1
00:00:01,350 --> 00:00:03,520
‫Let's now implement a route handler

2
00:00:03,520 --> 00:00:07,750
‫for post requests so that we can actually add a Natour

3
00:00:07,750 --> 00:00:09,023
‫to our data set.

4
00:00:10,470 --> 00:00:12,870
‫So just like with the doGET() request handler,

5
00:00:12,870 --> 00:00:15,350
‫let's start by adding a new route.

6
00:00:15,350 --> 00:00:19,220
‫So app.post this time, and remember

7
00:00:19,220 --> 00:00:22,120
‫now we use post so the post method here,

8
00:00:22,120 --> 00:00:26,140
‫because that's the kind of request that we want to handle.

9
00:00:26,140 --> 00:00:30,263
‫So requests that are made with the http post verb right?

10
00:00:32,483 --> 00:00:33,316
‫V1

11
00:00:34,610 --> 00:00:35,960
‫and tours.

12
00:00:35,960 --> 00:00:39,690
‫Just as we talked about in the REST API lecture,

13
00:00:39,690 --> 00:00:42,363
‫the URL is actually exactly the same.

14
00:00:43,390 --> 00:00:46,290
‫No matter if we want to get all the tours,

15
00:00:46,290 --> 00:00:48,800
‫or if we want to create a new tour,

16
00:00:48,800 --> 00:00:50,650
‫the URL is exactly the same.

17
00:00:50,650 --> 00:00:53,780
‫Then only thing that changes is the http method

18
00:00:53,780 --> 00:00:56,363
‫that we used for doing these requests.

19
00:00:57,592 --> 00:01:01,420
‫To get all the tours and post to create a new tour,

20
00:01:01,420 --> 00:01:04,337
‫then in here, our typical call-back function

21
00:01:04,337 --> 00:01:06,906
‫where we get access to the request

22
00:01:06,906 --> 00:01:10,810
‫and to the respond object so that we can get some data

23
00:01:10,810 --> 00:01:14,560
‫from the request and send back an appropriate response.

24
00:01:14,560 --> 00:01:16,800
‫Now remember that with a post request,

25
00:01:16,800 --> 00:01:20,790
‫we can send data from the client to the server, right?

26
00:01:20,790 --> 00:01:24,543
‫This data is then ideally available on the request.

27
00:01:25,690 --> 00:01:28,970
‫The request object again is what holds all the data,

28
00:01:28,970 --> 00:01:32,240
‫all the information, about the request that was done.

29
00:01:32,240 --> 00:01:35,190
‫If that request contains some data that was sent,

30
00:01:35,190 --> 00:01:38,840
‫that data should be on the request, right?

31
00:01:38,840 --> 00:01:42,890
‫Now out of the box, Express does not put that body data

32
00:01:42,890 --> 00:01:46,670
‫on the request, and in order to have that data available,

33
00:01:46,670 --> 00:01:49,176
‫we have to use something called middleware.

34
00:01:49,176 --> 00:01:52,100
‫We are gonna talk in great detail about middleware

35
00:01:52,100 --> 00:01:54,220
‫in a couple of lectures, but for now,

36
00:01:54,220 --> 00:01:56,280
‫in order to make this work, we need to include

37
00:01:56,280 --> 00:01:59,943
‫a simple middleware here at the top of the file.

38
00:02:01,860 --> 00:02:04,000
‫So actually, right here.

39
00:02:04,000 --> 00:02:08,490
‫What we need to do, is to say app.use

40
00:02:08,490 --> 00:02:09,370
‫then express

41
00:02:12,687 --> 00:02:13,520
‫.json

42
00:02:14,490 --> 00:02:16,030
‫Okay, and that's it.

43
00:02:16,030 --> 00:02:20,480
‫So again, this [express.json] here is middleware.

44
00:02:20,480 --> 00:02:23,510
‫And middleware is basically a function that can modify

45
00:02:23,510 --> 00:02:25,560
‫the incoming request data.

46
00:02:25,560 --> 00:02:28,370
‫It's called middleware because it stands between,

47
00:02:28,370 --> 00:02:31,390
‫so in the middle of the request and the response.

48
00:02:31,390 --> 00:02:34,030
‫It's just a step that the request goes through

49
00:02:34,030 --> 00:02:35,830
‫while it's being processed.

50
00:02:35,830 --> 00:02:38,440
‫And the step the requests go through, in this example

51
00:02:38,440 --> 00:02:42,330
‫is simply that the data from the body is added to it.

52
00:02:42,330 --> 00:02:44,410
‫So it's added to the request object

53
00:02:44,410 --> 00:02:45,963
‫by using this middleware.

54
00:02:47,560 --> 00:02:51,763
‫We use app.use in order to use middleware like this.

55
00:02:52,870 --> 00:02:55,250
‫And again, we will talk a lot more about middleware

56
00:02:55,250 --> 00:02:57,540
‫a bit later in this section.

57
00:02:57,540 --> 00:03:00,703
‫For now, just know that this is how we use middleware.

58
00:03:01,750 --> 00:03:04,110
‫All the details will then follow later.

59
00:03:04,110 --> 00:03:07,307
‫So for now, just to start, I want to actually show you

60
00:03:07,307 --> 00:03:09,830
‫the data from the body in the console,

61
00:03:09,830 --> 00:03:14,830
‫just to verify that it actually works, so req.body.

62
00:03:14,920 --> 00:03:17,960
‫Again, body is the property that is gonna be available

63
00:03:17,960 --> 00:03:21,130
‫on the request, because we used that middleware

64
00:03:21,130 --> 00:03:22,393
‫a couple of moments ago.

65
00:03:23,560 --> 00:03:27,090
‫So we want to log[req.body] to the console

66
00:03:27,090 --> 00:03:29,600
‫and then we also need to send back a response.

67
00:03:29,600 --> 00:03:34,083
‫So res.send and for now just some place holder here.

68
00:03:35,870 --> 00:03:37,020
‫Just 'Done' okay.

69
00:03:37,020 --> 00:03:39,070
‫So we always need to send back something

70
00:03:39,070 --> 00:03:42,600
‫in order to finish the so-called request/response cycle,

71
00:03:42,600 --> 00:03:44,980
‫which again we're gonna learn a bit more about later

72
00:03:44,980 --> 00:03:46,530
‫in this section.

73
00:03:46,530 --> 00:03:49,363
‫So let's now test this out, and create a new request

74
00:03:49,363 --> 00:03:51,200
‫for the post.

75
00:03:51,200 --> 00:03:53,680
‫Now here in postman, we can do something really nice

76
00:03:53,680 --> 00:03:56,133
‫which is to save all of these requests.

77
00:03:58,180 --> 00:04:01,200
‫I'm gonna start by creating a new collection,

78
00:04:01,200 --> 00:04:02,500
‫which I will call Natours.

79
00:04:06,570 --> 00:04:07,600
‫New collection.

80
00:04:07,600 --> 00:04:10,793
‫Now I will save this request inside that collection.

81
00:04:12,650 --> 00:04:14,573
‫So this one is Get all the Tours.

82
00:04:17,380 --> 00:04:20,290
‫Put it into Natours, and save.

83
00:04:20,290 --> 00:04:23,563
‫So now we have our Get requests right here.

84
00:04:26,070 --> 00:04:27,410
‫Well let's now copy this one right here,

85
00:04:27,410 --> 00:04:28,583
‫create a new one.

86
00:04:30,120 --> 00:04:31,970
‫So this one is a post request.

87
00:04:31,970 --> 00:04:35,330
‫Before doing it, I will actually also save it right

88
00:04:35,330 --> 00:04:36,853
‫to this collection.

89
00:04:38,080 --> 00:04:41,083
‫So Create New Tour.

90
00:04:43,443 --> 00:04:47,733
‫Here on the left side, we now have both of our requests.

91
00:04:49,070 --> 00:04:52,620
‫Let's now actually specify our body here,

92
00:04:52,620 --> 00:04:56,550
‫so the data that we basically want to send to the server.

93
00:04:56,550 --> 00:04:59,370
‫We come here to Body, and there are different ways

94
00:04:59,370 --> 00:05:02,250
‫of doing it now, but the easiest one is to simply say,

95
00:05:02,250 --> 00:05:06,260
‫Raw, and then Application JSON.

96
00:05:06,260 --> 00:05:09,470
‫All we have to do here is to basically specify some JSON,

97
00:05:09,470 --> 00:05:12,180
‫and that will then get transmitted to the server.

98
00:05:12,180 --> 00:05:13,760
‫So the first thing we want to specify

99
00:05:13,760 --> 00:05:17,150
‫is the name of the Tour, and you remember that in JSON,

100
00:05:17,150 --> 00:05:20,550
‫everything has to be in quotes and actually double quotes,

101
00:05:20,550 --> 00:05:21,873
‫not just any quotes.

102
00:05:22,810 --> 00:05:26,040
‫Let me just call this one a Test Tour, and let's take a look

103
00:05:26,040 --> 00:05:29,343
‫at what else we have in the tour data.

104
00:05:30,550 --> 00:05:32,850
‫So we have the name, we have the duration,

105
00:05:32,850 --> 00:05:35,033
‫and let's just put also the difficulty.

106
00:05:37,260 --> 00:05:38,720
‫So I'm not going to specify all of these

107
00:05:38,720 --> 00:05:40,893
‫because that takes way too much time.

108
00:05:42,500 --> 00:05:45,870
‫Let's just say the duration is 10 days,

109
00:05:45,870 --> 00:05:46,890
‫and the difficulty

110
00:05:50,250 --> 00:05:51,483
‫is easy.

111
00:05:52,800 --> 00:05:57,290
‫That as our body will be transmitted to the server.

112
00:05:57,290 --> 00:06:00,550
‫So that's tested out now, hitting send

113
00:06:00,550 --> 00:06:03,500
‫and here we get back our response, which is done, remember.

114
00:06:07,104 --> 00:06:09,520
‫Here is the response that we sent, so done.

115
00:06:09,520 --> 00:06:11,700
‫And you see that down here in our console,

116
00:06:11,700 --> 00:06:15,153
‫we now have an object which is basically the JSON

117
00:06:15,153 --> 00:06:17,750
‫that we sent in our body, right?

118
00:06:17,750 --> 00:06:19,600
‫So perfect, it works!

119
00:06:19,600 --> 00:06:21,170
‫It is no longer JSON, as you can see.

120
00:06:21,170 --> 00:06:23,860
‫It is truly a JavaScript object.

121
00:06:23,860 --> 00:06:27,000
‫Just to show you that we really needed middleware,

122
00:06:27,000 --> 00:06:28,350
‫let's comment this one out.

123
00:06:30,190 --> 00:06:31,688
‫Send it again.

124
00:06:31,688 --> 00:06:36,160
‫Now no longer have the request.body, right?

125
00:06:36,160 --> 00:06:39,093
‫That's why it's undefined now, 'cause it no longer exists.

126
00:06:40,440 --> 00:06:44,030
‫Give it a save, send our request again,

127
00:06:44,030 --> 00:06:45,403
‫and so now it's back.

128
00:06:48,220 --> 00:06:51,510
‫We have our post route all set up, it's working now

129
00:06:51,510 --> 00:06:53,810
‫and we also get access to the body,

130
00:06:53,810 --> 00:06:56,830
‫and so what we want to do now is to actually persist

131
00:06:56,830 --> 00:07:00,680
‫that data into this tour simple JSON file.

132
00:07:00,680 --> 00:07:04,090
‫We're actually gonna modify this file, so that the data

133
00:07:04,090 --> 00:07:07,500
‫is saved to our fictional database here.

134
00:07:07,500 --> 00:07:09,820
‫This JSON file right now kind of works

135
00:07:09,820 --> 00:07:11,623
‫as our fictional database.

136
00:07:12,850 --> 00:07:15,810
‫So let's now take care of that.

137
00:07:15,810 --> 00:07:18,063
‫I'm gonna go ahead and comment this one out.

138
00:07:19,250 --> 00:07:20,650
‫So let's get started.

139
00:07:20,650 --> 00:07:23,440
‫The first thing we need to do is to figure out the id

140
00:07:23,440 --> 00:07:25,240
‫of the new object.

141
00:07:25,240 --> 00:07:28,720
‫Remember, again in the lecture about REST API's,

142
00:07:28,720 --> 00:07:30,570
‫is that when we create a new object,

143
00:07:30,570 --> 00:07:33,200
‫we never specify the id of the object.

144
00:07:33,200 --> 00:07:35,623
‫The database usually takes care of that.

145
00:07:36,980 --> 00:07:40,470
‫A new object usually automatically gets it's new id.

146
00:07:40,470 --> 00:07:42,840
‫Well in this case, we do not have any database,

147
00:07:42,840 --> 00:07:46,020
‫and so what we're gonna do is to simply take the id

148
00:07:46,020 --> 00:07:48,833
‫of the last object and then add +1 to that.

149
00:07:50,020 --> 00:07:51,010
‫Let's do that very quickly,

150
00:07:51,010 --> 00:07:53,440
‫and that's just basic JavaScript.

151
00:07:53,440 --> 00:07:57,740
‫So newId it is tours, right?

152
00:07:57,740 --> 00:08:01,160
‫Remember that tours, we already have the data

153
00:08:01,160 --> 00:08:02,673
‫in this tours variable.

154
00:08:03,800 --> 00:08:06,500
‫So that's an array of all the tour objects,

155
00:08:06,500 --> 00:08:08,313
‫and so we want to get the last one,

156
00:08:09,150 --> 00:08:13,410
‫which is tours.length - 1,

157
00:08:13,410 --> 00:08:17,220
‫then the id property of that and we add + 1.

158
00:08:17,220 --> 00:08:18,823
‫So that is the new id.

159
00:08:21,533 --> 00:08:23,033
‫Next up, we create a new tour,

160
00:08:23,950 --> 00:08:28,070
‫and that tour will basically be the body that we send

161
00:08:28,070 --> 00:08:30,863
‫plus the new id that we just created.

162
00:08:31,950 --> 00:08:36,730
‫So we can use object.assign, which basically allows us

163
00:08:36,730 --> 00:08:40,070
‫to create a new object by merging two existing objects

164
00:08:40,070 --> 00:08:41,130
‫together.

165
00:08:41,130 --> 00:08:43,300
‫So the first object is gonna be

166
00:08:43,300 --> 00:08:44,920
‫id=newId,

167
00:08:48,270 --> 00:08:49,200
‫and then we want

168
00:08:51,140 --> 00:08:52,353
‫request.body.

169
00:08:54,330 --> 00:08:58,730
‫We could also had done req.body.id=newId,

170
00:09:00,250 --> 00:09:03,503
‫but I did not want to mutate the original body object.

171
00:09:04,740 --> 00:09:06,323
‫I just left it like this.

172
00:09:08,564 --> 00:09:11,720
‫That is the new tour, and now what we want to do

173
00:09:11,720 --> 00:09:16,120
‫is to push this tour into the tour array, right?

174
00:09:16,120 --> 00:09:19,130
‫So tours, is the array of the nine tours that we have

175
00:09:19,130 --> 00:09:20,330
‫at this point.

176
00:09:20,330 --> 00:09:25,163
‫We say push and push the new tour in there.

177
00:09:27,880 --> 00:09:31,500
‫That is the array which now has the new tour in it,

178
00:09:31,500 --> 00:09:35,110
‫but of course now we have to persist that into the file.

179
00:09:35,110 --> 00:09:37,855
‫That again is quite easy for you at this point,

180
00:09:37,855 --> 00:09:41,840
‫so use fs.write file.

181
00:09:41,840 --> 00:09:43,390
‫So which one should we use?

182
00:09:43,390 --> 00:09:46,540
‫writeFile or writeFileSync?

183
00:09:47,570 --> 00:09:50,070
‫The answer for that is very simple.

184
00:09:50,070 --> 00:09:52,010
‫We are inside of a call-back function,

185
00:09:52,010 --> 00:09:54,430
‫that is gonna run in the event loop.

186
00:09:54,430 --> 00:09:57,180
‫We can never, ever block the event loop.

187
00:09:57,180 --> 00:10:00,030
‫What we're gonna do is to use writeFile

188
00:10:00,030 --> 00:10:01,720
‫and not to Sync in this one.

189
00:10:01,720 --> 00:10:03,820
‫We want to pass in a call-back function

190
00:10:03,820 --> 00:10:05,800
‫that is gonna be processed in the background

191
00:10:05,800 --> 00:10:07,160
‫and as soon as it's ready,

192
00:10:07,160 --> 00:10:10,810
‫it's gonna put its event in one of the event loop queue,

193
00:10:10,810 --> 00:10:12,180
‫which is then gonna be handled

194
00:10:12,180 --> 00:10:14,760
‫as soon as the event loop passes that phase.

195
00:10:14,760 --> 00:10:17,360
‫Remember that from the Event Loop lecture?

196
00:10:17,360 --> 00:10:21,080
‫Anyway, let's get the file name from up here,

197
00:10:21,080 --> 00:10:23,650
‫because we will really override this file

198
00:10:23,650 --> 00:10:25,270
‫so that when we restart this server,

199
00:10:25,270 --> 00:10:26,823
‫it's then gonna be there.

200
00:10:28,040 --> 00:10:30,101
‫So where-

201
00:10:30,101 --> 00:10:31,018
‫right here.

202
00:10:31,937 --> 00:10:35,246
‫So that is the file that where we want to write to.

203
00:10:35,246 --> 00:10:37,733
‫The data that we want to write, which is tours,

204
00:10:39,040 --> 00:10:40,760
‫and then our call-back function,

205
00:10:40,760 --> 00:10:43,203
‫which in this case only has the error.

206
00:10:46,040 --> 00:10:49,890
‫Here I just noticed that we need to also stringify

207
00:10:49,890 --> 00:10:51,580
‫this object, right?

208
00:10:51,580 --> 00:10:53,680
‫We want json in this JSON file,

209
00:10:53,680 --> 00:10:57,020
‫and this right now is just a plain, normal JavaScript object

210
00:10:57,020 --> 00:10:58,580
‫and so we need to convert that.

211
00:10:58,580 --> 00:11:01,160
‫But that's again simple, already did that.

212
00:11:01,160 --> 00:11:02,320
‫JSON.stringify

213
00:11:05,510 --> 00:11:06,343
‫of the object.

214
00:11:07,930 --> 00:11:11,760
‫What do we want to do as soon as the file is written?

215
00:11:11,760 --> 00:11:13,340
‫Well, what we usually do is

216
00:11:13,340 --> 00:11:16,683
‫to send the newly created object as the response.

217
00:11:17,670 --> 00:11:18,600
‫Let's do that.

218
00:11:18,600 --> 00:11:21,650
‫So response, and then as always, we start by

219
00:11:21,650 --> 00:11:23,340
‫specifying the status code.

220
00:11:23,340 --> 00:11:26,483
‫In this case, it's not gonna be a 200, but a 201.

221
00:11:27,400 --> 00:11:30,190
‫So 201 which means created.

222
00:11:30,190 --> 00:11:34,090
‫200 stands for okay, 201 stands for created,

223
00:11:34,090 --> 00:11:36,260
‫which is exactly what happened here.

224
00:11:36,260 --> 00:11:38,513
‫We created a new resource on a server.

225
00:11:41,260 --> 00:11:45,873
‫So JSON, and it keeps adding this message here.

226
00:11:48,240 --> 00:11:50,993
‫Status is again, success.

227
00:11:52,500 --> 00:11:56,770
‫I'm not using the results property here, that we had before,

228
00:11:56,770 --> 00:11:59,263
‫because now I'm only sending back one result.

229
00:12:00,651 --> 00:12:02,203
‫Data is our envelope here.

230
00:12:04,100 --> 00:12:09,100
‫Tour is new tour.

231
00:12:09,230 --> 00:12:10,063
‫That's it!

232
00:12:10,063 --> 00:12:12,660
‫Give it a save here, and so that format it,

233
00:12:12,660 --> 00:12:14,260
‫or code a little bit.

234
00:12:14,260 --> 00:12:15,933
‫Let's add some more space here.

235
00:12:18,480 --> 00:12:20,533
‫I think we're ready to now give it a try.

236
00:12:23,180 --> 00:12:26,273
‫We can actually create a new tour, using this data here.

237
00:12:28,600 --> 00:12:30,440
‫So adjust this Test Tour,

238
00:12:30,440 --> 00:12:32,540
‫and with this data, and let's wait for it.

239
00:12:33,670 --> 00:12:34,620
‫What happened here?

240
00:12:35,780 --> 00:12:37,000
‫Let's see, ah okay.

241
00:12:37,000 --> 00:12:40,733
‫We have a problem that we sent a response twice basically.

242
00:12:40,733 --> 00:12:43,320
‫So we sent a response with JSON,

243
00:12:43,320 --> 00:12:45,530
‫and then again with .send.

244
00:12:45,530 --> 00:12:46,620
‫That's not allowed.

245
00:12:46,620 --> 00:12:48,990
‫That's actually why we get this error here.

246
00:12:48,990 --> 00:12:50,622
‫So it's actually nice that it happened here,

247
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‫so that you know what this standard error here means.

248
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‫HTTP_HEADERS_SENT cannot set headers after they are sent

249
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‫to the client.

250
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‫That happens when you try to send two responses.

251
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‫We need to get rid of that.

252
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‫Yeah, that was the only error that we had.

253
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‫That should now fix it.

254
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‫Give it a try.

255
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‫And indeed, here we go.

256
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‫So we have our id of 10, which our code created for us,

257
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‫and then the entire tour which is exactly the data

258
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‫that we sent as a body in our request.

259
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‫Now the thing is, that when we do get all tours here,

260
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‫it will not yet show up.

261
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‫If we go down here,

262
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‫actually it is already here.

263
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‫We have the one from before, so when we had that error,

264
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‫it actually also created this tour here.

265
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‫Then of course, the tour that we created with the id of 10.

266
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‫So this tour here is exactly this one

267
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‫that was created right now.

268
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‫If we do now, Test Tour 2, with the duration of just 5.

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‫Let's give this one a try,

270
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‫and if I do get all tours, then that shows up here as well.

271
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‫I said in the beginning that it wouldn't work,

272
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‫so that it wouldn't show up right away,

273
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‫because this only works if we restart the server.

274
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‫This file,

275
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‫the tour-simple.json file

276
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‫where our tours are coming from,

277
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‫is only read at the beginning when we start the server.

278
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‫Now the thing is that each time we save something

279
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‫to this JSON file, it will also reload the server.

280
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‫Let me prove that to you, so if I hit now save,

281
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‫then look what happens down here.

282
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‫So I save it, and so you see that down here

283
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‫it restarted the server.

284
00:14:44,980 --> 00:14:47,920
‫It also formatted the code, because of prettier.

285
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‫But what matters here, is that this code updated.

286
00:14:50,970 --> 00:14:52,780
‫That's why each time we save something here

287
00:14:52,780 --> 00:14:56,160
‫with our API, it will then immediately reload the server

288
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‫and will reload the content from the file into the tours,

289
00:15:00,230 --> 00:15:02,080
‫and we can then read that right away.

290
00:15:03,020 --> 00:15:06,400
‫That's why we have access immediately

291
00:15:06,400 --> 00:15:08,563
‫to all the newly created tours.

292
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‫Make sense?

293
00:15:10,550 --> 00:15:13,970
‫Well if not, please feel free to just ask your questions,

294
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‫and of course Q&A section, right?