resource.ts

import cdk = require('@aws-cdk/cdk');
import { cloudformation } from './apigateway.generated';
import { Integration } from './integration';
import { Method, MethodOptions } from './method';
import { RestApi } from './restapi';

export interface IRestApiResource {
    /**
     * The rest API that this resource is part of.
     *
     * The reason we need the RestApi object itself and not just the ID is because the model
     * is being tracked by the top-level RestApi object for the purpose of calculating it's
     * hash to determine the ID of the deployment. This allows us to automatically update
     * the deployment when the model of the REST API changes.
     */
    readonly resourceApi: RestApi;

    /**
     * The ID of the resource.
     */
    readonly resourceId: string;

    /**
     * The full path of this resuorce.
     */
    readonly resourcePath: string;

    /**
     * An integration to use as a default for all methods created within this
     * API unless an integration is specified.
     */
    readonly defaultIntegration?: Integration;

    /**
     * Method options to use as a default for all methods created within this
     * API unless custom options are specified.
     */
    readonly defaultMethodOptions?: MethodOptions;

    /**
     * Defines a new child resource where this resource is the parent.
     * @param pathPart The path part for the child resource
     * @param options Resource options
     * @returns A Resource object
     */
    addResource(pathPart: string, options?: ResourceOptions): Resource;

    /**
     * Defines a new method for this resource.
     * @param httpMethod The HTTP method
     * @param target The target backend integration for this method
     * @param options Method options, such as authentication.
     *
     * @returns The newly created `Method` object.
     */
    addMethod(httpMethod: string, target?: Integration, options?: MethodOptions): Method;
}

export interface ResourceOptions {
    /**
     * An integration to use as a default for all methods created within this
     * API unless an integration is specified.
     */
    readonly defaultIntegration?: Integration;

    /**
     * Method options to use as a default for all methods created within this
     * API unless custom options are specified.
     */
    readonly defaultMethodOptions?: MethodOptions;
}

export interface ResourceProps extends ResourceOptions {
    /**
     * The parent resource of this resource. You can either pass another
     * `Resource` object or a `RestApi` object here.
     */
    parent: IRestApiResource;

    /**
     * A path name for the resource.
     */
    pathPart: string;
}

export class Resource extends cdk.Construct implements IRestApiResource {
    public readonly resourceApi: RestApi;
    public readonly resourceId: string;
    public readonly resourcePath: string;
    public readonly defaultIntegration?: Integration;
    public readonly defaultMethodOptions?: MethodOptions;

    constructor(parent: cdk.Construct, id: string, props: ResourceProps) {
        super(parent, id);

        validateResourcePathPart(props.pathPart);

        const resourceProps: cloudformation.ResourceProps = {
            restApiId: props.parent.resourceApi.restApiId,
            parentId: props.parent.resourceId,
            pathPart: props.pathPart
        };
        const resource = new cloudformation.Resource(this, 'Resource', resourceProps);

        this.resourceId = resource.resourceId;
        this.resourceApi = props.parent.resourceApi;

        // render resource path (special case for root)
        this.resourcePath = props.parent.resourcePath;
        if (!this.resourcePath.endsWith('/')) { this.resourcePath += '/'; }
        this.resourcePath += props.pathPart;

        const deployment = props.parent.resourceApi.latestDeployment;
        if (deployment) {
            deployment.addDependency(resource);
            deployment.addToLogicalId({ resource: resourceProps });
        }

        // setup defaults based on properties and inherit from parent. method defaults
        // are inherited per property, so children can override piecemeal.
        this.defaultIntegration = props.defaultIntegration || props.parent.defaultIntegration;
        this.defaultMethodOptions = {
            ...props.parent.defaultMethodOptions,
            ...props.defaultMethodOptions
        };
    }

    public addResource(pathPart: string, options?: ResourceOptions): Resource {
        return new Resource(this, pathPart, { parent: this, pathPart, ...options });
    }

    public addMethod(httpMethod: string, integration?: Integration, options?: MethodOptions): Method {
        return new Method(this, httpMethod, { resource: this, httpMethod, integration, options });
    }
}

function validateResourcePathPart(part: string) {
    // strip {} which indicate this is a parameter
    if (part.startsWith('{') && part.endsWith('}')) {
        part = part.substr(1, part.length - 2);
    }

    if (!/^[a-zA-Z0-9\.\_\-]+$/.test(part)) {
        throw new Error(`Resource's path part only allow a-zA-Z0-9._- and curly braces at the beginning and the end: ${part}`);
    }
}