request-utils

request-utils is library designed to simplify the processing of HTTP Request handling and parameters parsing by abstracting commonly reused processing patterns.

It can be used with any framework that creates and uses HTTPRequest objects.

Installation

npm install @mediaxpost/request-utils

Usage

const ReqUtils = require('@mediaxpost/request-utils');

// Example Express.js handler
function handler(req, res, next) {
  const reqUtils = new ReqUtils(req);

  reqUtils.handleRequestAsync(
    {
      params: {
        dataVal1: {
          type: 'string',
          source: ['body', 'headers', 'query'],
          required: true
        },
        dataVal2: {
          type: 'string',
          source: ['body', 'headers', 'query'],
          required: true
        }
      },
      security: { super: true, server: true }
    },
    // Closure function that does processing if the request passes initial inspection
    (_req, _res, _next) => {
      console.log(_req.locals.dataVal1);
      console.log(_req.locals.dataVal2);
      _next();
    },
    next,
    res
  )
  .catch(() => {});
}

API Reference

new ReqUtils(req [, options]) ⟾ instanceof ReqUtils

Create an instance of ReqUtils with the req HTTP Request object provided. Additional configuration parameters may be passed in the options,

The options is a object why may contain any, all, or none of the following:

Param	Type	Default
checkPermissions	Function(HTTPRequest) ⟾ bool	A function to perform additional permission check which returns a boolean if the check passes
customErrorResponseCodes	CustomCodes	A `CustomCodes` object to be used with handleCustomErrors, which checks an error message for the message and sets the appropriate code
customResponseMessages	CustomMessages	A `CustomMessages` object which defines the error message details and status codes for various error codes
defaultAuthContext	AuthContext	A `AuthContext` object which defines the default AuthContext state

Defaults:

  // These are the default options
  {
    checkPermissions: ((req) => {
      return true;
    ),
    customErrorResponseCodes: {},
    customResponseMessages: {
      [200000]: { summary: 'OK', message: '', status: 200 },
      [400000]: { summary: 'Bad Request', message: 'The request is malformed.', status: 400 },
      [400001]: { summary: 'Non-Existent Record', message: 'The record requested does not exist.', status: 400 },    
      [400002]: { summary: 'Missing Parameters', message: 'The request is missing required parameters.', status: 400 },
      [401000]: { summary: 'Unauthorized', message: 'This request is not authorized.', status: 401 },    
      [403000]: {
        summary: 'Forbidden',
        message: 'The credentials provided are not authorized for this request',
        status: 403
      },
      [403001]: { summary: 'Forbidden', message: 'Secure endpoints can only be accessed via HTTPS.', status: 403 },
      [404000]: {
        summary: 'Not Found',
        message: 'The requested resource does not exist or you are not authorized to access it.',
        status: 404
      },    
      [408000]: { summary: 'Timed Out', message: 'The request timed out.', status: 408 },
      [429000]: { summary: 'Rate Limit', message: 'Rate limit has been exceeded', status: 429 },    
      [500000]: { summary: 'Could Not Connect', message: 'The server connection timed out', status: 500 },
      [500001]: { summary: 'General Server Error', message: 'A fatal error has occurred on the server.', status: 500 }
    },
    defaultAuthContext: { super: false, signed: false, server: false, client: false }
  }

Note: Most methods allow a req parameter to be passed to override the req that was passed into the constructor.

Request Handling

.handleRequest(params, handler, next, res[, req]) ⟾ void / Error

Using the params provides, performs the following, so long as the req has not already been processed.

Checks the AuthContext of the request against params.security. Sets 403000 error on failure.
Checks the Security requirement (params.secure) of the request. (Was this request made over HTTPS when secure == true?). Sets 403001 error on failure.
Retrieves all request parameters configured (params.params) from the request.
Checks required request parameters. Sets 400001 error on failure.
Handle default values for options request parameters
Validates that all request parameters are over the expected data types. Sets 400002 on failure.
Runs checkPermission. Sets 403000 error on failure.
If none of the above generates an error, then runs the handler function provided. If the handler throws an Exception, then sets a 500001 error.

next is the asynchronous handler used by ExpressJS, SailsJS, and other similar frameworks to continue execution or return errors. res is the HTTP Response object for the request. req is the HTTPRequest object.

params are outlined in the Request Handler Parameters below.

The handler is a function with a function signature as follow:

  (req, res, next) => {
    // Do something
  }

Example Usage:

  reqUtils.handleRequest({
    params: {

    },
    security: {
      super: true,    // Only accessible by super-users
      server: true,   // Only accessible from a sever-based context
      client: false
    },
    secure: false
  },
  (_req, _res, _next) => {

  }
  , next, res);

.handleRequestAsync(...) ⟾ Promise

Asynchronous version of .handleRequest.

   reqUtils.handleRequestAsync(...)
   .then(() => {
     // Post process successful request handling.
   })
   .catch((err) => {
     // Post-process unsuccessful request handling.
   });

Error Handling

.getResponseMessage(code, customMessages) ⟾ ResponseMessage / null

Checks the code for a match in the merged ReqUtils.customResponseMessages. If a match is found, then the corresponding response message is returned.

.handleCustomErrors(err, customCodes, customMessages) ⟾ object

Checks err.name for a match in the merged ReqUtils.customErrorResponseCodes and customCodes. If a match is found, then the found code is looked up in the merged ReqUtils.customResponseMessages and customMessages for a summary message. If no code is found, then the code is set to 500001. If no summary is found, then the summary message is set to 'An unexpected error has occurred -- {err.name}'. The code and error are then returned in a objects. If err is null, then the object returned contains a null message. If err.name is null, then it defaults to 'No details'.

  // { msg: 'Something went wrong', code: 500001 }

Utility

.setSkipAuth(value [,req])

Set the req.skipAuth flag with the value provided. Any non-boolean value will be coerced to a boolean.

.skipAuth([req]) ⟾ boolean

Return the value of the req.skipAuth flag.

.setTimedout([req])

Set the req.timedout flag to true and sets the req.respCode to 429000.

.setError(code [, req])

Set the req.hasError flag to true and sets the req.respCode to code provided.

.setData(data [, req])

Set the req.hasData flag to true and sets req.data to data provided, so that it can be processed downstream.

.hasResponse([req]) ⟾ boolean

Test the req to see if the hasData, hasError or timedout flags have been set

.setAuthContext(authContext [, req])

Set the req.authContext flags with fills from the defaultAuthContext.

.updateAuthContext(authContext [,req])

Merge authContext values into req.authContext values, overwriting any values currently set in req.authContext.

.checkAuthContext(options [,req]) ⟾ boolean

Compares the options values against the req.authContext ensuring that any option set true is also true in the req.authContext. Any value set false in the options is ignored. Returns false if any option is true, but the authContext is false.

.checkPermissions([req]) ⟾ boolean

Runs the configured checkPermissions function configured as a part of the initialization options for ReqUtils.

Parameter Binding

.retrieveParams(params [,req])

Sets the req.handler from the params provided, then gathers, parses, and converts these values from the request and places the values into both req.handler.[key].value req.locals.[key].

.compileRequiredParams(params) ⟾ object

Analyzes the params configured and creates a dictionary of required and optional parameters. This is used to validate the request in the handleRequest method.

  // { required: reqParams, optional: optParams }

.hasRequiredParams(requiredParams) ⟾ array

Analyzes the key values in the requiredParams and checks that each of them have a value. Each key name with a missing value is returned in an array. With an empty array being returned if there are no missing values. requiredParams is the .required key from the object returned from .compileRequiredParams

.handleDefaults(optionalParams [,req])

Reviews the optionalParameter key values set and compares the keys with the values set in req.locals. If any value is missing, then the default value is assigned to the key. optionalParams is the .options key from the object returned from .compileRequiredParams

.validateParams(params)

Validates all values in req.locals against the type specified for that key. Returns an array of field names where the key value does not match the given type specified in the params.

Types

Auth Context

Auth Context is an object hash which contains key and boolean value pairs. It is left up to the system designer what each of these contexts indicate. For example, in one system client could mean that the request originated in such a way that it is interpreted to be having come from a browser or mobile device, and server could mean the request originated from another server. Any custom keys and specific logic is left to the system designer to implement.

{
  super: false,
  signed: false,
  server: false,
  client: false
}

Request Parameter

A Request Parameter provides a definition for values that may be sent as a part of the incoming request, where to parse them from, their data type, whether they are required, a default value if they are missing, and optional validation parameters.

dataVal1: {
  type: 'string',
  required: true,
  source: ['body', 'headers', 'query'],
  default: (v) => { return(v); },
  options: {}
}

Key	Type	Description	Required
type	string	The data type for this parameter. See below.	Y
required	boolean	Whether the parameter is required.	Y
source	array(string)	The locations to search for the parameters. Sources are searched in the order provided and the first source to find the value is the one used. See below.	Y
default	value or function	The default value to use when the value can not be found. When passing a function, the existing value (including null and undefined) is passed into the function and the value returned is used as the default.	N
options	object	Additional validator.js options for the data type. See below.	N

Data Types and Validation options

The following data types are supported for parsing: int, float, bool, email, currency, uuid, url, fqdn, apikey, string, any. For more information, please see the validation-helper README

Sources

The following request sources are available:

Source	Description
`'params'`	Searched the request route parameters for the key. This is only supported in frameworks that perform route parameter binding to `req.params`.
`'header'`	Searches the request headers (lowercase) for the key.
`'body'`	Searches the form body (x-www-form-urlencoded) values for the key.
`'query'`	Searches the url query variables for the key.

Additionally, all requests will search for a JSON string passed to body.params, and parse that object into the appropriate data fields.

Request Parameter Collection

A collection of Request Parameters in Key / Request Parameter pairs

const params = {
  ['Test1']: {
    type: 'int',
    source: ['body'],
    required: false
  },
  ['Test2']: {
    type: 'int',
    source: ['body'],
    required: false
  }
};

Request Handler Parameters

{
  params: {
    ['Test1']: {
      type: 'int',
      source: ['body'],
      required: false
    }
  },
  security: {

  },
  secure: false
}

Key	Type	Description	Required
params	Request Parameter Collection	The request parameters for this handler.	Y
security	Auth Context	The required Auth Context for this request	N
secure	boolean	Whether this request is required to be made over HTTPS. Default: `false`.	N

CustomCodes

CustomCodes are a collection of named key and integer value pairs representing the response code to use when a specific err.name matches a given key.

{
  ['SequelizeUniqueConstraintError']: 400006,
  ['SequelizeDatabaseError']: 400103,
  ['SequelizeConnectionRefusedError']: 500002
}

ResponseMessage

  { summary: 'OK', message: '', status: 200 },

Key	Type	Description	Required
summary	string	The response summary for the specific response code	Y
message	string	The response message for detailed error information	Y
status	int	The HTTP Response status code	Y

CustomMessages

A collection of ResponseMessage objects, with a matching response code key.

{
  [200000]: { summary: 'OK', message: '', status: 200 },
  [400000]: { summary: 'Bad Request', message: 'The request is malformed.', status: 400 },
  [400001]: { summary: 'Missing Parameters', message: 'The request is missing required parameters.', status: 400 }
}

@mediaxpost/request-utils