add basics of multipart upload parsing

src/main.zig

@@ -46,9 +46,59 @@ fn generateImageId(buffer: []u8) []const u8 {
     return buffer[0..i];
 }
 
+const Part = struct {};
+
+const Multipart = struct {
+    body: []const u8,
+    boundary: []const u8,
+    cursor: usize = 0,
+
+    const Self = @This();
+
+    pub fn init(body: []const u8, content_type: []const u8) !Multipart {
+        // parse content_type into what we want (the boundary)
+        var it = std.mem.split(content_type, ";");
+        const should_be_multipart = it.next() orelse return error.MissingContentType;
+        if (!std.mem.eql(u8, should_be_multipart, "multipart/form-data"))
+            return error.InvalidContentType;
+
+        const should_be_boundary = it.next() orelse return error.MissingBoundary;
+        if (!std.mem.startsWith(u8, should_be_boundary, " boundary="))
+            return error.InvalidBoundary;
+
+        var boundary_it = std.mem.split(should_be_boundary, "=");
+        _ = boundary_it.next();
+        const boundary_value = boundary_it.next() orelse return error.InvalidBoundary;
+
+        return Self{ .body = body, .boundary = boundary_value };
+    }
+
+    pub fn next(self: *Self) !?Part {
+        return null;
+    }
+};
+
 fn uploadFile(response: *http.Response, request: http.Request) !void {
     std.log.info("upload! got {d} bytes", .{request.body.len});
 
+    // find content-type header
+    var it = request.iterator();
+    var content_type: ?[]const u8 = null;
+    while (it.next()) |header| {
+        if (std.mem.eql(u8, header.key, "Content-Type")) {
+            content_type = header.value;
+        }
+    }
+
+    if (content_type == null) return error.InvalidContentType;
+
+    // parse multipart data
+    var multipart = try Multipart.init(request.body, content_type.?);
+
+    while (try multipart.next()) |part| {
+        std.log.info("part: {}", .{part});
+    }
+
     var image_id_buffer: [256]u8 = undefined;
     const image_id = generateImageId(&image_id_buffer);