1
00:00:06,170 --> 00:00:09,010
So what exactly is reverse proxy in.

2
00:00:09,020 --> 00:00:15,800
Simply put a reverse proxy act as an intermediary between a client for example a browser and the resource

3
00:00:15,800 --> 00:00:17,120
itself.

4
00:00:17,120 --> 00:00:23,480
For example the most common use case on in generics is one we've already covered BHB when we implement

5
00:00:23,480 --> 00:00:32,240
a be back in using P P F be M engine X. acted as a reverse proxy between the client and BHB fbm.

6
00:00:32,270 --> 00:00:38,810
So in other words interpreting the client's request fetching that request from patch P If p.m. and then

7
00:00:38,810 --> 00:00:40,640
sending it back to the client.

8
00:00:40,670 --> 00:00:47,510
Hence the term reverse with the client assuming all requests are coming to and from that engine X server.

9
00:00:47,510 --> 00:00:50,800
This is of course a very powerful feature for many applications.

10
00:00:50,990 --> 00:00:56,740
But in the context of any generics as a web server it will most often be used to proxy somewhere the

11
00:00:56,780 --> 00:01:02,360
back in service be that patch be no Dodger s Ruby etc..

12
00:01:02,810 --> 00:01:06,250
I still have that engine Xserve from the previous list and running.

13
00:01:07,720 --> 00:01:09,580
Hello from in Genex.

14
00:01:09,610 --> 00:01:15,940
So to demonstrate the most basic reverse proxy I'll start a new web server using P HP.

15
00:01:15,970 --> 00:01:24,280
Again with that response style which echoes Hello from page B test that's working all 9 9 9 9 which

16
00:01:24,280 --> 00:01:25,470
it is now.

17
00:01:25,480 --> 00:01:29,740
Let's say we want to access this BHB server via our engineered server.

18
00:01:29,980 --> 00:01:38,040
This one on port 8 8 8 8 and we want to do so by accessing the slash P HP path or request you are right.

19
00:01:38,290 --> 00:01:43,570
I'll switch back to the engine XT configuration file we are using create that new location block for

20
00:01:43,570 --> 00:01:50,150
Slash patch P and now two proxy requests on this path to the PDB server.

21
00:01:50,170 --> 00:01:58,030
We can say proxy underscore pass which should look familiar from the Patch be back end Listen HTC be

22
00:01:58,120 --> 00:02:06,280
local post 9 9 9 9 the full You are all of that BHB server with a trailing slash which is important

23
00:02:06,400 --> 00:02:07,990
and will cover in a minute.

24
00:02:08,410 --> 00:02:11,950
I'll just wrap this in quotes to make it a bit more readable.

25
00:02:13,070 --> 00:02:20,330
Reload engine X server with the S flag and reload and now test this reverse proxy by requesting that

26
00:02:20,330 --> 00:02:21,250
slash patch.

27
00:02:21,340 --> 00:02:23,500
Request on our engine X server.

28
00:02:24,500 --> 00:02:26,470
Hello from BHB server.

29
00:02:26,780 --> 00:02:33,120
So a response clearly from I appear to be server but accessed and reverse proxied via a were engine

30
00:02:33,120 --> 00:02:37,350
X server kurla again with out the slash BHP.

31
00:02:37,550 --> 00:02:40,990
And again we're back to getting the engine X response as before.

32
00:02:41,730 --> 00:02:47,720
There is of course no restrictions to this proxy server or servers being on the same system either.

33
00:02:47,730 --> 00:02:50,610
For example I'll create a third location block.

34
00:02:51,490 --> 00:02:53,680
Listening for engine X org.

35
00:02:55,230 --> 00:02:58,130
And proxy this one to engine X dot org.

36
00:02:58,210 --> 00:02:59,710
So a remote site.

37
00:03:01,090 --> 00:03:03,070
Reload the configuration.

38
00:03:04,130 --> 00:03:04,710
Try that.

39
00:03:04,730 --> 00:03:06,430
Engine X or path.

40
00:03:08,960 --> 00:03:11,690
And we get a whole bunch of HDMI L..

41
00:03:11,880 --> 00:03:14,190
I'll access it via the browser.

42
00:03:17,630 --> 00:03:18,550
Where at load.

43
00:03:18,590 --> 00:03:25,400
As if we're visiting engine X dot org directly so a completely remote website being proxied via our

44
00:03:25,400 --> 00:03:26,140
server.

45
00:03:26,870 --> 00:03:32,750
Now when I mentioned the importance of keeping the trailing slash on the proxy drl the reason for this

46
00:03:32,750 --> 00:03:36,910
is because of how engine X handles proxy paths to demonstrate.

47
00:03:36,920 --> 00:03:44,080
I'll create a new page prescript to pass to appear to be server corlett show underscore request dot

48
00:03:44,130 --> 00:03:45,220
patch B.

49
00:03:46,010 --> 00:03:48,720
Open that new file and in.

50
00:03:48,740 --> 00:03:54,290
I'm simply going to echo out the request you are right as received on the pier to be server.

51
00:03:54,380 --> 00:03:57,960
So in other words what our engineers proxy is requesting.

52
00:04:00,320 --> 00:04:01,730
Server.

53
00:04:02,520 --> 00:04:03,190
Request.

54
00:04:03,210 --> 00:04:04,140
You are I.

55
00:04:06,460 --> 00:04:10,310
Save that and launched a BHB server with a new file.

56
00:04:11,270 --> 00:04:13,190
Show underscore request.

57
00:04:15,310 --> 00:04:15,500
OK.

58
00:04:15,520 --> 00:04:21,320
Now when we call this engine X server the HP server receives slash or root.

59
00:04:21,790 --> 00:04:25,560
So there's no request being passed to the pier every server.

60
00:04:25,570 --> 00:04:32,050
If however I changed the proxy path in the engine X configuration file to not include the trailing slash

61
00:04:32,200 --> 00:04:33,240
like so.

62
00:04:34,930 --> 00:04:36,580
Curl again.

63
00:04:37,360 --> 00:04:41,110
We get slash P B so the entire you are right.

64
00:04:41,140 --> 00:04:44,070
As we requested it from the engine X proxy server.

65
00:04:44,140 --> 00:04:50,960
What this means then is that unless we specify a proxy path engine X assumes the original request path.

66
00:04:51,130 --> 00:04:57,290
Now sure you can create use cases for this but ultimately it's inconsistent and not recommended.

67
00:04:57,370 --> 00:05:00,980
So at that request you arrive to the proxy Dural.

68
00:05:01,090 --> 00:05:07,720
In this case when having the U R L specified as before we can still pass a customer request after the

69
00:05:07,720 --> 00:05:13,290
proxy path say BHB slash some slash you are L..

70
00:05:14,760 --> 00:05:15,350
What the B.

71
00:05:15,370 --> 00:05:20,030
B server receives is that last part some u are l.

72
00:05:20,140 --> 00:05:23,780
Don't worry too much about the double slashes at the start here.

73
00:05:23,920 --> 00:05:29,980
It's just how engineers handles the u r l substitution but it's normalized automatically and shouldn't

74
00:05:29,980 --> 00:05:31,450
cause any issues.

75
00:05:31,510 --> 00:05:37,140
This then being a logical approach to passing request you rise to a proxy server.

76
00:05:37,210 --> 00:05:43,150
Another important aspect of using engine X as a reverse proxy is passing custom headers to either the

77
00:05:43,150 --> 00:05:50,140
proxy server I appear to be server in this case or to the client on the reverse part of the proxy.

78
00:05:50,220 --> 00:05:55,090
First we can pass headers to the client using the standard add header directive.

79
00:05:55,450 --> 00:06:00,280
I'll name this header proxied with a value of engine x.

80
00:06:00,940 --> 00:06:05,980
Reload our configuration and test by curling that patch piece path.

81
00:06:08,530 --> 00:06:10,190
And we see the header.

82
00:06:10,330 --> 00:06:13,270
Remember however this is being added to the client.

83
00:06:13,300 --> 00:06:18,760
Only on the reverse part of the proxy so to add a header that gets sent to the proxy server.

84
00:06:18,780 --> 00:06:22,740
O appear each piece server we have to change this slightly.

85
00:06:22,760 --> 00:06:31,530
First let's modify that show request file to print out all request headers var dump get all headers.

86
00:06:31,750 --> 00:06:38,380
If you're not familiar with Patch B var dump is just a very verbose way of logging out variable or the

87
00:06:38,380 --> 00:06:41,100
return value of this function in our case.

88
00:06:41,140 --> 00:06:43,110
Restart the peer to p server.

89
00:06:43,930 --> 00:06:44,970
Test that.

90
00:06:45,720 --> 00:06:51,180
We get all our headers but of course not that proxy to header We added as that's going to the client

91
00:06:51,810 --> 00:06:59,850
to add this to the proxy request then we can simply change add header to proxy set header meaning set

92
00:06:59,880 --> 00:07:03,530
this header on the proxy request reload.

93
00:07:04,710 --> 00:07:11,220
Call that again and this time the very first value of this dumped headers array is that proxy to header

94
00:07:11,490 --> 00:07:13,730
with the value in Genex.

95
00:07:13,890 --> 00:07:19,950
That wraps up using engine X as a reverse proxy which as you can see engine X makes very easy in the

96
00:07:19,950 --> 00:07:24,290
next list will apply what we've learnt here to create a basic load balancer.