HTTP also known as Hyper Text Transfer Protocol is a set of standards that allow users of the World Wide Web to exchange information found on web pages. It was originally devised by Tim Berners Lee in 1989. It is now coordinated by the W3C. While accessing web pages, including Http:// in front of the address tells the browser to communicate over HTTP. HTTP is an application protocol for transferring resources across the Internet. HTTP is a method for transferring information between a client and a web server. URLs that begin with Http:// use port 80 by default. The web browser uses HTTP to transmit request for the webpage to the server.
When the server sends back a response to the client, the thing that sends it is known as Status Codes. Status codes are in the form of numeric codes, which is accompanied by an explanation phrase that indicates if the response was a success or not. Error codes are status codes that indicate that there’s been a problem in accessing the information. Error codes are also followed by an explanation that tells the client about the problem. There are various types of Error codes;
HTTP Errors (Client-Side):
400 -Bad Request
Error 400 codes also known as Bad Request, are generally caused by wrong syntax, a size too large, etc.
This type of error is caused due to wrong authorization credentials.
It is usually caused when data is off-limits i.e. the information the client is searching is unavailable or if the user is not authorized to access the resource.
404 -Not Found
A 404 error is generated when the requested resources by the user is unavailable in the server.
405 -Method not allowed
It is caused when the user uses the wrong method to request the resource.
406 -Not Acceptable
Error 406 is generated when the data provided by a web server does not match the specifications mode in ‘Accept’ Header.
407 -Proxy Authentication Required
When authentication is required from the proxy server to gain access, this error is generated.
408 –Request Timeout
This error is generated when the client delayed making a request within the specified time by the server.
When two users make a request for the same resource simultaneously, this error is generated.
When a user requests a file that is no longer present at the server, then this error is generated.
411 –Length Required
If the user does not include the length of the specified resources, this error is generated.
412 –Precondition Failed
When the server does not meet one of the preconditions that the user put on the request, this error type is generated.
413 –Request Entity too large
Whenever a client makes a request which is too overwhelming for the server, this error pops up.
414 –Requested URL too long
When a server is unable to process the URL, because of limited resources and long string length.
415 –Unsupported media types
When a user uploads a media, which does not match the specified format of the resource.
416 –Request Range Not Satisfiable
When a client requests for only a small part of the file, instead of the entire file and if the requirement is not specified properly and part of the file requested does not exist, this type of error occurs.
417 –Expectation Error
When the server cannot meet specifications made in the request, this error is caused.
422 –Unprocessable Entity
When request made cannot be processed due to an error in semantic structure, this error occurs.
When a requested piece of data or resource has been locked, making it inaccessible for the server.
424 –Failed Dependency
When request made before is not fulfilled, due to which current request cannot be processed.
426 –Upgrade Required
It signifies that the client may need to switch over to a secure protocol like TLS to get the request processed.
444 –No Response
This error signifies that the server has simply rejected the client’s request and terminated connection.
449 –Retry With
This is a request made by the server to the client to make the request again after executing certain actions or making specific changes in the request.
499 –Client closed Request
When a client terminates a connection made with the server, while it’s processing the associated request.
450 –Blocked by Windows Parental Control
When blocked by parental control settings on the web browser, this error occurs.
HTTP Errors (Server Side)
500 –Internal Server Error
When the problem with the request cannot be specified by any other appropriate code, this error occurs.
501 –Not Implemented
It is the inability of the server to process a request, as it hasn’t been configured to respond to the request.
502 –Bad Gateway
If the proxy fails connecting with the web server, error 502 results.
503 –Service Unavailable
When the server is overloaded with multiple requests, it will temporarily stop entertaining new requests.
504 –Gateway Timeout
When requests made by a proxy server to the web server hosting a resource time out, error 504 is reported.
505 –HTTP Version not supported
An error code seen rarely is displayed when the web server does not support the protocol version of the client’s request.