BAEL-1821 (#4487)

* Moved Lambda examples to separate module
Implementation of API Gateway example

* Format fixes

* Format fixes

* Minor fixes

* Minor fixes

* Minor fixes

aws-lambda/pom.xml

@@ -0,0 +1,99 @@
+<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <artifactId>parent-modules</artifactId>
+        <groupId>com.baeldung</groupId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>com.baeldung</groupId>
+    <artifactId>aws-lambda</artifactId>
+    <version>0.1.0-SNAPSHOT</version>
+    <packaging>jar</packaging>
+    <name>aws-lambda</name>
+
+    <dependencies>
+
+        <dependency>
+            <groupId>com.amazonaws</groupId>
+            <artifactId>aws-java-sdk-dynamodb</artifactId>
+            <version>1.11.241</version>
+        </dependency>
+        <dependency>
+            <groupId>com.amazonaws</groupId>
+            <artifactId>aws-java-sdk-core</artifactId>
+            <version>1.11.241</version>
+        </dependency>
+        <dependency>
+            <groupId>com.amazonaws</groupId>
+            <artifactId>aws-lambda-java-core</artifactId>
+            <version>${aws-lambda-java-core.version}</version>
+            <exclusions>
+                <exclusion>
+                    <artifactId>commons-logging</artifactId>
+                    <groupId>commons-logging</groupId>
+                </exclusion>
+            </exclusions>
+        </dependency>
+        <dependency>
+            <groupId>com.amazonaws</groupId>
+            <artifactId>aws-lambda-java-events</artifactId>
+            <version>${aws-lambda-java-events.version}</version>
+            <exclusions>
+                <exclusion>
+                    <artifactId>commons-logging</artifactId>
+                    <groupId>commons-logging</groupId>
+                </exclusion>
+            </exclusions>
+        </dependency>
+        <dependency>
+            <groupId>com.google.code.gson</groupId>
+            <artifactId>gson</artifactId>
+            <version>${gson.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>commons-io</groupId>
+            <artifactId>commons-io</artifactId>
+            <version>${commons-io.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.googlecode.json-simple</groupId>
+            <artifactId>json-simple</artifactId>
+            <version>${json-simple.version}</version>
+        </dependency>
+    </dependencies>
+    <build>
+    <plugins>
+    <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-shade-plugin</artifactId>
+        <version>${maven-shade-plugin.version}</version>
+        <configuration>
+            <createDependencyReducedPom>false</createDependencyReducedPom>
+        </configuration>
+        <executions>
+            <execution>
+                <phase>package</phase>
+                <goals>
+                    <goal>shade</goal>
+                </goals>
+            </execution>
+        </executions>
+    </plugin>
+    </plugins>
+    </build>
+    <properties>
+        <json-simple.version>1.1.1</json-simple.version>
+        <org.json.version>20180130</org.json.version>
+        <commons-io.version>2.5</commons-io.version>
+        <aws-lambda-java-events.version>1.3.0</aws-lambda-java-events.version>
+        <aws-lambda-java-core.version>1.2.0</aws-lambda-java-core.version>
+        <gson.version>2.8.2</gson.version>
+        <aws-java-sdk-core.version>1.11.241</aws-java-sdk-core.version>
+        <maven-shade-plugin.version>3.0.0</maven-shade-plugin.version>
+        <maven-dependency-plugin.version>2.10</maven-dependency-plugin.version>
+    </properties>
+</project>

aws-lambda/src/main/java/com/baeldung/lambda/apigateway/APIDemoHandler.java

@@ -0,0 +1,166 @@
+package com.baeldung.lambda.apigateway;
+
+import com.amazonaws.services.dynamodbv2.AmazonDynamoDB;
+import com.amazonaws.services.dynamodbv2.AmazonDynamoDBClientBuilder;
+import com.amazonaws.services.dynamodbv2.document.*;
+import com.amazonaws.services.dynamodbv2.document.spec.PutItemSpec;
+import com.amazonaws.services.lambda.runtime.Context;
+import com.amazonaws.services.lambda.runtime.RequestStreamHandler;
+import com.baeldung.lambda.apigateway.model.Person;
+import org.json.simple.JSONObject;
+import org.json.simple.parser.JSONParser;
+import org.json.simple.parser.ParseException;
+
+import java.io.*;
+
+public class APIDemoHandler implements RequestStreamHandler {
+
+	private JSONParser parser = new JSONParser();
+	private  static final String DYNAMODB_TABLE_NAME = System.getenv("TABLE_NAME");
+
+	@Override
+	public void handleRequest(InputStream inputStream, OutputStream outputStream, Context context) throws IOException {
+
+		BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
+		JSONObject responseJson = new JSONObject();
+
+		AmazonDynamoDB client = AmazonDynamoDBClientBuilder.defaultClient();
+		DynamoDB dynamoDb = new DynamoDB(client);
+
+		try {
+			JSONObject event = (JSONObject) parser.parse(reader);
+
+			if (event.get("body") != null) {
+
+				Person person = new Person((String) event.get("body"));
+
+				dynamoDb.getTable(DYNAMODB_TABLE_NAME)
+						.putItem(new PutItemSpec().withItem(new Item().withNumber("id", person.getId())
+								.withString("firstName", person.getFirstName())
+								.withString("lastName", person.getLastName()).withNumber("age", person.getAge())
+								.withString("address", person.getAddress())));
+			}
+
+			JSONObject responseBody = new JSONObject();
+			responseBody.put("message", "New item created");
+
+			JSONObject headerJson = new JSONObject();
+			headerJson.put("x-custom-header", "my custom header value");
+
+			responseJson.put("statusCode", 200);
+			responseJson.put("headers", headerJson);
+			responseJson.put("body", responseBody.toString());
+
+		} catch (ParseException pex) {
+			responseJson.put("statusCode", 400);
+			responseJson.put("exception", pex);
+		}
+
+		OutputStreamWriter writer = new OutputStreamWriter(outputStream, "UTF-8");
+		writer.write(responseJson.toString());
+		writer.close();
+	}
+
+	public void handleGetByPathParam(InputStream inputStream, OutputStream outputStream, Context context)
+			throws IOException {
+
+		BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
+		JSONObject responseJson = new JSONObject();
+
+		AmazonDynamoDB client = AmazonDynamoDBClientBuilder.defaultClient();
+		DynamoDB dynamoDb = new DynamoDB(client);
+
+		Item result = null;
+		try {
+			JSONObject event = (JSONObject) parser.parse(reader);
+			JSONObject responseBody = new JSONObject();
+
+			if (event.get("pathParameters") != null) {
+
+				JSONObject pps = (JSONObject) event.get("pathParameters");
+				if (pps.get("id") != null) {
+
+					int id = Integer.parseInt((String) pps.get("id"));
+					result = dynamoDb.getTable(DYNAMODB_TABLE_NAME).getItem("id", id);
+				}
+
+			}
+			if (result != null) {
+
+				Person person = new Person(result.toJSON());
+				responseBody.put("Person", person);
+				responseJson.put("statusCode", 200);
+			} else {
+
+				responseBody.put("message", "No item found");
+				responseJson.put("statusCode", 404);
+			}
+
+			JSONObject headerJson = new JSONObject();
+			headerJson.put("x-custom-header", "my custom header value");
+
+			responseJson.put("headers", headerJson);
+			responseJson.put("body", responseBody.toString());
+
+		} catch (ParseException pex) {
+			responseJson.put("statusCode", 400);
+			responseJson.put("exception", pex);
+		}
+
+		OutputStreamWriter writer = new OutputStreamWriter(outputStream, "UTF-8");
+		writer.write(responseJson.toString());
+		writer.close();
+	}
+
+	public void handleGetByQueryParam(InputStream inputStream, OutputStream outputStream, Context context)
+			throws IOException {
+
+		BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
+		JSONObject responseJson = new JSONObject();
+
+		AmazonDynamoDB client = AmazonDynamoDBClientBuilder.defaultClient();
+		DynamoDB dynamoDb = new DynamoDB(client);
+
+		Item result = null;
+		try {
+			JSONObject event = (JSONObject) parser.parse(reader);
+			JSONObject responseBody = new JSONObject();
+
+			if (event.get("queryStringParameters") != null) {
+
+				JSONObject qps = (JSONObject) event.get("queryStringParameters");
+				if (qps.get("id") != null) {
+
+					int id = Integer.parseInt((String) qps.get("id"));
+					result = dynamoDb.getTable(DYNAMODB_TABLE_NAME).getItem("id", id);
+				}
+			}
+
+			if (result != null) {
+
+				Person person = new Person(result.toJSON());
+				responseBody.put("Person", person);
+				responseJson.put("statusCode", 200);
+			} else {
+
+				responseBody.put("message", "No item found");
+				responseJson.put("statusCode", 404);
+			}
+
+			JSONObject headerJson = new JSONObject();
+			headerJson.put("x-custom-header", "my custom header value");
+
+			responseJson.put("headers", headerJson);
+			responseJson.put("body", responseBody.toString());
+
+		} catch (ParseException pex) {
+			responseJson.put("statusCode", 400);
+			responseJson.put("exception", pex);
+		}
+
+		OutputStreamWriter writer = new OutputStreamWriter(outputStream, "UTF-8");
+		writer.write(responseJson.toString());
+		writer.close();
+	}
+
+}

aws-lambda/src/main/java/com/baeldung/lambda/apigateway/model/Person.java

@@ -0,0 +1,68 @@
+package com.baeldung.lambda.apigateway.model;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+
+public class Person {
+
+	private int id;
+	private String firstName;
+	private String lastName;
+	private int age;
+	private String address;
+
+	public Person(String json) {
+		Gson gson = new Gson();
+		Person request = gson.fromJson(json, Person.class);
+		this.id = request.getId();
+		this.firstName = request.getFirstName();
+		this.lastName = request.getLastName();
+		this.age = request.getAge();
+		this.address = request.getAddress();
+	}
+
+	public String toString() {
+		final Gson gson = new GsonBuilder().setPrettyPrinting().create();
+		return gson.toJson(this);
+	}
+
+	public int getId() {
+		return id;
+	}
+
+	public void setId(int id) {
+		this.id = id;
+	}
+
+	public String getFirstName() {
+		return firstName;
+	}
+
+	public void setFirstName(String firstName) {
+		this.firstName = firstName;
+	}
+
+	public String getLastName() {
+		return lastName;
+	}
+
+	public void setLastName(String lastName) {
+		this.lastName = lastName;
+	}
+
+	public int getAge() {
+		return age;
+	}
+
+	public void setAge(int age) {
+		this.age = age;
+	}
+
+	public String getAddress() {
+		return address;
+	}
+
+	public void setAddress(String address) {
+		this.address = address;
+	}
+}

pom.xml

@@ -18,6 +18,7 @@
         <module>atomix</module>
         <module>apache-cayenne</module>
         <module>aws</module>
+        <module>aws-lambda</module>
         <module>akka-streams</module>
         <module>algorithms</module>
         <module>annotations</module>