HTTP status code summary

##The client should continue to send requests . This provisional response is used to inform the client that part of its request has been received by the server and has not yet been rejected. The client SHOULD continue sending the remainder of the request, or ignore this response if the request has already been completed. The server must send a final response to the client after the request is completed. ##101##102The server has accepted the request, but has not yet deal with. Just as it may be denied, the request may or may not ultimately be executed. In the case of asynchronous operations, there is no more convenient way than sending this status code. The purpose of returning a 202 status code response is to allow the server to accept requests from other processes (such as a batch-based operation that is only performed once a day) without having to keep the client connected to the server until the batch operation is completed. A response that accepts request processing and returns a 202 status code should contain some information in the returned entity indicating the current status of the processing, as well as a pointer to a processing status monitor or status prediction so that the user can estimate whether the operation has been completed. The server has successfully processed the request, However, the returned entity header metainformation is not a certain set that is valid on the original server, but a copy from a local or third party. The current information may be a subset or a superset of the original version. For example, containing metadata for a resource may cause the origin server to know the super information about the metadata. Using this status code is not required and is only appropriate if the response would have returned 200 OK without this status code. ##204The server successfully processed the request, but No entity content needs to be returned, and updated meta information is expected to be returned. The response may return new or updated metainformation in the form of entity headers. These headers, if present, should correspond to the requested variables. If the client is a browser, the user's browser SHOULD retain the page for which the request was made without any changes to the document view, even if new or updated metainformation should be applied to the user's browser activity according to the specification Document in view. Since a 204 response is prohibited from containing any message body, it always ends with the first blank line after the message header. 205##Extended by WebDAV (RFC 2518) The status code means that the subsequent message body will be an XML message and may contain a series of independent response codes depending on the number of previous sub-requests. ##300##If the client sends a The server should return this status code when a conditional GET request has been granted and the document's contents have not changed (since the last access or according to the conditions of the request). A 304 response is prohibited from including a message body, so it always ends with the first blank line after the message header. The response MUST contain the following header information: Date, unless the server does not have a clock. If servers without clocks follow these rules, then proxy servers and clients can add the Date field to received response headers themselves (as specified in RFC 2068), and the caching mechanism will work normally. ETag and/or Content-Location, if the same request should have returned a 200 response. Expires, Cache-Control, and/or Vary, if its value may be different from the value corresponding to other previous responses to the same variable. If this response request uses strong cache verification, then this response should not contain other entity headers; otherwise (for example, a conditional GET request uses weak cache verification), this response is prohibited from containing other entity headers; this avoids Resolves inconsistencies between cached entity content and updated entity header information. If a 304 response indicates that an entity is not currently cached, the caching system must ignore the response and repeat the request without the restriction. If a 304 response is received that requires an update to a cache entry, the cache system must update the entire entry to reflect the values ​​of all fields that were updated in the response. ##305##403The server understood the request but rejected it Execute it. Unlike a 401 response, authentication does not provide any help, and the request should not be resubmitted. If this is not a HEAD request and the server wants to be able to explain why the request cannot be executed, then the reason for the rejection should be described in the entity. Of course, the server can also return a 404 response if it does not want the client to obtain any information. ##404##405##410The requested resource is on the server It is no longer available and does not have any known forwarding address. Such a situation should be considered permanent. If possible, clients with link editing capabilities should remove all references to this address with the user's permission. If the server does not know or cannot determine whether the condition is permanent, then the 404 status code should be used. Unless otherwise noted, this response is cacheable. The purpose of the 410 response is mainly to help website administrators maintain the website, notify users that the resource is no longer available, and the server owner hopes that all remote connections pointing to this resource will also be deleted. This type of incident is common among limited-time, value-added services. Similarly, the 410 response is also used to notify the client that resources originally belonging to an individual are no longer available on the current server site. Of course, do you need to mark all permanently unavailable resources as '410' Gone', and whether or not this mark needs to be maintained for how long, is entirely up to the server owner. ##411##416If the request contains a Range request header, and any data range specified in Range does not coincide with the available range of the current resource, and the If-Range request header is not defined in the request, then the server should return a 416 status code. If Range uses a byte range, then this situation means that the first byte position of all data ranges specified by the request exceeds the length of the current resource. The server should also include a Content-Range entity header to indicate the length of the current resource while returning the 416 status code. This response is also prohibited from using multipart/byteranges as its Content-Type. ##417##421The request format is correct, but because it contains Semantic error, unable to respond. (RFC 4918 WebDAV) 423 Locked The current resource is locked. (RFC 4918 WebDAV) Due to previous An error occurred in a certain request, causing the current request to fail, such as PROPPATCH. (RFC 4918 WebDAV) in WebDav Defined in the Advanced Collections draft, but not present in the WebDAV Sequenced Collections Protocol (RFC 3658). ##Clients should switch to TLS/ 1.0. (RFC 2817) 449Extended by Microsoft , indicating that the request should be retried after performing the appropriate action. 500##A server that works as a gateway or proxy An invalid response was received from the upstream server while trying to perform the request. ##503#The server does not support, or refuses to support, the HTTP version used in the request. This implies that the server is unable or unwilling to use the same version as the client. The response should contain an entity describing why the version is not supported and what protocols the server supports. ## By "Transparent Content Negotiation Agreement" (RFC 2295) extension, indicating that the server has an internal configuration error: the requested negotiation argument resource is configured to use itself in transparent content negotiation and is therefore not an appropriate focus in a negotiation process.

Status code	##Meaning
##100
The server has understood the client's request , and will notify the client through the Upgrade message header to use different protocols to complete this request. After sending the last blank line of this response, the server will switch to the protocols defined in the Upgrade header. Similar measures should only be taken when it would be more beneficial to switch to a new protocol. For example, there are advantages to switching to a new HTTP version over an older version, or switching to a real-time and synchronous protocol for delivering resources that take advantage of such features.
##Extended by WebDAV (RFC 2518) The status code indicates that processing will continue.	##200
The request was successful and the request was requested The response header or data body will be returned with this response.	##201
The request has been fulfilled and has A new resource has been created based on the request's needs, and its URI has been returned with the Location header. If the required resources cannot be created in time, '202 Accepted' should be returned.	##202
	##203
		The server successfully processed the request and returned nothing. But unlike a 204 response, a response returning this status code requires the requester to reset the document view. This response is mainly used to reset the form immediately after accepting user input so that the user can easily start another input. Like the 204 response, this response is prohibited from containing any message body and ends with the first blank line after the message header.
##206	The server has successfully processed a partial GET ask. HTTP download tools like FlashGet or Thunder use this type of response to resume interrupted downloads or break a large document into multiple download segments for simultaneous downloading. The request must include a Range header to indicate the range of content the client wishes to obtain, and may include an If-Range as a request condition. The response must contain the following header fields: Content-Range is used to indicate the range of content returned in this response; if Content-Type is multipart/byteranges For multi-part downloads, each multipart part should contain a Content-Range field to indicate the content range of this part. If a Content-Length is included in the response, its value must match the actual number of bytes in the content range it returns. Date ETag and/or Content-Location, if the same request should have returned a 200 response. Expires, Cache-Control, and/or Vary, if its value may be different from the value corresponding to other previous responses to the same variable. If this response request uses If-Range strong cache verification, then this response should not contain other entity headers; if this response request uses If-Range weak cache validation, then this response is prohibited from containing other entity headers; this avoids inconsistencies between cached entity content and updated entity header information. Otherwise, this response should contain all entity header fields that should be returned in a 200 response. If the ETag or Last-Modified headers do not match exactly, the client cache should not combine the content returned by the 206 response with any previously cached content. Any cache that does not support the Range and Content-Range headers is prohibited from caching the content returned by the 206 response.
##207
##The requested resource has a list of available resources Alternative feedback messages, each with its own specific address and browser-driven negotiation information. The user or browser can choose a preferred address for redirection. Unless this is a HEAD request, the response should include an entity with a list of resource attributes and addresses from which the user or browser can choose the most appropriate redirect address. The format of this entity is determined by the format defined by Content-Type. The browser may automatically make the most appropriate choice based on the format of the response and the browser's own capabilities. Of course, the RFC 2616 specification does not specify how such automatic selection should be performed. If the server itself already has a preferred feedback selection, the URI of this feedback should be specified in Location; the browser may use this Location value as the address for automatic redirection. Additionally, this response is cacheable unless otherwise specified.	##301
##The requested resource has been permanently moved to the new location, and any future references to this resource should use one of several URIs returned in this response. If possible, clients with link editing capabilities should automatically modify the requested address to the address returned from the server. Unless otherwise specified, this response is also cacheable. The new permanent URI should be returned in the Location field of the response. Unless this is a HEAD request, the response entity should contain a hyperlink to the new URI and a brief description. If this is not a GET or HEAD request, the browser prohibits automatic redirection unless confirmed by the user, because the conditions of the request may change accordingly. Note: For some browsers that use the HTTP/1.0 protocol, when the POST request they send gets a 301 response, the subsequent redirect request will become a GET method.	302	The requested resource now temporarily responds to requests from a different URI. Because such redirects are temporary, the client should continue to send future requests to the original address. This response is cacheable only if specified in Cache-Control or Expires. The new temporary URI should be returned in the Location field of the response. Unless this is a HEAD request, the response entity should contain a hyperlink to the new URI and a brief description. If this is not a GET or HEAD request, the browser prohibits automatic redirection unless confirmed by the user, because the conditions of the request may change accordingly. Note: Although the RFC 1945 and RFC 2068 specifications do not allow the client to change the request method when redirecting, many existing browsers regard the 302 response as a 303 response, and use the GET method to access the URI specified in the Location, regardless of The method of the original request. Status codes 303 and 307 were added to clarify what response the server expects from the client.
##303	The response corresponding to the current request can be in is found on another URI, and the client should use GET to access that resource. This method exists primarily to allow script-activated POST request output to be redirected to a new resource. This new URI is not a replacement reference to the original resource. At the same time, 303 responses are prohibited from being cached. Of course, the second request (redirect) might be cached. The new URI should be returned in the Location field of the response. Unless this is a HEAD request, the response entity should contain a hyperlink to the new URI and a brief description. NOTE: Many pre-HTTP/1.1 browsers do not correctly understand the 303 status. If you need to consider interaction with these browsers, the 302 status code should be sufficient, because most browsers handle 302 responses exactly the way the above specification requires the client to handle 303 responses.
##304
##The requested resource must be specified by agent can be accessed. The Location field will give the URI information where the specified proxy is located. The recipient needs to repeatedly send a separate request to access the corresponding resource through this proxy. Only the origin server can establish a 305 response. Note: RFC 2068 does not specify that a 305 response is intended to redirect a single request and can only be established by the origin server. Ignoring these restrictions can lead to serious safety consequences.	##306
##In the latest version of the specification, The 306 status code is no longer used.	307	The requested resource now temporarily responds to requests from a different URI. Because such redirects are temporary, the client should continue to send future requests to the original address. This response is cacheable only if specified in Cache-Control or Expires. The new temporary URI should be returned in the Location field of the response. Unless this is a HEAD request, the response entity should contain a hyperlink to the new URI and a brief description. Because some browsers cannot recognize the 307 response, the above necessary information needs to be added so that users can understand and submit it to new users. URI makes access request. If this is not a GET or HEAD request, the browser prohibits automatic redirection unless confirmed by the user, because the conditions of the request may change accordingly.
400	1. The semantics are incorrect. Currently The request cannot be understood by the server. The client should not resubmit this request unless modified. 2. The request parameters are incorrect.
401	The current request requires user authentication. The response MUST include a WWW-Authenticate header appropriate to the requested resource that asks for user information. The client can repeatedly submit a request containing the appropriate Authorization header. If the current request already included Authorization certificates, the 401 response indicates that the server verification has rejected those certificates. If the 401 response contains the same authentication query as the previous response, and the browser has attempted authentication at least once, the browser should display the entity information contained in the response to the user, because this entity information may contain relevant diagnostic information . See RFC 2617.
##402	##This status code is for future possibilities reserved for needs.
The request failed, the request requested The resource was not found on the server. There is no information to tell the user whether the condition is temporary or permanent. If the server knows the situation, it should use the 410 status code to inform that the old resource is permanently unavailable due to some internal configuration mechanism problems, and there is no jump address. The 404 status code is widely used when the server does not want to reveal why the request was rejected or no other suitable response is available.
##The request method specified in the request line Cannot be used to request the corresponding resource. The response must return an Allow header information to indicate the list of request methods that the current resource can accept. Since the PUT and DELETE methods will write resources on the server, most web servers do not support or do not allow the above request methods under the default configuration, and a 405 error will be returned for such requests.	##406
The content attribute of the requested resource cannot be The condition in the request header is met, so the response entity cannot be generated. Unless this is a HEAD request, the response should return an entity containing a list of entity attributes and addresses from which the user or browser can choose the most appropriate. The format of the entity is determined by the media type defined in the Content-Type header. The browser can make its own best choice based on the format and its capabilities. However, the specification does not define any criteria for making such automatic selections.	407	Similar to the 401 response, except that the client must authenticate on the proxy server. The proxy server must return a Proxy-Authenticate for identity queries. The client can return a Proxy-Authorization header for verification. See RFC 2617.
408	##The request timed out. The client did not complete sending a request within the time the server was prepared to wait. The client can resubmit this request at any time without making any changes.
##409	Due to and the requested resource There is a conflict between the current states and the request cannot be completed. This code should only be used if the user is believed to be able to resolve the conflict and resubmit a new request. The response should contain enough information for the user to discover the source of the conflict. Conflicts usually occur in the processing of PUT requests. For example, in an environment using version checking, if the version information attached to a modification request for a specific resource submitted by a PUT conflicts with a previous (third-party) request, then the server should return a 409 error at this time. Inform the user that the request cannot be completed. At this time, the response entity is likely to contain a difference comparison between the two conflicting versions, so that the user can resubmit the new version after merging.
##The server rejects content- Accept the request without the Length header. After adding a valid Content-Length header indicating the length of the request message body, the client can submit the request again.	##412
##The server is verifying the header in the request When prerequisites are given in the fields, one or more of them are not met. This status code allows the client to set preconditions in the request metainformation (request header field data) when retrieving the resource, thereby preventing the request method from being applied to the resource other than what it expects.	##413
The server refused to process the current request because The request submitted entity data that is larger than the server is willing or able to handle. In this case, the server can close the connection to prevent the client from continuing to send this request. If the situation is temporary, the server should return a Retry-After response header to inform the client how much time later it can try again.	414	The requested URI is longer than the server can interpret, so the server refuses to service the request. This is relatively rare. Common situations include: The form submission that should have used the POST method becomes the GET method, causing the query string to be too long. Redirect URI "black hole", for example, each redirection uses the old URI as part of the new URI, resulting in an overlong URI after several redirections. The client is trying to exploit the security holes in some servers to attack the server. This type of server uses a fixed-length buffer to read or operate requests. URI, when the parameters after GET exceed a certain value, buffer overflow may occur, causing arbitrary code to be executed [1]. Servers without such vulnerabilities should return a 414 status code.
##415	##For the current request method and all The requested resource and the entity submitted in the request are not in a format supported by the server, so the request was rejected.
specified in the request header Expect The expected content cannot be satisfied by the server, or the server is a proxy server and it has obvious evidence that the expected content cannot be satisfied on the next node of the current route.
##From the IP of the current client The number of connections from the address to the server exceeds the maximum allowed range of the server. Usually, the IP address here refers to the client address seen from the server (such as the user's gateway or proxy server address). In this case, the connection count may involve more than one end user.	##422
##From the IP of the current client The number of connections from the address to the server exceeds the maximum allowed range of the server. Usually, the IP address here refers to the client address seen from the server (such as the user's gateway or proxy server address). In this case, the connection count may involve more than one end user.	##422
	424
	425
	##426
		The server encountered an unexpected condition that prevented it from completing processing of the request. Generally speaking, this problem will occur when there is an error in the server's program code.
##501	The server does not support what the current request requires a certain function. When the server does not recognize the requested method and cannot support its request for any resource.
##502
##Due to temporary server maintenance or overload , the server is currently unable to process the request. This condition is temporary and will be restored after a period of time. If a delay can be expected, the response can include a Retry-After header to indicate the delay. If this Retry-After message is not given, the client SHOULD handle it the same way it handles a 500 response. Note: The existence of the 503 status code does not mean that the server must use it when it is overloaded. Some servers simply wish to deny connections from clients.	##504
##A server that works as a gateway or proxy When trying to execute a request, a response was not received in time from the upstream server (the server identified by the URI, such as HTTP, FTP, LDAP) or the secondary server (such as DNS). Note: Some proxy servers will return a 400 or 500 error	##505 ## when the DNS query times out.
	##506
##507	The server cannot store the information necessary to complete the request. Content. This condition is considered temporary. WebDAV (RFC 4918)
509	Server reached Bandwidth limitations. This is not an official status code, but is still widely used.
##510	##Get the strategies required for the resource and Not satisfied. (RFC 2774)

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