Recommended by Alibaba P8, Fiddler packet capturing tool (I)

Fiddler brief introduction

Fiddler It is on the client side and the server side HTTP agent
The most commonly used http One of the bag grabbing tools
Very powerful , yes web A handy tool for debugging

• Monitor the browser for all HTTP/HTTPS Traffic
• see 、 Analyze the details of the request content
• Forgery of client requests and server responses
• Test website performance decryption HTTPS Of web conversation
• overall situation 、 Local breakpoint function
• Third party plug-ins

Scenario usage scenario

• Interface debugging 、 The interface test 、 Online environment debugging 、web Performance analysis
• Before and after judgment bug、 development environment hosts To configure 、mock、 Weak network disconnection test

B/S framework

Write a program to deploy to web The server
web The server runs on the server , binding ip Address and listen on a port , Receive and process http request
Client pass http Protocol to get web pages on the server 、 Documents, etc.

working principle

HTTP

Hyper Text Transfer Protocol（ Hypertext transfer protocol ）
Transport protocol used to transfer hypertext from the world wide web server to the local browser
HTTP The protocol is based on TCP Application layer protocol , It doesn't care about the details of data transmission , It is mainly used to specify the data transmission format of the client and the server , It was originally used to transmit... To clients HTML Content of page . The default port is 80
http It's based on the request and response pattern 、 Stateless 、 Application layer protocol

complete HTTP agreement

complete http The protocol contains two parts: request and response

HTTP Request message

HTTP The request message is mainly composed of the request line 、 Request header 、 A blank line 、 Request body （ Request body ）4 Part of it is made up of

The following is fiddler Request message of a session

Request method （ Request Method）

Request method	remarks
GET	Request resources
POST	Submit resources
Head	Get response header
PUT	Replace the resources
DELETE	Delete resources
OPTIONS	Allow clients to view the performance of the server
TRACE	Echo requests received by server , For testing or diagnosing

URL

Uniform Resource Locator: Uniform resource locator , Used to describe resources on the Internet
Format ：schema://host[:port#]/path/.../[?query-string]

scheme： agreement , Such as http,https,ftp etc.
host： Domain name or IP Address
port： port
path： Resource path
query-string： Parameters sent

Such as ：https://www.baidu.com/s?wd= Meimeida

Request header （Request Header）

Request header	describe
Host	host ip Address or domain name
User-Agent	Client related information , If the operating system 、 Browser and other information
Accept	Specifies the type of information received by the client , Such as ：image/jpg,text/html,application/json
Accept-Charset	The character set accepted by the client , Such as gb2312、iso-8859-1
Accept-Encoding	Acceptable content coding , Such as gzip
Accept-Language	Accepted language , Such as Accept-Language:zh-cn
Authorization	The client provides to the server , Information for authority authentication
Cookie	Carry the cookie Information
Referer	Of the current document URL, From which link
Content-Type	Request body content type , Such as Content-Type: application/x-www-form-urlencoded
Content-Length	Data length
Cache-Control	Caching mechanisms , Such as Cache-Control:no-cache
Pragma	Prevent pages from being cached , and Cache-Control:no-cache It works the same

HTTP response message

HTTP The response message mainly consists of the status line 、 The message header 、 A blank line 、 Response Content 4 Part of it is made up of

The following is fiddler Response message of a session

Status code （Status Code）

To represent a web server HTTP Responding to the state of 3 Digit code

Status code	describe
1XX	Prompt information , The request was successfully received
2XX	success , The request was successfully processed 200
3XX	Redirection related 304
4XX	Client error 404
5XX	Server-side error 500

Response head （Response Header）

Response head	describe
Server	HTTP Software information of the server
Date	Time of response message
Expires	Specify cache expiration time
Set-Cookie	Set up Cookie
Last-Modified	Resource last modified
Content-Type	The type and character set of the response , Such as ：Content-Type: text/html; charset=utf-8
Content-Length	The length of the content
Connection	Such as Keep-Alive, To hold on to tcp The connection is not closed , Not permanently connected , The server can be set
Location	Indicates the location of the redirection , new URL Address , Such as 304 The situation of

GET request

Format http://host:port/path?xx=aa&yy=bb
Such as ：http://120.78.128.25/futureloan/mvc/api/member/register?mobilephone=13555555528&pwd= adorable
explain ：

• http/https: Protocol type
• host: Server host ip Address or domain name
• port: Port number , If it is 80 It can be omitted , Other ports must be specified
• path: Path to access resources
• ?: Separator , Used to distinguish path And parameters
• xx=aa、yy=bb: Request parameter list
• &: Connecting symbols for multiple parameters

To be continued , Please like the reminder