From 34a423c3608b2ec2c852986350152cb6c38ba4be Mon Sep 17 00:00:00 2001
From: Martin Ashby <martin@ashbysoft.com>
Date: Mon, 21 Aug 2023 22:10:31 +0100
Subject: initial

---
 .gitignore   |  2 ++
 Caddyfile    |  7 ++++++
 README.md    | 11 ++++++++++
 build.zig    | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/main.zig | 27 +++++++++++++++++++++++
 5 files changed, 117 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 Caddyfile
 create mode 100644 README.md
 create mode 100644 build.zig
 create mode 100644 src/main.zig

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..4c82b07
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+zig-cache
+zig-out
diff --git a/Caddyfile b/Caddyfile
new file mode 100644
index 0000000..633bf24
--- /dev/null
+++ b/Caddyfile
@@ -0,0 +1,7 @@
+{
+	order cgi before respond
+}
+
+http://localhost:8080
+
+cgi / zig-out/bin/cgifun
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..5556f06
--- /dev/null
+++ b/README.md
@@ -0,0 +1,11 @@
+# cgifun
+
+Just an extremely simple example of a CGI program with caddy web server and zig as the CGI program.
+
+To run:
+* Have caddy with [CGI plugin](https://caddyserver.com/docs/modules/http.handlers.cgi)
+* Have [zig](https://ziglang.org/download/) programming language.
+* `zig build && caddy run`
+* Open http://localhost:8080 in your browser
+
+You'll see a webpage full of environment variables which are passed as part of the CGI protocol to the cgifun program.
\ No newline at end of file
diff --git a/build.zig b/build.zig
new file mode 100644
index 0000000..d9cfe4d
--- /dev/null
+++ b/build.zig
@@ -0,0 +1,70 @@
+const std = @import("std");
+
+// Although this function looks imperative, note that its job is to
+// declaratively construct a build graph that will be executed by an external
+// runner.
+pub fn build(b: *std.Build) void {
+    // Standard target options allows the person running `zig build` to choose
+    // what target to build for. Here we do not override the defaults, which
+    // means any target is allowed, and the default is native. Other options
+    // for restricting supported target set are available.
+    const target = b.standardTargetOptions(.{});
+
+    // Standard optimization options allow the person running `zig build` to select
+    // between Debug, ReleaseSafe, ReleaseFast, and ReleaseSmall. Here we do not
+    // set a preferred release mode, allowing the user to decide how to optimize.
+    const optimize = b.standardOptimizeOption(.{});
+
+    const exe = b.addExecutable(.{
+        .name = "cgifun",
+        // In this case the main source file is merely a path, however, in more
+        // complicated build scripts, this could be a generated file.
+        .root_source_file = .{ .path = "src/main.zig" },
+        .target = target,
+        .optimize = optimize,
+    });
+
+    // This declares intent for the executable to be installed into the
+    // standard location when the user invokes the "install" step (the default
+    // step when running `zig build`).
+    b.installArtifact(exe);
+
+    // This *creates* a Run step in the build graph, to be executed when another
+    // step is evaluated that depends on it. The next line below will establish
+    // such a dependency.
+    const run_cmd = b.addRunArtifact(exe);
+
+    // By making the run step depend on the install step, it will be run from the
+    // installation directory rather than directly from within the cache directory.
+    // This is not necessary, however, if the application depends on other installed
+    // files, this ensures they will be present and in the expected location.
+    run_cmd.step.dependOn(b.getInstallStep());
+
+    // This allows the user to pass arguments to the application in the build
+    // command itself, like this: `zig build run -- arg1 arg2 etc`
+    if (b.args) |args| {
+        run_cmd.addArgs(args);
+    }
+
+    // This creates a build step. It will be visible in the `zig build --help` menu,
+    // and can be selected like this: `zig build run`
+    // This will evaluate the `run` step rather than the default, which is "install".
+    const run_step = b.step("run", "Run the app");
+    run_step.dependOn(&run_cmd.step);
+
+    // Creates a step for unit testing. This only builds the test executable
+    // but does not run it.
+    const unit_tests = b.addTest(.{
+        .root_source_file = .{ .path = "src/main.zig" },
+        .target = target,
+        .optimize = optimize,
+    });
+
+    const run_unit_tests = b.addRunArtifact(unit_tests);
+
+    // Similar to creating the run step earlier, this exposes a `test` step to
+    // the `zig build --help` menu, providing a way for the user to request
+    // running the unit tests.
+    const test_step = b.step("test", "Run unit tests");
+    test_step.dependOn(&run_unit_tests.step);
+}
diff --git a/src/main.zig b/src/main.zig
new file mode 100644
index 0000000..e4fab76
--- /dev/null
+++ b/src/main.zig
@@ -0,0 +1,27 @@
+const std = @import("std");
+
+/// Produces an HTML page listing the environment variables.
+pub fn main() !void {
+    const stdout = std.io.getStdOut().writer();
+    //
+    try stdout.writeAll("Content-Type: text/html\r\n");
+    try stdout.writeAll("\r\n");
+    try stdout.writeAll(
+        \\<!doctype HTML>
+        \\<html>
+        \\<body>
+        \\<p>Environment variables passed to CGI script:</p>
+        \\<ul>
+    );
+    for (std.os.environ) |env| {
+        try stdout.writeAll("<li>");
+        const env_slice = std.mem.sliceTo(env, 0);
+        try stdout.writeAll(env_slice);
+        try stdout.writeAll("</li>\n");
+    }
+    try stdout.writeAll(
+        \\</ul>
+        \\</body>
+        \\</html>
+    );
+}
-- 
cgit v1.2.3-ZIG