getData()));
+        WebClient.RequestHeadersSpec<?> header = headersSpec
+            .header(CE_ID, cloudEvent.getId())
+            .header(CE_SPECVERSION, cloudEvent.getSpecVersion().name())
+            .header(CONTENT_TYPE, APPLICATION_JSON)
+            .header(CE_TYPE, cloudEvent.getType())
+            .header(CE_TIME, cloudEvent.getTime().toString())
+            .header(CE_SOURCE, cloudEvent.getSource().toString())
+            .header(CE_SUBJECT, cloudEvent.getSubject());
+
+
+        //@TODO: improve extensions handling, at least now we will have a string version of the extension
+        for (String key : cloudEvent.getExtensionNames()) {
+            header.header(key, cloudEvent.getExtension(key).toString());
+        }
+        return header.retrieve();
+    }
+
+
+    //@TODO: create a print CLOUD EVENT helper
+
+}

pom.xml

@@ -71,6 +71,8 @@
         <module>formats/json-jackson</module>
         <module>http/vertx</module>
         <module>http/restful-ws</module>
+        <module>http/spring-boot-starter-web-cloudevents</module>
+        <module>http/spring-boot-starter-webflux-cloudevents</module>
         <module>kafka</module>
     </modules>