HTTP (Hypertext Transfer Protocol) error codes are standard response codes given by web applications and servers on the Internet. These codes are three-digit numbers. The first digit of this code indicates the response class, while the last two digits have no role in the status code. Familiarizing oneself with these codes is important when preparing for the AWS Certified Developer – Associate (DVA-C02) exam.
1. Informational responses (100–199)
These codes represent that the request has been received and understood, and the process is ongoing.
Example:
- 100 Continue: The client should continue with its request.
2. Successful responses (200–299)
These codes indicate that the client’s request was successfully received, understood, and accepted.
Example:
- 200 OK: The request was successful, and the server responds with the requested data.
- 201 Created: The request was successful, and a new resource was created as a result.
3. Redirection messages (300–399)
These statuses mean you have to take additional action to complete the request.
Examples:
- 301 Moved Permanently: The URL of the requested resource has been changed permanently. The new URL is given in the response.
- 303 See Other: The response can be found under another URI using the GET method.
4. Client error responses (400–499)
These are the HTTP status codes that indicate the request made by the client contains bad syntax or cannot be fulfilled.
Examples:
- 400 Bad Request: The server could not understand the request due to invalid syntax.
- 404 Not Found: The server can’t find the requested resource.
5. Server error responses (500–599)
These status codes serve as responses to HTTP requests that were correctly processed, but server errors have occurred.
Examples:
- 500 Internal Server Error: The server has encountered a situation it doesn’t know how to handle.
- 502 Bad Gateway: The server was acting as a gateway or proxy and received an invalid response from the upstream server.
It’s important to note that while dealing with AWS services like API Gateway or Lambda functions, we often encounter HTTP error responses due to various reasons, such as incorrect IAM roles, configuration errors, or system failures. Understanding what these HTTP error codes mean can streamline debugging process and improve system designs.
For example, in the case of a 503 Service Unavailable error, it could mean that the Lambda function you’ve configured with your REST API is timing out or has been throttled due to too many requests. In such cases, increasing the timeout duration or the provisioned concurrency can serve as a potential solution.
Study aids for the AWS Certified Developer exam, such as practice tests and exam guides, often include HTTP error codes as they test your ability to troubleshoot and debug applications that interact with AWS over HTTP(S).
In conclusion, understanding common HTTP status codes and what they indicate can be a critical tool for anyone looking to pass the AWS Certified Developer – Associate (DVA-C02) exam.
Practice Test
“Error 102” is an HTTP status code that indicates processing but no complete response is ready.
- 1) True
- 2) False
Answer: b) False
Explanation: There is no such standard HTTP status code as “102”.
“HTTP 200” status indicates what type of response?
- a) Success
- b) Client Error
- c) Server Error
- d) Informational response
Answer: a) Success
Explanation: HTTP 200 status code indicates that the request has succeeded.
“HTTP 400” status code refers to:
- a) Bad Request
- b) Not Found
- c) Unauthorized
- d) Payment Required
Answer: a) Bad Request
Explanation: A 400 Bad Request error means that the request that was sent to the server is incorrect or corrupted and that the server could not understand it.
“HTTP 404 Not Found” error indicates what?
- a) The requested resource could not be found on the server.
- b) Server is currently unable to handle the request.
- c) Client needs to authenticate to get network access.
- d) An error has occurred in the server.
Answer: a) The requested resource could not be found on the server.
Explanation: 404 Not Found means that the URL you are trying to reach could not be found on the server. It’s a general-purpose error message for when a webserver can’t find what you asked for.
What does “HTTP 500 Internal Server Error” mean?
- a) The client has provided invalid data.
- b) An error has occurred in the server.
- c) The client must authenticate themselves to get the requested response.
- d) The server has received valid request from the client.
Answer: b) An error has occurred in the server.
Explanation: This code indicates there is a problem on the server side. A 500 Internal Server Error is an indication that something has gone wrong within the web server’s software, preventing it from fulfilling the client request.
“HTTP 302 Found” status code represents:
- a) Redirect
- b) Not Modified
- c) Partial Content
- d) Unauthorized
Answer: a) Redirect
Explanation: HTTP 302 is a status code that tells a browser that the originally requested URL has been moved, and it should redirect its request to the given URL.
HTTP status codes only have 4xx and 5xx ranges.
- a) True
- b) False
Answer: b) False
Explanation: HTTP status codes occur in five classes, which are 1xx (Information), 2xx (Success), 3xx (Redirection), 4xx (Client Error), and 5xx (Server Error).
What does “HTTP 401 Unauthorized” imply?
- a) The client needs to authenticate to get the requested response.
- b) The server is temporarily unavailable.
- c) The client’s request is formed incorrectly.
- d) The request has been received by the server.
Answer: a) The client needs to authenticate to get the requested response.
Explanation: The HTTP 401 Unauthorized client error status response code indicates that the request has not been applied because it lacks valid authentication credentials for the target resource.
“HTTP 503 Service Unavailable” status code means the server is temporarily unable to handle the request.
- a) True
- b) False
Answer: a) True
Explanation: The HTTP 503 Service Unavailable server error response code indicates that the server is not ready to handle the request. This could occur due to overloading or maintenance of the server.
“HTTP 304 Not Modified” status code means the resource has not been modified since the last request.
- a) True
- b) False
Answer: a) True
Explanation: The HTTP 304 Not Modified client redirection response code indicates that there is no need to retransmit the requested resources as it has not changed since the last request.
Interview Questions
What does the HTTP error code 404 indicate?
HTTP error code 404 indicates that the requested page or resource could not be found on the server. It is a client-side error.
What does HTTP error code 500 represent?
HTTP error code 500 represents an Internal Server Error. It means the server encountered an unexpected condition which prevented it from fulfilling the request.
What does HTTP error code 400 mean?
HTTP error code 400 represents a Bad Request error. This typically means the server could not understand the request due to invalid syntax or request message framing.
What is HTTP error code 403?
HTTP error code 403 represents a Forbidden error. It indicates the server understood the request, but it refuses to authorize it.
What does the HTTP error code 503 represent?
HTTP error code 503 represents Service Unavailable error. It is a server-side error means that the server is temporarily unable to handle the request.
What does HTTP error code 401 mean?
HTTP error code 401 represents Unauthorized error. It indicates that the client must authenticate itself to get the requested response.
What is HTTP error code 504?
HTTP error code 504 represents Gateway Timeout error. It means the server, while acting as a gateway, did not get a response in time from the upstream server it accessed in attempting to complete the request.
What does HTTP error code 502 represents?
HTTP error code 502 represents Bad Gateway error. This typically happens when a server receives an invalid response from the upstream server it accessed in attempting to fulfill a request.
What is HTTP error code 301?
HTTP error code 301 represents Moved Permanently error. It means that the requested URL has been moved permanently and a new location has been assigned.
What is the meaning of HTTP error code 302?
HTTP error code 302 means Found or Moved Temporarily. It indicates that the requested resource has been temporarily moved to a different URI.
What does HTTP error code 307 mean?
HTTP error code 307 represents Temporary Redirect error. It means that the requested resource is temporarily located somewhere else, and the client should continue using the same request method for future requests.
What is HTTP error code 304?
HTTP error code 304 represents Not Modified status. It is used to reduce data transfer when the client’s cached copy of a specific resource is up-to-date.
What is the HTTP status code for ‘Request Timeout’?
HTTP status code for ‘Request Timeout’ is 408. It indicates that the client did not produce a request within the time the server was prepared to wait.
Which HTTP status code represents ‘Conflict’?
HTTP status code 409 represents ‘Conflict’. It indicates that the request could not be processed because of conflict in the current state of the resource.
What is the HTTP status code for ‘I’m a teapot’?
HTTP status code for ‘I’m a teapot’ is 418. This code was defined in 1998 as an April Fools’ joke, not expected to be implemented by actual HTTP servers.
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