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Hello, friends, in this video, we shall see the use of the session object in a flask application.

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Sessions are a little different from cookies where the cookies are stored in the client's computer.

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The session is stored on the server itself.

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So that is the main difference between the cookies and the sessions.

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What is the session session?

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Is the time interval between the time the user has logged into a Web application to the time the user

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is logged out of the application.

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So the time interval between these two instances, logging in to an application and logging out of the

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application, the time duration is called into session.

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So if you want a certain data to be persisted throughout this time interval, then certain session variables

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are stored which can be used across the different you else that the user might be visiting during the

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course of that session.

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So the data, which is not needed to be held across the session is that is those variables.

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Those are stored in a temporary directly in the server.

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When a client logs into or visits a particular Web application server, then each server, each client

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or each session is given a unique.

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So that particular decision is identified by this.

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Every session data, the variables are stored on the top of the cookies and the and the data is then

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encrypted with the help of a certain encryption key, which is called secret key.

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So therefore, what is necessary?

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If you want a certain Web application to hold certain session data, then the application configuration

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must have a secret key notified or stored.

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What is the decision object?

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Just like a cookie object.

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An object is also a dictionary object which contains the key value pairs.

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Key is the name of the station variable and the data is the associated value.

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So it is also a dictionary object.

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So first and foremost, you have to set the secret key app provided app is the name of your application

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object dark secret underscore key is equal to now.

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You find that a certain string is provided or given the value to this secret.

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Remember that this must be a very random and such a string which is not easily recognized or which is

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not easily, easily reproducible.

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So such a random string is used as secret key of the application in order to set the variable on your

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to do that sation, the name of the label that you want to use.

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Put it into the bracket is equal to the value.

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So this will set the value.

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And in order to remove the third transition variable, you just use the function called pop station

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or pop.

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Give the name of the variable that Flast will take, the values you put into position object and they

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will be serialized in the form of cookies.

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Some you know, sometimes what may happen that the sessions are not persisted throughout the session,

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even if the cookies are enable the sessions, the session variable does not contain or hold to the values.

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So what may be the reason?

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The reason may be that your Web browser may not be supporting the length of the cookie.

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That is all you have to verify that the site supported by the Web browser is matching with the size

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of the cookies in your application.

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If not, then there will be certain exception that may be generated.

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So these are all the different activities that you will have to verify with the help of an example.

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So set an example which will, you know, statistician, create a variable and read back to the station

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variable that I will demonstrate to you with the help of a python example running a flask application.

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So let us now try to understand how.

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The session is created, how the session variables are defined, even if needed, how the session variables

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are removed and how those variables remains persistent throughout the entire session.

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What is decision?

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The time interval for which the user is logged into a particular Web application and logged out of it?

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OK, so for this exercise, different resources that are needed from our last module are important first.

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So this long list of import.

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You have to import the flask object, the session object, the request object and the functions redirect

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you are for and render a template to, these are our requirements which we have imported.

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Then, as usual, cleared the last object.

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ABC called Flask Doubleheaders codename.

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This will create the flask application object.

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The mandatory thing is to set up a secret key of this plastic object, a secret key, you can give any

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string here.

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The rest of the.

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Script.

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Has three, you are really rules defined.

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One is the.

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Index, the other is a slash login and slash logout.

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So to begin with, when the server starts.

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And you give the localhost lost 5000, slash, this index will function, will be executed.

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So, as you will expect.

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In the very first place, as soon as you log into the server by this flash, you are well, there will

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be no username.

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That will be in the session object.

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What is the object?

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Incidently, it is a it is a dictionary of all the variables and its associated value.

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So you are you have just started the server.

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So naturally, there will be no you there will be no session variable by the name username.

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So this condition will be false.

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So this will not take place.

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So what what will happen?

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It will come into this.

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And the message that will be displayed are rendered on your brother's surface will be you are not logged

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in.

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And it will give you a hyperlink to this slash login you are in.

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And we'll ask you to click here to login.

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So if you click on this login, what will happen?

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This.

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Browser will be redirected towards this, you are logging.

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This is the second rule that has been defined here.

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And additionally, the road to function.

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Taking two arguments, as usual, the usual and the Metters.

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Get that post.

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OK, so for the first time in.

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The user clicks this click here to login.

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And for the first time, the Log-in, you are really stressed.

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Naturally, the request not matter will not be equal to post.

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It will be.

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It will be a great method, so therefore this.

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Rendered template session, that e-mail will.

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I mean, this action will take place.

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So what will happen, the browser will render that the template or the Web page for legislation or e-mail,

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which you will store into.

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The templates folder of your Web application.

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So at this juncture, we shall have a look at what is the intersession that Stephen.

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So this is the session that is the core of this session, not Estherville, in which basically there

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is a small form.

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In which there is an input type equal to text in which you can type the.

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Text, which will be stored in the attribute called name.

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And then the submit button, so if you click on the submit button, the data will be posted back to

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the same.

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You are ill because you have not given any other.

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You are as an action attribute.

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OK, so this is the.

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This is our.

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Not far.

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So the session will be opened in the browser will be textbooks, you will enter some user name submit

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the data will be now again redirected towards this login with the post maternelle.

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So that means now this.

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Will be executed.

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This condition is true, so session, not username, is equal to whatever username that you had, input

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will be faced from the request, object, request or form username.

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And the social variable will be variable by the name.

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Username will be set up and then your brother will be redirected towards.

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The you are all for index that are getting back to this leisz.

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The second time when it comes back to this, then the username is already present, so therefore.

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It will be fetched, and the text that will be rendered on your webpage or browser will be logged in

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as whichever username you might have given in the station.

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OK, so it will now tell you that you are logged in as this.

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OK.

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And it will again also give you another hyperlink.

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If you click on the hyperlink, it will redirect to your redirect the browser to the slash logout you

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are.

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OK, so what is this logout, you are doing it, we just pop the username session with evil that you

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had created and.

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So the media will be released and it will be again redirected towards the same index.

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Now the user name is not present.

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So again, back to this.

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You are not logged in and.

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You are given a chance by clicking the hyperlink to back to logging.

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So this is a slightly, uh, complex activity that we are going to perform as a demonstration of this

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example.

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OK, so the Python script is there.

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There are three warrants for the road logging and logging, and then, of course, there is a secondary

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e-mail page.

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Finally, there is a app that run in the department that we are to when the when this session is not

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people will be executed, the server will start.

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So this is the explanation of this.

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Gore on the flask application.

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So let us now try to understand how.

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The session is created, how the session variables are defined, even if needed, how the session variables

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are removed and how those variables remains persistent throughout the entire session.

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What is decision?

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The time interval for which the user is logged into a particular Web application and logged out of it?

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OK, so for this exercise, different resources that are needed from our flask model are important first.

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So this long list of import.

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You have to import the flask object, the session object, the request object and the functions redirect

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you are for and render a template.

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So these are our requirements which we have imported.

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Then, as usual, cleared the flask object.

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ABC to Flask DeVillers codename.

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This will create the flask application object.

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The mandatory thing is to set up a secret key of this plastic object, a secret key, you can give any

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string here.

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The rest of the.

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Script.

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Has three, you are really rules defined.

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One is the.

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Index, the other is lagging and the other is logout.

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So to begin with, when the server starts.

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And you give the localhost column five 5000, slash this index view function will be executed.

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So, as you will expect.

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And the very first place, as soon as you log into the server by the slash you are in, there will be

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no username.

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That will be in the session object.

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What is this object?

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Incidentally, it is a it is a dictionary of all the social variables and its associated values.

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So you are you have just started the server.

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So naturally, there will be no you there will be no session variable by the name username.

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So this condition will be false.

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So this will not take place.

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So what what will happen?

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It will come into this.

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And the message that will be displayed are rendered on your brother's surface will be you are not logged

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in.

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And it will give you a hyperlink to the slash login you are in.

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And we'll ask you to click here to login.

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So if you click on this login, what will happen?

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This.

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Browser will be redirected towards this, you are logging.

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This is the second rule that has been defined here.

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And additionally, the road to function.

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Taking two arguments, as usual, the usual and the Metters.

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Get that boost.

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OK, so for the first time in.

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The user clicks this click here to login.

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And for the first time, the in you are really stressed.

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Naturally, the request not matter will not be equal to post.

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It will be.

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It will be a great method, so therefore this.

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Rendered template session, that e-mail will.

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I mean, this action will take place.

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So what will happen, the browser will render that the template or the Web page or legislation or e-mail,

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which you will store into.

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The templates folder of your Web application.

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So at this juncture, we shall have a look at what is the intersession, that estimate.

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So this is the session of the court of this session that in which basically there is a small form.

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In which there is a input type is equal to text in which you can type the.

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Text, which will be stored in the attribute caller's name.

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And then the submit button, so if you click on the submit button, the data will be posted back to

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the same.

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You are ill because you have not given any other.

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You are as an action attribute.

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OK, so this is the this is our second not form.

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So is the mill will be opened in the browser, there will be textbooks, you will enter some name,

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press submit, the data will be now again redirected towards this login with the post method now.

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So that means now this.

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Will be executed.

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This condition is true, so session user username is equal to whatever username that you had, input

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will be first from the request, object, request or form username.

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And the social variable will be variable by the name.

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Username will be set up and then your browser will be redirected towards.

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The you are all for index that are getting back to this leisz.

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No second time when it comes back to this, then the username is already present, so therefore.

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It will be fetched, and the text that will be rendered on your webpage or browser will be logged in

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as whichever username you might have given intersession.

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OK, so it will now tell you that you are logged in as this.

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OK.

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And it will again also give you another hyperlink.

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If you click on the hyperlink, it will redirect to redirect the browser to the slash logout, you are

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a little.

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OK, so what is this logout you are doing, it will just pop the username session with one that you

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had created and.

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So the social media will be released and it will be again redirected towards the same index.

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Now the user name is not present.

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So again, back to this.

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You are not logged in and you are given a chance by clicking the hyperlink to back to login.

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So this is a slightly complex activity that we are going to perform as a demonstration of this example.

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OK, so the Python script is there.

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There are three warrants out the road, logging and logging, and then, of course, there is a 600

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e-mail page.

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Finally, there is an app that ran in the development that we are to.

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When the vendors next door will be executed, the server will start.

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So this is the explanation of this.

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More on the flask application.