About the log traffic monitoring and early warning small project | standardized return of interaction with the database in flask

stay flask It interacts with the database ：

Use orm Manipulate the database （orm Or at the bottom pymysql）

orm: object relational mapping( Object relation mapping )

flask Unnecessary and complex sql Deal with sentences It's just manipulation orm Objects will do

orm It is used to map the table structure in the database into model classes

The object generated by the class is each row of records in the database

The configuration file setting Add database configuration ：

first line ： Connect to database

SQLALCHEMY_DATABASE_URI = user name ： password @ Database host / database ？ Character set

After that model Create a new __init__.py

Create a db object Try to make db and app Binding   And import the table to run

dependent user.py

It is equivalent to creating a new user surface If the set field is specified as String type You need to specify the length

User Every other class Is a model It must inherit db.Model class

A class is mapped to a table in the database

Class will instantiate And every object instantiated It is a row of records in the table

user.py Inside ： New users

Then bind the blueprint to app above

Use dynamic url Implementation delete

User.query.get（） Use get lookup , Primary key only get You can only get To the first Therefore, only a single operation

Change ： Just the same, only one item can be modified

check ：

Type in the browser url What happens to the request ？

Client initiates request

The server receives the request     analysis http baotou （ The header field of the package has url And the request method ）    Get body data

adopt url And request methods to perform judgment processing

1. adopt url Come on url_map Find the corresponding... In the table endpoint

view_function Find the corresponding view function in the table

1. Judge whether the request method is correct

Call the corresponding view function for processing

It can be done by request Object to get the passed in parameters

You can also use dynamic url Get the parameters

If there is database operation Import the corresponding model class

Here by manipulating orm Object to manipulate the database , Add, delete, modify and query the database

For query operations , Database objects cannot be returned directly , It needs to be serialized

Corresponding format conversion is required , It is recommended to use json

Return to the corresponding api data

The serialization operation can be directly placed in user.py In the class of

So we don't need to return here manually

Put a single query and all queries in one function

When manipulating the database, you must remember to submit

The project needs to be standardized ：

Return to json Format     

Need to return the status code （status）： Define the logical state of the program

also message Explain the meaning of the status code

data Data returned by request Put all the data in data Inside

General format ：{“status”：10000,“message”：“ Data request successful ！”,“data”：[]}

So take this as a public setting Define a new folder libs（ Store public functions ）

And then create a utils（ It holds all the tools ）

In this way, standardization can be achieved Normalization

Start project ：

1. project   Set up a project team Divide responsibilities
2. Demand collection   Demand analysis
3. Design this project Product prototype   Database design , Interface design （url The ginseng ）
4. Write code
5. Test online

Flask Provide the interface You can add monitoring items Monitoring items can also be displayed

Because we don't have a front end now So we will show the operation later Can only be completed through the interface

For ordinary users , Only you can see the monitoring items you add

For Administrators , All the monitors can see

For the project user when It is recommended that the user password be hashed   For roles, it is recommended to set them to enumeration type

monitor What is stored inside is a monitoring table

Establish relationships between tables （ Be sure to set foreign keys ）

stay model Of user.py Inside with monitor Table create connection

On the command line Help manage flask Tools for ：flask-scrip

Once installed We give up server.py I've created a new one manage.py

Now our main program The core object It's all in the hands of manage.py 了

Now? python manage.py It is equivalent to an order Parameters can also be connected But it is also started by default

So we need to use the command line to specify the port Path, etc

Start the program from the command line ：python manage.py runserver -h 192.168.0.25 -p 8000

python manage.py There are three parameters

db

runserver： start-up

shell： Run one python Of shell Program

Equivalent to entering app Internal

Everything manipulated here is manipulated app

So there is one more object in the monitor attribute  monitor Attribute contains user Of id（ because id Is set to a foreign key ） Same monitoring items （ That is to say monitor Data in table ）

User pass monitor Property to find the monitor

monitor The table adds a reverse query user  moniter The object of can pass through user Property to find the user

This relationship is not database yes orm Of   There is no need to query the table

hold api More standardized ：flask-restful（ Is a style of software application ）（ Interviews often test ）

restful：

#REST（representational state transfer）(api Design method of ): Presentation layer state transition

It's not necessary It is just a general software design style

Generally speaking, it's Resources in the network in some form of state transition

resource： resources   That's data   For example, user data is a kind of resource Monitoring data is a kind of resource

representational： Some form of expression Such as JSON,html

state tranfer： State shift . adopt http Method realization （ In fact, it is equivalent to adding, deleting, modifying and checking users Use http The verb of This is a rest Rules of use ）

Such as Not used rest ：                      Used rest that url Just two or one

（ Different ways to do different things ）

       /user It is a kind of resource                        /user       /user/id

       /user/add                                      post Method

       /user/delete                                  delete Method

       /user/update                                 update Method

       /user/get                                      get Method

Divide by resources url, There is no need to divide it according to the action

Each type of resource is given to one or two url     adopt http Different methods are used to add, delete, modify and query such resources

accord with rest The structure of the principle We call it restful framework

This also carries the version number Specifies the api How to design The corresponding format is specified The status code is specified

every last url It represents a kind of resource

Client through four http Method to operate on server resources

such as For resources such as users (id yes user The database of id)

GET  /v1/user   Get all users

GET  /v1/user/id Get a user （v1 It's the version number  2 representative id）

POST /v1/user  New users

PUT /v1/user/id  New users

DELETE  /v1/user/id Delete user

Now you can go through server.py To run You can also run from the command line

about python call Linux command     Recommended subprocess

Inquiry is the easiest test ！！！！！

Query by criteria ：

Precise query filter_by     Fuzzy query filter

Filter_by No, filter flexible

Multiple conditions ：

Sort ：

Limit ：

Query summary ：

Query summary ：

1.User.query.all() all

2.User.query.get(pk) One

3.User.query.filter()

If the field to retrieve is a string （varchar,db.String）

User.username.startwith('')

User.username.endwitd('')

User.username.contains('')

User.username.like('') The passed in parameter needs to be added %

User.username.in_(['','','',''])

User.username==

If the field to be retrieved is an integer or date type ：

User.age.__lt__(18) Double underline

User.rdatetime.__gt__('.....')

User.age.__le__(18)

User.age.__ge__(18)

User.age.between(18,25)

Multiple conditions are retrieved together ：and_ or_

Necessary condition ：or_

Sort ：order_by()

Get the specified quantity ：limit（） offset（）

4.User.query.filter_by(username='xxx') User.query.filter(username== 'xxx')

Delete

Two kinds of deletion ：

1. Logical deletion , It's just an update （ When defining tables in a database , Add a field named isdelete, This field controls whether to delete ）

id=request.args.get(id) Used to receive get Parameters in the request

user=User.query.get(id)

user.isdelete=True

db.session.commit()

2. Physical delete （ Completely remove from database ）

id=request.args.get(id) Used to receive get Parameters in the request , if post Just put args Replace with form

user=User.query.get(id)

db.session.delete(user)

db.session.commit()

3. to update

id=request.args.get(id)

user=User.query.get(id)

# Modify the properties of an object

user.username=xxx

user.phone=xxx

# Commit changes

db.session.commit()

Need to submit ：

add to

user=User()

user.xxx=xxx

db.session.add(user)

db.session.commit()

Delete

user=User.query.get(id)

db.session.delete(user)

db.session.commit()

to update

user=User.query.get(id) # Get the objects in the database

# Modify the properties of an object

user.username=xxx

user.phone=xxx

# Commit changes

db.session.commit()

Standardized return ：

Our project usually prepares a description document （ You can directly extract part of the project document and put it into the description document ）, It is important to organize the documentation （ Documentation is for others to use ）

The request parameter is url The variable passed in after the value passing question mark

The returned parameters indicate what we are returning

The transmission on the network is usually in the form of string and json Format is to easily convert the string format to the desired object   Norms are conventions that return json Format

http The status code only focuses on whether the request is successfully connected to get data Instead of focusing on whether the data we get is what we need So each of our applications will have its own status code

（ Then you can describe the information message To see what kind of failure we are ）