1 00:00:00,590 --> 00:00:09,950 Let's continue building our arrest API in this demo now when they use a lot of thing to our application 2 00:00:10,430 --> 00:00:15,480 we might want to list all the notes created by him or her. 3 00:00:15,860 --> 00:00:25,340 So we are going to create Getaround that runs a crazy operation on dynamo Levy and returns up to say 4 00:00:25,610 --> 00:00:33,390 five nodes created by the user and sorted by the time stamp in descending order. 5 00:00:35,030 --> 00:00:46,610 So router are get slash API slash notes we call it nodes in plural form since we are expecting to receive 6 00:00:47,090 --> 00:00:50,330 one or more items in response. 7 00:00:50,720 --> 00:00:53,840 And then the processing function 8 00:00:56,520 --> 00:01:07,250 lets declare the pad on some variable table name is table name and so we specify the key condition expression 9 00:01:07,340 --> 00:01:19,910 are the where clause of our query operation as user ID equals colon U R and D and then define colon 10 00:01:19,910 --> 00:01:24,590 you ID using the expression attribute values. 11 00:01:24,690 --> 00:01:35,860 So we are attempting to create all items with hash key equal to the user id of the logged in user limit 12 00:01:35,910 --> 00:01:37,080 as a limit. 13 00:01:37,150 --> 00:01:44,770 And I want to create or limit variable or declared a limit variable to take in an optional limit value 14 00:01:44,800 --> 00:01:47,710 from the string. 15 00:01:47,780 --> 00:01:58,040 So if that calling application pro-white a limit value we return that main number of items as we default 16 00:01:58,460 --> 00:02:00,420 to about 5 items. 17 00:02:01,830 --> 00:02:10,260 We also want the items to be in reverse chronological order meaning the recently created Nel's should 18 00:02:10,270 --> 00:02:12,090 appear first. 19 00:02:12,090 --> 00:02:23,120 So so are the items by times Dan or the sarky in descending order to do that which specifies scanning 20 00:02:23,130 --> 00:02:32,690 less forward as far as and this would return items sorted by the sarky in descending order. 21 00:02:35,200 --> 00:02:45,720 Then since this is passionated query we want to restart key we have the user id We just need to know 22 00:02:45,760 --> 00:02:52,990 the time stamp from the last evaluated key return in the previous operation. 23 00:02:53,110 --> 00:03:01,290 So our API Quest can send in an optional star barometer as crazy string. 24 00:03:01,600 --> 00:03:08,430 And we use it as the star key to get to the next page of items. 25 00:03:08,540 --> 00:03:16,860 So let's define a variable star times tab and get its value from request. 26 00:03:16,930 --> 00:03:26,980 Dart Querrey Darkstar we have to pass the query string paramita call start to get that next page for 27 00:03:26,980 --> 00:03:28,220 the first page. 28 00:03:28,240 --> 00:03:32,410 We don't need to parse this Parminter. 29 00:03:32,830 --> 00:03:38,240 And if it is not Basto we assume it to be zero. 30 00:03:41,000 --> 00:03:51,800 Then if the start time span is greater than zero we populate the exclusive Starky to query the next 31 00:03:51,800 --> 00:03:53,930 page of results. 32 00:03:59,720 --> 00:04:03,860 Finally we call the document blind method. 33 00:04:04,550 --> 00:04:06,380 Just like that 34 00:04:31,550 --> 00:04:39,600 and in the success call we turn the data along with our 200 success response. 35 00:04:43,310 --> 00:04:45,340 Let's test this out. 36 00:04:51,200 --> 00:04:57,320 First let's make the API call without any start parameter 37 00:05:12,970 --> 00:05:22,720 and we do get five items with the latest item at the top and then we also have the last few valuated 38 00:05:22,720 --> 00:05:24,440 key here. 39 00:05:31,600 --> 00:05:41,290 Let's copy the time stamp from here and we'll pass it to the same request as a star parameter in the 40 00:05:41,290 --> 00:05:43,270 query string. 41 00:05:43,330 --> 00:05:49,230 So question mark Starr equal to the time stamp that be copied. 42 00:05:56,930 --> 00:06:00,820 Hit send and receive them. 43 00:06:00,820 --> 00:06:03,890 Next page of results. 44 00:06:03,950 --> 00:06:05,200 Awesome. 45 00:06:05,930 --> 00:06:15,290 So now our application can show the names created by the user and user can navigate through them page 46 00:06:15,290 --> 00:06:16,750 by page. 47 00:06:16,820 --> 00:06:26,170 Next if the user clicks on a node from this list he or she should be able to read the complete node. 48 00:06:26,220 --> 00:06:33,510 So for that let's create another API out to return the selected note. 49 00:06:33,710 --> 00:06:37,100 So we'll use the get method again. 50 00:06:37,340 --> 00:06:43,640 This time we want the user to parse the node ID of the node to be returned. 51 00:06:44,150 --> 00:06:55,370 And this should be mandatory parameter so we specify the mandatory pattern meters inside the API endpoint 52 00:06:55,490 --> 00:07:06,410 Lysa router door get slash API slash node slash colon node ID here. 53 00:07:06,560 --> 00:07:15,500 Note ID is the mandatory parameter that user must send in in order to make this API car. 54 00:07:15,620 --> 00:07:26,570 And then the processing function as usual we get the node Id passed by the user from request dog pass 55 00:07:26,630 --> 00:07:30,580 of it just like that. 56 00:07:30,720 --> 00:07:35,790 Then lets move the parents argument for our Querrey operation. 57 00:07:35,790 --> 00:07:42,380 This time we only have the note ID and we dont have the time stamp. 58 00:07:42,780 --> 00:07:51,950 So we'll create the global secondary index that we have created on the node ID to give. 59 00:07:52,460 --> 00:08:03,210 So Table name is table name index name as node ID index and we can find the actual indexed name from 60 00:08:03,210 --> 00:08:10,760 the indexes tab in the Dynamo the console right here. 61 00:08:11,690 --> 00:08:21,000 All right then we specify the red Glaus using the key condition expression lights. 62 00:08:21,330 --> 00:08:34,310 Note ID equal to call an ID and then we define the colon ID is an expression attribute values like so. 63 00:08:39,020 --> 00:08:51,770 We can also specify a limit as 1 since we don't expect to have two items with the same node ID then 64 00:08:51,770 --> 00:08:55,020 we call the document client operation. 65 00:08:55,160 --> 00:08:55,990 As usual 66 00:09:27,040 --> 00:09:35,330 and if that ease success response there is a possibility of an empty response as well. 67 00:09:35,930 --> 00:09:41,550 We just check if the state handout items is empty or not. 68 00:09:52,630 --> 00:10:09,810 If it has data out we return the first item from the Arey Lysa else we turn 4 0 for not found response. 69 00:10:09,820 --> 00:10:11,410 All right let's test the 70 00:10:15,060 --> 00:10:20,090 let's speak up a note Id from our dining table. 71 00:10:25,080 --> 00:10:26,810 And made the API call 72 00:10:43,400 --> 00:10:46,760 just like that. 73 00:10:46,940 --> 00:10:50,580 And we do get the requested item. 74 00:10:50,600 --> 00:10:52,330 Awesome. 75 00:10:53,480 --> 00:11:02,970 Now I'm going to duplicate an item inside dynamo D.B and change the user id times that A.I 76 00:11:14,610 --> 00:11:16,110 just like that. 77 00:11:17,520 --> 00:11:26,230 Let's assume that this item was inserted by another user called Test User 2. 78 00:11:26,340 --> 00:11:36,510 And now if we make a get request with this no tidy Ideally they should see an error because the item 79 00:11:36,510 --> 00:11:39,110 belongs to another user. 80 00:11:39,780 --> 00:11:41,030 Let's try that out. 81 00:11:48,340 --> 00:11:48,790 Oops. 82 00:11:48,830 --> 00:11:53,180 But the API returned the item from another user as well. 83 00:11:54,320 --> 00:12:01,850 And we'll fix this issue using fine grained access control when we implement Federated access using 84 00:12:01,990 --> 00:12:04,440 in the US go to meet her. 85 00:12:04,610 --> 00:12:09,460 Next up we want the users to be able to delete the display node. 86 00:12:09,740 --> 00:12:21,140 For that we're going to use the delete method router dot delete slash API slash no slash Kurland time 87 00:12:21,140 --> 00:12:23,930 stamp to delete an item. 88 00:12:23,930 --> 00:12:28,020 We must pass they complete primary key. 89 00:12:28,160 --> 00:12:30,630 We already have the user id with us. 90 00:12:30,650 --> 00:12:36,080 So we simply asked the user to provide us with the time stamp. 91 00:12:37,070 --> 00:12:47,340 And it should be a mandatory parameter and then the processing function we capture the time stamp from 92 00:12:47,440 --> 00:12:50,180 request Dar Patten's object 93 00:12:58,620 --> 00:13:08,570 pass it inside the parents variable as a key attribute along with the user id just like that. 94 00:13:08,960 --> 00:13:13,610 And then we called the document blind darg delete method 95 00:13:22,660 --> 00:13:24,420 just like that. 96 00:13:57,860 --> 00:14:00,060 Let's test this out. 97 00:14:05,890 --> 00:14:14,410 Simply big time stamp from Dynamo the table and make a delete request with that time stamp. 98 00:14:29,950 --> 00:14:31,770 Just like that. 99 00:14:32,170 --> 00:14:34,990 And we get 200 OK response. 100 00:14:35,290 --> 00:14:43,220 And if we refresh the data in the table in the code and so we do see that the item has been deleted 101 00:14:50,380 --> 00:15:02,250 ASA our API is now ready and we are now ready to integrate things that are front end to build and end 102 00:15:02,250 --> 00:15:06,740 to end web application. 103 00:15:06,750 --> 00:15:12,300 This has been a long lecture and thank you so much for bearing with me. 104 00:15:12,300 --> 00:15:15,780 If you need to take a break do take one. 105 00:15:15,810 --> 00:15:23,160 And when you come back we'll integrate this rest API with the front end application.