--- title: Upload YouTube thumbnail with the YouTube Data API and Rails slug: upload-youtube-thumbnail-with-the-youtube-data-api-and-rails published_at: 2021-03-01 18:00:29 +0000 updated_at: 2026-03-04 20:14:28 +0000 summary: description: Upload YouTube thumbnail with the YouTube Data API using Ruby on Rails. In this edition, we build on the previous episode by taking the base64 data URL for a png image, decode and write it to a Tempfile, then upload to the YouTube API to use as a thumbnail. Code: https://github.com/cjavdev/video_automation Twitter: https://twitter.com/cjav_dev Feedback: https://forms.gle/Q31hhjJGsMrvY4mL6 It turns out there's a really excellent tool called TubeBuddy that already exists and does most of what I was planning to build. I've started using TubeBuddy in the past few months and really like it. If you use this link to buy a license, I'll get a small cut for being an affiliate: https://www.tubebuddy.com/cjavdev. #rails #rubyonrails tags: [Upload YouTube Thumbnail API, YouTube Data API, YouTube Data API Ruby, Ruby, Rails, Ruby on rails, YouTube API Rails, Ruby Tempfile, Tempfile, PNG, PNG to Tempfile, PNG to Tempfile ruby, binmode, youtube api tutorial, youtube data api v3, ruby on rails 2021, ruby on rails projects, ruby on rails for beginners] views: 1675 author: CJ Avilla url: https://www.cjav.dev/videos/upload-youtube-thumbnail-with-the-youtube-data-api-and-rails youtube_url: https://www.youtube.com/watch?v=r5PIzDmRups youtube_id: r5PIzDmRups embed_url: https://www.youtube.com/embed/r5PIzDmRups thumbnail_url: https://i.ytimg.com/vi/r5PIzDmRups/hqdefault.jpg type: video --- # Upload YouTube thumbnail with the YouTube Data API and Rails *Published: March 01, 2021* *Views: 1675* ## Watch [Watch on YouTube](https://www.youtube.com/watch?v=r5PIzDmRups) [![Upload YouTube thumbnail with the YouTube Data API and Rails](https://i.ytimg.com/vi/r5PIzDmRups/hqdefault.jpg)](https://www.youtube.com/watch?v=r5PIzDmRups) ## Description Upload YouTube thumbnail with the YouTube Data API using Ruby on Rails. In this edition, we build on the previous episode by taking the base64 data URL for a png image, decode and write it to a Tempfile, then upload to the YouTube API to use as a thumbnail. Code: https://github.com/cjavdev/video_automation Twitter: https://twitter.com/cjav_dev Feedback: https://forms.gle/Q31hhjJGsMrvY4mL6 It turns out there's a really excellent tool called TubeBuddy that already exists and does most of what I was planning to build. I've started using TubeBuddy in the past few months and really like it. If you use this link to buy a license, I'll get a small cut for being an affiliate: https://www.tubebuddy.com/cjavdev. #rails #rubyonrails ## Transcript what's up everyone in this episode we are going to take our png data that's base64 encoded on the front end using the canvas element to convert from svg to png so we're going to take that data url we're going to pass it back to rails and then use that data with the youtube api to update a thumbnail so if you recall in the last episode we were working on automating our uh our ability to create thumbnails so i've got to restart the server here and then once this fires back up so if you recall this is what it looked like we have at the top this is an svg the second one is a canvas element and the third one is a png that was exported so if we inspect the png we'll see that right now the source of the png is this big long base64 encoded data so it's like a data url blob that's put on the image tag and what we want to do is when this button is clicked when this upload thumbnail button is clicked at the very top we want to make an api call to our back end to upload that thumbnail and so we're going to go do that now so i'm going to open up thumb.html.erb and the first so yeah at the very top we have the video title and subtitle i'm going to remove those and just keep the button element for now so we're rendering out the videos thumb dot svg so if we go to the video here so what we're doing is we are reading in the thumb base.svg.erb so we kind of made like an erb template svg.erb that is this base template and at the top we added d3.js and d3plus.js and then we have like a giant svg file and we went through and talked about how we get the font families to convert over from the svg into the pngs and at the bottom we have this little script tag that just has a text wrap so that if the font is you'll see here let's see i'm going to make that a little smaller make this bigger again sorry about that um so right now how uh how sort works in javascript is like going past the end there so i want to update this width to 1800 so now if we refresh now you see that uh how sort works in javascript that is like the title of the video and that is the png that's being exported so again the idea is that we have a whole bunch of youtube videos here that we're ingesting from the youtube api and we want to be able to just say like okay when we're when we're talking about this episode that talks about how this works in javascript we should be able to automatically create a thumbnail from from the api using this svg that is then generating a png based on the data that's on the video so right now we have the thumb svg data it's being rendered and converted to a png on the client now we need to go to uh to our controller and add a method to receive this svg file or the png file as data and then render that or like send that to youtube so right now we have this thumb.html.erb and it has a button so we have this upload button when the upload button is clicked we are preventing defaults we don't do the full page refresh we're grabbing the thumb.png that's the thumbnail that's this thumbnail so notice that the id of this is thumb dash png okay so thumb dash png we're grabbing the thumb png then we're creating a new form data object and we're appending the thumbnail as just the source that source attribute with all of the data and then we are making a post request with multi-part form data in the form data object to the video path slash thumb upload and then we're just going to like log out the response when we get it back so in our routes file we have a new route that we need to add for post that's going to be thumb upload and in our videos controller we need a new thumb upload action here and this is going to be pretty interesting so what we need to do is we need to first like extract the base64 encoded image then we need to decode the image data then what i think we want to do is create a temp file so create a temp file um and then we want to send the file data to the youtube api and then finally we want to close the temp file and then we'll just like render back some basic json so the very first thing we're going to do is extract the base64 encoded image so let's just say image is params thumbnail right because if we look at uh thumb.html.erb right our post request is passing the form data in this in this thumbnail attribute and so that should be the actual source attribute and the for the thumbnail we actually only want some of this so we want from the entire string we need to remove this first part of it right we don't actually care about data colon um image let's see if i can data colon image slash png data let's see data colon image slash png so that's the mime type and then base 64 comma we actually don't want that part so i'm going to say whatever the length so here this is going to be a string right and then we're getting a substring that's it that is starting after this point in the string and going up until the very end so that should give us the encoded image data then we want to decode the image with base64.decode64 and we're going to pass in the image data that should give us a decoded image next we want to create a temp file so we're going to just say file is temp file dot new and we can pass in an array where the this the last element of the array is the extension so we want this to be a png and then the first element uh we want i don't know some identifier or something so let's just use time.now.2i.2s so that we have some sort of name and then finally we want to send the data to the youtube api and we want to say like file.close file.unlink and i'll need to remember some of these temp file things but file.bin mode is true because we're using binary file dot write decode decoded image let's rename this decoded image decoded image and then file that rewind let's just look and see temp file ruby i need to remember and make sure that i'm using the right stuff here so temp file is going to just create a temporary file on the operating system and the things that we care about here are we we create the file then we want to make sure that we close it and unlink it so we did we do that close and unlink good and then what else do we need here how do we write to it hmm how do we write to the file oh here yeah just dot right okay and then yeah we just give it a string okay so i think bin mode is that actually right bin bin mode okay i'm pretty sure that's a thing but i don't know because we want it to be in binary mode and then ultimately we need to send the file to the youtube data api youtube data api for thumbnails so let's go to the reference and let's look at thumbnails set okay so we want to pass it as an image png so actually let's go look at our youtube service so in our youtube service we previously wrote some wrapper code around the youtube api right now we only have fetch videos that gives us a list of videos paginated and we have update video which syncs to the video at the bottom we have two helpers one is for initializing an instance of the youtube service and the second is for initializing an instance of the client given the credentials for the session which is injected when we initialize youtube so let's let's make a new a new youtube service object so in the videos controller in the thumb upload down here let's say y is equal to youtube.new and then youtube session.last should give us our last session that'll pass in and initialize the session then we want to call something like y.set thumbnail and we want to pass in the video and the file but right now we don't have the video yet so i'm realizing that we need to also well okay because routes because this is a member route under post thumb upload um then watch this so if we go to thumb dot html dot erb right like the the fetch the url that we're using is the video path so this will be like slash video slash one slash thumb upload and that one will be available or should be available i think as like params id so we want to say like uh video is equal to video.findparams id it might need to be params video id i'm not sure but that should give us the video object because we're gonna when we call set thumbnail we need to know which youtube id to use and we need to know the file i think um so let's go back to our youtube service and we'll add a new method here called set thumbnail it'll take in the video and the file and we're going to reuse our existing service object right because that's created for us down here so i'm going to say service dot and we need to figure out what the actual method is so youtube api github hmm last index 19 days ago whatever let's just look at this one so set thumb nail takes in the video id and okay so let's just call service.set thumbnail right because uh service is an instance of um youtube service so let's just make sure we're calling this on the right class wow this is a big class class yeah okay so we're in youtube service so that's good set thumbnail so we need the video id and then we need um the upload source which is going to be the file and then we need some options with our credentials um okay so set thumbnail we're going to give it video dot youtube id that's going to be our youtube video id we're also going to give it upload source is going to be the file and content type is image png i think and then options is the same as these options here okay all right so so we've got our youtube this is going to be our api call to youtube to upload the file and over here we are extracting the base64 encoded image we're decoding the image we're creating a new temp file we're writing the file then we're rewinding it so that we can re-read it as we are streaming the data to youtube and then after that's done we will close and unlink we should probably wrap this in like a begin um finally do we have finally or ensure it's ensure in uh in ruby okay just in case there's a failure on the api we want to make sure we're closing out the temp files and not leaving them hanging around um okay so what's next here is that we need to test it out uh okay so we go back to our video animations tab here and let's let's actually go to the sources and add some breakpoints so that we can walk through this so yeah so see this this id here should work for us we got multi-part form data um let's break there and click upload thumbnail all right so we have the source that looks cool um that's all of our data that we care about right uh or like that's the url the data url um that's embedded in the the png's source so now we're going to make a post request with multi-part form data i think this might need to be application json i don't remember and then we're passing the form data and then let's just go for it we okay so play and something failed so let's take a look uh undefined method square bracket for nil class is it not called thumbnail what did we call it oh is it not supposed to be multi-part form data let's see thumb um let's actually just leave out the content type since we're passing form data i think it should just know what we're talking about here uh maybe let's see okay clear that out click upload thumb all right we get a 500 undefined method bin mode okay so this was not a real thing videos controller let's take that out refresh click upload thumb 500 okay so hmm file okay so there's some sort of temp file bin mode thing maybe it's not a setter file.bin mode refresh clear oh yes okay so we got no content back but this in javascript this in javascript is in javascript so let's go back to this this video video 13. if we open this up in youtube and click edit video we see our new thumbnail awesome super cool so this in javascript awesome so that's not actually what we want it to be we want it to be the title we want the title be to be like how this works in javascript and maybe yeah maybe we can just keep the ticks um keep the ticks there and the subtitle is maybe like java script fundamentals and then if we click update video now our thumbnail should be different right so the thumbnail now has javascript fundamentals as the subheading then we have how this works in javascript as nice and big i don't know if i want the ticks or like technically i want this to be a different font but right now the svg that we're using or like the style that we're using doesn't support multiple it's pretty rudimentary but if we click upload thumbnail and wait a few seconds and then refresh this page we should have yeah boom brand new epic thumbnail so that is how you can take uh you know base64 encoded png data and pass it to your rails application upload that to youtube and use that as your your thumbnail data so hopefully that is helpful uh in the next episode so yeah i think in the next episode what makes the most sense is to try like right now the videos um or like these the subheading and heading for these videos is based on just like a string that i'm writing directly into the subtitle here what i think i really want to do is just create a series so you can select from all right which which series is this video a part of and then maybe also add support for managing playlists here so that when you are editing the video in this application you can pick which playlists on youtube it should go to that'll require that we use the youtube data api for playlists and that we list them and yeah but i think that would be cool because then you can do other things with the series like the series could have different fonts or different colors or a different like background color or something or even like a different svg template and so yeah i think the next part of this video series is going to be breaking out the concept of what is a series and um maybe even allowing uh managing um playlists so we'll see hopefully this was helpful if it was let me know in the comments below how you're going to use it or uh yeah super happy to help and share as i'm learning all of this cool stuff about the youtube api all right bye friends --- [Back to all videos](https://www.cjav.dev/videos) --- ## Hey Agent, thanks for visiting! 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