Elemental HTTP Server
Basic HTTP Server that reads from and writes to fs
Security Notice !!!
This server will expose some serious security vulnerabilities.
Do not run this in production, or leave it running on your local environment that is accessible from the public network.
Resources
Goals
Use http.createServer to create an instance of http.Server
The http server will serve html and css content that is stored on the file system. Each resource will be identified by it's corresponding file name. Store all resources in a public/ sub directory.
for example:
├── README.md
├── public
│ ├── css
│ │ └── styles.css
│ ├── helium.html
│ ├── hydrogen.html
│ └── index.html
└── server.js
If an http request asks for /hydrogen.html, then respond with the contents of public/hydrogen.html.
see the routing table below
POST Requests
An HTTP Client can issue POST Requests to a specific route identified by the uri /elements.
The POST Body will contain content of type application/x-www-form-urlencoded.
The HTTP Server will parse the form data, and save a file in the designated public directory, based on that content.
The form data will be:
| Name | Content |
|---|---|
| elementName | the Titlecased name of the element to be saved, for example "Boron" |
| elementSymbol | the element Symbol, for example: "B" |
| elementAtomicNumber | the element's atomic number, for example: 5 |
| elementDescription | a short description |
Use Postman to perform POST Requests with the proper form fields.
see the routing table below
Parse the request body, and write a new file (if it does not exist), to the public directory, named after the element's name, appended with the html file extension.
using the above example POST data, this file will be saved to ./public/boron.html
notice the areas of dynamic data, title tag, h1 tag, h2 tag, etc.
In other words, when a client performs a POST request with the 4 required post data fields, a new file will be created in a valid html5 format, containing the dynamic content from the post data fields.
The http server will respond to the POST request with an http response code 200, content type of application/json, and content body of { "success" : true }
GET Requests
The http server will respond to GET requests, and serve the contents of the public directory, serving each public file by it's name as the uri.
As new html pages are created, more content will be available.
If a resource path (url) does not exist, return a 404 response code and render the html contents of 404.html
Auto Updating Index
Each time a new resource is created (via POST), update the index.html file to reflect the newly created page.
When carbon.html is been added to the public/ directory, add a link to carbon.html in public.html.
Initial Routing Table
| HTTP | Path | File |
|---|---|---|
| GET | / | public/index.html |
| GET | /hydrogen.html | public/hydrogen.html |
| GET | /helium.html | public/helium.html |
| GET | /404.html | public/404.html |
| GET | /css/styles.css | public/css/styles.css |
| POST | /elements | - |
Get your initial file contents from here
Advanced
PUT Request
The http server can accept PUT requests to paths of resources that exist, example: /hydrogen.html
The PUT request contains a body similar to the POST request fields.
for your convenience, require all 4 fields be set to update the html file
| Name | Content |
|---|---|
| elementName | update the name of the element in the html document to this value |
| elementSymbol | update the element Symbol in the html document to this value |
| elementAtomicNumber | update the element's atomic number in the html document to this value |
| elementDescription | update the short description in the html document to this value |
If the requested path to update does not exist, return a 500 server error, content type application/json, and content body of { "error" : "resource /carbon.html does not exist" } (for example)
If the http PUT request successfully updates the requested html file, respond to the PUT request with an http response code 200, content type of application/json, and content body of { "success" : true }
DELETE Request
The http server can accept DELETE requests to paths of resources that exist, example: /hydrogen.html
The DELETE request contains no body.
If the requested path to delete does not exist, return a 500 server error, content type application/json, and content body of { "error" : "resource /carbon.html does not exist" }
If the http DELETE request successfully deletes the requested html file, respond to the DELETE request with an http response code 200, content type of application/json, and content body of { "success" : true }
2Advanced
HTTP Basic Auth
Resources
Goals
Use HTTP Basic Auth to protect the sensitive aspects of your server, POST, PUT, DELETE requests by requiring a correct username and password.
Check if the authorization header is present in the request, if it is not, require authorization (using Basic Auth) by sending a status code of 401, sending a response with a header of WWW-Authenticate with a value of Basic realm="Secure Area" and ending the request by responding with a body of <html><body>Not Authorized</body></html>
If the authorization header is present, decode and compare against your own internal valid login credentials.
To decode the authorization header, extract the value of the authorization header by removing the first part of the authorization header value.
Example authorization header value:
Basic Y2hhcmxlczoxMjM0NQ==
^------------------^--> only need this string
this string is Base64 encoded, decode it
var encodedString = 'Y2hhcmxlczoxMjM0NQ==';
var base64Buffer = new Buffer(encodedString, 'base64');
var decodedString = base64Buffer.toString();
decodedString will be the username password pair separated by a colon :
console.log(decodedString);
// username:password
extract the username and password from the decodedString, then compare against some stored username and password stored somewhere in memory.
Security Consideration Notice
You will be committing your code to a public github repository, where anyone can see your source code which will contain your secret username and password... so use caution and set it to some fake test credentials_
If the username and password match your secret values, allow the client to perform their requested operation.
If the username and password do not match your secret value, force them to attempt authentication again by sending a 401 status code, WWW-Authenticate header, and ending the request by responding with a body of <html><body>Invalid Authentication Credentials</body></html>
As long as the client continues to send the correct authorization header values, they do not need to keep re-authenticating. This is easily done in Postman.
