WEBVTT

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So far we have made some really good progress.

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We have created code which allows users to sign up and log into our web sites.

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Now many users don't like to be asked their email address and password every time they come back to

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the Web site.

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So what they do.

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They check the Remember Me box while logging in.

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So we need to write some code to activate that feature.

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OK so if you go back to the code we have written before we checked if the Remember Me box is not checked

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and then we echoed success straightaway.

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OK.

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Now if the remember the box is checked we going to write some code for that.

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So we have covered the logic of the code earlier but very briefly what are we going to do.

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We go to create a couple of variables but we're going to generate randomly.

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OK.

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And then we can test all those variables in a cookie or the user's device.

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Also we're going to store those variables in the Remember Me table.

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So when the user comes back we go to much or ever variables we retrieve from the cookie or their device

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with the variables that we find in the database.

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OK and if we how much we're going to log that's usery.

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OK.

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So let's go ahead and write some code.

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So first of all we're going to create these two variables.

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OK.

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So are you going to use a function called Open SSL.

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Ok random pseudo bytes as we do before.

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And this function takes as a barometer the number of bytes that you would like to generate.

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OK so let's go for 10 bytes for the first variable.

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Also if you want you can convert the outputs of the function which is in binary.

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You can convert it to a decimal.

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OK the function for that is binary to ex-head decimal.

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OK we have used this function before.

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You must be familiar with it.

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And LS generates the second variable in the same way.

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OK for a second variable you can go for 20 bytes if you like or.

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OK.

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Now the next step is to store these variables inside a cookie.

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OK so the next step.

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So to create a cookie we can use the function set cookie.

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OK so this function is going to take a few promises so the first problem is going to be the name of

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the cookie.

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OK.

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So let's go for

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remember me.

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All right.

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Then the second parameter is going to be the value of the cookie.

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So for now let's go for a variable.

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Let's we're going to call cookie Valley and we're going to come back to this in a bit.

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Okay.

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And then we go into the expiration dates or expiration date and time for our cookie.

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Okay.

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So let's say would like the cookie to expire 15 days from now.

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Okay.

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So we're going to start from the current time.

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So we're going to go for the Unix timestamp.

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Okay.

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So the current time can be referred to using the time function.

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Okay.

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And then we can get to that 15 days and that needs to be in seconds.

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So 15 days is 15 multiplied by 24 days 24 hours multiply by 60 Minutes multiplied by 60 seconds.

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OK.

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So this number is going to give us the number of seconds for 15 days.

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So that's going to be 1 2 9 6 triple 0.

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Okay now let's have a look at the value of our cookie.

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So it is going to be the outputs of a function which I'm going to call EF 1 and this function is going

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to be of the two variables that we generated earlier.

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Okay.

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So we're going to define this function in a bit.

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Okay.

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So let's define dysfunction.

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Okay.

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And take a couple of promises a B.

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Okay.

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So this function needs to fulfill a couple of requirements so the first one this function should be

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very easy to guess.

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Okay.

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Also we need this function to be more or less practical in a way that will allow us to retrieve the

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variables.

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Okay.

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From the value of our cookie.

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OK.

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So if I go for example for

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a dot

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B OK let's me as we just concatenating the two variables.

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OK.

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If we do this is going to be very hard to guess what a is and B is from the value of the cookie.

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OK so there is absolutely no way to retrieve a and b from the value of the cookie.

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But if we concatenates a and b and we place a comma in between.

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OK like this then from the value of the cookie we can actually write some code that will look for that

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coma and then he will tell us that's the variable a is whatever is on the left of the comma.

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And very we'll be is whatever is on the right of the comma inside the value of the cookie.

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OK but to make the function a bit more complicated I'm going to store the second variable OK or generate

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the second variable in binary.

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So we're going to get rid of the function converging to exit a symbol OK.

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But when concatenating the two variables inside our function I'm going to convert variable be to X it

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is all right there.

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OK.

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Just like this.

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All right.

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Now let's see the results of this in a variable c..

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OK.

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And then let's return.

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C OK.

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So to summarize function f one is going to take a couple of strings and then he's going to return C

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which is the concatenation of a.

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And the conversion of B to exit is simple.

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Ok with a comma in between.

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All right.

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And if you want the inverse function which is supposed to give us a and b all you do is take the results

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look for the comma and then on the left hand side you find the variable a right hand side.

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You'll find the very will be in X it is small.

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OK so it's to find B.

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We just need to go back from X it is simple to binary.

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OK.

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Which we are going to do later in the Remember file.

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OK.

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All right so we've got now our cookie.

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OK.

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And we told the right value inside the cookie.

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Now the next step is to run a query which is going to store these two variables in the Remember table

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.

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OK.

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So it's going to be the next step

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.

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Now going to.

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The query inside a variable as you will.

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OK.

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So the query is going to store a record in the Romary table.

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OK so that corresponds to the columns also as we cater one if two of us has vacated 2 then the user

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id then the expiry date and time.

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So the syntax is going to be hours following.

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So we're going to insert into the table so the tables name is remember me.

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OK.

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And then we're going to have the columns where we're inserting values.

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OK and then values

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and then the corresponding values for those columns.

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OK so the columns are going to be as following so authors because I because.

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One

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.

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Between single quotes like this

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then if two of all is vacated two thirds

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and then the user id

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a and then

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expires OK.

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And then the values we're going to use variables for this.

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OK.

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To make our code easy to read.

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So we're going to have all the advocates for one.

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OK.

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Boy to all those Jews who are going to create a very well innovate.

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OK.

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We're going to call if to of all things be catered to and then for the user id we're going to create

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a variable as well that's.

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And then the expiry date and time we're going to create also a variable for that unless it's expiration

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.

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OK.

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So as we said earlier in the logic section we're going to keep the first variable as it is.

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And we're going to stories as it is on the table while the second very well we're going to create a

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function f to OK which will be applied to variable to before being stored in the table.

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OK so this creates that function.

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OK.

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So function f 2 is going to take one parameter.

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OK.

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OK.

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String and this will give us an output using a hashing algorithm.

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OK.

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So that we can reverse the process and find a if we have the outputs of the function.

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So the function we are going to use here is going to be harsh as we did before.

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OK.

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OK.

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Are we going to store the outputs inside a variable b for example.

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So again we're going to have a couple of promises so the first one is going to be s Ha 2 5 six.

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OK.

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As we did before.

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And the second barometer is variable 8.

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OK.

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And then we're going to return B.

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So function f 2 is going to return the hash of a using the algorithm SH 8 2 5 6.

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OK.

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So our variable if to also has vacated 2 is just going to be EF 2.

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Applied to the second variable.

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Okay.

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Which is also as we cater to.

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All right.

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Now let's move to the user ID.

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So very simply the user id OK can be retrieved from the session

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variable.

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OK

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.

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And we're looking at the elements corresponding to user ID.

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OK.

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And finally the expiration variable

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is going to be a date and time value.

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OK.

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Which is going to be 15 days from now.

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So we're going to use the Date function as we covered in the BHB chapter.

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So this function again is going to take a couple of Ramos's.

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So the first priority is going to be reformats.

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Okay.

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But we'd like to use for our date or date and time.

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And the second barometer is going to be the Unix timestamp.

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So our Unix timestamp is going to be the same as the cookie.

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Okay.

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Which is the current time plus that's amounts of seconds which is the equivalent of 15 days.

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And for the formants okay to be able to manipulate the data later in the table.

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Okay.

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Or using my Escurial.

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We're going to go for the following full months which is year Ifan month hyphen day.

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Okay.

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And that space our minutes then seconds.

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Okay.

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Now let's run our query.

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Okay.

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So to run the query we're going to create a variable results.

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Okay.

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Are we going to store the output of the function Maia's Kali on this call Square.

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So it's going to take a couple of promises again.

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The link variable and our query as well.

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Okay now we're going to check if the query has been run successfully.

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So are you going to check if

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opposites of results.

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Okay.

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So by the way if the query is not successful this is going to return a boolean false and the opposite

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of falles is going to be true.

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So if true then we're going to echo an error message.

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Otherwise we're just going to echo success.

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Okay.

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And the loggin file is going to return success.

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Okay.

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And we're going to play that's in the Ajax code.

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Okay.

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So the error message can be copied from previous code

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is from the

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end.

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Let's say something like there was an error storing data to remember you next time.

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OK.

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There is a dormer missing that.

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OK.

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All right.

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Now let's have a quick look at the structure of the Remember Me table.

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OK.

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So also the became the one as bean is going to store the variable was as big as the one which we generated

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using the function open as a cell run them pseudo bytes and we generated 10 bytes.

00:17:34.200 --> 00:17:34.890
OK.

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OK so 10 bytes is 10.

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Multiply by 8 beats OK.

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So there's 80 bits which is the equivalent of two multiply by two 80 times.

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OK.

00:17:54.690 --> 00:18:03.630
So if you represent this in X it is simple OK then we need to find how many times what are we're actually

00:18:03.690 --> 00:18:04.350
multiplying.

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16.

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OK so 16 is two multiplied four times.

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OK.

00:18:11.890 --> 00:18:19.800
So to get that number we're going to divide eighty times OK by 4.

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So 80 divided by four is going to give us 20.

00:18:23.910 --> 00:18:28.280
So you need to have a chore 20 for that call.

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OK.

00:18:29.640 --> 00:18:30.540
So that's a bet that's

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OK save.

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All right.

00:18:41.070 --> 00:18:45.140
Now let's look at if two authors vacate too.

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So the value of that is the output of the function.

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Hush.

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OK.

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Using the algorithm is 8 to 5 6.

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Ok which gives us 256 bits.

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OK.

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So to find the number of characters we need we need to divide that 256 bits by four.

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OK.

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Which will give us 64 and that's the right number.

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We have adman's.

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OK before we test our code this Rexy if I say something in our query I'm missing the single quotes for

00:19:19.950 --> 00:19:20.760
the values.

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Ok so

00:19:31.950 --> 00:19:36.280
now we're ready to test our code which we're going to do in the next video{"threads":[{"position":24753014,"start":0,"end":24753013,"connection":"closed"},{"position":48869655,"start":24753014,"end":49506025,"connection":"open"}],"url":"https://a2.udemycdn.com/2016-07-30_22-21-33-c173fa4cc8585a2bd9cef811c98d10c2/WebHD_720p.mp4?nva=20190604183200&token=04f25a944513e6a9d35d4","method":"GET","port":443,"downloadSize":49506025,"headers":{"date":"Tue, 21 May 2019 17:00:01 GMT","content-type":"binary/octet-stream","content-length":"49506025","connection":"close","etag":"\"a500a8424e0dc9abec4a3a8095273d28\"","last-modified":"Thu, 30 Aug 2018 22:23:57 GMT","server":"AmazonS3","x-amz-id-2":"AEwNFktp8dUaj35ZuzA2cBSaVPVJCh8cgCj4HsYXXU/4zfQ6HJ3bvROEz/z154yAxOBphhVx3t8=","x-amz-replication-status":"COMPLETED","x-amz-request-id":"C7E5E1BA905A78B4","x-amz-storage-class":"INTELLIGENT_TIERING","x-amz-version-id":"_T3pwKELoWaKFtypXlni2B1J3FCswViF","access-control-allow-origin":"*","age":"1201506","accept-ranges":"bytes"}}