Multipart deserialization
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2f78490545
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96a46a98c9
1 changed files with 143 additions and 14 deletions
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@ -4,8 +4,7 @@ const util = @import("util");
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const max_boundary = 70;
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const FormFieldResult = struct {
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value: []const u8,
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params: FormDataParams,
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field: FormField,
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more: bool,
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};
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@ -138,13 +137,15 @@ fn parseFormField(boundary: []const u8, peek_stream: anytype, alloc: std.mem.All
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const disposition = headers.get("Content-Disposition") orelse return error.NoDisposition;
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return FormFieldResult{
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.field = .{
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.value = value.toOwnedSlice(),
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.params = try parseParams(alloc, FormDataParams, disposition),
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},
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.more = !terminal,
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};
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}
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pub fn parseFormData(boundary: []const u8, reader: anytype, alloc: std.mem.Allocator) !void {
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pub fn parseFormData(comptime T: type, boundary: []const u8, reader: anytype, alloc: std.mem.Allocator) !T {
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if (boundary.len > max_boundary) return error.BoundaryTooLarge;
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var stream = std.io.peekStream(72, reader);
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@ -156,17 +157,137 @@ pub fn parseFormData(boundary: []const u8, reader: anytype, alloc: std.mem.Alloc
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if (!std.mem.startsWith(u8, line, "--")) return error.InvalidMultipartBoundary;
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if (!std.mem.endsWith(u8, line, boundary)) return error.InvalidMultipartBoundary;
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if (try isFinalPart(&stream)) return;
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if (try isFinalPart(&stream)) return error.NoForm;
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}
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var fields = Intermediary(T){};
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while (true) {
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const field = try parseFormField(boundary, &stream, alloc);
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defer util.deepFree(alloc, field);
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const form_field = try parseFormField(boundary, &stream, alloc);
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std.debug.print("{any}\n", .{field});
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if (!field.more) return;
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inline for (std.meta.fields(Intermediary(T))) |field| {
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if (std.ascii.eqlIgnoreCase(field.name[2..], form_field.field.params.name.?)) {
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@field(fields, field.name) = form_field.field;
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break;
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}
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} else {
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std.log.debug("unknown form field {?s}", .{form_field.field.params.name});
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util.deepFree(alloc, form_field);
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}
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if (!form_field.more) break;
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}
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return (try parse(alloc, T, "", "", fields)).?;
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}
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fn parse(
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alloc: std.mem.Allocator,
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comptime T: type,
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comptime prefix: []const u8,
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comptime name: []const u8,
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fields: anytype,
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) !?T {
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if (comptime isScalar(T)) return try parseFormValue(alloc, T, @field(fields, prefix ++ "." ++ name));
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switch (@typeInfo(T)) {
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.Union => |info| {
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var result: ?T = null;
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inline for (info.fields) |field| {
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const F = field.field_type;
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const maybe_value = try parse(alloc, F, prefix, field.name, fields);
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if (maybe_value) |value| {
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if (result != null) return error.DuplicateUnionField;
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result = @unionInit(T, field.name, value);
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}
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}
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std.log.debug("{any}", .{result});
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return result;
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},
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.Struct => |info| {
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var result: T = undefined;
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var fields_specified: usize = 0;
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errdefer inline for (info.fields) |field, i| {
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if (fields_specified < i) util.deepFree(alloc, @field(result, field.name));
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};
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inline for (info.fields) |field| {
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const F = field.field_type;
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var maybe_value: ?F = null;
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if (try parse(alloc, F, prefix ++ "." ++ name, field.name, fields)) |v| {
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maybe_value = v;
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} else if (field.default_value) |default| {
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if (comptime @sizeOf(F) != 0) {
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maybe_value = try util.deepClone(alloc, @ptrCast(*const F, @alignCast(@alignOf(F), default)).*);
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} else {
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maybe_value = std.mem.zeroes(F);
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}
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}
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if (maybe_value) |v| {
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fields_specified += 1;
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@field(result, field.name) = v;
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}
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}
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if (fields_specified == 0) {
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return null;
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} else if (fields_specified != info.fields.len) {
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std.log.debug("{} {s} {s}", .{ T, prefix, name });
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return error.PartiallySpecifiedStruct;
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} else {
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return result;
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}
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},
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// Only applies to non-scalar optionals
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.Optional => |info| return try parse(alloc, info.child, prefix, name, fields),
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else => @compileError("tmp"),
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}
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}
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fn recursiveFieldPaths(comptime T: type, comptime prefix: []const u8) []const []const u8 {
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comptime {
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if (std.meta.trait.is(.Optional)(T)) return recursiveFieldPaths(std.meta.Child(T), prefix);
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var fields: []const []const u8 = &.{};
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for (std.meta.fields(T)) |f| {
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const full_name = prefix ++ f.name;
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if (isScalar(f.field_type)) {
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fields = fields ++ @as([]const []const u8, &.{full_name});
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} else {
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const field_prefix = if (@typeInfo(f.field_type) == .Union) prefix else full_name ++ ".";
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fields = fields ++ recursiveFieldPaths(f.field_type, field_prefix);
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}
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}
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return fields;
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}
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}
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fn Intermediary(comptime T: type) type {
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const field_names = recursiveFieldPaths(T, "..");
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var fields: [field_names.len]std.builtin.Type.StructField = undefined;
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for (field_names) |name, i| fields[i] = .{
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.name = name,
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.field_type = ?FormField,
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.default_value = &@as(?FormField, null),
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.is_comptime = false,
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.alignment = @alignOf(?FormField),
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};
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return @Type(.{ .Struct = .{
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.layout = .Auto,
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.fields = &fields,
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.decls = &.{},
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.is_tuple = false,
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} });
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}
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const FormFile = struct {
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@ -174,9 +295,8 @@ const FormFile = struct {
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data: []const u8,
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};
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fn parseFormValue(alloc: std.mem.Allocator, comptime T: type, field: FormField) !T {
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const is_optional = std.meta.trait.is(.Optional)(T);
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if ((comptime is_optional) and field.value.len == 0) return null;
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fn parseFormValue(alloc: std.mem.Allocator, comptime T: type, f: ?FormField) !T {
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const field = f orelse unreachable;
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if (comptime std.meta.trait.isZigString(T)) return field.value;
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@ -275,6 +395,15 @@ test "parseFormData" {
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\\
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);
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const T = struct {
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first: []const u8,
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second: []const u8,
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third: []const u8,
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};
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var stream = std.io.StreamSource{ .const_buffer = std.io.fixedBufferStream(body) };
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try parseFormData("abcd", stream.reader(), std.testing.allocator);
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const result = try parseFormData(T, "abcd", stream.reader(), std.testing.allocator);
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std.debug.print("\nfirst: {s}\n\n", .{result.first});
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std.debug.print("\nsecond: {s}\n\n", .{result.second});
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std.debug.print("\nthird: {s}\n\n", .{result.third});
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std.debug.print("\n{any}\n\n", .{result});
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}
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