docs: add introduce for http-std (#83)

Close #72

---------

Co-authored-by: xihale <[email protected]>
Co-authored-by: Jiacai Liu <[email protected]>

book-src/05-03-http-server-std.md

@@ -0,0 +1,12 @@
+## http.Server - std
+
+Starting with release 0.12.0, a very simple implementation of `http.Server` has been introduced.
+
+```zig
+{{#include ../src/05-03.zig }}
+```
+
+Note: The std implementation exhibits extremely poor performance. If you're planning beyond basic experimentation, consider utilizing alternative libraries such as:
+- <https://github.com/karlseguin/http.zig>
+- <https://github.com/zigzap/zap>
+- <https://github.com/mookums/zzz>

book-src/SUMMARY.md

@@ -29,6 +29,7 @@
 
   - [HTTP Get](./05-01-http-get.md)
   - [HTTP Post](./05-02-http-post.md)
+  - [HTTP Server Std](./05-03-http-server-std.md)
 
 - [Algorithms]()
 

build.zig

@@ -75,9 +75,11 @@ fn addExample(b: *std.Build, run_all: *std.Build.Step) !void {
                 // 04-01 start tcp server, and won't stop so we skip it here
                 // 04-02 is the server's client.
                 // 04-03 starts udp listener.
+                // 05-03 starts http server.
                 if (std.mem.eql(u8, "04-01", name) or
                     std.mem.eql(u8, "04-02", name) or
-                    std.mem.eql(u8, "04-03", name))
+                    std.mem.eql(u8, "04-03", name) or
+                    std.mem.eql(u8, "05-03", name))
                 {
                     continue;
                 }

src/05-03.zig

@@ -0,0 +1,22 @@
+// reference: https://pismice.github.io/HEIG_ZIG/docs/web/std-http/
+const std = @import("std");
+
+pub fn main() !void {
+    const addr = try std.net.Address.parseIp("127.0.0.1", 8080);
+    var server = try std.net.Address.listen(addr, .{ .reuse_address = true });
+
+    var buf: [65535]u8 = undefined;
+    const conn = try server.accept();
+
+    var client = std.http.Server.init(conn, &buf);
+
+    while (client.state == .ready) {
+        var request = client.receiveHead() catch |err| switch (err) {
+            std.http.Server.ReceiveHeadError.HttpConnectionClosing => break,
+            else => return err,
+        };
+        _ = try request.reader();
+
+        try request.respond("Hello http.std!", .{});
+    }
+}