HTTP Verbs

[mohamed-abdul-fattah]

You mentioned in #1

 xhr.open("GET", "user.json", true);

So,

1. What are other common HTTP verbs?
2. What are the differences between GET and POST?
3. What is the purpose of each HTTP verb?
4. Why cannot we use GET for all scenarios instead of using multiple HTTP verbs?

[al-amiir]

1) Other HTTP verbs :

• POST
• HEAD
• PUT
• DELETE
• CONNECT
• OPTIONS

2) Difference between GET & POST

• GET used to retrieve data from server
• POST used to send data to server

3) Purpose of each verb

• HEAD , gets the headers in the response of a request , without the body of response

• PUT , update the data retrieved from server through GET method , if any new POST request cause the data to be changed

• DELETE , deletes data

• CONNECT , establishes a tunnel to the server

• OPTIONS , describe the communication options for the server

4) Because every verb has it own properties , however GET could post data through query parameters , but data should be simple and not sensitive like password and username , right ?

[mohamed-abdul-fattah]

Q1. PATCH HTTP verb is missing. What is the purpose of PATCH and what is the difference between PATCH and PUT?. CONNECT is not common and you can discard this one.

Resource ignore the implementation section

[mohamed-abdul-fattah]

Q2. Key differences between GET and POST

• GET requests can be cached
• GET requests remain in the browser history
• GET requests can be bookmarked
• GET requests have length restrictions (about 2k characters in the URL bar differs from browser to browser)
• Search engines crawlers/spiders indexes the pages navigating via GET requests, and they might take actions if actions are implemented with GET HTTP method like creating some records unintentionally.
• GET requests can be copied via the URL and shared. That's why search filters are preferred to be GET requests to share your filter results easily with others. E.g. Here is a search result from Google https://www.google.com/search?channel=fs&client=ubuntu&q=search+result will take you to the same page I opened.

There for GET requests are only used to request data (not modify)

• POST requests are never cached
• POST requests do not remain in the browser history
• POST requests cannot be bookmarked
• POST requests have no restrictions on data length

[mohamed-abdul-fattah]

Q3. The reasons we cannot use GET over other HTTP verbs are as mentioned in Q2 (because it should not take actions). The reasons why we should not use like POST over DELETE is because these methods are following the semantics of a software architecture style called REST which we can ignore for now.