WEBVTT 00:05.140 --> 00:06.740 Hi everyone welcome back. 00:06.910 --> 00:12.850 So in this video we're going to be starting a new API which is basically we're going to call a bank 00:13.090 --> 00:13.650 a B. 00:13.690 --> 00:14.220 OK. 00:14.320 --> 00:20.920 Now we're going to be thinking about developing how we can develop a bank of very very basic bank account 00:21.310 --> 00:27.250 that supports severals features so you could open an account with the bank price of different accounts 00:27.550 --> 00:32.770 and then you can add some money into the bank account and then you can transfer some money from one 00:32.900 --> 00:33.900 hand to the other. 00:33.940 --> 00:34.880 OK. 00:35.020 --> 00:37.790 You can also there's a there's the bank here right. 00:37.830 --> 00:38.970 This is the bank. 00:39.100 --> 00:44.590 And then you can take a loan from the banks you can take one long year from from the bank and then it 00:44.620 --> 00:48.220 adds to your debt and then it Asadi. 00:48.360 --> 00:50.690 So you have more debt but you have more cash. 00:50.800 --> 00:53.930 So it increases your cash and increases your debt. 00:54.300 --> 00:54.790 OK. 00:54.850 --> 00:59.950 So you have all these transactions that we want to ensure that the transactions between the accounts 01:00.280 --> 01:02.860 are correct and there is no problem. 01:02.860 --> 01:07.040 So if you're taking money from one account you're adding it to the other again. 01:07.090 --> 01:07.820 OK. 01:07.840 --> 01:14.190 And the bank account also of course has its own bank account like like cash and so on. 01:14.230 --> 01:14.980 OK. 01:15.280 --> 01:22.900 So in this in this tutorial a set of videos actually we're going to be developing a restful API to support 01:22.900 --> 01:23.910 a couple of features. 01:23.920 --> 01:25.650 OK so let's do this. 01:25.660 --> 01:29.740 We're going to support a couple just the first one is going to be the register. 01:29.780 --> 01:30.330 OK. 01:30.340 --> 01:36.010 So we want the user to be able to register into your API results so the ad. 01:36.170 --> 01:37.690 OK so bad. 01:37.930 --> 01:47.230 Basically allows you to add the money to your bank account so you can for example pay as paying someone 01:47.230 --> 01:52.420 cash and then in the bank you can pay them cash give them cash in real life. 01:52.630 --> 01:55.050 And then they can add some money to your bank account. 01:55.060 --> 01:59.360 So that is like inserting money or or. 01:59.510 --> 02:01.800 No the opposite of withdrawing money. 02:01.810 --> 02:02.600 OK. 02:02.970 --> 02:08.180 And you can also transfer OK so you can transfer from one account to the other. 02:08.240 --> 02:14.250 So let's say you have $100 you can transfer it into your friend's account or pay. 02:14.560 --> 02:18.120 The other thing you were also do is to check balance. 02:18.130 --> 02:24.370 OK so we want the ability for a user to be able to check his balance and make sure that his balances 02:24.880 --> 02:31.260 like how he left it or if you just got his paycheck then it's it's increased in the right way. 02:31.270 --> 02:32.040 OK. 02:32.350 --> 02:35.950 There's also going to be implementing take a loan. 02:36.340 --> 02:39.870 And we're going to be implementing pay loan. 02:39.940 --> 02:40.490 OK. 02:40.660 --> 02:47.810 So loan is let's say you don't have enough money so I say you want to buy a car and it costs $5000 but 02:47.830 --> 02:49.640 you only have $4000. 02:49.720 --> 02:52.890 So you take a loan from the bank for $1000. 02:52.900 --> 02:58.340 You pay for the car and then you have a debt of $1000 a day. 02:58.960 --> 03:05.240 Now once you have extra money in your account let's say you just got your paycheck for another $5000. 03:05.410 --> 03:12.490 So now you can repay the bank account using your cash right so you can pay $1000 for your account and 03:12.490 --> 03:16.650 give it to the bank right away so you can pay the loan that you took previous. 03:17.020 --> 03:17.520 All right. 03:17.560 --> 03:23.620 So these are the six features that we'll be implementing and also these are the six resources so if 03:23.620 --> 03:26.090 I may add resources here. 03:26.260 --> 03:28.470 OK so these are the resources. 03:28.480 --> 03:32.390 Now let's talk about the your L and the or else should be straightforward. 03:32.410 --> 03:32.890 OK. 03:33.010 --> 03:39.700 So a registry is always going to be asked to cash register right as usual and is going to be add slash 03:39.730 --> 03:49.140 and transfer is going to be at last transfer and a check balance is going to me and slash balance making 03:50.290 --> 03:58.680 take loans going to be slashed a loan and payday loans are going to be slash pay loan. 03:58.680 --> 03:59.460 All right. 03:59.710 --> 03:59.930 OK. 03:59.930 --> 04:00.540 So let's take. 04:00.580 --> 04:03.120 Talk about the parameters of the work are out. 04:03.130 --> 04:07.630 Do we need for each of these resources for registration. 04:07.630 --> 04:14.950 Well as usual we want the username and the password OK for ADD. 04:15.080 --> 04:18.330 Well we need the username. 04:18.440 --> 04:18.920 OK. 04:18.950 --> 04:24.520 So user name password and the amount to add to the user. 04:24.530 --> 04:24.850 Right. 04:24.850 --> 04:29.390 So let's say I win at 200 dollars into this account to this past. 04:29.450 --> 04:30.460 OK. 04:31.010 --> 04:33.560 And then the third thing is transfer. 04:33.560 --> 04:40.770 So first of all I need my username to also authorize the transfers so I need my username and password 04:41.960 --> 04:48.010 and then I also use the username of the person I'm sending money to someone to call that to. 04:48.050 --> 04:53.950 OK so the person you do is an account or username. 04:54.230 --> 05:00.620 So I also need to and I also need the amount I need to know how many how much or how much money I'm 05:00.620 --> 05:02.980 transferring to that person to do. 05:03.350 --> 05:04.150 OK. 05:04.430 --> 05:11.900 So let's let's me and we draw a line here to make sure that we're dividing them equally and none of 05:11.900 --> 05:14.320 them seem on the other ones. 05:14.450 --> 05:15.210 OK. 05:15.590 --> 05:17.050 OK so what about balance. 05:17.060 --> 05:25.390 Well I need the username and the password right because I don't want anybody else to know my my my balance 05:25.610 --> 05:30.830 except it means I need to verify that this is indeed me who is checking my balance. 05:30.850 --> 05:31.680 OK. 05:32.320 --> 05:34.190 OK what about cloned. 05:34.240 --> 05:39.700 Well I need the user name and username password and the amount. 05:39.700 --> 05:42.100 How much do you want to take in loans. 05:42.100 --> 05:47.430 Right now you are getting $100 $200 loan and therefore the payday loan. 05:47.430 --> 05:54.790 I also need my username and password so I need to authorize some payment right so I can't let just anyone 05:54.840 --> 05:58.060 to do my name and right now would be ridiculous. 05:58.060 --> 05:59.330 So our author. 05:59.350 --> 06:03.910 So I need to give my username and password to authorize someone to to pay it. 06:03.960 --> 06:05.610 Then I also need to say amounts. 06:05.620 --> 06:07.510 So how much do I want to repay. 06:07.540 --> 06:15.590 So let's say I have debt to the bank if for example $1000 that maybe I only want to pay 500 of it. 06:15.640 --> 06:18.350 So I only have 500 a net gain. 06:18.580 --> 06:22.750 So how much do you want to send or how much do you want to pay your debt. 06:22.780 --> 06:23.350 OK. 06:23.530 --> 06:27.280 So these are the parameters now for the method. 06:27.580 --> 06:32.440 Well as you might have guessed all of them were sending some information to a server very we're not 06:32.440 --> 06:35.580 just getting resources we're posting something. 06:35.670 --> 06:45.730 So as the name might suggest Well we have post post post post so all of them are post. 06:45.760 --> 06:46.330 OK. 06:46.420 --> 06:50.770 So all of them is the message the method the method is post. 06:50.790 --> 06:51.450 OK. 06:51.810 --> 06:52.090 OK. 06:52.130 --> 06:55.750 So what about the state this goes OK so status goes. 06:55.870 --> 06:57.160 Let's talk about that. 06:57.400 --> 07:01.040 Well there's a few of them which are actually universal. 07:01.060 --> 07:05.340 OK so some status goes are going to be used in all of them. 07:05.350 --> 07:05.870 OK. 07:06.040 --> 07:08.210 So there's of course 200. 07:08.560 --> 07:09.180 OK. 07:09.310 --> 07:11.930 So 200 can be used in all of them right. 07:11.980 --> 07:16.290 Because that means everything went according to plan and there is no problems. 07:16.300 --> 07:17.260 OK. 07:17.920 --> 07:18.250 OK. 07:18.250 --> 07:19.640 What about some errors. 07:19.660 --> 07:21.310 Let's discuss some errors. 07:21.310 --> 07:23.970 So one of the errors is invalid user right. 07:23.980 --> 07:29.860 So for registration or any any of them the user might have given us. 07:29.860 --> 07:35.710 And if you look here you always give username password username password username password use any password 07:35.710 --> 07:37.800 username password and username password. 07:37.810 --> 07:38.410 OK. 07:38.770 --> 07:46.060 So one of the areas that might be in all of them is three Oelwein which means invalid username or three 07:46.060 --> 07:49.960 or two which means invalid password matching the user name. 07:49.990 --> 07:50.500 OK. 07:50.680 --> 07:55.390 So any of these might have two hundred three or one or zero. 07:55.420 --> 07:57.950 These are the universal status codes right. 07:57.970 --> 08:02.620 These are shared between all and all of them are guaranteed to kick. 08:02.620 --> 08:08.390 Can we turn one of these data goes right because any of them might have an invalid username three or 08:08.410 --> 08:13.560 once you do an invalid user name or an invalid password right. 08:13.690 --> 08:18.980 Or they might have just succeeded and you got to 200 basis so far so good. 08:19.270 --> 08:21.710 Now let's talk about three or three. 08:21.730 --> 08:22.890 Not enough money. 08:22.900 --> 08:23.410 OK. 08:23.500 --> 08:29.670 So I'm going to say this serial threes or maybe I'll read here so your theory is not enough money again 08:29.680 --> 08:31.690 so I'll do an x on the dollar sign. 08:31.690 --> 08:32.980 So not enough money. 08:33.190 --> 08:36.750 So which ones happens when you want it. 08:36.760 --> 08:39.250 Well when does this happen. 08:39.250 --> 08:44.770 Well when you want to pay someone or transfer someone some money but you don't have enough money. 08:44.800 --> 08:45.640 OK. 08:45.940 --> 08:48.090 OK so when does this happen. 08:48.130 --> 08:52.270 Well when you're transferring money so this can happen right Years 3 0 3. 08:52.270 --> 08:55.820 You don't have enough money so you can transfer it to someone. 08:55.830 --> 09:01.310 Right if you would try to transfer $200 and you only have $100 then you can do that right. 09:01.420 --> 09:03.080 Unless you take a loan. 09:03.550 --> 09:08.450 Another thing is if you try to pay for the low if you try to pay for a loan. 09:08.710 --> 09:15.940 So for example you have a low enough $1000 and you try to pay $500 but you don't have $500 and that 09:15.940 --> 09:17.630 should set off a 303. 09:17.650 --> 09:17.890 Right. 09:17.890 --> 09:19.380 Not enough money. 09:19.910 --> 09:20.810 All right. 09:20.980 --> 09:23.420 OK so we've talked about three or three. 09:23.420 --> 09:25.390 Now what about 3 0 4. 09:25.600 --> 09:27.320 Well what when does this happen. 09:27.370 --> 09:34.570 Well if someone Shiki tries to game the system by putting some amount of money which is less than or 09:34.570 --> 09:37.050 equal to zero or less than zero. 09:37.060 --> 09:37.860 OK. 09:38.170 --> 09:46.480 When that happens well what would happen if I say that I want to pay someone negative $5 then that means 09:46.540 --> 09:50.210 I'm adding into my account $5 right. 09:50.500 --> 09:53.800 So someone was either actually banks which how this bug me. 09:53.810 --> 09:59.620 You'd be surprised that people would put negative amounts and then this bank would wouldn't accept their 09:59.620 --> 10:00.610 operation. 10:00.610 --> 10:05.410 So if I for example I say I'm am so sorry for the US. 10:05.530 --> 10:06.720 There's not enough space here. 10:06.730 --> 10:14.080 But if I'm paid and then I'm transferring money to B and I say I want to transfer it to to be negative 10:14.080 --> 10:15.220 five dollars. 10:15.400 --> 10:22.480 Then what happens is the system ends up transferring five dollars from his account into his account 10:23.150 --> 10:24.510 that's crazy right. 10:24.640 --> 10:27.800 So we don't want our system to be that dumb. 10:27.820 --> 10:28.310 Right. 10:28.360 --> 10:34.330 So any of them which has an amount I'm going to add an additional airs three or four years which happens 10:34.330 --> 10:36.430 when the money is less than or equal to zero. 10:36.430 --> 10:40.420 So here for example is three or four years three or four. 10:40.420 --> 10:41.810 So amount is here. 10:41.950 --> 10:47.970 Here's also a mountaineer's amounts of three or four and three or four. 10:48.280 --> 10:49.250 OK. 10:49.660 --> 10:52.950 So these are all the years that we might have. 10:52.990 --> 10:57.260 So we might add some while we're coding the the application. 10:57.270 --> 11:03.910 But for now these are all the errors and the right protocol diagram that we're on hydro and we're going 11:03.910 --> 11:09.040 to stop here and in the next video we're going to start building this API according to this team over 11:09.040 --> 11:10.270 here. 11:10.270 --> 11:14.680 All right then so I'll post a video here and I'll see you in the next video. 11:14.680 --> 11:16.810 So until the next video happy any.