gobyexample/public/url-parsing
Oleg Butuzov 646c8b39da bugfix (mmcgrana/gobyexample#294) sha1 sum calculator
This bugfix implements correct way to calculate source sha1 hash, before it will changed,
by propagation of unchanged sources.

This commit will also include regenerated static files and *.hash files.
2019-10-22 14:27:02 +03:00

243 lines
11 KiB
Plaintext
Generated

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Go by Example: URL Parsing</title>
<link rel=stylesheet href="site.css">
</head>
<script>
onkeydown = (e) => {
if (e.key == "ArrowLeft") {
window.location.href = 'number-parsing';
}
if (e.key == "ArrowRight") {
window.location.href = 'sha1-hashes';
}
}
</script>
<body>
<div class="example" id="url-parsing">
<h2><a href="./">Go by Example</a>: URL Parsing</h2>
<table>
<tr>
<td class="docs">
<p>URLs provide a <a href="https://adam.herokuapp.com/past/2010/3/30/urls_are_the_uniform_way_to_locate_resources/">uniform way to locate resources</a>.
Here&rsquo;s how to parse URLs in Go.</p>
</td>
<td class="code empty leading">
</td>
</tr>
<tr>
<td class="docs">
</td>
<td class="code leading">
<a href="http://play.golang.org/p/fHTQn9X7l1B"><img title="Run code" src="play.png" class="run" /></a><img title="Copy code" src="clipboard.png" class="copy" />
<div class="highlight"><pre><span class="kn">package</span> <span class="nx">main</span>
</pre></div>
</td>
</tr>
<tr>
<td class="docs">
</td>
<td class="code leading">
<div class="highlight"><pre><span class="kn">import</span> <span class="p">(</span>
<span class="s">&quot;fmt&quot;</span>
<span class="s">&quot;net&quot;</span>
<span class="s">&quot;net/url&quot;</span>
<span class="p">)</span>
</pre></div>
</td>
</tr>
<tr>
<td class="docs">
</td>
<td class="code leading">
<div class="highlight"><pre><span class="kd">func</span> <span class="nx">main</span><span class="p">()</span> <span class="p">{</span>
</pre></div>
</td>
</tr>
<tr>
<td class="docs">
<p>We&rsquo;ll parse this example URL, which includes a
scheme, authentication info, host, port, path,
query params, and query fragment.</p>
</td>
<td class="code leading">
<div class="highlight"><pre> <span class="nx">s</span> <span class="o">:=</span> <span class="s">&quot;postgres://user:pass@host.com:5432/path?k=v#f&quot;</span>
</pre></div>
</td>
</tr>
<tr>
<td class="docs">
<p>Parse the URL and ensure there are no errors.</p>
</td>
<td class="code leading">
<div class="highlight"><pre> <span class="nx">u</span><span class="p">,</span> <span class="nx">err</span> <span class="o">:=</span> <span class="nx">url</span><span class="p">.</span><span class="nx">Parse</span><span class="p">(</span><span class="nx">s</span><span class="p">)</span>
<span class="k">if</span> <span class="nx">err</span> <span class="o">!=</span> <span class="kc">nil</span> <span class="p">{</span>
<span class="nb">panic</span><span class="p">(</span><span class="nx">err</span><span class="p">)</span>
<span class="p">}</span>
</pre></div>
</td>
</tr>
<tr>
<td class="docs">
<p>Accessing the scheme is straightforward.</p>
</td>
<td class="code leading">
<div class="highlight"><pre> <span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">u</span><span class="p">.</span><span class="nx">Scheme</span><span class="p">)</span>
</pre></div>
</td>
</tr>
<tr>
<td class="docs">
<p><code>User</code> contains all authentication info; call
<code>Username</code> and <code>Password</code> on this for individual
values.</p>
</td>
<td class="code leading">
<div class="highlight"><pre> <span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">u</span><span class="p">.</span><span class="nx">User</span><span class="p">)</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">u</span><span class="p">.</span><span class="nx">User</span><span class="p">.</span><span class="nx">Username</span><span class="p">())</span>
<span class="nx">p</span><span class="p">,</span> <span class="nx">_</span> <span class="o">:=</span> <span class="nx">u</span><span class="p">.</span><span class="nx">User</span><span class="p">.</span><span class="nx">Password</span><span class="p">()</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">p</span><span class="p">)</span>
</pre></div>
</td>
</tr>
<tr>
<td class="docs">
<p>The <code>Host</code> contains both the hostname and the port,
if present. Use <code>SplitHostPort</code> to extract them.</p>
</td>
<td class="code leading">
<div class="highlight"><pre> <span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">u</span><span class="p">.</span><span class="nx">Host</span><span class="p">)</span>
<span class="nx">host</span><span class="p">,</span> <span class="nx">port</span><span class="p">,</span> <span class="nx">_</span> <span class="o">:=</span> <span class="nx">net</span><span class="p">.</span><span class="nx">SplitHostPort</span><span class="p">(</span><span class="nx">u</span><span class="p">.</span><span class="nx">Host</span><span class="p">)</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">host</span><span class="p">)</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">port</span><span class="p">)</span>
</pre></div>
</td>
</tr>
<tr>
<td class="docs">
<p>Here we extract the <code>path</code> and the fragment after
the <code>#</code>.</p>
</td>
<td class="code leading">
<div class="highlight"><pre> <span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">u</span><span class="p">.</span><span class="nx">Path</span><span class="p">)</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">u</span><span class="p">.</span><span class="nx">Fragment</span><span class="p">)</span>
</pre></div>
</td>
</tr>
<tr>
<td class="docs">
<p>To get query params in a string of <code>k=v</code> format,
use <code>RawQuery</code>. You can also parse query params
into a map. The parsed query param maps are from
strings to slices of strings, so index into <code>[0]</code>
if you only want the first value.</p>
</td>
<td class="code">
<div class="highlight"><pre> <span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">u</span><span class="p">.</span><span class="nx">RawQuery</span><span class="p">)</span>
<span class="nx">m</span><span class="p">,</span> <span class="nx">_</span> <span class="o">:=</span> <span class="nx">url</span><span class="p">.</span><span class="nx">ParseQuery</span><span class="p">(</span><span class="nx">u</span><span class="p">.</span><span class="nx">RawQuery</span><span class="p">)</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">m</span><span class="p">)</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">m</span><span class="p">[</span><span class="s">&quot;k&quot;</span><span class="p">][</span><span class="mi">0</span><span class="p">])</span>
<span class="p">}</span>
</pre></div>
</td>
</tr>
</table>
<table>
<tr>
<td class="docs">
<p>Running our URL parsing program shows all the different
pieces that we extracted.</p>
</td>
<td class="code">
<div class="highlight"><pre><span class="gp">$</span> go run url-parsing.go
<span class="go">postgres</span>
<span class="go">user:pass</span>
<span class="go">user</span>
<span class="go">pass</span>
<span class="go">host.com:5432</span>
<span class="go">host.com</span>
<span class="go">5432</span>
<span class="go">/path</span>
<span class="go">f</span>
<span class="go">k=v</span>
<span class="go">map[k:[v]]</span>
<span class="go">v</span>
</pre></div>
</td>
</tr>
</table>
<p class="next">
Next example: <a href="sha1-hashes">SHA1 Hashes</a>.
</p>
<p class="footer">
by <a href="https://markmcgranaghan.com">Mark McGranaghan</a> | <a href="https://github.com/mmcgrana/gobyexample/blob/master/examples/url-parsing">source</a> | <a href="https://github.com/mmcgrana/gobyexample#license">license</a>
</p>
</div>
<script>
var codeLines = [];
codeLines.push('');codeLines.push('package main\u000A');codeLines.push('import (\u000A \"fmt\"\u000A \"net\"\u000A \"net/url\"\u000A)\u000A');codeLines.push('func main() {\u000A');codeLines.push(' s := \"postgres://user:pass@host.com:5432/path?k=v#f\"\u000A');codeLines.push(' u, err := url.Parse(s)\u000A if err != nil {\u000A panic(err)\u000A }\u000A');codeLines.push(' fmt.Println(u.Scheme)\u000A');codeLines.push(' fmt.Println(u.User)\u000A fmt.Println(u.User.Username())\u000A p, _ := u.User.Password()\u000A fmt.Println(p)\u000A');codeLines.push(' fmt.Println(u.Host)\u000A host, port, _ := net.SplitHostPort(u.Host)\u000A fmt.Println(host)\u000A fmt.Println(port)\u000A');codeLines.push(' fmt.Println(u.Path)\u000A fmt.Println(u.Fragment)\u000A');codeLines.push(' fmt.Println(u.RawQuery)\u000A m, _ := url.ParseQuery(u.RawQuery)\u000A fmt.Println(m)\u000A fmt.Println(m[\"k\"][0])\u000A}\u000A');codeLines.push('');
</script>
<script src="site.js" async></script>
</body>
</html>