openapi.spec.loader.ts

import * as _ from 'lodash';

import OpenAPIFramework, {
  OpenAPIFrameworkArgs,
  OpenAPIFrameworkConstructorArgs,
} from './framework';
import { OpenAPIFrameworkAPIContext } from './framework/types';

export class OpenApiSpecLoader {
  private opts: OpenAPIFrameworkArgs;
  constructor(opts: OpenAPIFrameworkArgs) {
    this.opts = opts;
  }

  load() {
    const framework = this.createFramework(this.opts);
    const apiDoc = framework.apiDoc;
    const routes = this.discoverRoutes(framework);
    return {
      apiDoc,
      routes,
    };
  }

  private createFramework(args: OpenAPIFrameworkArgs): OpenAPIFramework {
    const frameworkArgs: OpenAPIFrameworkConstructorArgs = {
      featureType: 'middleware',
      name: 'express-middleware-openapi',
      ...(args as OpenAPIFrameworkArgs),
    };

    console.log(frameworkArgs);
    const framework = new OpenAPIFramework(frameworkArgs);
    return framework;
  }

  private discoverRoutes(framework) {
    const routes = [];
    const toExpressParams = this.toExpressParams;
    framework.initialize({
      visitApi(ctx: OpenAPIFrameworkAPIContext) {
        const apiDoc = ctx.getApiDoc();
        for (const bp of ctx.basePaths) {
          for (const [path, methods] of Object.entries(apiDoc.paths)) {
            for (const [method, schema] of Object.entries(methods)) {
              const pathParams = new Set();
              for (const param of schema.parameters || []) {
                if (param.in === 'path') {
                  pathParams.add(param.name);
                }
              }
              const openApiRoute = `${bp.path}${path}`;
              const expressRoute = `${openApiRoute}`
                .split('/')
                .map(toExpressParams)
                .join('/');
              routes.push({
                expressRoute,
                openApiRoute,
                method: method.toUpperCase(),
                pathParams: Array.from(pathParams),
                schema,
              });
            }
          }
        }
      },
    });
    return routes;
  }

  private toExpressParams(part) {
    return part.replace(/\{([^}]+)}/g, ':$1');
  }
}