com.amazonaws.auth.policy.internal.JsonPolicyReader Maven / Gradle / Ivy

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The Amazon Web Services SDK for Java provides Java APIs for building software on AWS' cost-effective, scalable, and reliable infrastructure products. The AWS Java SDK allows developers to code against APIs for all of Amazon's infrastructure web services (Amazon S3, Amazon EC2, Amazon SQS, Amazon Relational Database Service, Amazon AutoScaling, etc).
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/*
 * Copyright 2010-2014 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.auth.policy.internal;

import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;

import com.amazonaws.auth.policy.Action;
import com.amazonaws.auth.policy.Condition;
import com.amazonaws.auth.policy.Policy;
import com.amazonaws.auth.policy.Principal;
import com.amazonaws.auth.policy.Principal.Services;
import com.amazonaws.auth.policy.Principal.WebIdentityProviders;
import com.amazonaws.auth.policy.Resource;
import com.amazonaws.auth.policy.Statement;
import com.amazonaws.auth.policy.Statement.Effect;
import com.amazonaws.util.json.JSONArray;
import com.amazonaws.util.json.JSONException;
import com.amazonaws.util.json.JSONObject;

/**
 * Generate an AWS policy object from a JSON string.
 */
public class JsonPolicyReader {

    /**
     * Converts the specified JSON string to an AWS policy object.
     *
     * @param jsonString
     *            the specified JSON string representation of this AWS access
     *            control policy.
     *
     * @return An AWS policy object.
     *
     * @throws IllegalArgumentException
     *             If the specified JSON string is null or invalid and cannot be
     *             converted to an AWS policy object.
     */
    public Policy createPolicyFromJsonString(String jsonString)  {

        if (jsonString == null) {
            throw new IllegalArgumentException("JSON string cannot be null");
        }

        Policy policy = new Policy();
        List statements = new LinkedList();
        try {
            JSONObject jPolicy = new JSONObject(jsonString);

            if (Arrays.asList(JSONObject.getNames(jPolicy)).contains(JsonDocumentFields.POLICY_ID)) {
                policy.setId(jPolicy.getString(JsonDocumentFields.POLICY_ID));
            }

            JSONArray jStatements = jPolicy.getJSONArray(JsonDocumentFields.STATEMENT);

            for (int index = 0 ; index < jStatements.length() ; index++) {
                Statement statement = convertStatement(jStatements.getJSONObject(index));
                if (statement != null) {
                statements.add(statement);
                }
            }
        } catch (Exception e) {
            String message = "Unable to generate policy object fron JSON string " + e.getMessage();
            throw new IllegalArgumentException(message, e);
        }
        policy.setStatements(statements);
        return policy;
    }

    private  Statement convertStatement(JSONObject jStatement) throws JSONException {
        if (!Arrays.asList(JSONObject.getNames(jStatement)).contains(JsonDocumentFields.STATEMENT_EFFECT)) {
            return null;
        }

        Statement statement;
        String jEffect = jStatement.getString(JsonDocumentFields.STATEMENT_EFFECT);
        if (JsonDocumentFields.EFFECT_VALUE_ALLOW.equals(jEffect)) {
            statement = new Statement(Effect.Allow);
        } else {
            statement = new Statement(Effect.Deny);
        }

        if (Arrays.asList(JSONObject.getNames(jStatement)).contains(JsonDocumentFields.STATEMENT_ID)) {
            statement.setId(jStatement.getString(JsonDocumentFields.STATEMENT_ID));
        }

        convertActions(statement, jStatement);
        convertResources(statement, jStatement);
        convertCondition(statement, jStatement);
        convertPrincipals(statement, jStatement);
        return statement;
    }

    private  void convertPrincipals(Statement statement, JSONObject jStatement) throws JSONException {
        if (!Arrays.asList(JSONObject.getNames(jStatement)).contains(JsonDocumentFields.PRINCIPAL)) {
            return;
        }

        if (jStatement.optString(JsonDocumentFields.PRINCIPAL).equals("*")) {
            statement.setPrincipals(Principal.All);
            return;
        }

        if (statement.getPrincipals() == null) {
            statement.setPrincipals(new LinkedList());
        }

        JSONObject jPrincipals = jStatement.getJSONObject(JsonDocumentFields.PRINCIPAL);
        String[] fields = JSONObject.getNames(jPrincipals);
        for (String field : fields) {
            String serviceId = jPrincipals.optString(field);
            if (serviceId != null && serviceId.length() > 0) {
                if (field.equalsIgnoreCase("AWS")) {
                    statement.getPrincipals().add(new Principal(serviceId));
                } else if (field.equalsIgnoreCase("Service")) {
                    statement.getPrincipals().add(
                            new Principal(Services.fromString(serviceId)));
                } else if (field.equalsIgnoreCase("Federated")) {
                    if (WebIdentityProviders.fromString(serviceId) != null) {
                        statement.getPrincipals().add(
                                new Principal(WebIdentityProviders.fromString(serviceId)));
                    } else {
                        statement.getPrincipals().add(
                                new Principal("Federated", serviceId));
                    }
                }
            } else {
                JSONArray jPrincipal = jPrincipals.getJSONArray(field);
                convertPrincipalRecord(field, statement, jPrincipal);
            }
        }
    }

    private void convertPrincipalRecord(String schema, Statement statement, JSONArray jPrincipal) throws JSONException {
        Principal principal = null;
        for (int index = 0 ; index < jPrincipal.length() ; index++) {
            if (schema.equals("AWS")) {
                if (jPrincipal.getString(index).equals("*")) {
                    principal = Principal.AllUsers;
                }
                principal = new Principal(jPrincipal.getString(index));
            } else if (schema.equals("Service")) {
                principal = new Principal(Services.fromString(jPrincipal.getString(index)));
            }
            statement.getPrincipals().add(principal);
        }
    }

    private void convertCondition(Statement statement, JSONObject jStatement) throws JSONException {
        if (!Arrays.asList(JSONObject.getNames(jStatement)).contains(JsonDocumentFields.CONDITION)) {
            return;
        }
        JSONObject jConditions = jStatement.getJSONObject(JsonDocumentFields.CONDITION);
        List conditions = new LinkedList();
        String[] types = JSONObject.getNames(jConditions);
        for (String type : types) {
             JSONObject jCondition = jConditions.getJSONObject(type);
             convertConditionRecord(conditions, type, jCondition);
        }
        statement.setConditions(conditions);
    }

    private void convertConditionRecord(List conditions, String type, JSONObject jCondition) throws JSONException {
        List values = new LinkedList();
        String[] keys = JSONObject.getNames(jCondition);
        for (String key : keys) {
            String value = jCondition.optString(key);
            if (value != null && value.length() > 0) {
                values.add(value);
            } else {
                JSONArray jValues = jCondition.getJSONArray(key);
                for (int index = 0; index < jValues.length(); index++) {
                    values.add(jValues.getString(index));
                }
            }
            conditions.add(new Condition().withType(type).withConditionKey(key).withValues(values));
        }
    }

    private void convertActions(Statement statement, JSONObject jStatement) throws JSONException {
        if (!Arrays.asList(JSONObject.getNames(jStatement)).contains(JsonDocumentFields.ACTION)) {
            return;
        }

        String actionName = null;
        List actions = new LinkedList();

        actionName = jStatement.optString(JsonDocumentFields.ACTION);
        if (actionName != null && actionName.length() > 0) {
            actions.add(new NamedAction(actionName));
            statement.setActions(actions);
            return;
        }

        JSONArray jActions = jStatement.getJSONArray(JsonDocumentFields.ACTION);
        for (int index = 0 ; index < jActions.length() ; index++) {
            actionName = jActions.getString(index);
            actions.add(new NamedAction(actionName));
        }
        statement.setActions(actions);
    }

    private void convertResources(Statement statement, JSONObject jStatement) throws JSONException {
        if (!Arrays.asList(JSONObject.getNames(jStatement)).contains(JsonDocumentFields.RESOURCE)) {
            return;
        }

        List resources = new LinkedList();
        String resourceId = jStatement.optString(JsonDocumentFields.RESOURCE);
        if (resourceId != null && resourceId.length() > 0) {
            resources.add(new Resource(resourceId));
            statement.setResources(resources);
            return;
        }

        JSONArray jResources = jStatement.getJSONArray(JsonDocumentFields.RESOURCE);
        for (int index = 0 ; index < jResources.length() ; index++) {
            resources.add(new Resource(jResources.getString(index)));
        }
        statement.setResources(resources);
    }

    /**
     *  An auxiliary class to help instantiate the action object.
     */
    private static class NamedAction implements Action {

        private String actionName;

        public NamedAction(String actionName) {
            this.actionName = actionName;
        }

        public String getActionName() {
             return actionName;
        }

    }

}