First implementation of Filter support in Spring

Still open
1. Support filter annotations
2. Add support for filters in spark

Author: sapessi

aws-serverless-java-container-core/src/main/java/com/amazonaws/serverless/proxy/internal/LambdaContainerHandler.java

@@ -30,6 +30,12 @@
  */
 public abstract class LambdaContainerHandler<RequestType, ResponseType, ContainerRequestType, ContainerResponseType> {
 
+    //-------------------------------------------------------------
+    // Constants
+    //-------------------------------------------------------------
+
+    public static final String SERVER_INFO = "aws-serverless-java-container";
+
     //-------------------------------------------------------------
     // Variables - Private
     //-------------------------------------------------------------

aws-serverless-java-container-core/src/main/java/com/amazonaws/serverless/proxy/internal/servlet/AwsFilterChainManager.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file except in compliance
+ * with the License. A copy of the License is located at
+ *
+ * http://aws.amazon.com/apache2.0/
+ *
+ * or in the "license" file accompanying this file. This file is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES
+ * OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions
+ * and limitations under the License.
+ */
+package com.amazonaws.serverless.proxy.internal.servlet;
+
+import java.util.Map;
+
+/**
+ * This implementation of the <code>FilterChainManager</code> object uses the <code>AwsServletContext</code> object
+ * to extract a list of <code>FilterHolder</code>s
+ */
+public class AwsFilterChainManager extends FilterChainManager<AwsServletContext> {
+
+    //-------------------------------------------------------------
+    // Constructors
+    //-------------------------------------------------------------
+
+    /**
+     * Creates a new FilterChainManager for the given servlet context
+     * @param context An initialized AwsServletContext object
+     */
+    AwsFilterChainManager(AwsServletContext context) {
+        super(context);
+    }
+
+    //-------------------------------------------------------------
+    // Implementation - FilterChainManager
+    //-------------------------------------------------------------
+
+    /**
+     * Returns the filter holders stored in the <code>AwsServletContext</code> object
+     * @return The map of filter holders
+     */
+    protected Map<String, FilterHolder> getFilterHolders() {
+        return servletContext.getFilterHolders();
+    }
+}

aws-serverless-java-container-core/src/main/java/com/amazonaws/serverless/proxy/internal/servlet/AwsHttpServletRequest.java

@@ -0,0 +1,290 @@
+/*
+ * Copyright 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file except in compliance
+ * with the License. A copy of the License is located at
+ *
+ * http://aws.amazon.com/apache2.0/
+ *
+ * or in the "license" file accompanying this file. This file is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES
+ * OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions
+ * and limitations under the License.
+ */
+package com.amazonaws.serverless.proxy.internal.servlet;
+
+import com.amazonaws.services.lambda.runtime.Context;
+
+import javax.servlet.AsyncContext;
+import javax.servlet.DispatcherType;
+import javax.servlet.ServletContext;
+import javax.servlet.http.Cookie;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpSession;
+import java.io.UnsupportedEncodingException;
+import java.net.URLEncoder;
+import java.nio.charset.StandardCharsets;
+import java.util.*;
+
+/**
+ * Base HttpServletRequest object. This object exposes some utility methods to work with request values such as headers
+ * and query string parameters. New implementations of <code>HttpServletRequest</code> can extend this class to reuse
+ * the utility methods
+ */
+public abstract class AwsHttpServletRequest implements HttpServletRequest {
+    //-------------------------------------------------------------
+    // Constants
+    //-------------------------------------------------------------
+
+    static final String HEADER_KEY_VALUE_SEPARATOR = "=";
+    static final String HEADER_VALUE_SEPARATOR = ";";
+    static final String FORM_DATA_SEPARATOR = "&";
+    static final String DEFAULT_CHARACTER_ENCODING = "UTF-8";
+    static final String HEADER_DATE_FORMAT = "EEE, d MMM yyyy HH:mm:ss z";
+    static final String ENCODING_VALUE_KEY = "charset";
+
+    // We need this to pickup the protocol from the CloudFront header since Lambda doesn't receive this
+    // information from anywhere else
+    static final String CF_PROTOCOL_HEADER_NAME = "CloudFront-Forwarded-Proto";
+
+    //-------------------------------------------------------------
+    // Variables - Private
+    //-------------------------------------------------------------
+
+    private Context lamdaContext;
+    private DispatcherType dispatcherType;
+    private Map<String, Object> attributes;
+
+    //-------------------------------------------------------------
+    // Constructors
+    //-------------------------------------------------------------
+
+    /**
+     * Protected constructors for implemnenting classes. This should be called first with the context received from
+     * AWS Lambda
+     * @param lambdaContext The Lambda function context. This object is used for utility methods such as log
+     */
+    AwsHttpServletRequest(Context lambdaContext) {
+        lamdaContext = lambdaContext;
+        attributes = new HashMap<>();
+
+        // TODO: We are setting this to request by default
+        dispatcherType = DispatcherType.REQUEST;
+    }
+
+    //-------------------------------------------------------------
+    // Methods - Protected
+    //-------------------------------------------------------------
+
+    /**
+     * Given the Cookie header value, parses it and creates a Cookie object
+     * @param headerValue The string value of the HTTP Cookie header
+     * @return An array of Cookie objects from the header
+     */
+    protected Cookie[] parseCookies(String headerValue) {
+        List<Cookie> output = new ArrayList<>();
+
+        for (AbstractMap.SimpleEntry<String, String> entry : this.parseHeaderValue(headerValue)) {
+            if (entry.getKey() != null) {
+                output.add(new Cookie(entry.getKey(), entry.getValue()));
+            }
+        }
+        Cookie[] returnValue = new Cookie[output.size()];
+        return output.toArray(returnValue);
+    }
+
+    protected String readPathInfo(String path, String resource) {
+        // TODO: Implement
+        return "/";
+    }
+
+    protected String readPathTranslated(String path) {
+        // TODO: Implement
+        return path;
+    }
+
+    /**
+     * Given a map of key/values query string parameters from API Gateway, creates a query string as it would have
+     * been in the original url.
+     * @param parameters A Map<String, String> of query string parameters
+     * @return The generated query string for the URI
+     */
+    protected String generateQueryString(Map<String, String> parameters) {
+        String params = null;
+        if (parameters != null && parameters.size() > 0) {
+            params = "";
+            for (String key : parameters.keySet()) {
+                String separator = params.equals("") ? "?" : "&";
+                String queryStringKey = key;
+                String queryStringValue = parameters.get(key);
+                try {
+                    // if they were URLDecoded along the way we should re-encode them for the URI
+                    if (!URLEncoder.encode(queryStringKey, StandardCharsets.UTF_8.name()).equals(key)) {
+                        queryStringKey = URLEncoder.encode(queryStringKey, StandardCharsets.UTF_8.name());
+                    }
+                    if (!URLEncoder.encode(queryStringValue, StandardCharsets.UTF_8.name()).equals(queryStringValue)) {
+                        queryStringValue = URLEncoder.encode(queryStringValue, StandardCharsets.UTF_8.name());
+                    }
+                } catch (UnsupportedEncodingException e) {
+                    // TODO: Should we stop for the exception?
+                    lamdaContext.getLogger().log("Could not URLEncode: " + queryStringKey);
+                    e.printStackTrace();
+                }
+                params += separator + queryStringKey + "=" + queryStringValue;
+            }
+        }
+
+        return params;
+    }
+
+    /**
+     * Generic method to parse an HTTP header value and split it into a list of key/values for all its components.
+     * When the property in the header does not specify a key the key field in the output pair is null and only the value
+     * is populated. For example, The header <code>Accept: application/json; application/xml</code> will contain two
+     * key value pairs with key null and the value set to application/json and application/xml respectively.
+     *
+     * @param headerContent The string value for the HTTP header
+     * @return A list of SimpleMapEntry objects with all of the possible values for the header.
+     */
+    protected List<AbstractMap.SimpleEntry<String, String>> parseHeaderValue(String headerContent) {
+        List<AbstractMap.SimpleEntry<String, String>> values = new ArrayList<>();
+        if (headerContent != null) {
+            for (String kv : headerContent.split(HEADER_VALUE_SEPARATOR)) {
+                String[] kvSplit = kv.split(HEADER_KEY_VALUE_SEPARATOR);
+
+                if (kvSplit.length != 2) {
+                    values.add(new AbstractMap.SimpleEntry<>(null, kv.trim()));
+                } else {
+                    values.add(new AbstractMap.SimpleEntry<>(kvSplit[0].trim(), kvSplit[1].trim()));
+                }
+            }
+        }
+        return values;
+    }
+
+    //-------------------------------------------------------------
+    // Implementation - HttpServletRequest
+    //-------------------------------------------------------------
+
+    @Override
+    public String getRequestedSessionId() {
+        // TODO: Throw not implemented
+        return null;
+    }
+
+    @Override
+    public HttpSession getSession(boolean b) {
+        return null;
+    }
+
+
+    @Override
+    public HttpSession getSession() {
+        return null;
+    }
+
+
+    @Override
+    public String changeSessionId() {
+        return null;
+    }
+
+
+    @Override
+    public boolean isRequestedSessionIdValid() {
+        return false;
+    }
+
+
+    @Override
+    public boolean isRequestedSessionIdFromCookie() {
+        return false;
+    }
+
+
+    @Override
+    public boolean isRequestedSessionIdFromURL() {
+        return false;
+    }
+
+
+    @Override
+    public boolean isRequestedSessionIdFromUrl() {
+        return false;
+    }
+
+    @Override
+    public Object getAttribute(String s) {
+        return attributes.get(s);
+    }
+
+    @Override
+    public Enumeration<String> getAttributeNames() {
+        return Collections.enumeration(attributes.keySet());
+    }
+
+    @Override
+    public void setAttribute(String s, Object o) {
+        attributes.put(s, o);
+    }
+
+
+    @Override
+    public void removeAttribute(String s) {
+        attributes.remove(s);
+    }
+
+    @Override
+    public String getServerName() {
+        return "lambda.amazonaws.com";
+    }
+
+
+    @Override
+    public int getServerPort() {
+        return 0;
+    }
+
+    @Override
+    public String getLocalName() {
+        return "lambda.amazonaws.com";
+    }
+
+
+    @Override
+    public String getLocalAddr() {
+        return null;
+    }
+
+
+    @Override
+    public int getLocalPort() {
+        return 0;
+    }
+
+    @Override
+    public boolean isAsyncStarted() {
+        return false;
+    }
+
+
+    @Override
+    public boolean isAsyncSupported() {
+        return false;
+    }
+
+
+    @Override
+    public AsyncContext getAsyncContext() {
+        return null;
+    }
+
+    @Override
+    public ServletContext getServletContext() {
+        return AwsServletContext.getInstance(lamdaContext);
+    }
+
+    @Override
+    public DispatcherType getDispatcherType() {
+        return dispatcherType;
+    }
+}