WEBVTT 00:00.050 --> 00:03.080 This is step number eight of the final project. 00:03.110 --> 00:10.610 What we're going to do now is to so when we receive here a notification that someone is ringing the 00:10.610 --> 00:11.000 bell. 00:11.040 --> 00:15.680 We're going to handle the open command so we can open the door. 00:15.680 --> 00:22.340 So we're going to open the door for 10s and then close it and come back to the initial state where the 00:22.340 --> 00:25.460 user can ask another request. 00:25.490 --> 00:30.410 Okay, so the first thing we need to do is to initialize the telegram updater. 00:30.410 --> 00:36.380 So that's what I'm going to do now and I'm going to create a new file here for the step number eight. 00:37.470 --> 00:40.440 Let's copy this inside the step number eight. 00:40.680 --> 00:43.650 Let's close and let's save as. 00:44.870 --> 00:45.650 Intercom. 00:47.090 --> 00:47.660 Step. 00:49.050 --> 00:49.560 Eight. 00:50.950 --> 00:55.870 All right, Now let's start with the initialization of the updater. 00:56.170 --> 01:00.790 So from telegram dot XT import. 01:01.990 --> 01:04.390 Of data and also comment. 01:04.960 --> 01:11.740 And we are going to initialize the data here when we initialize the telegram bot. 01:11.740 --> 01:16.840 So we have bot here, I'm going to do a data is equal to a data. 01:18.500 --> 01:22.530 Token is equal to telegram token. 01:22.550 --> 01:27.620 So the same token and then let's create a dispatcher for our commands. 01:28.010 --> 01:31.190 Dispatcher is equal to a data dot. 01:31.520 --> 01:32.600 Dispatcher. 01:33.230 --> 01:37.070 Then we are going to add handlers for the dispatcher. 01:37.070 --> 01:44.720 So let's put to do add handlers that I'm just going to do after the initialization. 01:44.720 --> 01:49.160 And then we need to do updater dot start polling. 01:49.160 --> 01:55.490 So we need to start getting the updates from the Telegram chat and where we are going to do that. 01:55.490 --> 01:57.410 Well, not just right now. 01:57.410 --> 02:01.820 We are going to do that after the Time.sleep So here we do. 02:03.260 --> 02:10.330 Um, actually, after we reset the input buffer, a data dot starts falling. 02:11.510 --> 02:11.780 Okay. 02:11.780 --> 02:14.030 Why do we do that after the time slip? 02:14.060 --> 02:14.930 Because. 02:14.930 --> 02:19.940 Well, we keep this time actually for the communication to be correctly initialized. 02:19.940 --> 02:25.310 So if you start polling before the communication is correctly initialized and in some of the callbacks, 02:25.310 --> 02:29.540 we're going to send some messages to the Arduino. 02:29.570 --> 02:32.480 Well, you may have some problems at this time. 02:32.480 --> 02:38.450 So we wait after the three seconds to start getting the telegram comments in our code. 02:38.570 --> 02:41.600 And if I do start polling, also need to do stop. 02:42.290 --> 02:44.610 So I'm going to do here print. 02:44.630 --> 02:45.920 So we already have the structure. 02:45.950 --> 02:46.220 Okay. 02:46.220 --> 02:47.420 Nothing more to do. 02:47.510 --> 02:51.950 The while loop with the try except so print. 02:53.290 --> 02:57.190 Stopping telegram a. 02:59.020 --> 03:06.550 Wait a few seconds and let's do a data dot stop. 03:07.450 --> 03:13.480 And then when we have end of program, we know everything is correctly finished. 03:13.600 --> 03:18.190 Okay, now let's add handlers. 03:18.370 --> 03:21.310 And so to add handlers, we will need some callbacks. 03:21.320 --> 03:26.470 I'm just going to create the callbacks on top of the telegram initialization here. 03:26.500 --> 03:32.260 Let's put telegram callbacks here and def. 03:32.260 --> 03:44.710 Let's create first a start handler with update context and let's say that we want to just greet the 03:44.710 --> 03:47.710 user that uses the Start command. 03:47.830 --> 03:56.270 So what we can do is to to send a is equal to, let's say, welcome 03:58.490 --> 04:01.430 plus and how to get the user first name. 04:01.430 --> 04:03.310 Well, that's something I'm going to show you here. 04:03.320 --> 04:12.860 You can do update for example, update dot effective user dot first name. 04:13.520 --> 04:18.320 Let's add an exclamation mark because we are very happy to send this message. 04:18.680 --> 04:20.240 And let's do context. 04:20.960 --> 04:32.990 Dot, dot, dot, send message with chat ID is equal to let's directly reply to update dot effective 04:33.890 --> 04:35.000 chatted. 04:35.000 --> 04:40.670 So as you can see we can get many information in a callback from the user, the chat, the message, 04:40.670 --> 04:46.640 everything and text is equal to string to send. 04:47.180 --> 04:48.050 All right. 04:48.140 --> 04:55.040 And let's add an open door handler, which is going to be more interesting here. 04:55.370 --> 04:58.220 Date context. 04:58.490 --> 05:02.330 Let's put pass for now and we're going to implement that. 05:02.330 --> 05:04.670 But first I'm going to add the handlers here. 05:04.790 --> 05:21.320 So Dispatcher Dot add handler, command handler with start keyword and start handler function and Dispatcher 05:21.470 --> 05:29.060 Dot add handler Command handler with open keyword. 05:29.930 --> 05:30.320 Okay. 05:30.320 --> 05:31.850 If you remember here. 05:31.850 --> 05:38.240 So in the protocol we have defined, we want to send open and we also here send a message to ask to 05:38.240 --> 05:39.590 send open or deny. 05:39.920 --> 05:46.220 So let's use open and this is going to be open door. 05:46.400 --> 05:55.840 Handler Okay, Let's actually start this just to check that the operator is working. 05:55.840 --> 05:57.480 So waiting for three seconds. 05:57.490 --> 05:58.120 Okay? 05:58.120 --> 05:59.650 And let's go to Telegram. 06:00.340 --> 06:02.590 Let's write start. 06:04.250 --> 06:05.120 And you can see. 06:05.150 --> 06:06.410 Welcome, Édouard. 06:06.560 --> 06:07.700 Well, that's me. 06:08.530 --> 06:11.140 And let's kill that Ctrl C. 06:11.410 --> 06:12.040 You can see. 06:12.070 --> 06:13.240 Wait a few seconds. 06:14.970 --> 06:17.160 And then we should have. 06:18.580 --> 06:19.510 End of program. 06:19.550 --> 06:19.780 Okay. 06:19.780 --> 06:21.220 So just be patient here. 06:21.460 --> 06:27.070 And you can see with the three dashes here, it's very easy to see the end of the logs. 06:28.570 --> 06:31.510 Okay, now let's write our open door handler. 06:31.630 --> 06:33.650 So what do we want to do here? 06:33.670 --> 06:35.380 First we want to. 06:35.410 --> 06:37.510 So now we know that we need to open the door. 06:37.510 --> 06:41.200 So we're going to send the command to the Arduino to open the door. 06:41.200 --> 06:48.280 So with the servo motor to print the text that the door is opened to play a sound with the buzzer and 06:48.280 --> 06:50.740 to change the Led to green. 06:50.770 --> 06:53.620 Okay, so for actions we need to send to the Arduino. 06:54.070 --> 06:59.740 We are also going to send the confirmation to Telegram so we can know in the chat that the door has 06:59.740 --> 07:03.760 been opened and then we will wait for 10s. 07:03.880 --> 07:07.610 And after 10s have passed, we are going to close the door. 07:07.630 --> 07:09.850 So let's start. 07:09.880 --> 07:19.190 I'm going to put print opening the door so we know in the log that this is happening and then we do 07:19.220 --> 07:19.850 send. 07:19.880 --> 07:31.660 So let's write the command to the Arduino, send to Arduino open door and then another send to Arduino. 07:31.670 --> 07:34.370 So let's write actually four of them. 07:35.870 --> 07:37.450 So we want to open the door. 07:37.460 --> 07:45.530 We also want to print text and to say that the door is opened. 07:46.700 --> 07:48.410 So that the user can go. 07:48.680 --> 07:51.380 We also want to play. 07:53.600 --> 07:55.580 Let's use 300 heads. 07:55.620 --> 08:00.020 Okay, So the higher the heads, basically, the higher the tone. 08:00.020 --> 08:06.430 And well, usually when you have a higher tone, a higher frequency, this is more welcoming. 08:06.440 --> 08:06.700 Okay? 08:06.710 --> 08:09.070 When you have a sound for a door. 08:09.080 --> 08:12.260 So we're going to put 300 and play that for five. 08:12.770 --> 08:22.850 So let's not put a space here 500 milliseconds and then we can do set led right is going to be zero 08:22.850 --> 08:27.800 and then green, 255 and then blue 000. 08:28.280 --> 08:28.520 Okay. 08:28.520 --> 08:35.540 And with this, we open the door, but then we need a mechanism that is going to close the door after 08:35.540 --> 08:36.170 10s. 08:36.170 --> 08:36.470 All right. 08:36.470 --> 08:39.770 Because the door is not going to close by itself. 08:39.920 --> 08:41.360 And so we can do time. 08:41.360 --> 08:43.970 Dot sleep ten. 08:44.780 --> 08:44.920 Okay. 08:44.930 --> 08:46.100 Don't worry about this time. 08:46.100 --> 08:46.560 That sleep. 08:46.560 --> 08:51.720 I'm going to explain to you just in a bit why use this here and how it's not going to be a problem. 08:51.720 --> 09:04.200 And so after 10s we can do so print closing the door and we can send commands to the Arduino and we'll 09:04.200 --> 09:11.340 just actually, after we have sent command to the Arduino here, we can also do bot dot send message 09:12.450 --> 09:13.620 to the chat. 09:13.950 --> 09:21.900 So chat ID is equal to update dot effective chat.id because we are in a callback. 09:21.900 --> 09:29.700 We have the update with the chat id and text is equal to opening the door. 09:30.870 --> 09:36.450 So we also have a confirmation on the telegram that our command was successfully processed. 09:36.570 --> 09:37.110 Okay. 09:37.380 --> 09:40.260 So then we wait for 10s and we close the door. 09:40.260 --> 09:43.680 So to close the door we send to Arduino. 09:43.710 --> 09:46.920 We're going to send also four commands. 09:49.310 --> 09:49.700 Okay. 09:49.700 --> 09:50.930 So we're going to send. 09:51.810 --> 09:58.140 Close the door and then print text. 09:58.170 --> 09:59.910 Let's go back to normal. 10:00.120 --> 10:00.660 Push on. 10:00.660 --> 10:03.690 Button to call. 10:04.470 --> 10:06.690 We're going to play also. 10:06.720 --> 10:07.590 Buzzer okay. 10:07.590 --> 10:09.840 To inform that the door is actually closing. 10:09.990 --> 10:11.160 Let's say 200. 10:11.160 --> 10:19.320 So a lower pitch for also 500 milliseconds and then set back to blue. 10:19.530 --> 10:24.750 So 000000 255. 10:25.620 --> 10:25.800 Okay. 10:25.800 --> 10:29.490 So as you can see, if you want to send comments to the Arduino, well, now that's very easy. 10:29.490 --> 10:36.630 You just do send to Arduino with the correct command and parameters and everything is going to be taken 10:36.630 --> 10:39.660 care of because you have written the code before to do that. 10:40.260 --> 10:40.770 Okay. 10:40.770 --> 10:47.940 And now if you remember, we still have a flag that we have set here, open door request. 10:47.970 --> 10:58.140 So what we want to do is we want to say that at the end open door request is equal to false so we can 10:58.140 --> 10:59.130 send a request. 10:59.130 --> 11:04.200 And then when we open the door, so we send the message from Telegram to the Raspberry Pi. 11:04.230 --> 11:06.060 This is going to open the door. 11:06.180 --> 11:12.290 And then after 10s close the door and then the open door request is no false. 11:12.300 --> 11:16.680 So we can send another request with another photo to telegram. 11:17.280 --> 11:17.790 Okay. 11:17.790 --> 11:24.060 And well, if we want actually to use the open door request boolean, which is a global variable, we 11:24.060 --> 11:30.930 need to do global open door request here because we are inside a function. 11:30.930 --> 11:36.270 So if you are inside a function in Python and you want to access a global variable to modify it, you 11:36.270 --> 11:39.350 need to use global open door request inside the function. 11:39.360 --> 11:44.460 Otherwise, well, you're just going to create a new variable open door request which is not going to 11:44.460 --> 11:45.480 be the global one. 11:45.480 --> 11:50.730 And one additional thing I'm going to do if open door request 11:53.580 --> 11:55.560 and put that inside the if. 11:55.740 --> 11:57.180 Why is that? 11:57.210 --> 11:58.380 Because. 11:58.710 --> 12:00.440 Well, let's open the three one. 12:01.720 --> 12:02.470 A chat. 12:04.260 --> 12:11.790 Thing is that if you send slash open command, so now the code is not running, so that's not going 12:11.790 --> 12:12.350 to work. 12:12.360 --> 12:16.440 But anytime you send open, that's going to go inside the open door. 12:16.470 --> 12:17.490 Handler Right. 12:17.520 --> 12:20.760 Like anytime you send start, it's going to say welcome. 12:20.760 --> 12:23.220 So every time you send open, it's going to go here. 12:23.220 --> 12:26.100 And so if you send open, it's going to open the door. 12:26.100 --> 12:31.020 But what we want in this application is that you only open the door when you have a request. 12:31.020 --> 12:32.850 So we check that what we have a request. 12:32.850 --> 12:35.940 If we have a request, we open the door and then we close it. 12:35.940 --> 12:38.820 And then we put the open door request to false. 12:38.820 --> 12:43.680 So of course this kind of decision is depending on your real application. 12:43.680 --> 12:47.190 Maybe you want to open the door at any time and then that's fine. 12:47.190 --> 12:48.180 You just don't put that. 12:48.180 --> 12:52.590 If here, here, just put it because well, I've decided in the application to do that. 12:52.590 --> 12:54.870 But this will depend on what you want to really do. 12:54.900 --> 12:55.710 Of course. 12:55.710 --> 13:00.630 And one other thing I'm going to add here, because if you just run like this, you may have some weird 13:00.630 --> 13:06.490 behaviors, for example, that if you send a request and then from telegram, you press, you send multiple 13:06.490 --> 13:12.190 times open, well, what you will see is that this is first going to be executed and then it's going 13:12.190 --> 13:13.530 to be executed again. 13:13.540 --> 13:14.290 Why is that? 13:14.290 --> 13:14.680 Because. 13:14.680 --> 13:18.880 Well, how is the updater working basically with the dispatcher? 13:19.120 --> 13:27.070 When you receive a keyword, it's going to directly call the callback function in a different thread. 13:27.070 --> 13:27.250 Okay. 13:27.310 --> 13:31.600 So that's why, for example, the time sleep is not a problem for the main thread because that's going 13:31.600 --> 13:32.830 to be on a different thread. 13:32.830 --> 13:33.090 Okay. 13:33.100 --> 13:35.830 So now we are going to talk about Multithreading. 13:35.830 --> 13:40.630 It's a bit more complex, but I'm going to keep things simple here so you can follow. 13:40.840 --> 13:47.650 So you have the main thread here in the while loop, and when you receive a command in a different thread, 13:47.650 --> 13:49.180 you're going to execute the callback. 13:49.180 --> 13:55.690 But if you receive multiple comments, all the callbacks are going to be executed one by one in these 13:55.690 --> 13:56.290 different threads. 13:56.290 --> 14:03.010 So if you receive multiple open door handler comments, it's going to be executed once and then another 14:03.010 --> 14:04.030 time, another time. 14:04.030 --> 14:09.430 And because of the time sleep, then if you receive, for example, three comments, well it's going 14:09.430 --> 14:16.180 to first spend 10s in that and then 10s in the second one and 10s in the third one. 14:16.180 --> 14:23.170 So what we want to do basically is to say that instead of queuing the callbacks, we want to execute 14:23.170 --> 14:25.660 them all inside different threads. 14:25.660 --> 14:31.600 So every time you receive a new command, you, you execute it in yet another thread so you can run 14:31.600 --> 14:33.850 multiple callbacks at the same time. 14:33.850 --> 14:36.460 And to do this, this is actually very easy. 14:36.460 --> 14:40.690 So it's a bit complicated to explain, but it's very easy to implement. 14:40.720 --> 14:49.360 You put run async, so run asynchronously is equal to true in the command handler. 14:49.360 --> 14:51.970 So you had a third optional argument here. 14:52.210 --> 14:59.050 And now that we have this, we have yet another problem because so let's say now you request the opening 14:59.050 --> 15:03.310 of the door, you receive that on Telegram and you send open three times. 15:03.400 --> 15:07.570 So the three open door handler are going to be executed at the same time. 15:07.810 --> 15:11.320 And the open door request is going to be true for all of them. 15:11.320 --> 15:15.640 So from three different threads, we're going to send this and then send this. 15:15.640 --> 15:16.810 So we don't want this. 15:16.810 --> 15:22.690 And I'm going to add yet another flag here that I'm going to name, Let's name it. 15:22.720 --> 15:26.230 Handling door is equal to false. 15:26.230 --> 15:32.890 So whenever we handle the door, which means basically that we open the door, we close the door, we 15:32.890 --> 15:34.120 deny the access. 15:34.270 --> 15:39.880 Every time we handle the door, we're going to put this flag to true so that any other callback will 15:39.880 --> 15:42.280 not be able to handle the door at the same time. 15:42.280 --> 15:44.380 And so in our. 15:45.160 --> 15:52.840 Open door handler I'm going to do also global handling though, so I can access the global variable 15:52.840 --> 15:54.100 and modify it. 15:54.100 --> 15:58.600 And so I'm going to check before I open the door, I'm going to check that I have an open door request 15:58.600 --> 16:05.320 and that I don't have the handling door flag on. 16:05.320 --> 16:12.700 And then if I open the door, I'm going to set the handling door flag to true. 16:13.960 --> 16:18.310 And once I am done, I'm going to set it to false. 16:21.310 --> 16:29.140 Okay, So that is maybe not the ideal best 100% solution to Multithreading, but this is going to be 16:29.140 --> 16:33.400 fine for our application and I don't want to go too deep on Multithreading here. 16:33.400 --> 16:38.800 That's out of the scope of this course, but we still need to work a bit on that. 16:38.800 --> 16:40.870 So we have an application that works well. 16:40.870 --> 16:42.100 So what's going to happen here? 16:42.100 --> 16:48.350 Let's say you send three open comments from Telegram and you have the open door request on because you 16:48.350 --> 16:50.330 have previously pressed on the push button. 16:50.330 --> 16:55.010 So you're going to have three callbacks that are going to be called, let's say the first one is going 16:55.010 --> 16:59.450 to see that, yes, we have a request and we don't have the handling door flag. 16:59.570 --> 17:05.660 So it's going to enter here and put the flag to true directly and then it's going to do its thing and 17:05.660 --> 17:06.860 sleep for 10s. 17:06.860 --> 17:11.630 And then the second and the third callbacks are going to be called independently. 17:11.630 --> 17:16.610 But when they are going to arrive at that, if they're going to see that, yes, we have the open door 17:16.610 --> 17:19.100 request, but this flag is already true. 17:19.100 --> 17:22.070 So we can't enter the if and we're going to exit. 17:22.070 --> 17:27.740 And so you're going to only have one callback that is working at a time. 17:27.740 --> 17:35.750 And finally, the last thing I'm going to add in the main loop here, I'm also going to add and not 17:36.350 --> 17:38.210 handling door. 17:38.330 --> 17:44.270 So basically we want to take a photo and send it to Telegram when we have at least five second passed 17:44.270 --> 17:50.810 and when we don't have an open door request that is currently on and also when we are not handling the 17:50.810 --> 17:51.080 door. 17:51.320 --> 17:51.540 Okay. 17:51.560 --> 17:54.950 Because if we are handling the door well, the button should not work. 17:54.980 --> 17:59.840 The button should only work after the door is correctly handled. 18:00.080 --> 18:00.860 All right. 18:01.100 --> 18:02.870 So now we can test this code. 18:02.870 --> 18:08.690 If you had some trouble about the Multithreading explanation, well, that's not a problem because this 18:08.690 --> 18:13.880 is something we haven't talked about in this course that's a bit outside of the scope and you can come 18:13.880 --> 18:17.300 back to it later and continue to make progress on the project. 18:17.300 --> 18:22.970 Basically, you could do without the Multithreading, but here this is just so we can improve the code 18:23.000 --> 18:24.800 to make it more robust. 18:24.800 --> 18:27.440 And now I'm going to run that code. 18:31.000 --> 18:31.330 Okay. 18:31.330 --> 18:33.070 We have the starting here. 18:33.430 --> 18:35.050 Waiting for three seconds. 18:35.050 --> 18:36.940 Main loop is starting. 18:37.300 --> 18:38.860 I open the telegram app. 18:38.860 --> 18:40.840 I'm going to press on the push button. 18:40.960 --> 18:41.650 You can see. 18:41.680 --> 18:43.420 Please wait for a few seconds. 18:44.170 --> 18:46.270 Someone is ringing the bell. 18:46.300 --> 18:48.730 He and well, let's say we want to open. 18:48.730 --> 18:51.820 So I'm going to send open or just click on open here. 18:52.570 --> 18:53.230 Okay. 18:53.230 --> 18:54.220 It's working. 18:54.250 --> 18:56.730 Door is opened, green led. 18:57.670 --> 18:58.720 The door is opened. 18:58.720 --> 19:00.130 Let's wait 10s. 19:01.590 --> 19:03.210 And we should have. 19:03.930 --> 19:04.700 Okay. 19:04.710 --> 19:05.400 Push on. 19:05.400 --> 19:06.270 Button to call. 19:06.870 --> 19:09.810 Blue led and the door is closed. 19:09.960 --> 19:16.590 And with the few additions we did here on the code, you can also try to send multiple open command 19:16.590 --> 19:19.430 here and you're going to see that they are not going to work. 19:19.440 --> 19:26.010 And also, if I send open now, well, the callback is still working, but we can't open the door because 19:26.010 --> 19:27.720 we don't have a request. 19:27.930 --> 19:28.440 All right. 19:28.440 --> 19:30.810 And that's the end of the step number eight. 19:30.810 --> 19:33.270 We're almost done with the final project.