Httpd Error Code 304
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Join the Stack Overflow Community Stack Overflow is a community of 4.7 million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up Why am I http 404 getting “(304) Not Modified” error on some links when using HttpWebRequest? up vote 18 down vote favorite 7 Any ideas why on some links that I try to access using HttpWebRequest I am getting "The remote server returned an error: (304) Not Modified." in the code? The code I'm using is from Jeff's post here (the page seems to have disappeared, see an archive http 403 copy at the Wayback Machine). Note the concept of the code is a simple proxy server, so I'm pointing my browser at this locally running piece of code, which gets my browsers request, and then proxies it on by creating a new HttpWebRequest, as you'll see in the code. It works great for most sites/links, but for some this error comes up. You will see one key bit in the code is where it seems to copy the http header settings from the browser request to it's request out to the site, and it copies in the header attributes. Not sure if the issue is something to do with how it mimics this aspect of the request and then what happens as the result comes back? case "If-Modified-Since": request.IfModifiedSince = DateTime.Parse(listenerContext.Request.Headers[key]); break; I get the issue for example from http://en.wikipedia.org/wiki/Main_Page PS. UPDATE HERE Still can't work this out. Basically I can identify 1 link which has an issue, and it seems to work fine, 2nd time it gets the error, 3rd time OK, 4th time gets the error, 5th time OK etc. As if there is some state not getting cleared
false. In other words, there is no need for the server to transfer a
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representation of the target resource because the request indicates that http 422 the client, which made the request conditional, already has a valid representation; the server is therefore
Http 500
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 http://stackoverflow.com/questions/2603595/why-am-i-getting-304-not-modified-error-on-some-links-when-using-httpwebrequ 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
referer DNT X-Forwarded-For Status codes 301 Moved Permanently 302 Found 303 See Other 403 Forbidden 404 Not Found 451 Unavailable For Legal Reasons v t e This is a list of Hypertext https://en.wikipedia.org/wiki/List_of_HTTP_status_codes Transfer Protocol (HTTP) response status codes. It includes codes from IETF internet standards, http://100pulse.com/http-statuscode/304.jsp other IETF RFCs, other specifications, and some additional commonly used codes. The first digit of the status code specifies one of five classes of response; an HTTP client must recognise these five classes at a minimum. The phrases used are the standard wordings, but any human-readable alternative can be provided. Unless otherwise http status stated, the status code is part of the HTTP/1.1 standard (RFC 7231).[1] The Internet Assigned Numbers Authority (IANA) maintains the official registry of HTTP status codes.[2] Microsoft IIS sometimes uses additional decimal sub-codes to provide more specific information,[3] but not all of those are here (note that these sub-codes only appear in the response payload and in documentation; not in the place of an actual HTTP http status code status code). Contents 1 1xx Informational 2 2xx Success 3 3xx Redirection 4 4xx Client Error 5 5xx Server Error 6 Unofficial codes 6.1 Internet Information Services 6.2 nginx 6.3 Cloudflare 7 See also 8 Notes 9 References 10 External links 1xx Informational[edit] Request received, continuing process. This class of status code indicates a provisional response, consisting only of the Status-Line and optional headers, and is terminated by an empty line. Since HTTP/1.0 did not define any 1xx status codes, servers must not[note 1] send a 1xx response to an HTTP/1.0 client except under experimental conditions.[4] 100 Continue The server has received the request headers and the client should proceed to send the request body (in the case of a request for which a body needs to be sent; for example, a POST request). Sending a large request body to a server after a request has been rejected for inappropriate headers would be inefficient. To have a server check the request's headers, a client must send Expect: 100-continue as a header in its initial request and receive a 100 Continue status code in response before sending the body. The response 417 Expectation Failed indicates th
is sent in response to a request (for a document) that asked for the document only if it was newer than the one the client already had. Normally, when a document is cached, the date it was cached is stored. The next time the document is viewed, the client asks the server if the document has changed. If not, the client just reloads the document from the cache. Why it Occurs The HTTP status code 304 Not Modified occurs if the client has performed a conditional GET request and access is allowed, but the document has not been modified. The server SHOULD respond with this status code. The 304 response MUST NOT contain a message-body, and thus is always terminated by the first empty line after the header fields. Fixing 304 Error Code You should never see this error in your Web browser. It should simply present the Web page from its cache - because it believes the page has not changed since it was last cached. If your client is not a Web browser, then it should equally be able to present the page from a cache. If unable to do so, it is not using the If_Modified_Since or related headers correctly. If you monitor your website through 100 pulse, we will intimate you through mail or short message service whenever you encounter 304 status code. Features Website Monitoring Monitor DNS Server Mail Server Monitoring Mysql Server Monitoring FTP Monitoring Port Monitoring Alerts & Reports Instant Notification Web Server Monitoring Report Public Report Template Free Uptime Button Monitoring Tools Webpage Availability Checker Port checker DNS Checker IP Finder Server location Finder and more... Reseller Affiliate Program Pricing Latest Updates Feedback Write a testimonial About Us Contact Us Follow Us on Twitter Facebook Server Time : 18-Oct-2016 18:49:01 GMT All Rights reserved © 100pulse.com Terms | Privacy | Sitemap