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I 1st it started here that I think to come out I'm USB keys have 2 files you'll need the beggar file in the the exploration box file if you don't have Vega inverter box there are some rules on their for Windows Linux variance limits and Mac but you'll need to have those installed on the new half hour lecture the hopefully will shorten that and then will have about an hour to run to the exercises but the exercises all walk you through starting a vagrant in everything needed I also have Charlie Sanders openly announced eraser and if you need a USB key idea of files from and as and
so you basically get half an hour you know that work and if you don't Daugherty might you compared with the neighbor I would appreciate feedback negative or positive I you can tweet me at projector and Mellissa's up there and my presentations are I get out i haven't put the latest this presentation yet but should be there tomorrow I guess a file long tiny C C H V exploration with an underscore will take you to this presentation but actually think any update that time so that we get the exercises the exercises will be in there to support them out when we start the exercises am so that the reason I started doing this is I actually have a previous life as a sysadmin and our given so I've actually done a lot of trouble shooting of HDP and don't to networks going to firewalls and now morals developers so I've seen both sides the I also talk about 6 request responses talk about proxies and troubleshooting initially to and then we'll get to the exercises that touch on all those and so HPs around since 1991 uh the 1st version and actually a version number but retroactively colored 0 . 9 I was standardizing 96 other and then we typically use now is standardized in 2007 that R C is very handy if you have any questions about how it should be works I was just updated a few months ago was broken up into smaller pieces have basically in preparation for B 2 82 2 has been a ratified standardized but it hasn't been published yet and that's a good you're out if you're interested and so the aged is stateless which means that at each time you connect to the server it doesn't really remember what you did the last thing we connected to the server and the only way around that is through cookies for a much and is text-based that's kind of the whole point presentation were going to look at the text is going across the wire and it's request-response cycle you client your browser will make a request to the server the server will respond and so on top real quick about URLs and so pretty much every piece that you're all on the screen will go from client to server except for the fragment the fragment just tells the browser to go to this specific spot on the page and indeed scheme is going to be a 2 D of the host is obvious you can specify username and password in URL Bregman against that but that's possible on and then the path is actually the piece that goes with that will be working with for the most part to the the and so the issue request with like this the other thing in green is called the method so for part of that and that's and the next thing as fast as the euro I'm usually is not the full you're usually it's just slashes starts with a slash in its relative to the top of the site and in the other version of a ship he specified there and in blue are the headers so the headers are sort of metadata about and what you wanna get or which 1 do you and in this case there's are those that accounting link there and the body I'm not I request our body if you just getting something a whatever everybody but supposing something were putting something you will have a body in this case I try to put something to Google's front-page prominent in work actually tried that and because of 4 0 5 here which defined and so that's the body text basically the content that you want to upload the this so the methods i talked about and normally when you do a when you go to a website you're going to do a GET request said they did this page good tools page do yet I'm opposed is when you want to update something or when you submit a form although some forms can actually do get depending on if you're changing something were just doing a query like when you go to Google's front page so that form when you type in the the query that's a get is Iraq's adjust asking for information around not asking to change anything at a point is actually an it's an update to or X is more of an observer your saying I'm giving you the whole thing replace whatever you gotta have anything otherwise creative and rails low we're on that that doesn't actually do the crate part of that and so it uses put a little bit of the delete does what it says if you have permission you actually can delete pages or resources through the web head is basically a GET request but without the body is saying show header is that I would get if I did the GET request for this Euro under the concept of safe methods and so safe methods don't have any effect on information I talked about the the coast it changes something when you submit a former changes something on the server I get is not is not the case I'm so this is a weight here is don't have your ABC change things when you do again because when Google comes scraping your site is going to do gets on your site if your site changes something on the back end you can have a bad day so but just keep safety in mind and there's also something called item potency and that means that you can call the same thing model times I mean you get to the dual front page mobile times the same thing same thing with the head the same thing with if you delete resource you know if you know the resources go beyond if it was there not as a points you're actually saying replace something so if it's there were placed it it's not they're related so the double the times doesn't matter and the 1 that's missing from this list the in his post so if you post something model times you'll end up with multiple copies of that thing do it and so request headers so we saw that we can provide those headers and these are some common headers the host header is is basically required and it says and the name of the website were accessing I'm and the reason that that was added is so you can have a you could host mobile websites sites on a single server and the accept header says a list of current the types that the browser would like to receive so the browser may say that it likes to have reached the peak in mice have J. Sun but not mistakes and also if the server knows how to do uh ation Alan J. Sun and pick 1 those but it wouldn't pick axonal did know anything else an and the word thereof accept headers you can actually specify relative quality sometimes a CQ number if you look at the center and that says I prefer for these types of things over the other things the default quality setting is 1 which means top priority and if you prefer Jason over X now you could set is quality to 0 . 9 in to 0 . 8 the have content length on a request header is the content of the body of the request that you're sending I'm and if you don't specify that it actually just did doesn't let you specify anything once you're uploaded the content like number bytes in the body the word the several close the connection I the content type tells what you're uploading him my uploading some HTML on of ligands maximal and wings and Jason the further is if you are a browser it's the page you're on when you click the link that is spelled incorrectly but since this dying and so that's what we use to have user agent is another name for a browser web client and it could be a web crawler uh could be various things and it's a string containing the information about the browser and and if you take a look at those those get to be pretty crazy long especially in Chrome and Firefox they try to pretend so back in the day there was something called browser sniffing the server would look at that string and try to determine how I'm in a exploring in giving this copy the page and your Firefox and give you this gap the page and which should be to be completely different and you will be like that because Google 131 canonical version of every page that it indexes and I didn't want you full it and so it is 1 thing going user see something else also browser sniffing is not used to mention a model and but you end up with these really long strings that tell you sort of all backwards compatibility that the browser tries to do the and we'll take a look at those centers in the exercises yeah but what it is the the yes the the so the
yes yes and then content type is only for a post or put in its 1 type the body that you're standing up to the server yes yeah and so authorization is for but if you ever get website and get the pop box and authorization is basically that information you type in username and password box but it's it's not encrypted is are hashed and sent were actually gonna there's an exercise are actually going to find that going across the wire arm accept-encoding and you can actually GZ things going to the server king and GZ all the content coming back to this basically says that's OK you can say content encoding Jesus comedy plate that tells the server hey I can this and save some of bin with across a lot I'm connection and you lose for keep alive it is the client saying hey I've made this request but when I'm done and then make another request don't bother turned down the TCP connection I wanna reuse it for the next request so from the web page and I know it's probably going to have some jobs scripts frolic has CSS on it lets me get those all in 1 without dropping the connection and cookie so I doubt about the yes from a kd is the server has synthesis cookie and we are supposed to return I could back to it and that maintain sessions of the server between the server and the client and that's the only thing they maintain the session between the client and server and that had a is limited to about 4 K of information so our if we do are cookie-based sessions in rails we do have to worry about that when you will was storable lot in that cookie a the the right so we made the request and the server responds with the Hb response are the 1st line is called the status line as get the HP version the interesting thing you can actually make a request for 1 version and get a different version back I find that a little on the the 2 1 there's our status code and then there's the description of stance can which created in this case and and then like the by the request and the response actually also has headers I and then it has a body and not every response has a body and there's a few that don't have to have a body created is actually 1 of those and so if you are doing a PUT or POST he could actually just say created in then don't give you anything back but you probably wanted your reader right so you probably want some some extra information there from so status gives so the status goes have different meanings and they're actually standardized um although occasionally you'll see some non-standard ones and the wondrous are informational you'll rarely see those the 200 0 which is seen as a time and usually forget you can get a 200 for a poster put your problem a C at 2 0 1 and redirection if I go do google that time it'll actually redirect you to www . google outcome that's a redirect and I believe that would be a a 301 if you send headers from the involved with caching which will do an exercise you'll get sometimes a bit not modified in that says hey you've told me you already have a copy this in your cash so I'm just gonna give you the metadata from the headers from I can give you the body you should use the body that I give you last time and so then we get the error response codes and so 400 so our client areas where the client made some sort of mistake the come unauthorized is but if you have not center-north indicator and the web server requires you to authenticate and the client is supposed to retry with the UK authenticated and so before does that pops the box up as detection using passive reasons With that had unforbidding means you probably either you're not and you can't authenticate or you've indicated that you still won't have permissions because but maybe you're not in administrator in the box and for a hour we also known before adaptation of phone and 4 0 7 is a proxy authentication required is like a 4 1 except it's the non-transparent proxy that is asking for our username and password that's pretty rare C but we will do a little better proxies but were not enough to an approximate indication of 4 22 is on cross in D which is a weird way of saying I don't understand what you're trying to ask me on that is recommended that's what I would recommend you therefore 20 or 4 29 R 4 0 9 if you are making an API request and it doesn't have the right information the needs in in the j sonorants known whatever but that you sent on server errors so if you were server crashes really badly you will see a 500 air and I believe you see that in rules a lot of times when you're debugging and 502 and 504 Gateway years so if you've got a reverse proxy as seen from your servers and your service of going down the take too long respond you'll see a 5 0 2 or a final 4 and there are plenty of others and I ran into a 5 of our 4 or 5 earlier as 1 of the April 1st are sees called I'm a teapot response before 18 code lecture when only then I'm sure someone is implemented and responses so like a request response has headers and the contemplate will almost always be there because you'll have a response that has content in the body the content type and it's the mind type so can be like text slash HTML and text slash plane applications such Jason Sun I was image slash JK English-Latvian G that tells the client what of police's and then it can handle that however expects you other content encoding is some i i talked about accept-encoding where you can't use a bit of the continent coding says the body has been Jesus and notice that the bodies GZ but that the headers actually still in plain text constant disposition is a little trick that to you use when you want to have when the person clicks on the link and you want them to download the file instead of how the file display in the browser I'm in that case you would use and cut and disposition header and you can also provide a default file name that the browser will try to save it as location location is used for redirecting and will have an exercise on the unusually on was provided a response code that has this as redirect and you provide the URL to redirect to in the location of the the Set-Cookie we talked about cookies for maintaining state linking sessions as set cookie tells the browser to remember this token there's just roughly a random string of characters and when it gets sent back by the browser and the server knows you associated with the session would set up in the database and www authenticate is that basically telling the browser that part of the box war and if there are attacked a username and password to provide that information to the server right so I will running the proxies will have some exercises on proxies so proxy is something that acts in place of another i in the case of the HDP proxy web proxy it intercepts are should be requests and so can modify their request so what it does is it in intercepts requests modifies it probably doesn't caching traps and says it on the server gets response back server can modified ending in an instance back to the point so it's it's in between the those the client and the server and a can modify pretty much anything the season the I'm surprise 0 good for caching I you can add security and so I've actually actually are exercises we will add some SSL to our our rose up and so you do this to simplify so you don't have to have the roles that to understand SSL but also consistency CPU done also can be used for load balancing and you can use for authentication and lightheaded where I had a patchy in front of a a application server and we added the popup of an occasion for with Apache the acting as a reverse proxy little talk 1
2nd and so the transparent proxies and basically you don't have so anything up its input itself into the stream of the network and there's non-transparent proxies which lots and if you're working in a big company you'll have to configure browser to point at the proxy that's a non-transparent proxy and we can exercise in but reversed in for a proxy so the proxy you haven't work that's it's sort of right next the firewalls would be a for a proxy air averse proxy sits next to the servers so right near the servers anything that's any price is added on the server in is a reverse proxy and we will actually have exercise on both of us and the a CDN is accounted delivery network is basically a paid service but that does proxying for caching purposes so you can catalyst that accountant and in technical things in here I will can to mention to only things it can provide protect you from a distributed denial of services and if you got a big site you should probably looking into these and troubleshooting so any network from you have yet to think about the OSI model and I wish I had true that for a for that but see you've basically got the physical layer you got the network layer gets transport layer which is TCP then better applications and so there's a lot of things that can go wrong you never never cable that you could have your your routers down on board the servers not learning so all those different layers have to think about when you have a problem troubleshooting is trying to figure out which layer it is and then narrowing down and so for the 1st tools came can I connect to the by the address that the service on on from 1 that is sometimes be firewalls will prevent that either following your company or the viral on the other hand trace artist similar but it shows you all the mountain between so maybe the never is down between an your interactive Irene Google trace trout my be P find at reuse in our exercises as a good way to tell if if the porters listening if I got connectivity to the IP address that tone that will tell me if the services listening and and that's actually kind where I start it can start a little and then if you tell it doesn't work I'll try to lower layers that does work on try their providers but during a server and you wanna see if you're services listening you units that on Linux that's desk PLAN t it's easy mnemonic to from the new member on back uh doesn't have all those options are you'd use dash in a in the referee listen and then so that's gonna list left side if there was all the IP addresses which is usually don't always be your IP address and colon in the board number so if you're looking to see browser earning become less side for something called 3 thousand system use that fall portorož an telit doesn't work with HDS because it's encrypted so you have to use this tool that addresses all provides called as client and with an exercise and that's tcpdump if you really wanna see all the detail was going across the wire it'll tell you everything that we got a short exercise on that there's so much information browse than couple hours and outlier shot is a good way to visually see what's going on I you can actually take the output of tcpdump has to file pull it in Wireshark I Wireshark as a nice feature tcpdump shows you each individual packet and the dead disjoint on when having communication between a client and server and your Paga's can only be so big so by the communication will be broken up into pieces and Wireshark is nice feature to put all those back together which is chemical right so as I said each of the 2 was recently approved and ratified it came out a project at Google called speedy as PDY apparently they want to make it speed say to write the words we I'm so as I said we can we can compress we can't use that the body you but we can't initially 1 boy 1 we can compress the headers at each bag as part of a to 2 that allows header compression but the another thing uh the at the standard of the requirement required but every it'd be tunable mentation out there requires the last and that's problem because it's got t alas or SSL has a protocol negotiation built into it and that particle the gotiation can say Haiti of a should be 2 I like to use that give speedy 3 and like use that but it's not fall back to THE 1 I am so I said that is to be is all text it should be 2 that turns out not to be the case because were compressing matters and it has the same semantics you will be able use town that you will be able to use that tcpdump but you will be able use some of the other tools that will be looking at today but I did get an example the work with they should be to other we can do as an exercise the and when you're making a lot of small requests on like let's say you've got a lot of the icons on your page and ideally you would just get each icon individually but those items are only will you know 25 K or something but that when the header is that a couple k are starting large overhead if we can compresses down to you know a couple dozen bytes would save a lot of been with under some other features in each machine with its in Sec and basically this is a band with I get the variation to its B 2 is it multiplexes the connections you can actually have multiple files coming across at the same time with a single TCP connection right now your browser has to make and multiple TCP connections but I don't know the browser to they started like Ford a timely annotated sign and but that means you uh TCP connection takes up resources and it takes time to set up a city just want to see the connection that was so sometimes that's 1 thing they've done seeking grab giving you can grab your HTML file and you can actually start processing and see head doesn't outstrip against an image is I've got some CSS undergrad while those 2 2nd grab although simultaneously so as the save a lot of time a server push the server can actually know hair he's getting the 1605 0 he needs a CSS file to under start given to 2 and even if you can ask for and the client and say well I'll take that uh I have an association of Ireland in the that is as file you can stop give that to me the and which is kind of weird with guassian I don't know how it knows what's been cashing what's what doesn't put it the possibility is there to save some time I am so when we do web design and web development and we've got the acid type right and that combines all jobs give files in 1 big file it combines the CSS we probably combined that in 1 file the images we probably has something to do something cusp writing where we put a bunch of images in 1 file and CSS tested go grab each piece to put each icon on their i've you look at the yeah I know I've looked at the home patriotic and it's gotten all the icons on laughter those are on 1 file and the CSS gymnastics we have to do is a pain in the butt and age me too will hopefully allow us to stop doing that we can just write it the way that it should have been written in the 1st place not worry about formants if beauty http to should I do that force H V 2 is kind of weird that it starts with a 1 . 1 connection and upgrades and so that the semantics that are pretty crazy you probably on and get involved in that and will will see a little bit about of that in the verb boss of the velocity of the tools we use which show a little bit of and so where's http to working at from 41 hazard far 36 I 11 but only in 1 is then so nobody has yet except in data but engine accesses supported by the end of 2015 they already support us be 3 1 which is pretty darn close and I could not get curl to work with and next using speedy or it to be to of so curl for used right now you have to specify the HTTP to flag and a for this I had to manually compiled that feature in a Wireshark to will have their currently in the beta series 1 . 9 9 out of 10 she's doesn't seem them plants which seems a little weird does months be available you
alright so it's time for the exercises I need a day that neural real quick and but but the Charlie will be walking around how the people get started and the exercise is base of leaves starting on page 27 of this arm and so the 1st step is
basically at the bigger box with Beckham in there but do a about an innovator in this is h you'll be in the box and then you can move on to the slide 28 I will read all support H he beats you probably not for a long time and so realms really does Maurice he and you'll hear the unicorn or your promo are what supports that so when those supporting the 2 that we will have a build into rules rels itself sources right behind them but right now if you wanted and you would put a proxy for an input into next is my recommendation and next said they have 95 per cent of the lowest b the time of service on the Internet so you would use a reverse proxy that well aid rails also dozens more h to be s so you probably want yes on your sides you probably that pricing other questions 1 of the things that you hear
about the efficiency this
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we and and and the it would be the a false we have 10 minutes left and what should be served you got this virtual machine that you can start up or you can leave it running you can data necessary to newer later and we the exercise at all so I my e-mail address my tutor are In the presentation you can ask me questions later I think in the centimeter it it FIL would the rule of his allusion to them
Computer animation
Computer file
Key (cryptography)
Variance
Cuboid
Limit (category theory)
Rule of inference
Inverter (logic gate)
Window
Logical constant
Gateway (telecommunications)
Randomization
Video projector
System administrator
Scientific modelling
Client (computing)
Disk read-and-write head
Front and back ends
Maxima and minima
Medical imaging
Web service
Mathematics
Code
Error message
Information security
Descriptive statistics
Touchscreen
Software developer
Electronic mailing list
Sound effect
Bit
Instance (computer science)
Arithmetic mean
Process (computing)
Duality (mathematics)
Quicksort
Cycle (graph theory)
Web page
Point (geometry)
Numbering scheme
Computer file
Firewall (computing)
Code
Rule of inference
Number
Goodness of fit
Crash (computing)
Database
Authorization
Scripting language
Form (programming)
Authentication
Default (computer science)
Information
Content (media)
Set (mathematics)
Line (geometry)
Cartesian coordinate system
Uniform resource locator
Word
Personal digital assistant
Query language
HTTP cookie
Intercept theorem
State observer
Web crawler
Length
Code
State of matter
Multiplication sign
1 (number)
Weight
Mereology
Logic synthesis
Web 2.0
Video game
Plane (geometry)
Linker (computing)
Cuboid
Central processing unit
Electronic visual display
Area
Email
Closed set
Price index
Connected space
Shooting method
Website
Right angle
Lastteilung
Data type
Reverse engineering
Server (computing)
Presentation of a group
Adaptive behavior
Web browser
Metadata
Revision control
String (computer science)
Proxy server
Graphical user interface
Mobile Web
Consistency
Subject indexing
Computer animation
Password
Computer network
Dependent and independent variables
Musical ensemble
Multiplication sign
Scientific modelling
ACID
Client (computing)
Function (mathematics)
Mereology
Disk read-and-write head
IP address
Semantics (computer science)
Medical imaging
Web service
Computer configuration
Data compression
Velocity
Single-precision floating-point format
Flag
Physical system
Boss Corporation
Email
Closed set
Electronic mailing list
Bit
Connected space
Process (computing)
Telecommunication
Website
output
Right angle
Whiteboard
Data type
Bounded variation
Web page
Point (geometry)
Content delivery network
Server (computing)
Overhead (computing)
Computer file
Firewall (computing)
Virtual machine
Similarity (geometry)
Web browser
Streaming media
Webdesign
Computer icon
Number
Router (computing)
Proxy server
Associative property
Units of measurement
Address space
Series (mathematics)
Multiplication
Standard deviation
Hazard (2005 film)
Information
Forcing (mathematics)
Projective plane
Interactive television
Planning
Denial-of-service attack
Cartesian coordinate system
Particle system
Word
Computer animation
Personal digital assistant
Web-Designer
Computer network
Communications protocol
Slide rule
Web service
Computer animation
Internetworking
Multiplication sign
Source code
Cuboid
Proxy server
Rule of inference
Reverse engineering
Revision control
Slide rule
Arithmetic mean
Voting
Computer animation
Physical law
Dependent and independent variables
Right angle
Line (geometry)
Regular graph
Units of measurement
Area
Computer animation
Right angle
Data structure
Theory
Computer animation
Theory
Email
Computer animation
Presentation of a group
Virtual machine
Rule of inference
Address space

Metadata

Formal Metadata

Title http://exploration
Title of Series RailsConf 2015
Part Number 66
Number of Parts 94
Author Buchek, Craig
License CC Attribution - ShareAlike 3.0 Unported:
You are free to use, adapt and copy, distribute and transmit the work or content in adapted or unchanged form for any legal and non-commercial purpose as long as the work is attributed to the author in the manner specified by the author or licensor and the work or content is shared also in adapted form only under the conditions of this license.
DOI 10.5446/30663
Publisher Confreaks, LLC
Release Date 2015
Language English

Content Metadata

Subject Area Information technology
Abstract We're web developers. But how well do we know the web's core protocol, HTTP? In this lab, we'll explore the protocol to see exactly what's going on between the browser and the web server. We'll cover: HTTP basics HTTP methods (GET, POST, PUT, etc.) HTTPS Troubleshooting tools Proxies Caching HTTP/2 We'll investigate how we can take advantage of HTTP features to troubleshoot problems, and to improve the performance of our Rails apps.

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