I think ... - webserverhttps://blog.kmonsoor.com/2021-04-16T00:00:00+06:00Deploying a short-link aka go-link server using only Caddyserver2021-04-16T00:00:00+06:002021-04-16T00:00:00+06:00Khaled Monsoortag:blog.kmonsoor.com,2021-04-16:/deploying-golink-server-using-Caddy/<p>Yeah, there are tons of open-source, full-fledged link-shorteners. But, none were exactly what I wanted. Hence, the minimal approach only utilizing the amazing webserver, <code>Caddy</code>. Here we go&nbsp;&hellip;</p><p>Before I go into any details, please note that I&rsquo;ve used the term &ldquo;shortlink-server&rdquo; instead of &ldquo;url-shortener&rdquo; because the difference is significant for this post. A url-shortener takes a long url, and gives a short url, then redirects any requests for the shortened link to its long counterpart. On the contrary, shortlink-server takes both the long and short url, then only does the redirect-ion&nbsp;part.</p> <h2 id="backstory">Backstory<a class="headerlink" href="#backstory" title="Permanent link">&para;</a></h2> <p>If I wanted an amazing, personal url-shortener or &ldquo;go link&rdquo; server, there are many amazing solutions out there, which are not only free or open-source but full-fledged as well for personal or public usage. Rather, I wanted some &ldquo;service&rdquo; that will &ldquo;resolve&rdquo; my personal, short links. I have been using bit.ly for a long time for its customizable &ldquo;short-half&rdquo; part, but the problem with bit.ly is &ndash; for some God-forsaken reason &ndash; blocked by the Bangladeshi govt. So, I needed a replacement to be properly &ldquo;glocal&rdquo;. There are many free (unbranded) and commercial (branded) options as well, but I wanted something that will be resolved via my hosted service (and personal domain) and as cheap as possible. So, basically solution for a poor nerd&nbsp;:D</p> <p>Before jumped into this solution, I tried (deployed <span class="amp">&amp;</span> tested) few others myself, mainly <a href="https://github.com/kellegous/go">kellegous/go</a>, <a href="kutt.it">kutt.it</a> and <a href="https://github.com/adamyi/golinks">adamyi/golinks</a>. But, all of them &ldquo;too featureful&rdquo; for my&nbsp;needs. </p> <p><img alt="Simple, on-prem short-link server using Caddy webserver" src="https://i.imgur.com/4nZbnUE.png"></p> <p>What I wanted is to be able&nbsp;to:</p> <ul> <li>resolve only my custom shortlinks (hence, no need for&nbsp;url-shortener)</li> <li>not a public, internet-facing service (hence, any frontend, authentication, email verification etc. would be overkill&nbsp;)</li> <li>minimal setup (if possible, no webapp at&nbsp;all)</li> </ul> <p>Given my previous experience with <code>Caddy</code> webserver, which is an amazing one(<a href="https://caddyserver.com/docs/">why?</a>), I had a gut feeling that Caddy has something for me &ndash; under the sleeve &ndash; to meet my minimal set of requirements. Thankfully, I managed to find&nbsp;it.</p> <p>I believe <span class="caps">NGINX</span>, currently the most popular webserver, has some kind of similar mechanism as well. But, I&rsquo;m not an expert, and once I was genuinely intimidated by its config file syntax. <span class="caps">YMMV</span>.</p> <h2 id="what-you-gonna-need">What you gonna need?<a class="headerlink" href="#what-you-gonna-need" title="Permanent link">&para;</a></h2> <ul> <li>your own domain which will be the root of the shortlinks. While sub-domained <span class="caps">URL</span> like <code>go.yourname.com/*</code> is quite common, if you have some short domain, like you.co/*, only for this purpose, that&rsquo;s fine as&nbsp;well.</li> <li>A webhost server or public-facing instance with its own, <strong>public</strong> IPv4&nbsp;address.</li> <li>working knowledge of&nbsp;Linux</li> </ul> <h2 id="step-1-point-your-subdomain-to-the-right-place">Step-1: Point your subdomain to the right place<a class="headerlink" href="#step-1-point-your-subdomain-to-the-right-place" title="Permanent link">&para;</a></h2> <ul> <li>Find out what&rsquo;s the <strong>puplic IPv4 address</strong> of your instance that&rsquo;ll act as the webserver. It&rsquo;s usually on the cloud management dashboard.<ul> <li>make sure that, regardless of your cloud architecture (e.g. <span class="caps">VPC</span>, subnet, firewall etc.), the <span class="caps">SSL</span> port (<code>:443</code>) of the instance is reachable from the public&nbsp;internet.</li> </ul> </li> <li>now go to your domain name registrar (or, <span class="caps">DNS</span> management provider which in my case is Cloudflare). There, you need to point shortlink subdomain (<code>go.</code>)to the webserver&rsquo;s <span class="caps">IP</span>&nbsp;address.</li> </ul> <p>Actually, you can do this step at the last. But for some reason, I prefer it to do first. Because sometimes, <a href="https://blog.cloudflare.com/never-deal-with-dns-propagation-again/"><span class="caps">DNS</span> propagation</a> takes some time. But, once my webservice is up and running, I like to see the result instantaneously.&nbsp;;)</p> <h2 id="step-2-install-caddy-the-mighty-webserver">Step-2: Install Caddy, the mighty webserver<a class="headerlink" href="#step-2-install-caddy-the-mighty-webserver" title="Permanent link">&para;</a></h2> <p>Depending on your host <span class="caps">OS</span> (mine is Ubuntu 20.04 <span class="caps">LTS</span>), you need to install the <code>Caddy</code> webserver. While there are some hacky solutions to run, I think running Caddy as a background server is the simplest to manage. In fact, the documentation of Caddy is excellent, I&rsquo;d better leave that part to&nbsp;you. </p> <p>After running with the default config(<code>Caddyfile</code>) which is in Ubuntu&rsquo;s case located as <code>/etc/caddy/Caddyfile</code>, it should have a status somewhat like the below image. Please note that, in many cases, if running without <code>sudo</code> Caddy cannot attach itself with the <span class="caps">SSL</span> port (<code>:443</code>) which is necessary for serving <code>https://</code>. So, check for that error message in the &ldquo;status&rdquo;&nbsp;log.</p> <p><img alt="Caddy service on Ubuntu" src="https://i.imgur.com/cfS5nvZ.png?1"></p> <p><em><strong><span class="caps">P.S.</span></strong> By the way, want your console and command prompt to look 🚀 like mine? Here&rsquo;s the guide: <a href="https://blog.kmonsoor.com/pimp-up-my-terminal/">How do I pimp up my terminal on&nbsp;Linux</a></em></p> <h2 id="step-3-tell-caddy-your-short-links-to-redirect">Step-3: Tell Caddy your short-links to redirect<a class="headerlink" href="#step-3-tell-caddy-your-short-links-to-redirect" title="Permanent link">&para;</a></h2> <p>Now, it&rsquo;s time to configure Caddy to actually do the&nbsp;job.</p> <p>Caddy has its native <code>redir</code> <span class="dquo">&ldquo;</span>directive&rdquo; to redirect incoming web-request from one to another. While the <code>map</code> directive is relatively new, it makes the config file i.e. Caddyfile look elegant in case you have (or, will have in the long run) a long list of&nbsp;short-links.</p> <p>Here&rsquo;s mine which is working&nbsp;&hellip; </p> <div class="highlight"><pre><span></span><code><span class="linenos" data-linenos=" 1 "></span># /etc/caddy/Caddyfile <span class="linenos" data-linenos=" 2 "></span> <span class="linenos" data-linenos=" 3 "></span>go.kmonsoor.com { # replace it your web-url root <span class="linenos" data-linenos=" 4 "></span> <span class="linenos" data-linenos=" 5 "></span> map {path} {redirect-uri} { <span class="linenos" data-linenos=" 6 "></span> /blog https://blog.kmonsoor.com <span class="linenos" data-linenos=" 7 "></span> /photos https://photos.kmonsoor.com <span class="linenos" data-linenos=" 8 "></span> <span class="linenos" data-linenos=" 9 "></span> /resume https://drive.google.com/file/d/1nMS3i1ai6nsI70zZ7NFnNQ_XmvAa4GOl <span class="linenos" data-linenos="10 "></span> /resume-doc https://docs.google.com/document/d/1ECx1Yr8Jzz9I3S5VcoKnZQz56oIht2XaM5gSNetcWag <span class="linenos" data-linenos="11 "></span> <span class="linenos" data-linenos="12 "></span> /rickrolled https://www.youtube.com/watch?v=dQw4w9WgXcQ <span class="linenos" data-linenos="13 "></span> <span class="linenos" data-linenos="14 "></span> # will add new ones here like the above <span class="linenos" data-linenos="15 "></span> # ... <span class="linenos" data-linenos="16 "></span> } <span class="linenos" data-linenos="17 "></span> <span class="linenos" data-linenos="18 "></span> # this below code is required to actually make the above `map` work <span class="linenos" data-linenos="19 "></span> <span class="linenos" data-linenos="20 "></span> @hasRedir expression `{redirect-uri} != &quot;&quot;` <span class="linenos" data-linenos="21 "></span> redir @hasRedir {redirect-uri} <span class="linenos" data-linenos="22 "></span> <span class="linenos" data-linenos="23 "></span> # code below is to set the default response if the requested shortlink isn&#39;t here <span class="linenos" data-linenos="24 "></span> respond &quot;Thas&#39;s an unknown short URL ... :(&quot; <span class="linenos" data-linenos="25 "></span>} </code></pre></div> <p>Note: Don&rsquo;t forget to restart the <code>caddy</code> service to let the new config to take&nbsp;effect.</p> <h2 id="step-4-profit">Step-4: Profit !<a class="headerlink" href="#step-4-profit" title="Permanent link">&para;</a></h2> <p>Yeah, that&rsquo;s it. Now, add some own personal stuff with some cool short-links, and proudly share with the&nbsp;world.</p> <h2 id="whats-next">What&rsquo;s next ?<a class="headerlink" href="#whats-next" title="Permanent link">&para;</a></h2> <p>I&rsquo;m thinking that given the very low workload my shortlink resolver needs — unless I&rsquo;m becoming an overnight internet sensation — using a server instance only for this purpose is overkill. My next goal is to have the same service using some &ldquo;serverless&rdquo; function or using the &ldquo;<a href="https://developers.cloudflare.com/workers/examples/redirect">worker on the edge</a>&rdquo; thing from Cloudflare. Let&rsquo;s see&nbsp;;)</p>