WEBVTT 00:04.530 --> 00:10.320 As you might have noticed by now that engine X configuration syntax closely resembles that of a programming 00:10.320 --> 00:17.610 language implementing in some ways the concept of scope includes and in this lesson in variables and 00:17.610 --> 00:22.290 conditionals variables exist in two forms variables. 00:22.290 --> 00:29.460 We set ourselves and engine exis own built in variables we can find a list of these engine X variables 00:29.490 --> 00:37.680 in the engine X dot org documentation alphabetical index of variables which lists each of the available 00:37.680 --> 00:45.690 variables with the module that makes it available modules like hgt underscore core and h.t. dp log. 00:45.790 --> 00:50.420 Really being part of engine X so you don't have to manually add them. 00:50.580 --> 00:53.410 Now these native variables can be extremely useful. 00:53.430 --> 00:58.470 So let's switch back to that configuration file and see how we could use them. 00:58.470 --> 01:06.220 I'll clear all of these locations from the previous lesson create a new location for Slash inspect. 01:06.450 --> 01:09.210 And in this location simply return a few of these. 01:09.210 --> 01:17.900 Engine X variables return status 200 a string and using double quotation marks. 01:17.910 --> 01:21.750 We can directly embed variables into this response string. 01:22.110 --> 01:28.470 First one I'll add is the host variable variables being prefixed with a dollar sign. 01:28.470 --> 01:30.620 Add a new line character. 01:30.630 --> 01:40.960 You are a new line and ARGs which is the requests query string save this and reload the configuration. 01:42.640 --> 01:44.890 Navigate to that new location. 01:45.490 --> 01:46.950 Slash inspect. 01:47.990 --> 01:50.780 And we see each variable on its own line. 01:50.780 --> 01:56.150 The host which is the server I see as I'm not using the domain name and the request. 01:56.150 --> 01:58.530 You are I slash inspect. 01:58.550 --> 02:02.780 Of course we didn't pass a query string so the args variable is empty. 02:02.780 --> 02:12.470 But if I add query name equals Ray that's now also returned albeit in its complete string form. 02:12.470 --> 02:18.050 We can however use a variation of the args variable to get individual query parameters. 02:18.080 --> 02:20.470 I'll change this string to name. 02:21.390 --> 02:23.730 Argh underscore name. 02:23.940 --> 02:30.960 So based on the query string engine it compiles a named variable for each parameter prefixed with Arg 02:31.560 --> 02:33.570 save and reload this. 02:34.520 --> 02:38.890 Reload and this time we get the value of the name parameter. 02:38.930 --> 02:46.160 So already a very powerful feature set of engine X engine X also allows us to perform basic conditionals 02:46.400 --> 02:53.000 or if statements which most commonly will be used in conjunction with one of these variables before 02:53.000 --> 02:54.150 I demonstrate however. 02:54.170 --> 03:01.640 Note that the use of engine X conditionals inside location contexts is highly discouraged as this can 03:01.640 --> 03:04.030 lead to some very unexpected behaviour. 03:04.190 --> 03:09.440 Now the technicalities of this is beyond the scope of what we can cover here but if you'd like to read 03:09.440 --> 03:14.770 more on the subject I've linked to a very detailed explanation in the list and resources. 03:15.020 --> 03:15.430 Righto. 03:15.440 --> 03:21.620 Outside of this location context then I'll create a conditional which for the sake of demonstrating 03:21.930 --> 03:27.300 chicks are hypothetical AP Iki if with braces. 03:27.410 --> 03:32.640 Note the space between the F and the braces being required for this syntex to be valid. 03:32.920 --> 03:35.870 Argh underscore a p Iki. 03:35.880 --> 03:43.760 So checking the value of the API key query parameter not equal to 1 2 3 4. 03:43.820 --> 03:50.810 Meaning if the user does not pass the value 1 2 3 4 as the API key parameter in the query string to 03:50.870 --> 03:57.020 any you are a return of foro 1 which is the unauthorized status code. 03:57.020 --> 03:59.600 Incorrect API key. 03:59.600 --> 04:00.980 Save this. 04:03.300 --> 04:07.740 Reload with alt that API parameter key this time just requesting the root. 04:07.740 --> 04:08.300 You are right. 04:08.310 --> 04:11.240 So their demo site and we're denied. 04:11.370 --> 04:15.150 As per that conditional add the API key parameter. 04:15.150 --> 04:22.980 However with a value of 1 2 3 4 and were served indexed update the amelle as the conditional did not 04:22.980 --> 04:28.860 evaluate to true image and style sheet simply being missing as the internal requests for those didn't 04:28.860 --> 04:31.080 include the API key parameter. 04:31.420 --> 04:36.960 OK as I mentioned we can also set our own variables within range and X configuration. 04:36.960 --> 04:43.400 I'll get rid of all this and to create a new variable we can say set the variable name. 04:43.440 --> 04:47.220 I'll make this weekend and the variable value. 04:47.430 --> 04:50.060 No so no equals sign. 04:50.070 --> 04:56.910 Just the standard engine X director format variables can be set to simple strings such as this example 04:57.360 --> 04:59.520 integers or booleans. 04:59.520 --> 05:06.270 True and false then for another hypothetical use case we can check if it is weakened by creating an 05:06.330 --> 05:11.940 if statement and using the date underscore local engine x variable. 05:11.940 --> 05:18.930 This variable holding an ISO date time string for the local time and instead of a simple equals or not 05:18.960 --> 05:20.400 equals operator. 05:20.430 --> 05:28.860 We can use a regular expression as with location contexts folder checking on this variable for Saturday 05:29.220 --> 05:30.940 or Sunday. 05:31.170 --> 05:36.130 In which case if this is true set weekend 2 Yes. 05:37.460 --> 05:40.510 So starting out we said weekend to be No. 05:40.640 --> 05:46.970 Check the local date to see if it is in fact Saturday or Sunday which if it is we changed the value 05:46.970 --> 05:48.870 of weekend to be yes. 05:49.570 --> 05:52.720 Change this location to is WEEKEND. 05:53.300 --> 05:56.490 Returning two hundred and the weekend variable. 05:56.520 --> 05:57.990 So yes or no. 05:58.930 --> 06:01.540 Save and reload the configuration. 06:03.170 --> 06:09.850 Navigate to that you are I is under school weekend and it being a Monday at the time of recording this 06:10.150 --> 06:11.540 we get no. 06:13.190 --> 06:16.770 Change the condition to check for Monday instead then. 06:17.670 --> 06:19.910 I'll rename this variable to mun. 06:21.840 --> 06:25.440 And said the location to is Monday. 06:26.800 --> 06:27.860 Reload. 06:30.290 --> 06:32.490 Navigate to is Monday. 06:34.630 --> 06:38.320 And this time we get yes as this conditional evaluator. 06:38.330 --> 06:44.380 True true and updated the variable to be yes in the next place and we'll use some of these variables 06:44.380 --> 06:46.930 to learn about rewrites and redirects.