#Express-CRUD

Table Of Content

• General
  • Requirements
• Installation
• Configuration
  • Importing The Module
  • Initialization
• Usage
  • Creating a Simple CRUD Module
  • Creating a Simple Static Module
  • Using Hooks
    • Pre Hooks
    • Post Hooks
  • Model Dependecies
• Additional Information
  • Options Object
  • Output Object

##General A simple to use, server side, generic module for adding CRUD module to your Express application. This module will allow you to add a simple CRUD module for a specific model / static file without you to have to worry about common modules implementations.

###Requirements For you to be able to use this module you need the follwing things:

• Express Application
• Static File to use / Mongoose Scheme

##Installation To install the module use:

npm install express-generic-crud

##Configuration ###Importing The Module To import the module use the following:

var expressCRUD = require('express-generic-crud');

###Initialization To initialize thhe module use the init API Usage:

/**
  @param: app - {Express Application}
**/
expressCRUD.init(app);

The Express-CRUD module will automatially add a crud method which would be described within the Usage section

##Usage ###Creating a Simple CRUD Module To create a simple CRUD module you would need to have a basic mongoose scheme which it you can set with the following API on the Express Application:

/**
  This method is added dynamically on runtime,
  This is a helper method to create generic CRUD module
  @param: path - {String} - path which will be routed to the application
  @param: scheme - {Mongoose Model} - The Model which will be used to create the CRUD operations on
  @returns: {Crud} - Crud object to manipulate
**/
var crud = app.crud(path, scheme);

After using this method, The followings routes would be provided for you

• /path (GET) - Get array list from the DB
• /path (POST) - Create new item in DB with specific details
• /path/:id (GET) - Get a specific item with id of :id
• /path/:id (PUT) - Update a specific item within the DB
• /path/:id (DELETE) - Delete specific item from DB

###Creating a Simple Static Module To create a get method to a staitc data, use the same API with the following options parameter:

/**
  This method is added dynamically on runtime,
  This is a helper method to create static data API
  @param: path - {String} - path which will be routed to the application
  @param: data - {Object} - The object you want to open API to
  @param: options - {Object} with:
            resourceType - {String} static for exporting static data object
**/
app.crud(path, data, {resourceType : 'static'});

###Using Hooks Hooks are a way for the developer to intervene with the internal of the CRUD generic module, There are two available hooks: pre-hooks and post-hooks

####Pre Hooks Pre-Hooks are available for each operation that been defined and one can register to listen to such a hook with the following API on the Crud object (See Creating A Simple CRUD Module):

/**
  Registration of Pre-Hook method
  @param operation - {String} one of the followings:
                      -. list
                      -. create
                      -. read
                      -. update
                      -. delete
  @param callback - {Function} in the form of callback(context, next)
                      context - {Context} object
                      next - {Function} async next method - must be called to complete the operation
*/
crud.pre(operation, callback);

The Context object is overloaded with relevant details for each operation, Here is the list of available methods for Context objects per opeartion:

• Create / Update Operation:

  /**
    Create / Update Instance Details Getter
    @returns {Object} - The details which with them the data would be created / updated
  */
  context.getDetails();
    
  /**
    Create / Updtate Instance Details Setter
    @param newDetails - {Object} set the details which with them the new instance would be created / updated
  */
  context.setDetails(newDetails);
    

For an example, to use a pre hook for create operation, use the following example:

// Create a pre create hook
crud.pre('create', function(context, next){
    console.log('Pre Create Hook');

    next();
});

####Post Hooks Post-Hooks are available for each operation that been defined and one can register to listen to such a hook with the following API on the Crud object (See Creating A Simple CRUD Module):

/**
  Registration of Post-Hook method
  @param operation - {String} one of the followings:
                      -. list
                      -. create
                      -. read
                      -. update
                      -. delete
  @param callback - {Function} in the form of callback(context, next)
                      context - {Context} object
                      next - {Function} async next method - must be called to complete the operation
*/
crud.post(operation, callback);

The Context object is overloaded with relevant details for each operation, Here is the list of available methods for Context objects per opeartion:

• All Operations:

  /**
    Getter for the output object
    @returns {Output}
  */
  context.getOutput();
    
  /**
    Setter for a new Output object
  */
  context.setOutput(newDetails);

  For you to get the relevant error / result - use the getResult(), getError() getters which their documentation is found under Output Object

For the API call:

  var result = context.getOutput().getResult();

here is a relevant result for each operation that been done

• List Operation: result - {Array} of instances

• Create / Read / Update / Delete Operation result - {Instance} single scheme instance

For an example of a post hook after a read operation:

  // Register for post read hook
  crud.post('read', function(context, next){
      console.log('Post Read');
      
      next();
  });

###Model Dependecies This feature should be available soon.

##Additional Information ###Options Object This is an object as a thirs parameter to the crud method, it can consist of the followings:

• resourceType - {String} - Set the resource of which to create the CRUD module
  • mongodb - use mongodb as the resource to use the CRUD for
  • static - export static data object API
• id - {String} - id which by it db index will be resolved upon

###Output Object

/**
 * Error getter
 * @returns {Error}
 */
function getError();

/**
 * Error setter
 * @param {Error} - New Error
 */
function setError(err);

/**
 * Result getter
 * @returns {*}
 */
function getResult();

/**
 * Result setter
 * @param {Object} new Result
 */
function setResult(result);

/**
 * Is Error
 * @returns {boolean}
 */
function isError();