SHA1 digest (Bun)

In this example we're going to create a server-side app that calculates SHA-1 digests, using a built-in function of Zig's standard library.

Creating the app

First, we'll initialize the project:

mkdir sha1
cd sha1
bun init

bun init helps you get started with a minimal project and tries to guess sensible defaults. Press ^C anytime to quit

package name (sha1):
entry point (index.ts): src/index.js

Next, we install bun-zigar and add a sub-directory for zig files:

bun install bun-zigar
bunx bun-zigar preload
mkdir zig

Then we add sha1.zig:

const std = @import("std");

pub fn sha1(bytes: []const u8) [std.crypto.hash.Sha1.digest_length * 2]u8 {
    var digest: [std.crypto.hash.Sha1.digest_length]u8 = undefined;
    std.crypto.hash.Sha1.hash(bytes, &digest, .{});
    return std.fmt.bytesToHex(digest, .lower);
}

Followed by index.js:

import { sha1 } from '../zig/sha1.zig';

console.log(sha1('hello world').string);

Then we run it:

bun src/index.js

After a while, we get the result:

2aae6c35c94fcfb415dbe95f408b9ce91ee846ed

We would get the same digest if we calculate it using sha1sum:

echo -n "hello world" | sha1sum

2aae6c35c94fcfb415dbe95f408b9ce91ee846ed  -

Configuring the app for deployment

We follow the same steps as described in the the hello world example. First we change the import statement:

import { sha1 } from '../lib/sha1.zigar';

console.log(sha1('hello world').string);

Then we create bun-zigar.toml:

optimize = "ReleaseSmall"

[sourceFiles]
"lib/sha1.zigar" = "zig/sha1.zig"

[[targets]]
platform = "linux"
arch = "x64"

[[targets]]
platform = "linux"
arch = "arm64"

[[targets]]
platform = "linux-musl"
arch = "x64"

[[targets]]
platform = "linux-musl"
arch = "arm64"

Finally we build the necessary libraries for platforms we intend to support:

bunx bun-zigar build

Source dode

You can find the complete source code for this example here.

Conclusion

Okay, that wasn't much of a server-side app. At least it does something. In the next example we'll build a server-side app for real, one that actually listens for remote requests.

---

Image filter example