Common HTTP Status Codes (HTTP state code) description

As an Internet developer, the meaning of the HTTP status returned by some servers must be well-understood, and only these status code one by one can be figured out, and all the problems encountered in the work are handled with ease. Well, let's look at the more common HTTP status codes here!

2 Opening (successful request) indicates that the status code of the request was successfully processed.

200 (success) The server has successfully processed the request. Typically, this indicates that the server provided the requested Web page.
201 (created) The request was successful and the server created a new resource.
202 (accepted) the server has accepted the request but has not yet processed it.
203 (non-authoritative information) the server has successfully processed the request, but the information returned may be from another source.
204 (no content) the server successfully processed the request, but did not return any content.
205 (reset content) the server successfully processed the request, but did not return any content.
206 (partial) The server successfully processed a partial GET request.

3 Start (Request redirected) indicates that a request needs to be completed and further action is required. Typically, these status codes are used for redirection.

300 (multiple options) for requests, the server can perform a variety of operations. The server can select an action based on the requestor (user agent) or provide a list of actions for the requestor to select.
301 (permanently moved) The requested page has been permanently moved to a new location. When the server returns this response (a response to a GET or HEAD request), the requestor is automatically forwarded to the new location.
302 (Temporary move) The server is currently responding to requests from a Web page in a different location, but the requestor should continue to use the original location for future requests.
303 (View other locations) The server returns this code when the requestor should use a separate GET request for the different locations to retrieve the response.
304 (not modified) The requested webpage has not been modified since the last request. When the server returns this response, the Web page content is not returned.
305 (using a proxy) the requestor can only use the proxy to access the requested Web page. If the server returns this response, it also indicates that the requestor should use the proxy.
307 (Temporary redirect) The server is currently responding to requests from a Web page in a different location, but the requestor should continue to use the original location for future requests.

4 Start (Request error) These status codes indicate a possible error in the request and hinder the processing of the server.

The

400   (Error request) server does not understand the syntax of the request.   the
401   (unauthorized) request requires authentication. The server may return this response for pages that need to log on.  
403   (Forbidden) The server rejects the request. The
404   (not found) server could not find the requested Web page. The
405   (method Disabled) Disables the method specified in the request.  
406   (not accepted) cannot use the requested content attribute to respond to the requested Web page.  
407   (requires proxy authorization) This status code is similar to 401 (unauthorized), but specifies that the requestor should authorize the use of the proxy.
408   (Request timed out)   timeout occurs when the server waits for a request.  
409   (conflict)   The server conflicts when the request is completed. The server must include information about the conflict in the response.  
410   (deleted)   The server returns this response if the requested resource has been permanently deleted.  
411   (requires a valid length) the server does not accept requests that do not contain a valid Content-Length header field.  
412   (precondition not met) the server does not meet one of the prerequisites set by the requestor in the request.  
413   (Request entity is too large) the server cannot process the request because the request entity is too large to exceed the processing power of the server.  
414   (The requested URI is too long) the URI of the request (usually the URL) is too long and the server cannot process it.   The format of the
415   (Unsupported media type) request is not supported by the requested page.  
416   (the request scope does not meet the requirements) if the page cannot provide the requested scope, the server returns this status code.  
417   (unmet expectations) the server does not meet the requirements of the expected Request header field.

5 Start (server error) These status codes indicate that the server has an internal error while trying to process the request. These errors may be the error of the server itself, not the request.

500 (server internal error) the server encountered an error and could not complete the request.
501 (not yet implemented) the server does not have the capability to complete the request. For example, this code may be returned when the server does not recognize the request method.
502 (Error Gateway) The server receives an invalid response from the upstream server as a gateway or proxy.
503 (Service Unavailable) the server is not currently available (due to overloading or downtime maintenance). Typically, this is only a temporary state.
504 (Gateway Timeout) The server acts as a gateway or proxy, but does not receive requests from the upstream server in a timely manner.
505 (HTTP version not supported) the HTTP protocol version used in the request is not supported by the server.

1XX-Informational Tips
These status codes represent a temporary response. The client should be prepared to receive one or more 1xx responses before receiving a regular response.

· 100-continue the initial request has been accepted, the customer should continue to send the remainder of the request. (HTTP 1.1 new)
· 101-switching Protocols Server translates the client's request to another protocol (HTTP 1.1 new)

2XX-Success
This type of status code indicates that the server successfully accepted the client request.

· 200-ok Everything is OK, the answer document for Get and post requests is followed.
· The 201-created server has created the document, and the location header gives its URL.
· 202-accepted has accepted the request, but the processing has not been completed.
· The 203-non-authoritative information document has returned normally, but some of the answer headers may be incorrect because a copy of the document is being used, non-authoritative (HTTP 1.1 new).
· 204-no Content does not have a new document, the browser should continue to display the original document. This status code is useful if the user refreshes the page on a regular basis and the servlet can determine that the user's document is new enough.
· 205-reset content is not new, but the browser should reset what it displays. Used to force the browser to clear the form input (HTTP 1.1 new).
· The 206-partial Content client sent a GET request with a range header (block request) and the server completed it (HTTP 1.1 new).

3xx-redirect
The client browser must take more action to implement the request. For example, the browser might have to request a different page on the server, or repeat the request through a proxy server.

· 300-multiple Choices Customer-requested documents can be found in multiple locations that are listed in the returned document. If the server wants to make a preference, it should be indicated in the location answer header.
· 301-moved permanently The document requested by the customer elsewhere, the new URL is given in the location header, and the browser should automatically access the new URL.
· 302-found is similar to 301, but the new URL should be treated as a temporary replacement, not a permanent. Note that the corresponding status information in HTTP1.0 is "Moved temporatily". When the status code appears, the browser can

To automatically access the new URL, so it is a useful status code. Note that this status code can sometimes be used with 301 substitutions. For example, if the browser mistakenly requests Http://host/~user (the trailing slash is missing)

, some servers return 301, and some return 302. Strictly speaking, we can only assume that the browser will automatically redirect only if the original request is get. See 307.
· 303-see other is similar to 301/302, except that if the original request is post,location, the redirect target document specified by the header should be fetched via get (HTTP 1.1 new).
· The 304-not Modified client has a buffered document and issues a conditional request (typically providing a if-modified-since header indicating that the customer only wants to update the document than the specified date). The server tells the customer that the original buffered

The document can also continue to be used.
· 305-use Proxy The document requested by the client should be extracted via the proxy server indicated by the location header (HTTP 1.1 is new).
· 307-temporary Redirect and 302 (Found) are the same. Many browsers incorrectly respond to a 302 response for redirection, even if the original request is post, even though it can actually only be re-answered when the POST request is 303

Directional. For this reason, HTTP 1.1 has been added in 307 to allow for more cleanup of the region in several status codes: When a 303 response occurs, the browser can follow the redirected get and post requests, and if the 307 answer, the browser can only follow

The redirect to the GET request. (HTTP 1.1 new)

4xx-Client Error
An error occurred and the client appears to be having problems. For example, a client requests a page that does not exist, and the client does not provide valid authentication information.

· 400-bad request syntax error occurred.
· 401-unauthorized access was denied and the customer attempted to access a password-protected page without authorization. A www-authenticate header is included in the answer, and the browser displays the user name/Password dialog box and then fills in the

The

Applies the authorization header again after the request is made. IIS defines a number of different 401 errors, which indicate a more specific cause of the error. These specific error codes are displayed in the browser but are not displayed in the IIS log:
• 401.1-Logon failed.
• 401.2-server configuration causes logon failure.
• 401.3-The ACL is not authorized because of a resource limitation.
• 401.4-Filter Authorization failed.
401.5-isapi/cgi application authorization failed.
401.7– Access is denied by the URL authorization policy on the WEB server. This error code is specific to IIS 6.0. The
403-forbidden resource is not available. The server understands the customer's request, but refuses to process it. This is usually caused by the permissions set on the file or directory on the server. Forbidden Access: IIS defines a number of different 403 errors, which are referred to as

The more specific cause of the error:
• 403.1-execution access is forbidden.
• 403.2-read access is forbidden.
• 403.3-write access is forbidden.
• 403.4-Requires SSL.
• 403.5-Requires SSL 128. The
403.6-ip address is denied.
• 403.7-Requires a client certificate.
• 403.8-site access is denied.
• 403.9-excessive number of users.
• 403.10-Invalid configuration.
• 403.11-Password change.
• 403.12-Deny access to the mapping table.
• 403.13-client certificate is revoked.
• 403.14-Reject directory list.
• 403.15-Client access permission exceeded.
• 403.16-client certificate is not trusted or invalid.
• 403.17-The client certificate has expired or is not yet valid.
• 403.18-The requested URL cannot be executed in the current application pool. This error code is specific to IIS 6.0.
• 403.19-CGI cannot be executed for clients in this application pool. This error code is specific to IIS 6.0.
403.20-passport logon failed. This error code is specific to IIS 6.0.
404-not Found cannot find a resource at the specified location. This is also a common answer.  
• 404.0-(none) – No files or directories found.
• 404.1-Unable to access the WEB site on the requested port. The
404.2-web service extension lockout policy blocks this request. The
404.3-mime mapping policy blocks this request. The
405-method not allowed request method (GET, POST, HEAD, DELETE, PUT, Trace, and so on) does not apply to the specified resource, and the HTTP verb used to access this page is not allowed (the method is not allowed) (HTTP 1.1

New
· 406-not acceptable The specified resource has been found, but its MIME type is incompatible with the client specified in the Accpet header, the client browser does not accept the MIME type of the requested page (HTTP 1.1 new).
· 407-proxy authentication Required requires proxy authentication, similar to 401, to indicate that the client must be authorized by the proxy server first. (HTTP 1.1 new)
· 408-request Timeout The customer has not made any requests during the waiting time of the server license. Customers can repeat the same request at a later time. (HTTP 1.1 new)
· 409-conflict is usually associated with a put request. The request cannot succeed because the request conflicts with the current state of the resource. (HTTP 1.1 new)
· The document requested by 410-gone is no longer available, and the server does not know which address to redirect to. It differs from 404 in that returning 407 means that the document permanently leaves the specified position, and 404 indicates that the unknown

Reason document is not available. (HTTP 1.1 new)
· The 411-length Required server cannot process the request unless the client sends a content-length header. (HTTP 1.1 new)
· 412-precondition Failed Some of the prerequisites specified in the request header failed (HTTP 1.1 new).
· 413–request Entity Too Large the size of the target document exceeds the size that the server is currently willing to handle. If the server thinks it can process the request later, it should provide a Retry-after header (HTTP 1.1

New).
· 414-request URI Too Long URI is too lengthy (HTTP 1.1 new).
· 415– media types not supported.
· The 416–requested range not satisfiable server does not meet the Range header specified by the customer in the request. (HTTP 1.1 New) · 417– execution failed.
· 423– a locked error.

5XX-Server Error
The server could not complete the request because it encountered an error.

· The 500-internal server Error server encountered unexpected conditions and was unable to complete the client's request.
· 500.12-The application is busy restarting on the WEB server.
· The 500.13-web server is too busy.
· 500.15-Direct Request Global.asa is not allowed.
· 500.16–unc authorization credentials are incorrect. This error code is specific to IIS 6.0.
· The 500.18–url authorization store cannot be opened. This error code is specific to IIS 6.0.
· 500.100-Internal ASP error.
· The 501-not implemented server does not support the functionality required to implement the request, and the header value specifies the configuration that is not implemented. For example, a customer sends a put request that is not supported by the server.
· When a gateway or proxy is 502-bad, the server returns an illegal response in order to complete the request to access the next server. Also said the Web server received an invalid response when it was used as a gateway or proxy server

。
· The 502.1-cgi application timed out.
· 502.2-CGI Application error.
· The 503-service unavailable service is unavailable and the server is unable to answer due to maintenance or overloading. For example, a servlet might return 503 if the database connection pool is full. When the server returns 503, it can provide a

Retry-after head. This error code is specific to IIS 6.0.
· When the 504-gateway Timeout network is timeout, it is used by the server acting as the proxy or gateway, indicating that the answer cannot be received from the remote server in a timely manner. (HTTP 1.1 new).
· The HTTP version indicated in the request is not supported by the 505-HTTP version not supported server. (HTTP 1.1 new)

----such as the following is when I do picture upload, to determine whether it is a picture, and return the status code! --------

Try
{
System.Drawing.Image img = System.Drawing.Image.FromStream (postedfile.inputstream);
Postedfile.saveas (Savepath + @ "\" + Snewfilename + sextension);
Context. Response.Write (TempPath + snewfilename + sextension);
Context. Response.statuscode = 200;
}
catch (ArgumentException ex)
{
Context. Response.Write (ex. Message);
Context. Response.statuscode = 403;
}

Common HTTP Status Codes (HTTP state code) description