1.1 Request and Response

Request and response model

Developer tools left bar request, right bar response

How to send a request

  • Methods:

    Use the Chrome address bar

    Use the curl command

  • concept

    The tool that helps send requests is called a User Agent.

How to make a response

  • Need to programming

    Node.js has an HTTP module that does this

    VSCode creates a terminal and runs Node server.js 8888

    Curl the path under this port in cmder. VSCode will refresh the terminal

  • Pay attention to

    This code is the server code and is generally placed on the server.

    Path is the path /x without query parameters

    Query is the object form of the query parameter {a:’1′}

    QueryString is a string form of a query parameter, okay? a=1

    PathWithQuery is a pathWithQuery parameters

    Request is the request object

    Response is the response object

Code logic

  • grammar

  • logic

    The code is executed every time a request is received.

    Use if else to determine the path, return different content.

    If it’s a known path, always return 200.

    If the path is unknown, 404 is returned.

    Content-type indicates the “Type/syntax” of the Content

    Response.write () can fill in the returned content

    Response.end () indicates that the response can be sent to the user

conclusion

  • Server program – example above

  • Web page –

    / path returns an HTML content

    The /x path returns one CSS content

    The /y path returns a JS content

  • Note –

    The suffix in the URL is useless. /y.css is not necessarily CSS content

    The content-type is what determines the file Type

1.2 HTTP

Systematic learning

  • Basic concepts – request, response

  • How to debug – with Node.js, you can use log/debugger

  • Resources – Use Node.js and look at the Node.js documentation

  • Standard – HTTP specification documents: RFC2612, etc

HTTP Basic Concepts

request
Request verb Path + Query parameters Protocol name/version Host: domain name or IPAccept: text/ htmlContent-type: format of the request body Enter the request body (upload content)Copy the code

Three parts: request line, request header, request body

Request verbs GET/POST/PUT/PATCH/DELETE, etc

The request body is generally empty in a GET request

Case insensitive

RFC 2612 chapter 5

  • The GET demo –

  • The POST –

The response
Protocol name/version status code Status string Content-Type: response body format Enter Response body (download Content)Copy the code

Three parts: status line, response header, response body

Common status codes:

Section 6 of RFC 2612

  • Demo –

Response body –

Construct the request with curl

When the server is enabled

The curl -v http://127.0.0.1:8888Copy the code

Set the request verb
-X POST
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Set paths and query parameters

Add it directly after the URL

Set the request header
-H 'Name:Value'
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or

--header 'Name:Value'
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Set the request body
-d 'contents'Copy the code

or

--data 'contents'Copy the code

Read the request with Node.js
Read request verb

request.method

Curl sends GET and POST requests

GET the request verbs GET and POST in the terminal, respectively

Read the path

Request. url path with query parameters

Path Indicates a pure path without query parameters

Query Has only query parameters

Read request header

request.headers['Accept']

Read request body
Set the response with Node.js
Set the response status code

response.statusCode = 200

Example Change the status code 200 to 201

Using curl, you can obtain the status code 201

Setting the response header

response.setHeader('Content-Type','text/html');

Set the response body

Response. Write (' content ')

Append content:

The server
Server Setup Procedure

  1. Buy a server in Aliyun

  2. Copy the local public key to ali cloud ~/.ssh/authorized_keys

    Get the local public key first

    Echo 'Local public key' >> ~/. SSH /authorized_keysCopy the code

  3. Remotely operate the cloud machine locally using SSH root@ instance IP

    Access files in the root directory of the server

  4. You can name the instance IP in hosts

    Notepad opens hosts as an administrator and names the instance IP address aliyun1

  5. To exit the cloud machine, type Exit.

How do I prevent SSH jams

Method 1 –

Add to /etc/ssh/ssh_config at the end

Host *    ServerAliveInterval 30
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Method 2 –

You can do this twice with Echo (locally, not in the cloud)

echo "Host *" >> /etc/ssh/ssh_configecho "  ServerAliveInterval 30" >> /etc/ssh/ssh_config
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Creating an Application Account

The Linux root account has the highest permissions to prevent attacks, so create a new application account.

Steps:

  • adduser river

  • Enter new UNIX password: Enter the password

  • Enter your password again

  • Press Enter all the way, then run the command —

    mkdir /home/river/.sshcp ~/.ssh/authorized_keys /home/river/.ssh/chmod 755 /home/river/.ssh/authorized_keyschown river:river /home/river/.ssh/authorized_keys
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  • Finally, SSH river@aliyun1 can be implemented

sudo

Add sudo permission to river (root)

adduser river sudo
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What is sudo?

Super User DO, similar to “Run as administrator” on Windows

When using the river account, if you encounter special operations before using sudo, please exit root

You need to enter the password of the river user

sudo !! Execute the preceding command with sudo

Installation Node. Js 14

steps

curl -sL https://deb.nodesource.com/setup_14.x | sudo bash -sudo apt-get updatesudo apt-get install -y nodejsnode -vnpm -vnpx -v
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Install git

steps

sudo apt install git
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Git -m “XXX”

Learn vim

The deployment of application

1. The cloning nodejs – test

clone https://github.com/RiverCui/nodejs-test.git
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2. Create a log in the nodejs-test file

cd nodejs-testtouch log
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3. Start the command

node server.js 8888 > log 2>&1 &
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This process is already running in the background with id 19405, local port of curl remote machine:

To shut down the process, run the following command

kill -9 id
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4. Make the start command into a start file

touch startecho 'node server.js 8888 > log 2>&1 &'chmod +x ./start
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Now you can run start directly

. / start or sh. / startCopy the code

Since start is run through Node, it can pass at this point

killall node
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Stop all Node processes

After starting the command, you can access the page using Ali Cloud IP+ port number

How to Restart an Application

SSH frank@ instance ipcd nodejs-testCopy the code

Pull the latest code

git pull
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Start the

killall nodesh ./start
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