handle library side of headers

src/interface.zig

@@ -0,0 +1,42 @@
+const std = @import("std");
+
+pub const Header = extern struct {
+    name_ptr: [*]u8,
+    name_len: usize,
+
+    value_ptr: [*]u8,
+    value_len: usize,
+};
+pub const Response = extern struct {
+    ptr: [*]u8,
+    len: usize,
+
+    headers: [*]Header,
+    headers_len: usize,
+};
+
+pub const Request = extern struct {
+    method: [*]u8,
+    method_len: usize,
+
+    content: [*]u8,
+    content_len: usize,
+
+    headers: [*]Header,
+    headers_len: usize,
+};
+
+pub fn toHeaders(allocator: std.mem.Allocator, headers: std.StringHashMap([]const u8)) ![*]Header {
+    var header_array = try std.ArrayList(Header).initCapacity(allocator, headers.count());
+    var iterator = headers.iterator();
+    while (iterator.next()) |kv| {
+        header_array.appendAssumeCapacity(.{
+            .name_ptr = @constCast(kv.key_ptr.*).ptr,
+            .name_len = kv.key_ptr.*.len,
+
+            .value_ptr = @constCast(kv.value_ptr.*).ptr,
+            .value_len = kv.value_ptr.*.len,
+        });
+    }
+    return header_array.items.ptr;
+}

src/main-lib.zig

@@ -1,40 +1,76 @@
 const std = @import("std");
+const interface = @import("interface.zig");
 const testing = std.testing;
 
-const Response = extern struct {
-    ptr: [*]u8,
-    len: usize,
-};
-
+const log = std.log.scoped(.@"main-lib");
 var child_allocator = std.heap.raw_c_allocator; // raw allocator recommended for use in arenas
 var arena: std.heap.ArenaAllocator = undefined;
 
-export fn handle_request() *Response {
+const Response = struct {
+    body: *std.ArrayList(u8),
+    headers: *std.StringHashMap([]const u8),
+};
+
+export fn handle_request() ?*interface.Response {
     arena = std.heap.ArenaAllocator.init(child_allocator);
     var allocator = arena.allocator();
-    var al = std.ArrayList(u8).init(allocator);
-    var writer = al.writer();
 
-    writer.print(" 2.", .{}) catch unreachable;
+    // setup response body
+    var response = std.ArrayList(u8).init(allocator);
 
-    // Cannot simply return &Blah. Need to assign to var first
-    var rc = &Response{
-        .ptr = al.items.ptr,
-        .len = al.items.len,
+    // setup headers
+    var headers = std.StringHashMap([]const u8).init(allocator);
+    handleRequest(.{
+        .body = &response,
+        .headers = &headers,
+    }) catch |e| {
+        log.err("Unexpected error processing request: {any}", .{e});
+        if (@errorReturnTrace()) |trace| {
+            std.debug.dumpStackTrace(trace.*);
+        }
+        return null;
+    };
+    // Marshall data back for handling by server
+    var rc = &interface.Response{
+        .ptr = response.items.ptr,
+        .len = response.items.len,
+
+        .headers = interface.toHeaders(allocator, headers) catch |e| {
+            log.err("Unexpected error processing request: {any}", .{e});
+            if (@errorReturnTrace()) |trace| {
+                std.debug.dumpStackTrace(trace.*);
+            }
+            return null;
+        },
+        .headers_len = headers.count(),
     };
     return rc;
 }
 
 /// having request_deinit allows for a general deinit as well
 export fn request_deinit() void {
-    std.log.debug("deinit", .{});
     arena.deinit();
 }
 
-export fn add(a: i32, b: i32) i32 {
-    return a + b;
+// ************************************************************************
+// Boilerplate ^^, Custom code below
+// ************************************************************************
+//
+// handleRequest function here is the last line of boilerplate and the
+// entry to a request
+fn handleRequest(response: Response) !void {
+    // setup
+    var response_writer = response.body.writer();
+    // real work
+    response_writer.print(" 2.", .{}) catch unreachable;
+    try response.headers.put("X-custom-foo", "bar");
 }
 
-test "basic add functionality" {
-    try testing.expect(add(3, 7) == 10);
+test "handle_request" {
+    defer request_deinit();
+    child_allocator = std.testing.allocator;
+    const response = handle_request().?;
+    try testing.expectEqualStrings(" 2.", response.ptr[0..response.len]);
+    try testing.expectEqualStrings("X-custom-foo", response.headers[0].name_ptr[0..response.headers[0].name_len]);
+    try testing.expectEqualStrings("bar", response.headers[0].value_ptr[0..response.headers[0].value_len]);
 }

src/main.zig

@@ -1,32 +1,34 @@
 const std = @import("std");
 const builtin = @import("builtin");
-
+const interface = @import("interface.zig");
 const Watch = @import("Watch.zig");
-const serveFn = *const fn () *ServeReturn;
+const serveFn = *const fn () ?*interface.Response;
 const requestDeinitFn = *const fn () void;
 
 const timeout = 250;
 
-const ServeReturn = extern struct {
-    ptr: [*]u8,
-    len: usize,
-};
-
 const FullReturn = struct {
     response: []u8,
     executor: *Executor,
 };
 
 const Executor = struct {
+    // configuration
     path: [:0]const u8,
+
+    // fields used at runtime to do real work
     library: ?*anyopaque = null,
     serveFn: ?serveFn = null,
     requestDeinitFn: ?requestDeinitFn = null,
+
+    // fields used for internal accounting
     watch: ?usize = null,
     reload_lock: bool = false,
     in_request_lock: bool = false,
 };
 
+// TODO: This should be in a file that maybe gets reloaded with SIGHUP
+// rather than a file watch. Touching this config is pretty dangerous
 var executors = [_]Executor{
     .{ .path = "zig-out/lib/libfaas-proxy-sample-lib.so" },
     .{ .path = "zig-out/lib/libfaas-proxy-sample-lib2.so" },
@@ -47,25 +49,16 @@ const SERVE_FN_NAME = "handle_request";
 const PORT = 8069;
 
 fn serve(allocator: std.mem.Allocator, response: *std.http.Server.Response) !*FullReturn {
-    var null_server = std.http.Server.init(allocator, .{});
-    defer null_server.deinit();
-    var data: [14]u8 = @constCast(&[_]u8{0x00} ** 14).*;
-    var child_response = std.http.Server.Response{
-        .server = &null_server,
-        .request = response.request,
-        .connection = .{
-            .conn = .{
-                .stream = .{ .handle = 0 },
-                .protocol = .plain,
-            },
-        },
-        .address = .{ .any = .{
-            .data = data,
-            .family = 0,
-        } },
-        .headers = response.headers,
-    };
-    _ = child_response;
+    // pub const Request = extern struct {
+    //     method: [*]u8,
+    //     method_len: usize,
+    //
+    //     content: [*]u8,
+    //     content_len: usize,
+    //
+    //     headers: [*]Header,
+    //     headers_len: usize,
+    // };
     // if (some path routing thing) {
     // TODO: Get request body into executor
     // TODO: Get headers back from executor
@@ -74,14 +67,27 @@ fn serve(allocator: std.mem.Allocator, response: *std.http.Server.Response) !*Fu
     executor.in_request_lock = true;
     errdefer executor.in_request_lock = false;
     // Call external library
-    var serve_result = executor.serveFn.?();
+    var serve_result = executor.serveFn.?().?; // ok for this pointer deref to fail
 
     // Deal with results
+    // var content_type_added = false;
+    // for (0..serve_result.headers_len) |inx| {
+    //     const head = serve_result.headers[inx];
+    //     try response.headers.append(
+    //         head.name_ptr[0..head.name_len],
+    //         head.value_ptr[0..head.value_len],
+    //     );
+    //
+    //     // TODO: are these headers case insensitive?
+    //     content_type_added = std.mem.eql(u8, head.name_ptr[0..head.name_len], "content-type");
+    // }
+    // if (!content_type_added)
+    //     try response.headers.append("content-type", "text/plain");
+    _ = response;
     var slice: []u8 = serve_result.ptr[0..serve_result.len];
-    var rc = &FullReturn{
-        .executor = executor,
-        .response = slice,
-    };
+    var rc = try allocator.create(FullReturn);
+    rc.executor = executor;
+    rc.response = slice;
     return rc;
 }
 fn getExecutor(key: usize) !*Executor {
@@ -231,7 +237,7 @@ pub fn main() !void {
 
     try installSignalHandler();
     while (true) {
-        var arena = std.heap.ArenaAllocator.init(std.heap.c_allocator);
+        var arena = std.heap.ArenaAllocator.init(allocator);
         defer arena.deinit();
 
         processRequest(arena.allocator(), &server) catch |e| {
@@ -283,7 +289,6 @@ fn processRequest(allocator: std.mem.Allocator, server: *std.http.Server) !void
     if (full_response) |f|
         response_bytes = f.response;
     res.transfer_encoding = .{ .content_length = response_bytes.len };
-    try res.headers.append("content-type", "text/plain");
     try res.headers.append("connection", "close");
     if (builtin.is_test) writeToTestBuffers(response_bytes, res);
     try res.do();
@@ -306,6 +311,8 @@ fn writeToTestBuffers(response: []const u8, res: *std.http.Server.Response) void
 }
 fn testRequest(request_bytes: []const u8) !void {
     const allocator = std.testing.allocator;
+    var arena = std.heap.ArenaAllocator.init(allocator);
+    defer arena.deinit();
 
     var server = std.http.Server.init(allocator, .{ .reuse_address = true });
     defer server.deinit();
@@ -317,7 +324,7 @@ fn testRequest(request_bytes: []const u8) !void {
     const server_thread = try std.Thread.spawn(
         .{},
         processRequest,
-        .{ allocator, &server },
+        .{ arena.allocator(), &server },
     );
 
     const stream = try std.net.tcpConnectToHost(allocator, "127.0.0.1", server_port);