--- title: Ruby Sinatra Starter slug: ruby-sinatra-starter published_at: 2020-04-23 14:33:38 +0000 updated_at: 2023-01-30 22:51:08 +0000 summary: description: In this edition of Stripe Developer Office Hours, follow along as CJ Avilla walks through the fundamentals of working with Ruby Sinatra. For a getting started guide for Ruby on Rails checkout this other video: https://youtu.be/vULdSKCUhOs. ### Resources Sinatra web framework http://sinatrarb.com/ curl command line tool https://curl.haxx.se/ dotenv Ruby gem https://github.com/bkeepers/dotenv Stripe Webhooks Guide https://stripe.com/docs/webhooks/build Stripe Event Types https://stripe.com/docs/api/events/types Code: https://github.com/stripe-samples/developer-office-hours/tree/master/starter ### Table of contents 01:40 Agenda 02:39 Install starter with Stripe CLI 03:43 Create directory structure 03:54 Implement base client HTML 05:48 Install dependencies 08:32 Implement base server.rb 11:36 Add GET route for html file 13:20 Configure Sinatra 19:27 Add GET route for JSON to server 21:05 Add fetch to client to retrieve public key 24:30 Add POST route for JSON to server 28:10 Add fetch POST from client to server 36:33 Add webhook handler ### Presenter CJ Avilla, Developer Advocate at Stripe - https://twitter.com/cjav_dev ### Support If you have a question, please feel free to reach out to our support team on Discord at https://stripe.com/go/developer-chat. ### Updates Sign up to stay updated with developer news: https://go.stripe.global/dev-digest ### Feedback If you have any feedback about this or other episodes, let us know: https://forms.gle/VjNqzRhotM2snYo88. #Stripe #Payments tags: [stripe, payments, sinatra, getting started with ruby sinatra, Stripe Samples Ruby Sinatra, How to use Ruby Sinatra with Stripe, Stripe and Ruby, Stripe and Ruby Sinatra, @cjav_dev] views: 8026 author: CJ Avilla url: https://www.cjav.dev/videos/ruby-sinatra-starter youtube_url: https://www.youtube.com/watch?v=8aA9Enb8NVc youtube_id: 8aA9Enb8NVc embed_url: https://www.youtube.com/embed/8aA9Enb8NVc thumbnail_url: https://i.ytimg.com/vi/8aA9Enb8NVc/hqdefault.jpg type: video --- # Ruby Sinatra Starter *Published: April 23, 2020* *Views: 8026* ## Watch [Watch on YouTube](https://www.youtube.com/watch?v=8aA9Enb8NVc) [![Ruby Sinatra Starter](https://i.ytimg.com/vi/8aA9Enb8NVc/hqdefault.jpg)](https://www.youtube.com/watch?v=8aA9Enb8NVc) ## Description In this edition of Stripe Developer Office Hours, follow along as CJ Avilla walks through the fundamentals of working with Ruby Sinatra. For a getting started guide for Ruby on Rails checkout this other video: https://youtu.be/vULdSKCUhOs. ### Resources Sinatra web framework http://sinatrarb.com/ curl command line tool https://curl.haxx.se/ dotenv Ruby gem https://github.com/bkeepers/dotenv Stripe Webhooks Guide https://stripe.com/docs/webhooks/build Stripe Event Types https://stripe.com/docs/api/events/types Code: https://github.com/stripe-samples/developer-office-hours/tree/master/starter ### Table of contents 01:40 Agenda 02:39 Install starter with Stripe CLI 03:43 Create directory structure 03:54 Implement base client HTML 05:48 Install dependencies 08:32 Implement base server.rb 11:36 Add GET route for html file 13:20 Configure Sinatra 19:27 Add GET route for JSON to server 21:05 Add fetch to client to retrieve public key 24:30 Add POST route for JSON to server 28:10 Add fetch POST from client to server 36:33 Add webhook handler ### Presenter CJ Avilla, Developer Advocate at Stripe - https://twitter.com/cjav_dev ### Support If you have a question, please feel free to reach out to our support team on Discord at https://stripe.com/go/developer-chat. ### Updates Sign up to stay updated with developer news: https://go.stripe.global/dev-digest ### Feedback If you have any feedback about this or other episodes, let us know: https://forms.gle/VjNqzRhotM2snYo88. #Stripe #Payments ## Transcript [Music] in this episode we'll cover foundational topics and dig into the basics of Sinatra the web framework how it works and how we use Sinatra as a base for developer office hours episodes and also the stripe samples which is a collection of github repositories demonstrating integrations with many striped products so you might just be getting started and are curious about how to build an application from scratch to take your first online payment and this episode will cover some of the basics to help you get started quickly with Ruby and Sinatra if you already have a back-end set up and are comfortable adding new routes and are looking to add a stripe integration you may want to check out other office hours episodes where we show how to migrate or where we show how to integrate specific stripe products and features so why Sinatra Sinatra is a small and flexible framework it focuses on quickly creating web applications in Ruby with minimal effort and this allows us to keep the code for a demo concise while also showing a real working example so if you're working in a more feature-rich will have application framework like Ruby on Rails the same fundamentals apply but are implemented in a little different way and a bigger codebase that is more opinionated so it might be helpful to watch and refer to two other episodes that we've recorded before the first is an episode about managing your environment variables with Ruby and the second is an introduction to the stripe CLI so if you haven't watched those you might want to go head over and check those out as a quick agenda for today we're gonna cover how to set up the client with a basic static HTML file and stripe j/s installed and then we're going to show how to install dependencies with bundler and a gem file next we're gonna implement a basic Sinatra server dot RB file and show how to add and remove get and post routes and also at the end we'll wrap up with showing how to set up a post route specifically for setting up a web hook handler alright so let's jump right in and start writing some code okay so here in our office hours directory we just have a blank and empty directory and so the the point of today's show is to walk you through how we set up our starter template for all office hours episodes and really this is kind of the base for stripe samples so if you wanted to kind of just jump right to the end what you could do is use the stripe see a lie and say stripe samples list and find the office hour the developer office hours stripe sample here and then we could say stripe samples create developer office hours and this will install download and install the developer office hours starter template and today we're going to be talking about Ruby with the Sinatra framework and so now once I've run that stripe sample and I have this pulled down this is the code that we're going to implement today so we have a director server directory we have a client directory the client has an index.html file the server directory has a gem file with our dependencies and a server dot RB file and then there's also these dot M files which we talked about in the previous episode about managing environment variables so this is what we're gonna build today and we'll start actually from scratch so we're gonna remove that ok so we're gonna start from scratch so the first thing we need to do is create two directories a client and a server ok and I'm going to start off with building just a really basic client on HTML file ok so we'll start in here index dot HTML and it starts off blank we're just gonna add some HTML and we'll call this like developer office hours starter ok I'm gonna add some CSS and just like a little bit of structure so that we have something to look at now while we're here in almost all stripe samples we're gonna use the stripe stripe GS which is a client side library for or making calls to stripe and interacting with stripe the way this works is you install stripe j/s the library with this script tag and then we're gonna often in developer office hours we'll write an inline script in other cases we might include a script from that's a somewhere else in our in our in our project but for today we're just gonna console dot log hello world from this static inline script file so that's really kind of all we're gonna do with the client for now is just set up a really basic HTML file okay so we've installed yeah we've installed stripe we also usually will say you know initialize an instance of the stripe object this stripe class comes from or this constructor function really comes from the stripe J's library and this is a like a publishable key that you can find in your dashboard will show how to load that publishable key from the server ok so now that we've got that installed let's head over to our server and kind of walk through step by step how a the Sinatra server and the starter is set up so the very first thing we want to do is install dependencies the way this works in ruby with bundler which is a gem is we create a file called gem file and it looks just like this gem file there's no extension and inside the gem file we call source for rubygems.org that's where we want to install gems from and then we use the method called gem to specify what libraries we want to install so in today's episode we're going to use Sinatra that's the web framework we're gonna use stripe so stripe ruby is a set of ruby bindings Ruby language bindings to the stripe API so that we can interact with the API by calling methods on Ruby objects rather than having to like form our own HTTP requests will also use JSON which is just kind of like a helper live for formatting JSON and finally we'll use dot n which is to manage our environment variables another helpful library that you might want to use is Sinatra reload this is not usually in our stripe samples but it's not really required this just is a tool that will auto reload Sinatra every time you make a change to the ruby dot or BR to the server dot RB file so it's helpful but not required so I'm gonna add it just for the purposes of the demonstration today so I don't have to constantly restart the server ok so these are our dependencies that's how you specify what libraries you want to use and if you decide you wanted to add another library later here you would come into your gem file and add a new gem here ok now once you have all the gems defined in the gem file we need to install those so we can do that I'm actually gonna do that in another window here so I'm gonna go into my server directory say gem R um so if you don't already have bundler installed then you want to say gem install bundler that installs this tool that we're going to use to install dependencies from the gem file so if you don't already have that installed you'll want to install bundler and then you can say bundle install and that will look at the gem file that's in your current directory and go out to ruby gems and download and install these okay so the gem file I tried to be fancy and use this reload but it's not working so I'll just remove that ok bundle install the basic dependencies so you'll see that all of these dependencies were installed and we are ready to go ok the next step is we need to implement server dot RB so within the server directory we create a new file called server dot RB and the very first thing that you do in most ruby files is require any dependencies that you may need to so at the top we're gonna say require stripe and require dot and okay called en load to load our environment variables and then in in order to initialize the stripe Ruby client library we need to call striped API key and pass in the stripe secret and this is going to be the stripe secret key that's stored in our environment variables again for reference I'd recommend going and checking out the dot end environment variables episode that talks all about how to manage dot end files and environment variables okay the next thing we'll do just to test that this is working is will print out stripe plan dot list so that'll just fetch our plans we already have some plans created in the dashboard and so we know by hitting this API endpoint we'll get something back so now we can just say actually let's keep that open and then in this other window we can say Ruby Ruby server and we got ah right so we don't have any end file installed yet okay let's run it again alright so now we're getting back our plans directly from the stripe API by calling that stripe : : plan list so that verifies that we have at least set our API key correctly and we're able to use stripe now the API key that we set here is going to be tied directly to your stripe account and so in test mode you'll want to go into your stripe dashboard go to the developer section and find your API keys this API key in test mode is going to start with SK underscore test underscore and then a random string when you go to production when you go live you wanna take real charges and real payments this will be SK underscore Live they never ever want to share your live secret key because that is basically full access to your stripe account so here in development this should be your SK test stripe secret key and so that's that's really how you initialize the stripe Ruby client and we are ready to go and ready to make API requests with the stripe API okay the next thing we want to do is require Sinatra and start interacting with this web framework so Sinatra is very simple in order to add a new route a new get route so that your server can accept get requests we add we call get and we pass in the path that we want to this route to match up with and then you pass a block and whatever you returned from this block is what is returned so if we say hello strive devs then when we make a get request to slash we should receive this string back so we can do that by saying let's start up our Ruby server okay so that's the server server log running in the background by default Sinatra starts on localhost port four five six seven so now if we make a curl request to localhost four five six seven we should get back that string hello stripe Deb's because curl so curl is a command-line tool for making HTTP requests by default curl is gonna send a get request and we're passing in this localhost being the domain or the the host that we want to send a request to and then the colon followed by the port that we want to send the request to it's implied that we're sending slash as the root so this is our get request to the root and we can see in our server log that we did receive a request that was a get request to slash and it used HTTP 1.1 and we responded with a 200 status code so this all looks very good okay so typically when we go to the root route we actually want to return some HTML page this is usually like the static HTML page that is the index for our application and so what we want to do now is make it so that our get slash returns the HTML file for the client okay so with Sinatra you can modify some of the settings of the web server by calling set and then passing in some configuration so there's some predefined settings that we can set so one is static and we pass in true and that means that we want to be able to serve static assets ok so the static setting when enabled uses the public directory by default but because we want to make the stripe samples consistent across different web frameworks having the name of the client directory be public does not match all different client directories so we need to specify the public folder when working with Sinatra we also need to set the public folder to line up with all of our other stripe samples so we typically call the directory where we hold the static assets client and it lives in a directory that is a sibling of the server directory so at this point what we usually do is we want to pass in something like this client and by passing in dot dot slash client we're saying that when you serve static assets serve them from this directory that is up one and called client finally we want to also set the port set port for two for two so by default the port that Sinatra starts up on is four five six seven but again for consistency across all web frameworks we want to make sure that we're using the same port whether we're in Sinatra or Express or rails or whatever so we specify the port to be for two for two for consistency but also to be a little cheeky because four to four to is that special test card that we always use so we're this is how we specify the port now when you look at the stripe sample when you look at the actual stripe sample what you'll see is that rather than having the client directory hard-coded like this we use something like file join file der name underscore underscore file underscore underscore and we pass in the environment variable static dur and that's what we're setting as the public folder so why don't we break that down just a little bit and look at how each of those pieces impact the thing that's being printed out so let's let's just print this out and take a look in fact let's go one by one so this underscore underscore file in Ruby refers to the file name of the current file that's being executed so in this case because our file is called server dot RB underscore underscore file refers to the string server dot RB when we pass that into file name this is going to find the directory name where this file lives so in this case because we're running directly in the server directory file dot dur name is going to return dot and then when we do file dot join we're saying join the directory path to the current file with n dot static dur so let's let's print each of these things out you all together now okay so now we have let's also comment this out okay all right let's go check out what this looks like in practice so we'll just go back over to our server directory and say Ruby server and see what we get printed out here so the static dur is dot dot slash client and our file is server dot RB so the file dot dur name of server dot RB is dot and then all together is dot slash dot dot slash client so that means go up a directory into the client directory so it's equivalent of dot slash client which is what we want as our public folder okay so we'll delete all of that and then re-enable all of our settings here ok so that's what's happening when we're configuring Sinatra into the public directory for Sinatra now how do we actually respond with HTML for this get route the first thing we want to do is set the content type of the response so we say a content type is text HTML and then we want to send a file back so we're gonna say send file file dot join and again we're using this file that joined which combines all of the the components of a file path together in a an environment in like platform agnostic way so that it works it should work across Windows and Mac ok and also unix so we're saying file dot join and the first thing we want to pass in is that public directory and then the name of the HTML file that we're returning so we can access this public folder that we set here as a setting by using the settings so we have a settings dot public folder and pass in now index.html so that's going to combine our public folder with the index dot HTML file which is the file we want to respond with so now if we restart our server and make a curl request this time we have configured the port two-four two-four to localhost 4 - 4 - and we actually get back the HTML for our client index.html page so that's beautiful that's exactly what we want and it turns out that if we go to the browser now and enter in localhost for two for two we actually get back the content of that index the HTML page so we are we're looking good all right so that's how we return the index.html page and that's how we create our route route for for returning that let's see how we can make a route that returns JSON so this might be used when you're making an ajax request from the client to your server to retrieve something from the server so this is we're not gonna be creating anything but we'll be retrieving something from the server in many of the samples we use this to retrieve the public keys the publishable keys so that the publishable keys can be stored in environment variables and don't need to really be hard-coded into the client so we can add another route and again this is going to be a get route so we can say get two public keys do so here I'm specifying an actual path so I'm saying slash public keys this is making it so that when I make a request to my server I have to add slash public keys for it to evaluate this block and return something from this block so here I want to say something like content type in this case I'm going to be returning JSON so I want to say application JSON and the key that I want to return is in our environment variables and it's going to call it be called stripe public key I believe and to JSON and let's go let's go test that out so if we restart our Ruby server and we use curl again and this time we need to specify the path public keys and we do get back JSON and that key does look like our publishable key PK test so that lines up great at this point let's go modify our index.html file so that rather than using our hard-coded public key here we're fetching the public key from our you get route that's on the server and setting that on stripe so I'm gonna I'm gonna use fetch the fetch API so we say fetch and we pass in the path that we want to call so public key public keys so the fetch API returns a promise that resolves with this response object and then you have to call response dot JSON if it's a if it's a JSON response and that itself also returns a promise that when resolved we'll pass this data to console dot log so we know that data should have a key attribute and we want to use that to initialize a new instance of stripe and stored in the stripe variable so we can say stripe equals stripe data key and that will configure a new instance of stripe and set that value here so that we can use it throughout our new client-side application okay so let's let's go fire this up and see if it works in our browser so if we use right click and go to inspect this is how you open the browser console and there's a bunch of different tabs here the one that we're interested in is sources and then sometimes on the left you have to select index or the page that you're looking to test with I'm going to refresh and make this a little bigger okay so now you can see the code that you've written down below and if you want you can add breakpoints by clicking on the numbers the numbers on the in the in the gutter here so if we refresh the page we'll see that the browser is now making a request to slash public keys and the data it gets back is this key has this key property that has pk test and we're using that to now initialize our instance of stripe so we hit go ahead now there's a little warning here about cross-site resources and cookie attributes you can it's safe to ignore this there's like an issue with Chrome so we have now set our instance of stripe that's great inverse is gonna console.log our key here so now we are making a get request to our server and server is accessing an environment variable called stripe public key and returning that as JSON to our client another way that you might see this is in the dev tools here there's another tab called network and you can see all of the requests that are happening from your browser and so we see one of them is to slash public keys if we can click on that and we can see all the information about the request that was made and so if we look at the response I don't know why it's not telling us what the response is let's refresh and go to public keys and that's interesting it's not showing us the response but it usually will show you the the actual JSON response that you that was returned but we can see like other information about the response the fact that we set the content type to application JSON and yep so that's another way that you can sort of debug is by using these two tabs within the chrome developer tools okay let's make this a little bit more complex now let's send a post request let's learn how to add a route that receives post requests on our server and then we'll add just like a button to this page that when clicked will send a post request to Sinatra okay so let's start back on our server the first thing we're gonna do is add a new post route the way that looks is we say post and we'll call this like my post route and it will receive a post request and when when a server receives a post request this is like most common way to think about this is when a form is filled out on a page and someone clicks submit the data that's in the form that you have like typed into the fields in the form and the the check boxes that you've clicked and the radio buttons that you've filled in and maybe files that you've uploaded all of that data is collected up into something called the post body and the post body is going to be sent to the server so now within this post route we need a way to access all the data that was sent to us so for for a get request most of the time you are responding just like retrieving some resource and responding with that and you might have some query string parameters that included in the in the URL that's sent with the get request but with the post request you're almost always going to have some body some post body that you're gonna use to modify your response and typically a post request is used to create a resource on your server so for this example I'm just going to show how to access those post variables or the post body and the way this looks is we're gonna use JSON dot parse to parse the data that was sent to us in the post body so we'll say like maybe our data is json.parse request body dot read and we're gonna say symbolise names true that way the data that is returned has is going to be a JSON object where the keys are all symbols so that we can use them in Ruby as we would any other hash that has normal like these these style symbols as the keys and then we'll just we'll console that log the data that we received post with data to JSON to my post and then we will just respond and kind of like echo back that same data so we want to say now data to JSON that's what we want to return from our post row okay so now let's take a look at what that looks like so we'll restart our server now with curl you can we've seen how to make get requests with curl another thing you can do with curl is send post requests and you do that by using the - X command and specifying the HTTP method that you want to use so in this case we're making a post request to localhost 4 - 4 - to my post route I believe we called it and then you can use - D to pass in some data test 1 2 3 we'll just like make a JSON object here that we're passing in okay so the data that we got back was test 1 2 3 as a JSON object it's valid and then also in the console we see here that post was received with this data test 1 2 3 - my post route that's great ok so let's now go to our client to make a button that when clicked we can make a post request to this new post route ok so I'm going to add a button here very simple just IDE is gonna be BTN we'll say click me and so we need to grab reference to the buttons we're gonna get get reference to that HTML element the button by ID and then we're gonna add a click handler so that when the button is clicked we run a function that's going to be passed in as a callback and inside of that function we'll make a fetch request this time that is we're going to use fetch with a post request we'll make a post request to our server and then we'll just kind of like log out the data that we receive back so the first step is to grab reference to the button and we do that by ID so document here document dot get element by ID is a way to pass in the ID of an HTML element and grab reference to it so now we have a reference to the button and now we're saying BTN dot add eventlistener click so now we're saying like when the button receives a click event run this function so we're passing it a callback so this function that takes e and now we're calling eat up preventdefault this is a way that we can say run run this callback function when the button is clicked prevent the default meaning prevent submitting the form or prevent fully yeah fully posting the form we want to prevent the default usually because we're gonna make the request with Ajax and we don't want the whole page to reload and we're not building like an older style page that's fully submitting the form yet at this point we're just gonna make an AJAX request every time the button is clicked so now we're going to make a post request to my post route okay so this is how we use fetch the fetch API to make a post request so we pass in the route is the first argument that's a string and then we can pass this options block and in the options block the first thing we're saying is we're configuring it as a post request so this is like we're sending data to the server and configuring the content type as application JSON so we're going to send JSON to the server and then we need to specify the post bodies this is all the data that we want to send to the server now this data might be data that you have collected up from form elements or other HTML elements that are on the page or it might be data that you're just hard coding here so for now we're just gonna say like test and then abc123 that'll be one of the properties we'll say maybe a payment method is something like p.m. card visa that's one of our test payment method IDs you can use we might also say like customer cost 1 2 3 ABC right so this is like all the data that you can send from the front end to the back end this data you're collecting from the customer and passing to your own server so that you can make decisions and build logic about the data that's being sent to your server so this is this is where we're specifying the arguments that we're passing to our server now these can also be nested so you might have something like address which itself is an object and in here we have like line 1 we have 1 2 3 Main Street ok so that's how you would specify a nested object all this is going to be string if I'd into a JSON blob and posted to our server okay so then we will receive the response back again we have to parse it into JSON that returns a promise that resolves and then we're just going to console dot log the data that we get back and again because we're using this new this my post route kind of a simulated test route it's just going to echo back the same data that we're sending it so we should receive back the same data that we're sending here okay so let's go restart our server and check out what that looks like in the browser so if we refresh the page we should see a button here and we do big beautiful click me submit button again we can use a break point by clicking in the gutter on line 34 so that we can see when we click when we click on the button we will break in here but I noticed that there is an error so you can see in the console that there's an error by looking at this red X and it tells us there's one error 21 warnings or if you if you pull up in this console and you scroll through anywhere you see this uncaught syntax error and anytime you see like a red line that is going to be a an error that you need to address so here we have unexpected identifier index and then colon 44 that's that means line 44 so if we click on that and it says address unexpected identifier well this is kind of telling us like roughly where the error is and in fact this is because I did not put a comma after this string for customer and before I added this other key for address so I need to have a comma at the end at the end of this line after I put the string for cuss to let me go modify that okay that's how you find and fix some types of bugs and then if you you can clear the console here to see if there's any other error so if we refresh the page okay no more errors we do have some warnings but that's ok so now let's again we have our breakpoint there let's click on click me all right once we clicked the button we called this function so now we're in we're in the callback for the function and we're about to make this fetch request which is again going to execute this function when it resolves successfully so I will push play here and we can also look at the server log and see the requests come into the server log so the most recent thing was get public keys now if we push play we're we should see a request to my post route we can also see that in the in the network logs also so let's push play play means like keep going through the debugger so go to the next place where there's a breakpoint so I'm gonna I'm gonna remove that breakpoint and remove this one down here and click play so now another request was sent and we see success and the data that we got back so we got back this test we got our payment method our address line one which is nested all right so all of that data is coming back and where we're seeing that success console log here let's go look in the server log in fact we do see in the server log post with and then test and here's all of our data that we got back that's from our post route here in our server log so that's great ok so this is this is functioning as expected now if we click this button a bunch of times we'll see all of the HTTP requests that are being made there in the log and we can also again look at the network tab and see all these post requests getting fired off okay so preview decided to work this time so now we can see the this is the response that we're getting back another thing when you're making a post request in the network tab when you look at the post request if you scroll to the bottom you'll see the arguments passed in the request payload this is the same as the body the request body that's being sent so this is the data that is being received now by our server and then this in in preview is the data that we're receiving back from our server ok so that is how we add a post request and how we kind of connect it to our client let's go add one more route to our server for handling a web hook ok so this is how you add you know get request to send a file get request to send some JSON post request to receive some JSON and respond with JSON again like you might make a decision in here that says you know put something in the DB or fire API request - - stripe or to another third-party this is we're gonna build all of your like automation logic and sort of kick things off when you're handling these requests that are coming in from the client okay so the next the next request or the next route that we want to add is for handling web hooks so if you head over to stripe and go to the documentation under web hooks under building web hooks you'll find a bunch of different snippets and today in the example code for Sinatra we're actually just gonna copy this and then we'll talk through each of the bits so a web hook so to take a step back a web hook is a way that you can tell a third party where to send a notification when an event happens so in the case of stripe when a payment is processed or when a invoice payment fails or when a customer is modified or when a subscription renews all these are events that when fired on your account stripe can notify you of so it web hook is an API that is kind of like a way for a third party to tell you about something rather than you you know most of the time when we interact with an API we're creating or retrieving resources from the API maybe we're creating a charge or retrieving all of our plans right but a web hook is a way for a third party to tell you when something happens and so it's a very common tool that we use in all of our integrations and they're very dependable and it's a great way to automate some of your workflow that's based on these events that are firing so in in almost all examples we're gonna have a web hook Handler and so this is this is one way that we can set up a web hook handler so we are going to receive a post request the post request is coming directly from stripe in this case and the user never really sees the data that's related to a web hook a web hook is all between the two servers so the stripe system is sending a post request to your system the user is not involved in that in anyway other than they may have taken some action that resulted in triggering a webhook but they're not redirected here the user never sees this page this is all just like from stripe to your service so the very first thing we do is similar to in our post route we're gonna access this request body so we're saying request body that read that's our payload then we're gonna create a variable called event that we'll use below begin rescue end this is how we do a try-catch in ruby is with begin rescue end and so we are now going to use stripe event construct from and pass in the json parsed payload so the same way that we parse the payload up here and symbolize the the names - - to be or that we set the names in the resulting object to be symbolized we're gonna do the same thing here and pass the result in to construct from for event and this is going to create an event object that has all of the data related to the notification that you received then we're gonna if for some reason we fail to parse the JSON we're gonna respond with 400 otherwise we're gonna handle the event type so we have a switch so we have a case statement case when and each event type so all the different notifications that might be posted to your server will have a type specified with them and so there's a giant list of different event types that you that you may encounter so if we pull up the list of events that are available here you'll see there's this huge list of different webhook notification events you can see when a customer is deleted or when a discount is updated or when a subscription trial will end so these are all different event types so file created that's the event type that's the string that we want to match so in you might go through an ad when and then the event type as a string to handle different event types and automate different different situations so here we have a couple of examples so payment intent dot succeeded is an event type and the way that you can access the data that's returned from or that's passed to you in a webhook event is through event a dated object and these are going to be different depending on the event type so for event for an event type that is payment intent on succeeded when you access event data object the type of object that you get back is a payment intent so then you can take action on that payment intent maybe want to look at the status of the payment intent or the amount that the payment intent was for so you might also implement a function called handle payment intent succeeded so this is where we're handling the event type and doing different automations if we didn't specify or if we're not handling a specific event type we might return with the status 400 for those we're not handling and then at the end we're just simply returning a status of 200 in this status again is being returned back directly back to stripe so this is how we set up a web hook handler we actually have a separate episode that is all about web hooks so if you're curious about more details about this or about how to verify the signatures and kind of secure your web hook handler so that you know you're you know that you're receiving the web hook from stripe and it's verified that it's only from stripe and no third party is trying to like send post requests directly to your web book handler to get free access to things then we have a whole other episode about how to do signature verification and so I would go I would recommend going and looking at that so that's really how you use the stripe starter and how the stripe starter is built hopefully this was useful and learning some of the fundamentals of how we use Sinatra with stripe samples and also with developer office hours hopefully this was useful and we'll see you next time you --- [Back to all videos](https://www.cjav.dev/videos) --- ## Hey Agent, thanks for visiting! 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