WEBVTT 00:00.200 --> 00:04.560 The goal is to take our password manager to the next level. 00:05.000 --> 00:09.160 And in order to do that, we need to add a search functionality. 00:09.200 --> 00:13.000 It's not good enough just to look through the data file anymore. 00:13.400 --> 00:19.600 What we want to be able to do is to type a website into the website entry, and then hit search, and 00:19.600 --> 00:25.400 we get a pop up showing us our email and the password that was saved for that website. 00:25.760 --> 00:27.120 So this is the goal. 00:27.960 --> 00:35.880 But where we're currently at is we have a text file which contains the name of the website, the email 00:35.880 --> 00:37.000 and the password. 00:37.200 --> 00:42.920 This is very difficult to search and this is a really terrible format to work with. 00:43.320 --> 00:48.320 So we're going to be levelling up our data storage in our password manager. 00:48.320 --> 00:55.320 And we're going to switch from saving data straight to a text file to a fancier data format, which 00:55.320 --> 00:56.800 is called JSON. 00:57.360 --> 00:57.720 Nope. 00:57.720 --> 01:01.560 This is not the latest, hottest DJ on the block. 01:01.560 --> 01:01.690 Lock. 01:01.890 --> 01:07.050 It's actually JSON, which stands for JavaScript Object Notation. 01:07.610 --> 01:14.410 This was something that was designed originally for JavaScript, but because it has such a simple structure 01:14.410 --> 01:19.650 and it's so easy to understand and work with that it's been adopted by many, many different fields, 01:19.650 --> 01:20.970 including Python. 01:21.410 --> 01:26.930 This is probably one of the most popular ways of transferring data, especially when you're transferring 01:26.930 --> 01:28.650 data across the internet. 01:29.010 --> 01:31.170 So this is what we're going to be learning about. 01:31.170 --> 01:36.730 And for those of you looking at this slide, you might have already realized that it's kind of similar 01:36.730 --> 01:39.730 to the dictionaries that we've been working with in Python. 01:39.770 --> 01:40.210 Right? 01:40.810 --> 01:49.250 A JSON is essentially composed of a bunch of nested lists and dictionaries, and it has that key value 01:49.250 --> 01:50.730 pair data structure. 01:51.090 --> 01:57.330 This is essentially what we're aiming for, so that we can store our data in this format. 01:57.330 --> 02:04.230 And we'll be able to easily load up this data and search through it for the particular website that 02:04.230 --> 02:05.910 we want the information for. 02:06.630 --> 02:14.350 To work with JSON data in Python, we can use the inbuilt JSON library, and we're going to use it to 02:14.390 --> 02:18.630 write, read and update data to a JSON file. 02:19.070 --> 02:22.150 To begin, I'm going to simplify our code a little bit. 02:22.150 --> 02:27.510 I'm going to get rid of this message box which asks the user okay or cancel. 02:27.710 --> 02:33.310 We're just going to assume that once they click add, then they're happy with the email and password. 02:33.950 --> 02:39.110 So now that we've cut down that little bit of code, it makes this a little bit easier to understand. 02:39.470 --> 02:45.030 All that we're doing here is we're checking to make sure that the length of the website entry and the 02:45.030 --> 02:48.390 length of the password entry is equal to zero. 02:48.830 --> 02:52.670 And you might still have the length checking for the email entry. 02:52.870 --> 03:00.150 But remember that at the end of previous lessons, we actually inserted a default value so we can actually 03:00.150 --> 03:02.710 skip that check as well if you wanted to. 03:03.910 --> 03:09.200 The reason why we want all code as simple as possible is so that when we're working with the JSON and 03:09.200 --> 03:14.320 we're learning about how to work with it, as long as everything else is simple, then we can focus 03:14.320 --> 03:16.080 on the new things that we're learning. 03:16.680 --> 03:24.080 In this case, instead of opening a data dot txt file, I'm going to change the data format to a dot 03:24.120 --> 03:32.720 JSON and instead of using the append mode, I'm going to use the write mode because I'm going to be 03:32.720 --> 03:35.920 writing to this data dot JSON file. 03:36.440 --> 03:40.880 Now, in order to write to a JSON file, we don't use this line of code. 03:41.280 --> 03:45.440 Instead we use a method called JSON dot dump. 03:46.360 --> 03:53.480 And that of course requires us to import the JSON module, which should be inbuilt to Python so you 03:53.480 --> 03:55.200 don't actually have to install it. 03:55.800 --> 04:01.600 Now, once we've imported our JSON module we can say JSON dot dump. 04:02.080 --> 04:04.800 And this takes a number of inputs. 04:04.800 --> 04:10.580 But the most important are the things that you want to dump and the file that you want to dump it to. 04:11.020 --> 04:14.700 The data that we want to put in here should go in as a dictionary. 04:15.180 --> 04:20.580 Essentially, what we want to create is a new dictionary, which I'll call new data. 04:20.900 --> 04:23.180 And it's going to be a nested dictionary. 04:23.540 --> 04:28.460 So the first level key is going to be the website, because this is what we're going to be searching 04:28.460 --> 04:29.580 through eventually. 04:29.980 --> 04:33.740 And the website is going to itself contain a dictionary. 04:34.340 --> 04:41.220 Now this dictionary contains two keys the email and also the password. 04:42.460 --> 04:45.540 The values for each of these are pretty self-explanatory. 04:45.540 --> 04:52.420 It's the email that we got from this line of code, and the password is the password that we got from 04:52.420 --> 04:53.540 this line of code. 04:55.700 --> 05:01.100 Now that we've created this new dictionary called New Data, well, that is what we're going to use 05:01.100 --> 05:03.700 to dump into our JSON file. 05:03.980 --> 05:06.580 Let's go ahead and dump our new data. 05:06.630 --> 05:08.190 So that's the first input. 05:08.630 --> 05:13.510 Now the next input is going to be the data file that we want to put it into. 05:13.830 --> 05:17.390 So that is going to be the file that we opened up inside this line. 05:18.110 --> 05:22.030 Let's provide our data file as the location to dump this data. 05:22.470 --> 05:31.670 And now if I go ahead and hit run and I create a new entry for my Amazon website password, generate 05:31.670 --> 05:33.510 the password, hit add. 05:34.510 --> 05:40.150 Then you can see that we've got our brand new data JSON file that's just been created. 05:40.590 --> 05:46.230 So just as a quick reminder, when you open a file in write mode, if that file doesn't exist, it will 05:46.270 --> 05:47.510 actually create it. 05:47.790 --> 05:50.670 So we've created this new file data dot JSON. 05:50.670 --> 05:54.990 And we've dumped the data that we entered into that file. 05:54.990 --> 05:59.750 So now if I open this up you can see we've got a JSON format in here. 05:59.910 --> 06:04.510 And we've got our Amazon website and all of its associated data. 06:05.510 --> 06:09.690 Notice how this data is not very easy to read for a human. 06:10.130 --> 06:14.450 So we can actually improve that by adding one other argument. 06:14.610 --> 06:16.530 And it's an argument called indent. 06:16.890 --> 06:23.770 This we can provide the number of spaces to indent all the JSON data so that it becomes much easier 06:23.770 --> 06:24.490 to read. 06:24.650 --> 06:27.450 So I'm going to go ahead and delete everything that's in here. 06:27.850 --> 06:30.290 And I'm going to run the code again. 06:31.130 --> 06:39.450 And this time once I save this data into my data dot JSON, you can see everything is all indented and 06:39.450 --> 06:41.930 it's much easier for the human to read. 06:43.010 --> 06:50.450 Now that we've seen how we can write data to a JSON file, the next step I want to show you is how you 06:50.450 --> 06:54.610 can load data from the JSON file, or how to read from it. 06:55.610 --> 07:00.570 To read JSON data, we use the JSON module and we call the load method. 07:01.010 --> 07:03.810 So I'm going to go ahead and comment out this line of code. 07:04.130 --> 07:11.460 And now that I've actually got some data in my JSON data file, I'm going to try and read from it. 07:11.500 --> 07:16.500 We call the JSON dot load method and we pass in the file path. 07:16.500 --> 07:18.380 Or you can see here the PHP. 07:18.900 --> 07:21.660 So that's the only required input. 07:22.020 --> 07:28.100 The file that we're going to pass in is our data file which we opened up over here. 07:28.620 --> 07:35.660 And what we're going to do is we're going to change this from write mode to read mode. 07:36.740 --> 07:42.020 Once we've loaded up the data we're going to save it inside a variable called data. 07:42.180 --> 07:43.860 And then I'm just going to print it out. 07:44.340 --> 07:50.180 So when I hit run right now and I simply add any sort of gobbledygook. 07:50.340 --> 07:55.260 But as long as I can hit the add button, it's going to trigger this part of the code. 07:55.660 --> 08:02.540 And now if we take a look inside our console, you can see that data is being printed down here, but 08:02.540 --> 08:06.180 without any of these indentations or any of the formatting. 08:06.460 --> 08:15.600 Instead, what that load method does is it essentially takes this JSON data and converts it into a Python 08:15.600 --> 08:16.480 dictionary. 08:17.040 --> 08:24.920 So this data, if we actually do a type check on it, you can see has a type of dictionary. 08:24.920 --> 08:27.760 This is just a normal Python dictionary. 08:28.400 --> 08:37.400 So essentially we can use Json.dumps and Json.load to serialize and deserialize from JSON data to Python 08:37.400 --> 08:38.240 dictionaries. 08:38.520 --> 08:41.800 And it allows us that free interchange of information. 08:42.440 --> 08:47.760 We change it into a JSON to store it, and then we take it out of storage and turn it into a Python 08:47.760 --> 08:50.640 dictionary to easily work with it in our code. 08:51.720 --> 08:57.960 Now that we've seen how to write, how to read, the last thing I want to show you is how to update 08:57.960 --> 08:58.600 data. 08:58.920 --> 09:05.360 Because if we have a new piece of data come in, we want to add to this JSON, but we don't want to 09:05.400 --> 09:06.440 overwrite it. 09:06.840 --> 09:10.080 But we also don't want to just append to the end of it. 09:10.080 --> 09:14.170 Because you can imagine if we had something that we just appended to the end. 09:14.410 --> 09:16.970 That's not a valid data structure. 09:16.970 --> 09:19.290 And that's why we're getting all of these errors. 09:19.810 --> 09:24.930 Instead of doing it manually, we're going to use the built in method JSON dot update. 09:25.250 --> 09:26.810 And here's how it works. 09:27.210 --> 09:31.330 So we've already got some data inside our data dot JSON file. 09:31.330 --> 09:38.170 And what we want to do is we want to take that data and we want to update what's existing in there with 09:38.170 --> 09:40.490 the new data that's being passed in. 09:41.650 --> 09:45.410 To do that, we first have to load up the data. 09:45.450 --> 09:47.530 So I'm going to uncomment this line. 09:47.810 --> 09:54.570 And once we've gotten hold of the data we're going to say data dot update. 09:56.450 --> 09:59.490 And we update it with the new data. 09:59.850 --> 10:06.090 What's happened so far is we have our data loaded up into a dictionary. 10:06.490 --> 10:12.330 We use the update method to update that dictionary with some new piece of data. 10:13.030 --> 10:19.590 Now, the next thing we want to do is we want to actually write that data back into this file. 10:19.870 --> 10:24.670 So we have to use this line of code using JSON dump. 10:26.910 --> 10:32.870 But instead of dumping the new data we're going to dump that data that we updated right here. 10:34.310 --> 10:38.190 Essentially what we're doing here is a three step approach. 10:38.430 --> 10:40.510 We're reading the old data. 10:41.710 --> 10:46.350 We're updating old data with new data. 10:46.830 --> 10:49.910 And we're finally saving the updated data. 10:50.910 --> 10:52.470 Here we've got two things happening. 10:52.470 --> 10:55.110 We've got reading and we've got writing. 10:55.470 --> 10:59.190 So we can split this code into two sections. 10:59.510 --> 11:02.910 First we open the file in read mode. 11:03.150 --> 11:10.070 We get hold of the data, we update the data, and then we open up the file again. 11:10.630 --> 11:13.560 But in this case we open it in write mode. 11:15.000 --> 11:23.280 This time we're going to dump the data that we've updated over here into that data file using this particular 11:23.280 --> 11:24.360 indent format. 11:25.560 --> 11:31.480 And once we've written to file and we delete all the text from our website and password entries, and 11:31.480 --> 11:38.000 these lines of code now replace our previous functionality where we were saving just plain text to our 11:38.000 --> 11:39.080 data dot text. 11:39.600 --> 11:41.720 Let's go ahead and run it and test it out. 11:42.120 --> 11:46.080 Currently we have a single entry inside our data dot JSON. 11:46.520 --> 11:52.880 So if we go ahead and add a new entry say for eBay and we generate password, click add. 11:53.600 --> 11:58.760 If we go back to our data dot JSON, you can see how it's now been updated. 11:59.200 --> 12:06.520 This entire JSON has now been updated to have two entries Amazon and eBay. 12:06.880 --> 12:11.680 It didn't just appended it actually added it into the dictionary. 12:11.680 --> 12:14.440 And that's all thanks to that update method. 12:14.780 --> 12:21.860 and once it updated that data, then we told it to save the updated data back into the data file and 12:21.860 --> 12:24.020 wipe all of the previous data. 12:24.900 --> 12:32.820 So now that we're able to read, write, and update JSON data, the next step is to think about what 12:32.860 --> 12:35.140 situations might this fail? 12:35.740 --> 12:43.220 And one of the biggest problems we have at the moment is we're trying to open up this file, load up 12:43.220 --> 12:45.180 the data and update it. 12:45.540 --> 12:52.060 But if we actually had no data in here, say the first time we ran our program, or indeed if we didn't 12:52.100 --> 12:59.620 actually have this data dot JSON file, then you can see that the first time I run it and I try to save 12:59.620 --> 13:00.500 a password. 13:02.540 --> 13:04.260 Then it's going to crash. 13:04.500 --> 13:07.300 And we get some exceptions being thrown. 13:07.580 --> 13:09.820 But we know all about exceptions now. 13:09.900 --> 13:15.260 So in the next lesson that's what we're going to tackle for all of that and more. 13:15.460 --> 13:16.660 Head over to the next lesson.