Analysis of common HTTP response messages

This is when I use ASP, some of the analysis notes about HTTP response messages, fragmented records,

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The HTTP response Code Response code consists of three-bit decimal digits, which appear in the first line of the response sent by the HTTP server.

The response code is divided into five types, denoted by their first digit:

1XX: Information, request received, continue processing

2XX: Success, Behavior is successfully accepted, understood and adopted

3xx: Redirect, in order to complete the request, the action must be further performed

4XX: Client error, request contains syntax error or request cannot be implemented

5XX: Server error, server cannot implement an apparently invalid request

The following table shows each response code and what it means:

100 continue

101 Group Exchange Association

OK

201 was created

202 are adopted

203 Non-authorised information

204 No Content

205 Resetting Content

206 part of the content

300 + Options

301 Permanently transmitted

302 found

303 See other

304 not changed

305 using Proxies

307 Temporary redirection

400 Error request

401 Not authorized

402 Request for payment

403 Forbidden

404 Not Found

405 Methods not allowed

406 Not Accepted

407 Request for Proxy authorization

408 Request timed out

409 conflicts

410 Out of date

411 length of the requirement

412 Premise not established

413 The request instance is too large

414 Request URI too large

415 Unsupported media types

416 The range of requests that cannot be satisfied

417 Expectations of failure

500 Internal Server Error

501 Not used

502 Gateway Error

503 Unavailable Services

504 Gateway Timeout

505 HTTP version is not supported

The HTTP header header is composed of a primary key/value pair. They describe the properties of the client or server, the resources being transferred, and the connection that should be implemented.

Four different types of head labels:

1. Generic header: Can be used for a request or for a response, and is associated with a transaction as a whole rather than a specific resource.

2. Request Header: Allows the client to pass information about itself and the form of the desired response.

3. Response header: The server and the response to transmit its own information.

4. Entity Header: Defines the information for the transmitted resource. Can be used for requests or for responses.

Header Format:<name>:<value><crlf>

The following table describes the headers used in the http/1.1

The Accept defines the types of media that clients can handle, sort by priority, and in a comma-delimited list, you can define multiple types and use wildcards. For example: Accept:image/jpeg,image/png,*/*accept-charset defines the character sets that the client can handle, sort by priority, and in a comma-delimited list, you can define multiple types and use wildcards. Example: Accept-charset:iso-8859-1,*,utf-8

accept-encoding defines the encoding mechanism that the client can understand. Example: accept-encoding:gzip,compress

accept-language defines a list of natural languages that the client is willing to accept. Example: Accept-language:en,de

accept-ranges A response header that allows the server to indicate that it will accept requests for the resource component at a given offset and length. The value of the header is understood as the unit of measure for the requested range. such as Accept-ranges:bytes or Accept-ranges:none

age allows the server to specify the length of time, in seconds, that has elapsed since the server generated the response. The header is used primarily for caching responses. Example: age:30

allow a response header that defines a list of HTTP methods supported by the Zhiyuan in the request URI. Example: Allow:get,put

AUTHORIZATION A response header that defines the authorization (domain and encoded user ID and password) necessary to access a resource. Example: Authorization:basic yxv0ag9yonboaww=

cache-control A generic header for defining cache directives. Example: cache-control:max-age=30

Connection A generic header that indicates whether the socket connection is saved as open. Example: Connection:close or Connection:keep-alive

content-base An entity header that defines a base URI in order to resolve relative URLs within the entity scope. If you do not define a content-base header to resolve relative URLs, use the content-location URI (present and absolute) or use a URI request. Example: content-base:http://www.myweb.com

content-encoding A type of media modifier that indicates how an entity is encoded. For example: Content-encoding:zipcontent-language is used to specify the natural language type of data in the input stream. Example: Content-language:en

content-length Specifies the length of the bytes contained in the request or response data. Example: content-length:382

content-location Specifies the resource location (URI) contained in the request or response. If it is a must. To the URL it also acts as a starting point for the relative URL of the parsed entity. Example: Content-location:http://www.myweb.com/news

A MD5 digest of the CONTENT-MD5 entity used as a checksum. Both the sender and the receiver calculate the MD5 summary, and the recipient compares the value that it calculates with the value passed in this header. Example: content-md5: <base64 of MD5 digest>

The Content-range is sent along with some entities, indicating the low and high byte offsets of the inserted bytes, as well as the total length of the entity. Example: content-range:1001-2000/5000

Contern-type indicates the MIME type of the entity being sent or received. Example: content-type:text/html

Date when the HTTP message was sent. Example: DATE:MON,10PR 18:42:51 GMT

ETag An entity header that assigns a unique identifier to the resource being sent. For resources that can use multiple URL requests, the etag can be used to determine whether the actual resource being sent is the same resource. For example: ETag: ' 208f-419e-30f8dc99 '

Expires The validity period of the specified entity. Example: expires:mon,05 Dec 12:00:00 GMT

form A request header, given the e-mail address of the human user who controls the user agent. For example: from: [email protected]

Host name of the resource being requested by host . This domain is mandatory for requests that use http/1.1. Example: Host:www.myweb.com

if-modified-since If a GET request is included, the request is conditionally dependent on the last modified date of the resource. If this header appears, and the resource has been modified since the specified date, a 304 response code should be reversed. Example: IF-MODIFIED-SINCE:MON,10PR 18:42:51 GMT

If-match If included in a request, specify one or more entity tags. Only the resources whose etag is labeled with the list are sent. Example: If-match: ' 208f-419e-308dc99 '

If-none-match If a request is included, specify one or more entity tags. The resource's etag does not match any one of the criteria in the list, and the operation executes. Example: If-none-match: ' 208f-419e-308dc99 '

If-range An entity tag for the specified resource, and the client already has a copy of this resource. Must be used in conjunction with the range header. If this entity has not been modified since it was last retrieved by the client, the server sends only the specified range, otherwise it will send the entire resource. Example: Range:byte=0-499<crlf>if-range: ' 208f-419e-30f8dc99 '

if-unmodified-since This entity is returned only if the requested entity has not been modified since the specified date. Example: IF-UNMODIFIED-SINCE:MON,10PR 18:42:51 GMT

last-modified Specifies the date and time that the requested resource was last modified. Example: LAST-MODIFIED:MON,10PR 18:42:51 GMT

location for a resource that has already been moved, it is used to redirect the requestor to another position. Used in conjunction with status Code 302 (temporary movement) or 301 (permanent move). Example: location:http://www2.myweb.com/index.jsp

max-forwards A request header for the trace method to specify the maximum number of proxies or gateways that the request is routed through the gateway. The proxy or gateway should reduce this number before passing the request. Example: Max-forwards:3

Pragma A generic header that sends implementation-related information. Example: Pragma:no-cache

proxy-authenticate is similar to Www-authenticate, which is intentionally requesting authentication from the next server only from the request chain (proxy). Example: Proxy-authenticate:basic realm-admin

proxy-proxy-authorization is similar to authorization, but does not intentionally deliver anything that is further than the instant server chain. Example: Proxy-proxy-authorization:basic yxv0ag9yonboaww=

The public list shows the set of methods supported by the server. Example: Public:options,mget,mhead,get,head

range Specifies the offset range of a unit of measure and a partially requested resource. Example: range:bytes=206-5513

Refener A request header field that indicates the initial resource that generated the request. For an HTML form, it contains the address of the Web page for this form. Example: refener:http://www.myweb.com/news/search.html

retry-after A response header domain that is sent by the server in conjunction with a status code of 503 (unable to provide a service) to indicate how long to wait before requesting a request again. This time can be a date, or it can be a unit of seconds. Example: retry-after:18

Server A header that identifies the Web server software and its version number. Example: server:apache/2.0.46 (WIN32)

transfer-encoding A generic header that indicates the type of transformation that corresponds to the message body that is reversed by the receiving party. Example: transfer-encoding:chunked

Upgrade allows the server to specify a new protocol or a new protocol version, which is used in conjunction with response Encoding 101 (switching protocol). Example: upgrade:http/2.0

user-agent defines the type of software used to generate the request (typically, such as a Web browser). For example: user-agent:mozilla/4.0 (compatible; MSIE 5.5; Windows NT; Digext)

Vary A response header that is used to indicate that a response entity is selected from the available response representations using server-driven negotiation. For example: Vary: *via A generic header with all intermediate hosts and protocols to satisfy the request. Example: via:1.0 fred.com, 1.1 wilma.com

The Warning is used to provide a response header for response status supplemental information. Example: warning:99 www.myweb.com Piano needs tuning

www-authenticate A response header that prompts the user agent to provide a user name and password, which is used in conjunction with status Code 401 (not authorized). Responds to an authoritative header. Example: Www-authenticate:basic realm=zxm.mgmt

Analysis of common HTTP response messages