HTTP Status Code List _ Basic Tutorial

We often encounter 404, 500, 302 and other hints, what exactly do they mean? In addition to these common status codes, what are some of the possible status codes that we have not encountered yet? Here I made a summary, share with you.

HTTP Status Code Summary description
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Success 2XX successfully processed the requested status code.
200 the server has successfully processed the request and provided the requested Web page.
204 The server successfully processed the request, but did not return any content.
REDIRECT 3XX use redirects in each request no more than 5 times.
301 The requested page has been permanently moved to a new location. When URLs change, use 301 code. The new URL is saved in the Search engine index.
302 The requested Web page is temporarily moved to a new location. The original URL is saved in the Search engine index.
304 If the page has not been updated since the requestor last requested it, use 304 code to tell the search engine robot that it saves bandwidth and overhead.
Client Error 4XX indicates a possible error in the request and prevents the server from processing.
400 the server does not understand the syntax of the request.
403 The server denied the request.
404 the server could not find the requested Web page. Pages that do not exist on the server often return this code.
410 after the requested resource is permanently deleted, the server returns this response. This code is similar to the 404 (not Found) code.
However, in the case where the resource existed before and now does not exist, it is sometimes used to replace the 404 code. If the resource has been permanently deleted, you should use 301 to specify a new location for the resource.
Server error 5XX indicates that an internal error occurred while the server was processing the request. These errors may be the error of the server itself, not the request.
500 the server encountered an error and could not complete the request.
503 servers are not currently available (due to overloading or downtime maintenance). Typically, this is only a temporary state.

Detailed decomposition:

2XX success

200 normal; The request is complete.
201 Normal; Immediately after the POST command.
202 normal; Accepted for processing, but processing is not yet complete.
203 normal; Part of the information-the returned information is only part of it.
204 normal; No response-the request has been received, but there is no information to echo back.

3XX redirection

301 Moved-The requested data has a new location and the change is permanent.
302 found-The requested data temporarily has a different URI.
303 See other-the response to the request can be found under another URI, and the response should be retrieved using the GET method.
304 unmodified-The document was not modified as expected.
305 using a proxy-the requested resource must be accessed through the proxy provided in the Location field.
306 unused-no longer in use; Keep this code for future use.

Errors that occur in the 4XX client

400 Error request-There is a syntax problem in the request, or the request cannot be satisfied.
401 Unauthorized-The client is not authorized to access the data.
402 Payment required-Indicates that the billing system is valid.
403 Forbidden-access is not required even with authorization.
404 Not Found-the server cannot find the given resource; The document does not exist.
407 Proxy authentication Request-The client must first use the proxy to authenticate itself.
415 media type is not supported-the server denies the service request because the format of the requested entity is not supported.

Errors that occur in the 5XX server

500 INTERNAL Error-the server could not complete the request because of an unexpected situation.
501 not executed-the server does not support the requested tool.
502 Error Gateway-server received an invalid response from the upstream server.
503 Unable to get service-the server cannot process the request due to temporary overload or maintenance.

504 Gateway Timeout
When a server acting as a gateway or agent attempts to execute a request, it fails to receive a response from the upstream server (the server that the URI identifies, such as HTTP, FTP, LDAP), or the secondary server (such as DNS).
Note: Some proxy servers return 400 or 500 errors in DNS query timeout

505 HTTP Version not supported
The server does not support or refuses to support the HTTP version used in the request. This implies that the server cannot or does not want to use the same version as the client. The response should contain an entity that describes why the version is not supported and which protocols the server supports.

506 Variant Also negotiates
Extended by the Transparent Content negotiation Protocol (RFC 2295), there is an internal configuration error on behalf of the server: The requested negotiation meta-resource is configured to use itself in transparent content negotiation, so it is not an appropriate focus in a negotiation process.

507 Insufficient Storage
The server cannot store the content necessary to complete the request. The situation is considered to be temporary. WebDAV (RFC 4918)

508 Loop Detected
An infinite loop appears in the server discovery request

509 Bandwidth Limit exceeded
The server reached the bandwidth limit. This is not an official status code, but is still widely used.

510 Not Extended
The policies needed to get resources are not met. (RFC 2774)

How to handle common errors

500 error

500 error is the webmaster often encountered problems, on my experience, causes and solutions are summarized as follows:

1, the number of users running too much, the pressure on the server is too large, the server can not respond, the report HTTP500 error.

This is the main reason why the website reported 500 error, why many websites suddenly reported 500 error (Service unavailable)? 90% is due to excessive space pressure, beyond the limits set by the space quotient.

Encounter this problem, it is best to find the first time the space provider after-sales service, they will generally help you recycle the application pool, the problem will be resolved. If you do not find after-sales service, you can in the space management background, find the "recycling application pool" that project, manually execute it yourself. However, some space management backgrounds do not provide this service.

2, if the possibility of excluding the 1th, then a big reason is the procedural problems.

Can do a simple test page, to see if it can run successfully, and then detect the error page, so that targeted changes.

Where the connection is not made, the HTTP500 error is reported. The problem is solved by manual or auto-correlation.

3, if the operation in the test needs to insert data into the database, if the large amount of data causes the table space in the database is full, or the buffer pool is small can not satisfy the data access, etc., can cause HTTP500 error.

The solution is to adjust the database, modify the connection pool size, and so on, according to individual circumstances to correct.

HTTP Status Code Summary description
-----------------------------------------------------------------------------------------------------------

Success 2XX successfully processed the requested status code.
200 the server has successfully processed the request and provided the requested Web page.
204 The server successfully processed the request, but did not return any content.
REDIRECT 3XX use redirects in each request no more than 5 times.
301 The requested page has been permanently moved to a new location. When URLs change, use 301 code. The new URL is saved in the Search engine index.
302 The requested Web page is temporarily moved to a new location. The original URL is saved in the Search engine index.
304 If the page has not been updated since the requestor last requested it, use 304 code to tell the search engine robot that it saves bandwidth and overhead.
Client Error 4XX indicates a possible error in the request and prevents the server from processing.
400 the server does not understand the syntax of the request.
403 The server denied the request.
404 the server could not find the requested Web page. Pages that do not exist on the server often return this code.
410 after the requested resource is permanently deleted, the server returns this response. This code is similar to the 404 (not Found) code.
However, in the case where the resource existed before and now does not exist, it is sometimes used to replace the 404 code. If the resource has been permanently deleted, you should use 301 to specify a new location for the resource.
Server error 5XX indicates that an internal error occurred while the server was processing the request. These errors may be the error of the server itself, not the request.
500 the server encountered an error and could not complete the request.
503 servers are not currently available (due to overloading or downtime maintenance). Typically, this is only a temporary state.

Detailed decomposition:

2XX success

200 normal; The request is complete.
201 Normal; Immediately after the POST command.
202 normal; Accepted for processing, but processing is not yet complete.
203 normal; Part of the information-the returned information is only part of it.
204 normal; No response-the request has been received, but there is no information to echo back.

3XX redirection

301 Moved-The requested data has a new location and the change is permanent.
302 found-The requested data temporarily has a different URI.
303 See other-the response to the request can be found under another URI, and the response should be retrieved using the GET method.
304 unmodified-The document was not modified as expected.
305 using a proxy-the requested resource must be accessed through the proxy provided in the Location field.
306 unused-no longer in use; Keep this code for future use.

Errors that occur in the 4XX client

400 Error request-There is a syntax problem in the request, or the request cannot be satisfied.
401 Unauthorized-The client is not authorized to access the data.
402 Payment required-Indicates that the billing system is valid.
403 Forbidden-access is not required even with authorization.
404 Not Found-the server cannot find the given resource; The document does not exist.
407 Proxy authentication Request-The client must first use the proxy to authenticate itself.
415 media type is not supported-the server denies the service request because the format of the requested entity is not supported.

Errors that occur in the 5XX server

500 INTERNAL Error-the server could not complete the request because of an unexpected situation.
501 not executed-the server does not support the requested tool.
502 Error Gateway-server received an invalid response from the upstream server.
503 Unable to get service-the server cannot process the request due to temporary overload or maintenance.

504 Gateway Timeout
When a server acting as a gateway or agent attempts to execute a request, it fails to receive a response from the upstream server (the server that the URI identifies, such as HTTP, FTP, LDAP), or the secondary server (such as DNS).
Note: Some proxy servers return 400 or 500 errors in DNS query timeout

505 HTTP Version not supported
The server does not support or refuses to support the HTTP version used in the request. This implies that the server cannot or does not want to use the same version as the client. The response should contain an entity that describes why the version is not supported and which protocols the server supports.

506 Variant Also negotiates
Extended by the Transparent Content negotiation Protocol (RFC 2295), there is an internal configuration error on behalf of the server: The requested negotiation meta-resource is configured to use itself in transparent content negotiation, so it is not an appropriate focus in a negotiation process.

507 Insufficient Storage
The server cannot store the content necessary to complete the request. The situation is considered to be temporary. WebDAV (RFC 4918)

508 Loop Detected
An infinite loop appears in the server discovery request

509 Bandwidth Limit exceeded
The server reached the bandwidth limit. This is not an official status code, but is still widely used.

510 Not Extended
The policies needed to get resources are not met. (RFC 2774)

How to handle common errors

500 error

500 error is the webmaster often encountered problems, on my experience, causes and solutions are summarized as follows:

1, the number of users running too much, the pressure on the server is too large, the server can not respond, the report HTTP500 error.

This is the main reason why the website reported 500 error, why many websites suddenly reported 500 error (Service unavailable)? 90% is due to excessive space pressure, beyond the limits set by the space quotient.

Encounter this problem, it is best to find the first time the space provider after-sales service, they will generally help you recycle the application pool, the problem will be resolved. If you do not find after-sales service, you can in the space management background, find the "recycling application pool" that project, manually execute it yourself. However, some space management backgrounds do not provide this service.

2, if the possibility of excluding the 1th, then a big reason is the procedural problems.

Can do a simple test page, to see if it can run successfully, and then detect the error page, so that targeted changes.

Where the connection is not made, the HTTP500 error is reported. The problem is solved by manual or auto-correlation.

3, if the operation in the test needs to insert data into the database, if the large amount of data causes the table space in the database is full, or the buffer pool is small can not satisfy the data access, etc., can cause HTTP500 error.

The solution is to adjust the database, modify the connection pool size, and so on, according to individual circumstances to correct.

1**: Request received, continue processing
2**: Successful operation received, analysis, acceptance
3**: Completion of this request must be further processed
4**: request contains an error syntax or cannot be completed
5**: The server failed to perform a fully valid request

100--customer must continue to make a request
101--client requires server to convert HTTP protocol version on request

200--Trading Success
201--prompt to know the URL of the new file
202--accepted and processed, but processing not completed
203--return information is indeterminate or incomplete
204--request received, but return information is empty
205--the server has completed the request, the user agent must reset the files that are currently viewed
206--server has completed a partial user's GET request

300--requested resources can be obtained in multiple places
301--Delete request data
302--found the request data at a different address
303--advising customers to access other URLs or access methods
304--client has performed a get, but the file has not changed
The resource requested by 305--must be obtained from the address specified by the server
306--code used in previous versions of HTTP, no longer used in the current version
307--declaring the requested resource temporary deletion

400--error requests, such as syntax errors
401--Request Authorization failed
402--reserved valid Chargeto header response
403--Request not allowed
404--no files, queries, or URLs found
405--the method defined by the user in the Request-line field does not allow
406--request resource is inaccessible based on accept drag sent by user
407--similar to 401, the user must first be authorized on the proxy server
408--client does not complete the request within the user-specified time of starvation
409--the current resource state, the request cannot be completed
This resource is no longer available on the 410--server and has no further reference address
411--server rejects user-defined Content-length property requests
412--one or more request header fields are incorrect in the current request
413--the requested resource is greater than the size allowed by the server
414--The requested resource URL is longer than the length allowed by the server
415--requesting a resource does not support requesting an item format
The 416--request contains a range request header field that does not have a range indication value within the current request resource, requesting
Also does not contain the If-range request header field
417--server does not meet the expected value specified by the request Expect header field, if it is a proxy server, it may be the next
A primary server does not meet the request

500--Server generates internal error
501--server does not support the requested function
502--server is temporarily unavailable, sometimes to prevent system overloads
503--server overload or pause repair
504--Gateway overload, Server uses another gateway or service to respond to users, waiting time setting value is longer
505--server does not support or deny the HTTP version specified in the request header

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English version:

100:continue
101:switching protocols
102:processing

200:ok
201:created
202:accepted
203:non-authoriative Information
204:no Content
205:reset Content
206:partial Content
207:multi-status

300:multiple Choices
301:moved Permanently
302:found
303:see Other
304:not Modified
305:use Proxy
306: (Unused)
307:temporary Redirect

400:bad Request
401:unauthorized
402:payment granted
403:forbidden
404:file not Found
405:method not allowed
406:not acceptable
407:proxy Authentication Required
408:request time-out
409:conflict
410:gone
411:length Required
412:precondition Failed
413:request Entity Too Large
414:request-uri Too Large
415:unsupported Media Type
416:requested Range Not satisfiable
417:expectation Failed
422:unprocessable Entity
423:locked
424:failed Dependency

500:internal Server Error
501:not implemented
502:bad Gateway
503:service unavailable
504:gateway Timeout
505:http Version not supported
507:insufficient Storage

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