When a browser requests a service from a web server, an error might occur.
This is a list of HTTP status messages that might be returned:
|100 Continue||The server has received the request headers, and the client should proceed to send the request body|
|101 Switching Protocols||The requester has asked the server to switch protocols|
|103 Checkpoint||Used in the resumable requests proposal to resume aborted PUT or POST requests|
|200 OK||The request is OK (this is the standard response for successful HTTP requests)|
|201 Created||The request has been fulfilled, and a new resource is created|
|202 Accepted||The request has been accepted for processing, but the processing has not been completed|
|203 Non-Authoritative Information||The request has been successfully processed, but is returning information that may be from another source|
|204 No Content||The request has been successfully processed, but is not returning any content|
|205 Reset Content||The request has been successfully processed, but is not returning any content, and requires that the requester reset the document view|
|206 Partial Content||The server is delivering only part of the resource due to a range header sent by the client|
|300 Multiple Choices||A link list. The user can select a link and go to that location. Maximum five addresses|
|301 Moved Permanently||The requested page has moved to a new URL|
|302 Found||The requested page has moved temporarily to a new URL|
|303 See Other||The requested page can be found under a different URL|
|304 Not Modified||Indicates the requested page has not been modified since last requested|
|306 Switch Proxy||No longer used|
|307 Temporary Redirect||The requested page has moved temporarily to a new URL|
|308 Resume Incomplete||Used in the resumable requests proposal to resume aborted PUT or POST requests|
4xx: Client Error
|400 Bad Request||The request cannot be fulfilled due to bad syntax|
|401 Unauthorized||The request was a legal request, but the server is refusing to respond to it. For use when authentication is possible but has failed or not yet been provided|
|402 Payment Required||Reserved for future use|
|403 Forbidden||The request was a legal request, but the server is refusing to respond to it|
|404 Not Found||The requested page could not be found but may be available again in the future|
|405 Method Not Allowed||A request was made of a page using a request method not supported by that page|
|406 Not Acceptable||The server can only generate a response that is not accepted by the client|
|407 Proxy Authentication Required||The client must first authenticate itself with the proxy|
|408 Request Timeout||The server timed out waiting for the request|
|409 Conflict||The request could not be completed because of a conflict in the request|
|410 Gone||The requested page is no longer available|
|411 Length Required||The "Content-Length" is not defined. The server will not accept the request without it|
|412 Precondition Failed||The precondition given in the request evaluated to false by the server|
|413 Request Entity Too Large||The server will not accept the request, because the request entity is too large|
|414 Request-URI Too Long||The server will not accept the request, because the URL is too long. Occurs when you convert a POST request to a GET request with a long query information|
|415 Unsupported Media Type||The server will not accept the request, because the media type is not supported|
|416 Requested Range Not Satisfiable||The client has asked for a portion of the file, but the server cannot supply that portion|
|417 Expectation Failed||The server cannot meet the requirements of the Expect request-header field|
5xx: Server Error
|500 Internal Server Error||A generic error message, given when no more specific message is suitable|
|501 Not Implemented||The server either does not recognize the request method, or it lacks the ability to fulfill the request|
|502 Bad Gateway||The server was acting as a gateway or proxy and received an invalid response from the upstream server|
|503 Service Unavailable||The server is currently unavailable (overloaded or down)|
|504 Gateway Timeout||The server was acting as a gateway or proxy and did not receive a timely response from the upstream server|
|505 HTTP Version Not Supported||The server does not support the HTTP protocol version used in the request|
|511 Network Authentication Required||The client needs to authenticate to gain network access|
The values of the numeric status code to HTTP requests are as follows. The data sections of messages Error, Forward and redirection responses may be used to contain human-readable diagnostic information.
These codes indicate success. The body section if present is the object returned by the request. It is a MIME format object. It is in MIME format, and may only be in text/plain, text/html or one fo the formats specified as acceptable in the request.
The request was fulfilled.
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.
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 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.
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.
The parameter to this message gives a specification of charging schemes acceptable. The client may retry the request with a suitable ChargeTo header.
The request is for something forbidden. Authorization will not help.
Not found 404
The server has not found anything matching the URI given
Internal Error 500
The server encountered an unexpected condition which prevented it from fulfilling the request.
Not implemented 501
The server does not support the facility required.
Service temporarily overloaded 502 (TO BE DISCUSSED)
The server cannot process the request due to a high load (whether HTTP servicing or other requests). The implication is that this is a temporary condition which maybe alleviated at other times.
Gateway timeout 503 (TO BE DISCUSSED)
This is equivalent to Internal Error 500, but in the case of a server which is in turn accessing some other service, this indicates that the respose from the other service did not return within a time that the gateway was prepared to wait. As from the point of view of the clientand the HTTP transaction the other service is hidden within the server, this maybe treated identically to Internal error 500, but has more diagnostic value.
Note: The 502 and 503 codes are new and for discussion, September 19, 1994
The codes in this section indicate action to be taken (normally automatically) by the client in order to fulfill the request.
The data requested has been assigned a new URI, the change is permanent. (N.B. this is an optimisation, which must, pragmatically, be included in this definition. Browsers with link editing capabiliy should automatically relink to the new reference, where possible)
The response contains one or more header lines of the form
URI: String CrLf
Which specify alternative addresses for the object in question. The String is an optional comment field. If the response is to indicate a set of variants which each correspond to the requested URI, then themultipart/alternative wrapping may be used to distinguish different sets
The data requested actually resides under a different URL, however, the redirection may be altered on occasion (when making links to these kinds of document, the browser should default to using the Udi of the redirection document, but have the option of linking to the final document) as for "Forward".
The response format is the same as for Moved .
Note: This status code is to be specified in more detail. For the moment it is for discussion only.
Like the found response, this suggests that the client go try another network address. In this case, a different method may be used too, rather than GET.
The body-section contains the parameters to be used for the method. This allows a document to be a pointer to a complex query operation.
The body may be preceded by the following additional fields as listed.
If the client has done a conditional GET and access is allowed, but the document has not been modified since the date and time specified in If-Modified-Since field, the server responds with a 304 status code and does not send the document body to the client.
Response headers are as if the client had sent a HEAD request, but limited to only those headers which make sense in this context. This means only headers that are relevant to cache managers and which may have changed independently of the document`s Last-Modified date. Examples include Date , Server and Expires .
The purpose of this feature is to allow efficient updates of local cache information (including relevant metainformation) without requiring the overhead of multiple HTTP requests (e.g. a HEAD followed by a GET) and minimizing the transmittal of information already known by the requesting client (usually a caching proxy).RITNIKOTKATA.COM