[HTTP column introduction] HTTP learning and cognition
Silly little y Typing Code 2021-08-03 04:08:56

Preface

Because I want to be a browser Historical record . Get... Directly through code
Online inquiries will use Cookie, So let's learn Cookie, And then use Cookie To get the history
Then I found it HTTP Related content , Then create this column to study HTTP

That's learning HTTP Involved again Network protocol , Nature leads to Seven layer network structure
So! , The connection between Internet knowledge ambiguous Relationships are unclear , She might have an affair with him !

Then I will HTTP It's time to learn , Later, I have time to study other network related knowledge
such as TCP、UDP And so on, the other brothers of the network structure


Network structure diagram

Let's look at some pictures first and get back some knowledge about network protocols

Below are the seven story and five story structures
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This is the four layer protocol corresponding to the seven layer standard protocol
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7 Layer refers to OSI Seven layer protocol model , Mainly : application layer (Application)、 The presentation layer (Presentation)、 The session layer (Session)、 Transport layer (Transport)、 The network layer (Network)、 Data link layer (Data Link)、 The physical layer (Physical).

OSI Model The main agreement Company function major equipment TCP/IP
application layer Telnet、FTP、HTTP、SNMP etc. Data flow Determine the communication object , Provide an interface to access network services gateway application layer
The presentation layer CSS GIF HTML JSON XML GIF Data flow Responsible for data coding 、 conversion ( Interface and binary data conversion , Conversion between high-level language and machine language ) data compression 、 decompression , encryption 、 Decrypt . It is processed into different formats according to different application purposes , It shows that we see all kinds of file extensions . gateway application layer
The session layer FTP SSH TLS HTTP(S) SQL Data flow Responsible for establishing 、 maintain 、 Control session simplex (Simplex)、 Half duplex (Half duplex)、 full duplex (Full duplex) Three communication modes of service gateway application layer
Transport layer TCP UDP Data segment Responsible for segmentation 、 Combined data , Realize end-to-end logical connection and three handshakes (Three-way handshake), Connection oriented (Connection-Oriented) Or non connection oriented (Connectionless-Oriented) Service for , Flow control (Flow control) It all happens on this floor . It's the first end-to-end , That is, the level from host to host . gateway application layer
The network layer IP(IPV4、IPV6) ICMP Data packets Responsible for managing network addresses , Positioning equipment , Decide the route Router , Bridge router application layer
Data link layer 802.2、802.3ATM、HDLC frame Responsible for preparing physical transmission ,CRC check , Error notification , Network topology , Flow control, etc Switch 、 bridge 、 network card application layer
The physical layer V.35、EIA/TIA-232 Bit stream It's a real physical link , Be responsible for sending data in the form of bit stream 、 receive A hub 、 Repeater , cable , transmitter , Receiver application layer

Data transmission process demonstration
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HTTP Study

Hypertext transfer ​​ agreement (HTTP) Is an application layer protocol for transmitting hypermedia documents , for example HTML. It's for Web The browser and Web Designed for communication between servers , But it can also be used for other purposes .HTTP Follow the classic client - Server model , The client opens the connection and makes a request , Then wait until a response is received .HTTP It's a stateless protocol , This means that the server does not keep any data between the two requests ( state ).
HTTP Is an extensible protocol , It relies on resources and uniform resource identifiers (URI)、 Simple message structure and client - Server traffic and other concepts . On top of these basic concepts , Many extensions have been developed over the years , These extensions use new HTTP Method or header adds updated functionality and semantics .


summary

This column mainly updates about HTTP Relevant knowledge content learning , Because of their own knowledge storage relationship

So some content will learn from others , Mainly for Learn and share , In case of infringement , Just contact me to modify ~

This article refers to :https://blog.csdn.net/u010359398/article/details/82142449

Please bring the original link to reprint ,thank
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