Enforce "no-magic-numbers" liniting rule by using constants instead o…

…f the concrete value (e.g. HTTP and RPC status codes)

package.json

@@ -13,6 +13,7 @@
   "scripts": {
     "build": "tsc -p src/",
     "test": "jest --config test/jest.config.json",
+    "lint": "tslint --project src/",
     "debug": "TS_NODE_PROJECT=src/tsconfig.json TS_NODE_FILE=true node -r ts-node/register --inspect=0.0.0.0 --inspect-brk example/server.ts",
     "start": "ts-node --project src/tsconfig.json example/server.ts",
     "gen-doc": "typedoc --hideGenerator --tsconfig src/tsconfig.json --out docs/ src/"

src/authentication.ts

@@ -3,6 +3,7 @@
  */
 
 import * as crypto from 'crypto';
+import { HTTP } from './constants';
 import { ILogger } from './interfaces';
 
 export function generateAuthMiddleware(apiKeyHash: string, log: ILogger) {
@@ -12,15 +13,15 @@ export function generateAuthMiddleware(apiKeyHash: string, log: ILogger) {
     // Check if API key was provided
     if (!apiKey) {
       log.warn('Unsuccessful authentication attempt (missing API key)');
-      return res.status(401).json({ error: 'MISSING_APIKEY', message: 'No API key provided via the HTTP \'authorization\' header' });
+      return res.status(HTTP.UNAUTHORIZED).json({ error: 'MISSING_APIKEY', message: 'No API key provided via the HTTP \'authorization\' header' });
     }
 
     // Check if API key is correct
     const hash: string = crypto.createHash('sha256').update(apiKey, 'utf8').digest('hex');
 
     if (hash !== apiKeyHash) {
       log.warn('Unsuccessful authentication attempt (incorrect API key)');
-      return res.status(401).json({ error: 'WRONG_APIKEY', message: 'The provided API key is incorrect' });
+      return res.status(HTTP.UNAUTHORIZED).json({ error: 'WRONG_APIKEY', message: 'The provided API key is incorrect' });
     }
 
     // Authenticated successfully

src/rpc-schema.ts → src/constants.ts

@@ -1,8 +1,28 @@
+/** HTTP constants (https://tools.ietf.org/html/rfc2616#section-10) */
+export const HTTP = {
+  OK: 200,
+  BAD_REQUEST: 400,
+  UNAUTHORIZED: 401,
+  INTERNAL_SERVER_ERROR: 500,
+};
+
+/** JSON RPC 2.0 constants (https://www.jsonrpc.org/specification) */
+export const RPC = {
+  VERSION: '2.0',
+  ERROR: {
+    PARSE_ERROR: -32700,
+    INVALID_REQUEST: -32600,
+    METHOD_NOT_FOUND: -32601,
+    INVALID_PARAMS: -32602,
+    INTERNAL_ERROR: -32603,
+    SERVER_ERROR: -32000,
+  },
+};
+
 /**
  * JSON schema for validating RPC requests
  * Taken from: https://github.com/fge/sample-json-schemas/blob/master/jsonrpc2.0/jsonrpc-request-2.0.json
  */
-
 export const rpcRequestSchema = {
   description: 'A JSON RPC 2.0 request',
   oneOf: [

src/rpc-endpoint.ts

@@ -1,7 +1,7 @@
 import * as Ajv from 'ajv';
 import { Express } from 'express';
+import { HTTP, RPC, rpcRequestSchema } from './constants';
 import { IEndpointOptions, ILogger, IRpcModule, IRpcRequest, IRpcResponse } from './interfaces';
-import { rpcRequestSchema } from './rpc-schema';
 
 /**
  * JSON-RPC 2.0 endpoint class
@@ -36,7 +36,7 @@ export class RpcEndpoint {
   static coerceRequestsToJsonRpc2Middleware(req, res, next) {
     RpcEndpoint.getRpcRequests(req).forEach((rpcRequest) => {
       if (typeof rpcRequest === 'object' && !rpcRequest.hasOwnProperty('jsonrpc')) {
-        rpcRequest.jsonrpc = '2.0';
+        rpcRequest.jsonrpc = RPC.VERSION;
         if (!rpcRequest.hasOwnProperty('id')) {
           rpcRequest.id = null;
         }
@@ -51,8 +51,8 @@ export class RpcEndpoint {
     const ajv = new Ajv();
     const validate: Ajv.ValidateFunction = ajv.compile(rpcRequestSchema);
     if (!validate(req.body)) {
-      return res.status(400).json({
-        code: -32600,
+      return res.status(HTTP.BAD_REQUEST).json({
+        code: RPC.ERROR.INVALID_REQUEST,
         message: 'Invalid Request: The JSON sent is not a valid request object.',
         data: validate.errors,
       });
@@ -71,7 +71,7 @@ export class RpcEndpoint {
       throw {
         name: 'Method not found',
         message: `The method '${method}' does not exist / is not available.`,
-        rpcErrCode: -32601,
+        rpcErrCode: RPC.ERROR.METHOD_NOT_FOUND,
       };
     }
   }
@@ -110,7 +110,7 @@ export class RpcEndpoint {
       } catch (err) {
         return {
           error: {
-            code: err.rpcErrCode || -32000,
+            code: err.rpcErrCode || RPC.ERROR.SERVER_ERROR,
             message: `${err.name}: ${err.message}`,
             data: err.stack,
           },
@@ -120,13 +120,13 @@ export class RpcEndpoint {
 
     const responses: IRpcResponse[] = results.map((result, index) => {
       return {
-        jsonrpc: '2.0',
+        jsonrpc: RPC.VERSION,
         id: rpcRequests[index].id,
         ...result,
       };
     });
 
-    const statusCode = responses.filter((rsp) => rsp.error).length > 0 ? 500 : 200;
+    const statusCode = responses.filter((rsp) => rsp.error).length > 0 ? HTTP.INTERNAL_SERVER_ERROR : HTTP.OK;
 
     if (!Array.isArray(req.body)) {
       return res.status(statusCode).json(responses[0]);

src/rpc-server.ts

@@ -5,6 +5,7 @@ import * as morgan from 'morgan';
 import * as nconf from 'nconf';
 import { Writable } from 'stream';
 import { generateAuthMiddleware } from './authentication';
+import { HTTP, RPC } from './constants';
 import { IEndpointOptions, ILogger, IServerOptions } from './interfaces';
 import { RpcEndpoint } from './rpc-endpoint';
 export { RpcEndpoint } from './rpc-endpoint';
@@ -164,15 +165,15 @@ export class RpcServer {
     // Register error middleware
     app.use(function errorMiddleware(err, req, res, next) {
       if (err.type === 'entity.parse.failed') {
-        return res.status(400).json({
-          code: -32700,
+        return res.status(HTTP.BAD_REQUEST).json({
+          code: RPC.ERROR.PARSE_ERROR,
           message: 'Parse error: Invalid JSON was received by the server.',
           data: err.stack,
         });
       }
 
-      return res.status(500).json({
-        code: -32000,
+      return res.status(HTTP.INTERNAL_SERVER_ERROR).json({
+        code: RPC.ERROR.SERVER_ERROR,
         message: 'An unexpected server error has occurred',
         data: err.stack,
       });

tslint.json

@@ -2,6 +2,6 @@
   "extends": "@decentro/tslint",
   "rules": {
     "ban-types": false,
-    "no-magic-numbers": false
+    "no-magic-numbers": true
   }
 }