A Hacky Guide to Hive (part 2.1) YO broadcast

Broadcasting

<p dir="auto"><a href="https://peakd.com/dev/@felixxx/a-hacky-guide-to-hive-part-15" target="_blank" rel="noreferrer noopener" title="This link will take you away from hive.blog" class="external_link">Last post, I talked about how you can <em>get data from the blockchain.<br /> For some applications that might be all you ever need. <p dir="auto">But maybe you want to <em>store something <em>on chain.<br /> For example: you want to make a vote: <p dir="auto"><img src="https://images.hive.blog/768x0/https://files.peakd.com/file/peakd-hive/felixxx/23tRrRPGbYfyCGnXPHV7aVow71dGKnoNVAeJNDbhht5R2ZKNGeyfMk1Ds3XeSNHPgD6zA.png" alt="mouthpiece.png" srcset="https://images.hive.blog/768x0/https://files.peakd.com/file/peakd-hive/felixxx/23tRrRPGbYfyCGnXPHV7aVow71dGKnoNVAeJNDbhht5R2ZKNGeyfMk1Ds3XeSNHPgD6zA.png 1x, https://images.hive.blog/1536x0/https://files.peakd.com/file/peakd-hive/felixxx/23tRrRPGbYfyCGnXPHV7aVow71dGKnoNVAeJNDbhht5R2ZKNGeyfMk1Ds3XeSNHPgD6zA.png 2x" /> <h3>Python broadcast <p dir="auto">Assuming you have <a href="https://github.com/holgern/beem/tree/master" target="_blank" rel="noreferrer noopener" title="This link will take you away from hive.blog" class="external_link">Beem installed, the easiest way to vote for this post would be: <pre><code>from beem import Hive hive = Hive(keys=['yourpostingkey']) account = 'youraccount' hive.vote(weight=100, account=account, identifier='@felixxx/a-hacky-guide-to-hive-part-21-yo-broadcast') <p dir="auto">While this may be a neat example of how to do get the job done, it's not the best way to go about it.<br /> I just wanted to come in hot and start with a working example. <p dir="auto">Clearly you could improve this code a lot, but before that, the most important here:<br /> For it to work, there must be a private key stored in the code itself. That's not good. That's not safe.<br /> There are many different ways to make this safer and I will adress some, but for now: <h3>System Design <p dir="auto">This may be a <em>hacky guide, but I don't want to write a <em>shitty guide.<br /> The first line of defence against vulnerabilities and errors is to adress them at system design level. <p dir="auto">You could go ahead and write a long script that looks something up on chain and then reacts to events somehow and broadcasts a transaction, and loop over all this somehow...<br /> You could automate something on chain like this. That approach works and I've seen it and done it. <p dir="auto">If you aren't careful, you will end up with a pile of spagetthi code with your keys somewhere inside of it, though. <p dir="auto">I am not the right guy to write a guide on system design, but I'll not just hack away, either.<br /> I don't want to just post code snippets. I will lace in the design principles, that I have settled on. <h3>Python limitations <p dir="auto">Leaving design and safety aside: if you look at this stuff with only your Python hat on, eventually you will run into a wall. There are problems that are very hard or impossible to solve, if you try to do everything in a single script. <h2>user broadcast <p dir="auto">If you want to have <strong>users input something, Python is in most cases the wrong toolbox. <p dir="auto">First of all: if you don't have to, you shouldn't be involved in the signing of other people's transactions. In <a href="https://developers.hive.io/" target="_blank" rel="noreferrer noopener" title="This link will take you away from hive.blog" class="external_link">the documentation it says: <blockquote> <p dir="auto">By utilizing Authenticating services, you can eliminate or give more confidence to user, so they are assured their keys are safe. They can securely interact with your application, website or service. <p dir="auto">So, right out of the gate: I don't want to touch anyone's keys.<br /> And if I don't have the keys, this whole Python-side signing stuff is useless. <p dir="auto">The good news: You can just hand over those responsibilities to a third party.<br /> That makes your life easier and the final application safer. <h3>Custom User Client <p dir="auto">I need to be careful here to not overuse the expression <em>client.<br /> In the last post, I talked about writing your own <em>custom client for Hive.<br /> That was in Python, and like I wrote above, this can do a lot of things and get you quite far. <p dir="auto">But you may also want to build your own <em>custom user client, that allows your <strong>users to broadcast to the blockchain, without you being directly involved in signing process. In this case it is easiest to just leave the Python environment and use javascript instead. <p dir="auto">If you want to just stay in Python, and don't plan on making user interfaces, the next part might seem useless at first. I am trying to make a point though. Please bear with me... <h2>YO <p dir="auto">As an example, I created a really simple game.<br /> It only has one move: an empty custom transaction on the Hive blockchain, of the type 'YO'. <h3>Code Example with <a href="https://github.com/hive-keychain/hive-keychain-extension/blob/master/documentation/README.md#requestcustomjson" target="_blank" rel="noreferrer noopener" title="This link will take you away from hive.blog" class="external_link">Hive Keychain <pre><code><!DOCTYPE html> <html> <style>button{margin:124px;font-size:48px;}</style> <button id="yo_button">YO</button> <script> let yo_button = document.getElementById("yo_button") yo_button.onclick = () => { window.hive_keychain.requestCustomJson( null, 'YO', 'Posting', '{}', 'YO broadcast', (response) => { console.log(response.result); } ) } </script> </html> <ul> <li><p dir="auto">save as <code>yo.html <li><p dir="auto">you <strong>need Keychain browser extension installed<br /> <a href="https://chromewebstore.google.com/detail/hive-keychain/jcacnejopjdphbnjgfaaobbfafkihpep" target="_blank" rel="noreferrer noopener" title="This link will take you away from hive.blog" class="external_link">for chrome<br /> <a href="https://addons.mozilla.org/en-US/firefox/addon/hive-keychain/" target="_blank" rel="noreferrer noopener" title="This link will take you away from hive.blog" class="external_link">for firefox<br /> you <strong>don't<span> want the SDK or anything else from <a href="https://github.com/hive-keychain" target="_blank" rel="noreferrer noopener" title="This link will take you away from hive.blog" class="external_link">https://github.com/hive-keychain <li><p dir="auto">you will have to <strong>serve this somehow, otherwise keychain won't work.<br /> From <strong>inside the directory, which <code>yo.html is stored in:<br /> <code>python -m http.server -b 127.0.0.1 8080 <li><p dir="auto">Alternatively, in Visual Studio Code, try <a href="https://github.com/ritwickdey/vscode-live-server" target="_blank" rel="noreferrer noopener" title="This link will take you away from hive.blog" class="external_link">Live Server <li><p dir="auto">For other <em>requests: <a href="https://github.com/hive-keychain/hive-keychain-extension/blob/master/documentation/README.md" target="_blank" rel="noreferrer noopener" title="This link will take you away from hive.blog" class="external_link">The part of keychain's documentation that you actually need <p dir="auto">If it all went right, you can now make a <em>move.<br /> Follow this url: <h4><span><a href="http://127.0.0.1:8080/yo.html" target="_blank" rel="noreferrer noopener" title="This link will take you away from hive.blog" class="external_link">http://127.0.0.1:8080/yo.html <p dir="auto">Result looks like this: <p dir="auto"><span><a href="https://hivehub.dev/tx/eb025cf797ee5bc81d7399282268079cc29cc66d" target="_blank" rel="noreferrer noopener" title="This link will take you away from hive.blog" class="external_link">https://hivehub.dev/tx/eb025cf797ee5bc81d7399282268079cc29cc66d <h2>Microservices <p dir="auto">Now you have a <em>custom user client in javascript.<br /> It's extremely simple, but it's unique. 🦄<br /> As far as I am aware, only I have ever made a <code>YO <em>on chain.<br /> It's a minimalistic game that only I have played so far, and that has no goal, but ...works.<br /> Maybe you want to join... <p dir="auto">Next episode, I will demonstrate how to <em>observe a <code>YO live.<br /> That will end with a <code>YO client in Python, which I can later build a <code>YO API on. <p dir="auto">Don't worry! I will connect all the services later.<br /> What I want to emphasize: Even though these <em>services and <em>clients can all work as parts of the same <em>system, they each do fundamentally different jobs.<br /> Looking up Hive blockchain data is a different procedure than broadcasting to the chain.<br /> I will keep this stuff apart on the system level side of things. <p dir="auto">This comes with the immediate benefit, that I can work on them separately.<br /> I mean: the broadcasting part of the client already fully works.<br /> Anyone can now <code>YO in 15 lines of code. <p dir="auto">Maybe someone wants to even upload this html to their webserver. 😬 <p dir="auto">Anyways, to build things like this is probably best described as <em>microservice architecture.<br /> <a href="https://www.youtube.com/watch?v=y8OnoxKotPQ" target="_blank" rel="noreferrer noopener" title="This link will take you away from hive.blog" class="external_link">Here's a video, that I found eye opening and entertaining. Please watch, if you haven't already. <h3>Get and Set <p dir="auto">If you are coming from traditional game- or web-development this might apear unusual or complicated. You might try to view these things as <em>get and <em>set methods; If you don't need to broadcast any other transactions than your own, you could even get away with treating it that way. <p dir="auto">While you can access a lot of blockchain information like you would a REST API or something, A Hive broadcast is much different than a <em>set method, though.<br /> That may make some stuff seem more complicated, but it comes with advantages: <h3>Authentication <p dir="auto">If you want to build anything that requires users to have an <em>account, you will have to enter the world of <em>user authentication. If you've ever touched the topic before, you know how that can be a huge pain. If not, then google it. There are huge libraries dedicated to user auth, password hashing and whatnot. <p dir="auto">Maybe all the above sounded complicated and you don't understand what I am trying to get at. Maybe you can't (at this point) appreciate, how the above demonstration entirely eliminates the need for any authentication measures on your end... <p dir="auto">Let me tell you: It's a big deal. That just solved a big problem with no effort. You don't need any infrastructure, no user tables...<br /> A lot of stuff just happened <em>en passant.<br /> I tried leveraging Keychain and Hive's protocol to do the heavy lifting. <p dir="auto">Maybe <a href="/@brianoflondon/hive-has-the-best-log-in-and-authentication-system-on-the-internet">this post explains it better. <h3>Hive Blockchain <p dir="auto">I will expand on all this in further posts, but for now: <p dir="auto">Trying to build anything directly <em>on chain (for Hive) comes at a price. It has strict limitations.<br /> But if you stay inside this framework, you can build amazingly cheap and tight applications.<br /> <sub><strong>the rhymes! <p dir="auto">I may have left a lot of threads open with this post.<br /> I hope that with a few more posts, it will all come together. <p dir="auto">Maybe all the above wasn't news to you.<br /> Maybe this post was to much talking and to little action.<br /> But I have to go over some fundamental concepts for the rest to make sense.<br /> I'll try sprinklig in useful code examples - maybe that can keep some of you interested, or attract new readers. <h2>Notes <ul> <li>This is a work in progress and subject to change.<br /> With this one, I am really not sure, if I didn't try too much... <li>I appreciate feedback - it could help me a lot, but: <ul> <li><strong>please try to not comment 'That's not right' without further explanation.<br /> At least provide a link or something. <li><strong>please don't just come up with questions just for the sake of it.<br /> I am trying to publish something helpful here, work <strong>with me please.