The Back-End for Groupd - A social networking application to find team mates for start up projects.
Groupd-BackEnd was undertaken as an assignment for a semester long third year project. This assignment was devised and developed as a group project with ImErvin. Groupd-BackEnd, the groupd API with contributions from both parties, is one of three parts of the assignment. The other two sections include Groupd-FrontEnd, the web application developed by ImErvin, and Groupd-Mobile-Application, the cross platform mobile application developed by taraokelly. For more details about Groupd, please go to the About Groupd section.
Groupd is a social networking site devised to help users find team mates to work on a project idea they may have. Groupd was designed with developers in mind, however, Groupd encourages and welcomes users of all professions and needs to use this platform to find teammates. Together, Ervin and I developed a shared database(see Planning for database schema) and RESTful API to manage our database and administer our CRUD features to assist our two front-ends(see Groupd-BackEnd and Groupd-Mobile-Application for full documentation). We wanted Groupd to allow users post their desired projects, communicate with other users and to work on projects with other users. Groupd can be used to recreationaly and/or to gain experience and to eventually build a portfolio from projects they have worked on. Groupd is also useful for finding team members for a start up business.
Groupd began as a inidivual project by ImErvin. Ervin set out to design and develop a RESTful API and a web-app to utilize the API. He set out to design an API that employs the CRUD functionalities, and does so adhering to the correct usage of the HTTP verbs; GET, POST, PUT, and DELETE.
Many modern applications use a common API to connect their mobile applications and web applications to the same database. ImErvin and I decided to try and learn how this method is implemented. We decided to form a group, where one creates the web application and the other creates the mobile applications but connect it to the same API.
Upon joining as a group, the team realized that we could add extra features. Together, we designed a new database schema, attached below, and updated the API to correspond with these changes.
The database holds a two seperate collections, users and projects. These collections are basically an array of objects. These are the schemas for the objects.
The users collection stores user objects containing user details. The front-end applications can create, display, update or delete users from the user collection. Mongoose will set the data fields to null if data fields are not present when storing/updating. Most of the data types are Strings with a few Number data types (any number type). For users, the username is the "primary key" used to retrieve users. The integrity of the primary key is set by the front end by not allowing users to create duplicate usernames.
Here is a visual representation of the Schema written in Javascript.
The projects collection stores project objects containing project details. The front-end applications can create, dispaly, update or delete projects from the projects collection. Similar to above, empty datafields will be set to null. The project schema holds mostly String data types with the exception of one number and one Date type. For projects, the projectId is the "primary key" used to retrieve a project. The integrity of the primary key is set by the POST method for /api/projects by creating a unique projectId for each project.
The team decided that using _id, the default id given to objects by the database, was not adequate for testing routes so we decided to create a unique id function.
Here is a visual representation of the Schema written in Javascript.
ExpressJS
Express is a minimal and flexible Node.js web application framework that provides a robust set of features for web and mobile applications. It is an open source framework developed and maintained by the Node.js foundation.
Mongoose
Mongoose is a way to make connection with MongoDB database. It provides MongoDB validation and query building in a very simple manner and it makes development fast. Mongoose is built upon the MongoDB driver to provide programmers with a way to model their data.
MongoDB
MongoDB is a NoSQL, open source database that uses a document-oriented data model. Instead of using tables and rows as in relational databases, MongoDB is built on an architecture of collections and documents. Documents comprise sets of key-value pairs and are the basic unit of data in MongoDB.
The team had no experience with using MongoDB in the past and we decided that it would be a great opprotunity to learn such an up and coming database. MongoDB has grown rapidly and is the leading NoSQL database, for this reason we decided it was a good idea to tackle this new technology and see what it's all about!
Why ExpressJS and Mongoose
The reason behind using ExpressJS was because ImErvin decided to use the MEAN stack as the web stack for the web application and taraokelly was goiing to use Angualar2 with Ionic2 which compliments the MEAN stack. Node.js is very fast and efficient for processesing a large amount of requests, and if the application was to scale, node.js would play a great role in allowing it to do so. Express.js is the main framework available for Node.js so it was a no brainer to stick with the popular choice.
Mongoose and ExpressJS were chosen as a pair because together they are known to be a very efficient method of creating RESTful APIs. A RESTful API holds no state of the requester and simply recieves requests and responds to those requests. A RESTful approach to designing an API is the modern approach and as a team we deicded it would be a challenging task to tackle.
The heavy lifting is done by mongoose when working with MongoDB and because of the time limitation, mongoose was the right choice to get a quick and efficient prototype up and running. Mongoose and Express have great synergy when it comes to quickly parsing a datbase and responding to server requests and they are both popular and modern technologies.
- Due to time limitations we decided to store the comments in the project document, rather the comments as a seperate document with a reference to it in the project document.
The API is hosted on localhost on port 8080 with a prefix '/api'.
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/api/ - GET
Returns a welcoming message.
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/api/users - GET
Returns all the users in the database with all their details.
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/api/users - POST
Will recieve a user object, compare usernames to every other user object and attempt to add a new user to the collection if that username does not exist.
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/api/users/:username - GET
Will recieve a user's username as a parameter and findOne user with that username. If successful, it will return the user with the username passed in as a parameter, if unsuccessful, it will return an error message.
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/api/users/:username - DELETE
Will recieve a user's username as a parameter and findOneAndRemove a user with that username. If successfull, it will return a message, if unsuccessful it will return an error message.
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/api/users/:username - PUT
Will recieve a user object and user's username as a parameter, compare usernames to ever other user object and attempt to update that user. If some user details are null in the user object coming in through the PUT request, it will use the details already stored and only update those which have changed.
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/api/projects - GET
Will return all the projects in the database and their details.
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/api/projects - POST
Will recieve a project object and attempt to put it on the database. A unique projectId is generated on this route and uses recursive function to generate a new projectId if the previously generated one already exists in the system.
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/api/projects/:projectId - GET
Will recieve a projectId as a parameter and findOne project in the database that matches that projectId. If successful, it will return that project or else it will return an error message.
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/api/projects/:projectId - DELETE
Will recieve a projectId as a parameter and findOneAndRemove a project from the database. If successful, it will return a message indicating the the project was deleted, or else it will return an error message.
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/api/projects/:projectId - PUT
Will recieve a project object and projectId as a parameter and attempt to update the project with the projectId (parameter). If some project details are null in the project object coming in through the PUT request, it will use the details already stored and only update those which have changed.
Download and install Node.js and npm, if not already downloaded or installed. You can find the necessary download here.
Download and install MongoDB if you have not done so already. You can find the MongoDB download page here.
Clone this repository. Run the following command in the API directory:
npm install
If successful, then start the server by run the following command:
node apiServer.js
Access the API by sending methods to http://127.0.0.1:8080/api/.. using cURL or other data transfer tools.
To conclude, this project has been a rewarding experience. Working in a group has been a great contributor to this. Together, we built an effective RESTful API with a well thought out database schema. However, we wished we had time to implement all the database the way we had planned, that we could have avoided straying away from our original database schema. We would have referenced a seperate comments document, rather than embeding the comments in the projects document, as the comments are indeed related data to the project, however the comments change with differing volatiliy to the rest of the project data. Finally, we would add a property like, "dormant": true/false. This property would be used in the place of actually deleting the user document, would solve the problem of the referenced usernames being confused with old/new users, and would serve useful to offer old users a recovery option.
Deploying the database onto a cloud and using the same database between apps would be another feature that we wanted to implement if we had the time. Upon attempting to deploy it to AWS, there were public IP errors and the API was not reachable outside of the virtual machine. We decided if we had future opprotunity to develop this, we would use Heroku or Microsoft Azure to host the database and API.
References:
https://www.youtube.com/watch?v=-o_VGpJP-Q0
Ervin Mamutov - G00311015@gmit.ie Tara O'Kelly - G00322214@gmit.ie