Adding a very initial version of the RestApiPlugin

Requires a bunch of testing for corner cases and error scenarios.

app/server/appsmith-plugins/pom.xml

@@ -16,6 +16,7 @@
 
     <modules>
         <module>postgresPlugin</module>
+        <module>restApiPlugin</module>
     </modules>
 
 </project>

app/server/appsmith-plugins/postgresPlugin/pom.xml

@@ -17,8 +17,8 @@
     <maven.compiler.target>${java.version}</maven.compiler.target>
     <plugin.id>postgres-plugin</plugin.id>
     <plugin.class>com.external.plugins.PostgresPlugin</plugin.class>
-    <plugin.version>0.0.1</plugin.version>
+    <plugin.version>1.0-SNAPSHOT</plugin.version>
-    <plugin.provider>Arpit Mohan</plugin.provider>
+    <plugin.provider>tech@appsmith.com</plugin.provider>
     <plugin.dependencies />
   </properties>
 

app/server/appsmith-plugins/restApiPlugin/pom.xml

@@ -0,0 +1,85 @@
+<?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">
+  <modelVersion>4.0.0</modelVersion>
+
+  <groupId>com.external.plugins</groupId>
+  <artifactId>restApiPlugin</artifactId>
+  <version>1.0-SNAPSHOT</version>
+
+  <name>restApiPlugin</name>
+
+  <properties>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    <java.version>11</java.version>
+    <maven.compiler.source>${java.version}</maven.compiler.source>
+    <maven.compiler.target>${java.version}</maven.compiler.target>
+    <plugin.id>restapi-plugin</plugin.id>
+    <plugin.class>com.external.plugins.RestApiPlugin</plugin.class>
+    <plugin.version>1.0-SNAPSHOT</plugin.version>
+    <plugin.provider>tech@appsmith.com</plugin.provider>
+    <plugin.dependencies />
+  </properties>
+
+  <dependencies>
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <version>4.11</version>
+      <scope>test</scope>
+    </dependency>
+
+    <dependency>
+      <groupId>org.pf4j</groupId>
+      <artifactId>pf4j-spring</artifactId>
+      <version>0.5.0</version>
+    </dependency>
+
+    <dependency>
+      <groupId>com.appsmith</groupId>
+      <artifactId>interfaces</artifactId>
+      <version>1.0-SNAPSHOT</version>
+    </dependency>
+
+    <dependency>
+      <groupId>org.springframework</groupId>
+      <artifactId>spring-webflux</artifactId>
+      <version>5.1.5.RELEASE</version>
+    </dependency>
+
+    <dependency>
+      <groupId>org.projectlombok</groupId>
+      <artifactId>lombok</artifactId>
+      <version>1.18.8</version>
+      <scope>provided</scope>
+    </dependency>
+
+  </dependencies>
+
+  <build>
+    <plugins>
+      <plugin>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <version>3.8.1</version>
+      </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-jar-plugin</artifactId>
+        <version>3.1.2</version>
+        <configuration>
+          <archive>
+            <manifestEntries>
+              <Plugin-Id>${plugin.id}</Plugin-Id>
+              <Plugin-Class>${plugin.class}</Plugin-Class>
+              <Plugin-Version>${plugin.version}</Plugin-Version>
+              <Plugin-Provider>${plugin.provider}</Plugin-Provider>
+              <Plugin-Dependencies>${plugin.dependencies}</Plugin-Dependencies>
+            </manifestEntries>
+          </archive>
+        </configuration>
+      </plugin>
+    </plugins>
+  </build>
+
+</project>

app/server/appsmith-plugins/restApiPlugin/src/main/java/com/external/plugins/RestApiPlugin.java

@@ -0,0 +1,83 @@
+package com.external.plugins;
+
+import com.appsmith.external.models.ActionConfiguration;
+import com.appsmith.external.models.Param;
+import com.appsmith.external.models.ResourceConfiguration;
+import com.appsmith.external.plugins.BasePlugin;
+import com.appsmith.external.plugins.PluginExecutor;
+import lombok.extern.slf4j.Slf4j;
+import org.json.JSONObject;
+import org.pf4j.Extension;
+import org.pf4j.PluginWrapper;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.MediaType;
+import org.springframework.web.reactive.function.BodyInserters;
+import org.springframework.web.reactive.function.client.ClientResponse;
+import org.springframework.web.reactive.function.client.WebClient;
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+public class RestApiPlugin extends BasePlugin {
+
+    public RestApiPlugin(PluginWrapper wrapper) {
+        super(wrapper);
+    }
+
+    @Slf4j
+    @Extension
+    public static class RestApiPluginExecutor implements PluginExecutor {
+
+        @Override
+        public Flux<Object> execute(ResourceConfiguration resourceConfiguration,
+                                    ActionConfiguration actionConfiguration,
+                                    List<Param> params) {
+            JSONObject requestBody = actionConfiguration.getBody();
+            if(requestBody == null) {
+                requestBody = new JSONObject();
+            }
+            Map<String, Param> propertyMap = params.stream()
+                    .collect(Collectors.toMap(Param::getKey, param -> param));
+
+            String path = (actionConfiguration.getPath() == null) ? "" : actionConfiguration.getPath();
+            String url = resourceConfiguration.getUrl() + path;
+            HttpMethod httpMethod = actionConfiguration.getHttpMethod();
+            if(httpMethod == null) {
+                return Flux.error(new Exception("HttpMethod must not be null"));
+            }
+
+            log.debug("Going to make a RestApi call to url: {}, httpMethod: {}", url, httpMethod);
+
+            WebClient webClient = WebClient.builder()
+                    .baseUrl(url)
+                    .defaultHeader(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_JSON_VALUE)
+                    .build();
+
+            WebClient.RequestHeadersSpec<?> request = webClient.method(httpMethod)
+                    .body(BodyInserters.fromObject(requestBody));
+
+            Mono<ClientResponse> responseMono = request.exchange();
+            return responseMono.flatMapMany(response -> {
+                log.debug("Got response: {}", response);
+                List<String> contentTypes = response.headers().header(HttpHeaders.CONTENT_TYPE);
+                Class clazz = String.class;
+                if (contentTypes != null && contentTypes.size() > 0) {
+                    String contentType = contentTypes.get(0);
+                    boolean isJson = MediaType.APPLICATION_JSON_UTF8_VALUE.toLowerCase()
+                            .equals(contentType.toLowerCase()
+                                    .replaceAll("\\s", ""))
+                            || MediaType.APPLICATION_JSON_VALUE.equals(contentType.toLowerCase());
+
+                    if (isJson) {
+                        clazz = JSONObject.class;
+                    }
+                }
+                return response.bodyToFlux(clazz);
+            });
+        }
+    }
+}

app/server/appsmith-plugins/restApiPlugin/src/test/java/com/external/plugins/RestApiPluginTest.java

@@ -0,0 +1,20 @@
+package com.external.plugins;
+
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+
+/**
+ * Unit test for simple App.
+ */
+public class RestApiPluginTest
+{
+    /**
+     * Rigorous Test :-)
+     */
+    @Test
+    public void shouldAnswerWithTrue()
+    {
+        assertTrue( true );
+    }
+}