304 Http Error
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sections of messages Error, Forward and redirection responses may be used to contain human-readable diagnostic information. Success 2xx These codes indicate success. The body section if present is the object 302 http error returned by the request. It is a MIME format object. It is in MIME 301 http error format, and may only be in text/plain, text/html or one fo the formats specified as acceptable in the request. OK
403 Http Error
200 The request was fulfilled. CREATED 201 Following a POST command, this indicates success, but the textual part of the response line indicates the URI by which the newly created document should be known. Accepted
Html Code 404
202 The request has been accepted for processing, but the processing has not been completed. The request may or may not eventually be acted upon, as it may be disallowed when processing actually takes place. there is no facility for status returns from asynchronous operations such as this. Partial Information 203 When received in the response to a GET command, this indicates that the returned metainformation is not a http error code 500 definitive set of the object from a server with a copy of the object, but is from a private overlaid web. This may include annotation information about the object, for example. No Response 204 Server has received the request but there is no information to send back, and the client should stay in the same document view. This is mainly to allow input for scripts without changing the document at the same time. Error 4xx, 5xx The 4xx codes are intended for cases in which the client seems to have erred, and the 5xx codes for the cases in which the server is aware that the server has erred. It is impossible to distinguish these cases in general, so the difference is only informational. The body section may contain a document describing the error in human readable form. The document is in MIME format, and may only be in text/plain, text/html or one for the formats specified as acceptable in the request. Bad request 400 The request had bad syntax or was inherently impossible to be satisfied. Unauthorized 401 The parameter to this message gives a specification of authorization schemes which are acceptable. The client should retry the request with a suitable Authorization header. PaymentRequir
false. In other words, there is no need for the server to transfer a
Http 400 Errors
representation of the target resource because the request indicates that 400 http the client, which made the request conditional, already has a valid representation; the server is therefore 400 response error redirecting the client to make use of that stored representation as if it were the payload of a 200 OK response. The server generating a https://www.w3.org/Protocols/HTTP/HTRESP.html 304 response MUST generate any of the following header fields that would have been sent in a 200 OK response to the same request: Cache-Control, Content-Location, Date, ETag, Expires, and Vary. Since the goal of a 304 response is to minimize information transfer when the recipient already has one or more cached https://httpstatuses.com/304 representations, a sender SHOULD NOT generate representation metadata other than the above listed fields unless said metadata exists for the purpose of guiding cache updates (e.g., Last-Modified might be useful if the response does not have an ETag field). Requirements on a cache that receives a 304 response are defined in Section 4.3.4 of RFC7234. If the conditional request originated with an outbound client, such as a user agent with its own cache sending a conditional GET to a shared proxy, then the proxy SHOULD forward the 304 response to that client. A 304 response cannot contain a message-body; it is always terminated by the first empty line after the header fields. Source: RFC7232 Section 4.1 304 Code References Rails HTTP Status Symbol :not_modified Go HTTP Status Constant http.StatusNotModified Symfony HTTP Status Constant Response::HTTP_NOT_MODIFIED Python2 HTTP Status Constant httplib.NOT_MODIFIED Python3+ HTTP Status Constant http.client.NOT_MODIFIED Python3.5+ HTTP Status Constant http.HTTPStatus.NOT_MODIFIED← Return to httpstatuses.com
here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this site About Us Learn more http://stackoverflow.com/questions/20978189/how-304-not-modified-works about Stack Overflow the company Business Learn more about hiring developers or posting ads with us Stack Overflow Questions Jobs Documentation Tags Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow https://www.addedbytes.com/articles/for-beginners/http-status-codes/ is a community of 4.7 million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up How “304 Not Modified” works? up vote 80 down vote favorite 19 http error How "304 Not Modified" is generated? How does a browser determine whether the response to a http request is 304.? Is it set by the browser or sent from the server? If sent by server, how does server know the data available in cache, also how does it set 304 to an image? My Guess, if generated by browser function is_modified() { return get_data_from_cache() === get_data_from_url(); }; function get_data_from_cache() 304 http error { return some_hash_or_xxx_function(cache_data); } function get_data_from_url() { return some_hash_or_xxx_function(new_data); } function some_hash_or_xxx_function(data) { // do something with data // what is that algorithm.? return result; } console.log(is_modified()); I am relying on 3rd party API provider to get data, parse & push it to DB. The data may or may not change during every request, but the header always sends 200, I do not want to parse, check the last Unique ID in DB & so on.. to determine the change in data, nor compare the result directly rather I md5(), sha1() & crc32() HASHed the result & works fine, but wondering the algorithm to determine 304 I want to use same kind of algorithm to determine the change in data. http browser http-headers firebug http-status-code-304 share|improve this question edited Feb 10 '14 at 17:17 asked Jan 7 '14 at 17:36 VenomVendor 6,78383773 1 Did you Google it? developers.google.com/speed/articles/caching mobify.com/blog/beginners-guide-to-http-cache-headers –SLaks Jan 7 '14 at 17:42 Yes I googled for how 304 not modified works, but did not get any answer. –VenomVendor Jan 7 '14 at 18:01 1 You need to be a bit more general. google.com/search?q=http%20caching –SLaks Jan 7 '14 at 18:01 add a comment| 1 Answer 1 active oldest votes
Articles Code Recommended Most Popular HTTP Status Codes for Beginners All valid HTTP 1.1 Status Codes simply explained. HTTP, Hypertext Transfer Protocol, is the method by which clients (i.e. you) and servers communicate. When someone clicks a link, types in a URL or submits out a form, their browser sends a request to a server for information. It might be asking for a page, or sending data, but either way, that is called an HTTP Request. When a server receives that request, it sends back an HTTP Response, with information for the client. Usually, this is invisible, though I'm sure you've seen one of the very common Response codes - 404, indicating a page was not found. There are a fair few more status codes sent by servers, and the following is a list of the current ones in HTTP 1.1, along with an explanation of their meanings. A more technical breakdown of HTTP 1.1 status codes and their meanings is available at http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html. There are several versions of HTTP, but currently HTTP 1.1 is the most widely used. Informational 100 - ContinueA status code of 100 indicates that (usually the first) part of a request has been received without any problems, and that the rest of the request should now be sent.101 - Switching ProtocolsHTTP 1.1 is just one type of protocol for transferring data on the web, and a status code of 101 indicates that the server is changing to the protocol it defines in the "Upgrade" header it returns to the client. For example, when requesting a page, a browser might receive a statis code of 101, followed by an "Upgrade" header showing that the server is changing to a different version of HTTP. Successful 200 - OKThe 200 status code is by far the most common returned. It means, simply, that the request was received and understood and is being processed.201 - CreatedA 201 status code indicates that a request was successful and as a result, a resource has been created (for example a new page).202 - AcceptedThe status code 202 indicates that server has received and understood the request, and that it has been accepted for processing, although it may not be processed immediately.203 - Non-Authoritative InformationA 203 status code means that the request was received and understood, and that information sent back about the response is from a third party,