Move json and query helpers
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parent
039377f168
commit
a28af9e1fe
2 changed files with 1057 additions and 0 deletions
677
src/http/json.zig
Normal file
677
src/http/json.zig
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@ -0,0 +1,677 @@
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const std = @import("std");
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const mem = std.mem;
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const Allocator = std.mem.Allocator;
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const assert = std.debug.assert;
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// This file is largely a copy of std.json
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const StreamingParser = std.json.StreamingParser;
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const Token = std.json.Token;
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const unescapeValidString = std.json.unescapeValidString;
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const UnescapeValidStringError = std.json.UnescapeValidStringError;
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pub fn parse(comptime T: type, body: []const u8, alloc: std.mem.Allocator) !T {
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var tokens = TokenStream.init(body);
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const options = ParseOptions{ .allocator = alloc };
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const token = (try tokens.next()) orelse return error.UnexpectedEndOfJson;
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const r = try parseInternal(T, token, &tokens, options);
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errdefer parseFreeInternal(T, r, options);
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if (!options.allow_trailing_data) {
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if ((try tokens.next()) != null) unreachable;
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assert(tokens.i >= tokens.slice.len);
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}
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return r;
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}
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pub fn parseFree(value: anytype, alloc: std.mem.Allocator) void {
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parseFreeInternal(@TypeOf(value), value, .{ .allocator = alloc });
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}
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// WARNING: the objects "parse" method must not contain a reference to the original value
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fn hasCustomParse(comptime T: type) bool {
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if (!std.meta.trait.hasFn("parse")(T)) return false;
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if (!@hasDecl(T, "JsonParseAs")) return false;
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return true;
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}
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///// The rest is (modified) from std.json
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/// A small wrapper over a StreamingParser for full slices. Returns a stream of json Tokens.
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pub const TokenStream = struct {
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i: usize,
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slice: []const u8,
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parser: StreamingParser,
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token: ?Token,
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pub const Error = StreamingParser.Error || error{UnexpectedEndOfJson};
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pub fn init(slice: []const u8) TokenStream {
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return TokenStream{
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.i = 0,
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.slice = slice,
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.parser = StreamingParser.init(),
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.token = null,
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};
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}
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fn stackUsed(self: *TokenStream) usize {
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return self.parser.stack.len + if (self.token != null) @as(usize, 1) else 0;
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}
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pub fn next(self: *TokenStream) Error!?Token {
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if (self.token) |token| {
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self.token = null;
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return token;
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}
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var t1: ?Token = undefined;
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var t2: ?Token = undefined;
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while (self.i < self.slice.len) {
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try self.parser.feed(self.slice[self.i], &t1, &t2);
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self.i += 1;
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if (t1) |token| {
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self.token = t2;
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return token;
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}
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}
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// Without this a bare number fails, the streaming parser doesn't know the input ended
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try self.parser.feed(' ', &t1, &t2);
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self.i += 1;
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if (t1) |token| {
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return token;
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} else if (self.parser.complete) {
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return null;
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} else {
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return error.UnexpectedEndOfJson;
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}
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}
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};
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/// Checks to see if a string matches what it would be as a json-encoded string
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/// Assumes that `encoded` is a well-formed json string
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fn encodesTo(decoded: []const u8, encoded: []const u8) bool {
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var i: usize = 0;
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var j: usize = 0;
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while (i < decoded.len) {
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if (j >= encoded.len) return false;
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if (encoded[j] != '\\') {
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if (decoded[i] != encoded[j]) return false;
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j += 1;
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i += 1;
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} else {
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const escape_type = encoded[j + 1];
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if (escape_type != 'u') {
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const t: u8 = switch (escape_type) {
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'\\' => '\\',
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'/' => '/',
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'n' => '\n',
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'r' => '\r',
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't' => '\t',
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'f' => 12,
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'b' => 8,
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'"' => '"',
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else => unreachable,
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};
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if (decoded[i] != t) return false;
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j += 2;
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i += 1;
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} else {
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var codepoint = std.fmt.parseInt(u21, encoded[j + 2 .. j + 6], 16) catch unreachable;
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j += 6;
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if (codepoint >= 0xD800 and codepoint < 0xDC00) {
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// surrogate pair
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assert(encoded[j] == '\\');
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assert(encoded[j + 1] == 'u');
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const low_surrogate = std.fmt.parseInt(u21, encoded[j + 2 .. j + 6], 16) catch unreachable;
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codepoint = 0x10000 + (((codepoint & 0x03ff) << 10) | (low_surrogate & 0x03ff));
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j += 6;
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}
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var buf: [4]u8 = undefined;
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const len = std.unicode.utf8Encode(codepoint, &buf) catch unreachable;
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if (i + len > decoded.len) return false;
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if (!mem.eql(u8, decoded[i .. i + len], buf[0..len])) return false;
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i += len;
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}
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}
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}
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assert(i == decoded.len);
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assert(j == encoded.len);
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return true;
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}
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/// parse tokens from a stream, returning `false` if they do not decode to `value`
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fn parsesTo(comptime T: type, value: T, tokens: *TokenStream, options: ParseOptions) !bool {
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// TODO: should be able to write this function to not require an allocator
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const tmp = try parse(T, tokens, options);
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defer parseFree(T, tmp, options);
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return parsedEqual(tmp, value);
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}
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/// Returns if a value returned by `parse` is deep-equal to another value
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fn parsedEqual(a: anytype, b: @TypeOf(a)) bool {
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switch (@typeInfo(@TypeOf(a))) {
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.Optional => {
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if (a == null and b == null) return true;
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if (a == null or b == null) return false;
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return parsedEqual(a.?, b.?);
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},
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.Union => |info| {
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if (info.tag_type) |UnionTag| {
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const tag_a = std.meta.activeTag(a);
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const tag_b = std.meta.activeTag(b);
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if (tag_a != tag_b) return false;
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inline for (info.fields) |field_info| {
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if (@field(UnionTag, field_info.name) == tag_a) {
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return parsedEqual(@field(a, field_info.name), @field(b, field_info.name));
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}
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}
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return false;
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} else {
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unreachable;
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}
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},
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.Array => {
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for (a) |e, i|
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if (!parsedEqual(e, b[i])) return false;
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return true;
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},
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.Struct => |info| {
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inline for (info.fields) |field_info| {
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if (!parsedEqual(@field(a, field_info.name), @field(b, field_info.name))) return false;
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}
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return true;
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},
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.Pointer => |ptrInfo| switch (ptrInfo.size) {
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.One => return parsedEqual(a.*, b.*),
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.Slice => {
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if (a.len != b.len) return false;
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for (a) |e, i|
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if (!parsedEqual(e, b[i])) return false;
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return true;
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},
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.Many, .C => unreachable,
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},
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else => return a == b,
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}
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unreachable;
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}
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const ParseOptions = struct {
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allocator: ?Allocator = null,
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/// Behaviour when a duplicate field is encountered.
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duplicate_field_behavior: enum {
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UseFirst,
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Error,
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UseLast,
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} = .Error,
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/// If false, finding an unknown field returns an error.
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ignore_unknown_fields: bool = false,
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allow_trailing_data: bool = false,
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};
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const SkipValueError = error{UnexpectedJsonDepth} || TokenStream.Error;
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fn skipValue(tokens: *TokenStream) SkipValueError!void {
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const original_depth = tokens.stackUsed();
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// Return an error if no value is found
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_ = try tokens.next();
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if (tokens.stackUsed() < original_depth) return error.UnexpectedJsonDepth;
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if (tokens.stackUsed() == original_depth) return;
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while (try tokens.next()) |_| {
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if (tokens.stackUsed() == original_depth) return;
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}
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}
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fn ParseInternalError(comptime T: type) type {
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// `inferred_types` is used to avoid infinite recursion for recursive type definitions.
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const inferred_types = [_]type{};
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return ParseInternalErrorImpl(T, &inferred_types);
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}
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fn ParseInternalErrorImpl(comptime T: type, comptime inferred_types: []const type) type {
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if (hasCustomParse(T)) {
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return ParseInternalError(T.JsonParseAs) || T.ParseError;
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}
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for (inferred_types) |ty| {
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if (T == ty) return error{};
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}
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switch (@typeInfo(T)) {
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.Bool => return error{UnexpectedToken},
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.Float, .ComptimeFloat => return error{UnexpectedToken} || std.fmt.ParseFloatError,
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.Int, .ComptimeInt => {
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return error{ UnexpectedToken, InvalidNumber, Overflow } ||
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std.fmt.ParseIntError || std.fmt.ParseFloatError;
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},
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.Optional => |optionalInfo| {
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return ParseInternalErrorImpl(optionalInfo.child, inferred_types ++ [_]type{T});
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},
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.Enum => return error{ UnexpectedToken, InvalidEnumTag } || std.fmt.ParseIntError ||
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std.meta.IntToEnumError || std.meta.IntToEnumError,
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.Union => |unionInfo| {
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if (unionInfo.tag_type) |_| {
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var errors = error{NoUnionMembersMatched};
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for (unionInfo.fields) |u_field| {
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errors = errors || ParseInternalErrorImpl(u_field.field_type, inferred_types ++ [_]type{T});
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}
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return errors;
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} else {
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@compileError("Unable to parse into untagged union '" ++ @typeName(T) ++ "'");
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}
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},
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.Struct => |structInfo| {
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var errors = error{
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DuplicateJSONField,
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UnexpectedEndOfJson,
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UnexpectedToken,
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UnexpectedValue,
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UnknownField,
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MissingField,
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} || SkipValueError || TokenStream.Error;
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for (structInfo.fields) |field| {
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errors = errors || ParseInternalErrorImpl(field.field_type, inferred_types ++ [_]type{T});
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}
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return errors;
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},
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.Array => |arrayInfo| {
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return error{ UnexpectedEndOfJson, UnexpectedToken } || TokenStream.Error ||
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UnescapeValidStringError ||
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ParseInternalErrorImpl(arrayInfo.child, inferred_types ++ [_]type{T});
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},
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.Pointer => |ptrInfo| {
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var errors = error{AllocatorRequired} || std.mem.Allocator.Error;
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switch (ptrInfo.size) {
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.One => {
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return errors || ParseInternalErrorImpl(ptrInfo.child, inferred_types ++ [_]type{T});
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},
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.Slice => {
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return errors || error{ UnexpectedEndOfJson, UnexpectedToken } ||
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ParseInternalErrorImpl(ptrInfo.child, inferred_types ++ [_]type{T}) ||
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UnescapeValidStringError || TokenStream.Error;
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},
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else => @compileError("Unable to parse into type '" ++ @typeName(T) ++ "'"),
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}
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},
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else => return error{},
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}
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unreachable;
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}
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fn parseInternal(
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comptime T: type,
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token: Token,
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tokens: *TokenStream,
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options: ParseOptions,
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) ParseInternalError(T)!T {
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if (comptime hasCustomParse(T)) {
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const val = try parseInternal(T.JsonParseAs, token, tokens, options);
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defer parseFreeInternal(T.JsonParseAs, val, options);
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return try T.parse(val);
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}
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switch (@typeInfo(T)) {
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.Bool => {
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return switch (token) {
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.True => true,
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.False => false,
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else => error.UnexpectedToken,
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};
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},
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.Float, .ComptimeFloat => {
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switch (token) {
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.Number => |numberToken| return try std.fmt.parseFloat(T, numberToken.slice(tokens.slice, tokens.i - 1)),
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.String => |stringToken| return try std.fmt.parseFloat(T, stringToken.slice(tokens.slice, tokens.i - 1)),
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else => return error.UnexpectedToken,
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}
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},
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.Int, .ComptimeInt => {
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switch (token) {
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.Number => |numberToken| {
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if (numberToken.is_integer)
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return try std.fmt.parseInt(T, numberToken.slice(tokens.slice, tokens.i - 1), 10);
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const float = try std.fmt.parseFloat(f128, numberToken.slice(tokens.slice, tokens.i - 1));
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if (@round(float) != float) return error.InvalidNumber;
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if (float > std.math.maxInt(T) or float < std.math.minInt(T)) return error.Overflow;
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return @floatToInt(T, float);
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},
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.String => |stringToken| {
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return std.fmt.parseInt(T, stringToken.slice(tokens.slice, tokens.i - 1), 10) catch |err| {
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switch (err) {
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error.Overflow => return err,
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error.InvalidCharacter => {
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const float = try std.fmt.parseFloat(f128, stringToken.slice(tokens.slice, tokens.i - 1));
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if (@round(float) != float) return error.InvalidNumber;
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if (float > std.math.maxInt(T) or float < std.math.minInt(T)) return error.Overflow;
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return @floatToInt(T, float);
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},
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}
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};
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},
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else => return error.UnexpectedToken,
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}
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},
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.Optional => |optionalInfo| {
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if (token == .Null) {
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return null;
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} else {
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return try parseInternal(optionalInfo.child, token, tokens, options);
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}
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},
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.Enum => |enumInfo| {
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switch (token) {
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.Number => |numberToken| {
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if (!numberToken.is_integer) return error.UnexpectedToken;
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const n = try std.fmt.parseInt(enumInfo.tag_type, numberToken.slice(tokens.slice, tokens.i - 1), 10);
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return try std.meta.intToEnum(T, n);
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},
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.String => |stringToken| {
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const source_slice = stringToken.slice(tokens.slice, tokens.i - 1);
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switch (stringToken.escapes) {
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.None => return std.meta.stringToEnum(T, source_slice) orelse return error.InvalidEnumTag,
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.Some => {
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inline for (enumInfo.fields) |field| {
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if (field.name.len == stringToken.decodedLength() and encodesTo(field.name, source_slice)) {
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return @field(T, field.name);
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}
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}
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return error.InvalidEnumTag;
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},
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}
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},
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else => return error.UnexpectedToken,
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}
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},
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.Union => |unionInfo| {
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if (unionInfo.tag_type) |_| {
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// try each of the union fields until we find one that matches
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inline for (unionInfo.fields) |u_field| {
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// take a copy of tokens so we can withhold mutations until success
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var tokens_copy = tokens.*;
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if (parseInternal(u_field.field_type, token, &tokens_copy, options)) |value| {
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tokens.* = tokens_copy;
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return @unionInit(T, u_field.name, value);
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} else |err| {
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// Bubble up error.OutOfMemory
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// Parsing some types won't have OutOfMemory in their
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// error-sets, for the condition to be valid, merge it in.
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if (@as(@TypeOf(err) || error{OutOfMemory}, err) == error.OutOfMemory) return err;
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// Bubble up AllocatorRequired, as it indicates missing option
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if (@as(@TypeOf(err) || error{AllocatorRequired}, err) == error.AllocatorRequired) return err;
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// otherwise continue through the `inline for`
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}
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}
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return error.NoUnionMembersMatched;
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} else {
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@compileError("Unable to parse into untagged union '" ++ @typeName(T) ++ "'");
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}
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},
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.Struct => |structInfo| {
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switch (token) {
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.ObjectBegin => {},
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else => return error.UnexpectedToken,
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}
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var r: T = undefined;
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var fields_seen = [_]bool{false} ** structInfo.fields.len;
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errdefer {
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inline for (structInfo.fields) |field, i| {
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if (fields_seen[i] and !field.is_comptime) {
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parseFreeInternal(field.field_type, @field(r, field.name), options);
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}
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}
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}
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while (true) {
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switch ((try tokens.next()) orelse return error.UnexpectedEndOfJson) {
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.ObjectEnd => break,
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.String => |stringToken| {
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const key_source_slice = stringToken.slice(tokens.slice, tokens.i - 1);
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var child_options = options;
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child_options.allow_trailing_data = true;
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var found = false;
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inline for (structInfo.fields) |field, i| {
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// TODO: using switches here segfault the compiler (#2727?)
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if ((stringToken.escapes == .None and mem.eql(u8, field.name, key_source_slice)) or (stringToken.escapes == .Some and (field.name.len == stringToken.decodedLength() and encodesTo(field.name, key_source_slice)))) {
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// if (switch (stringToken.escapes) {
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// .None => mem.eql(u8, field.name, key_source_slice),
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// .Some => (field.name.len == stringToken.decodedLength() and encodesTo(field.name, key_source_slice)),
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// }) {
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if (fields_seen[i]) {
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// switch (options.duplicate_field_behavior) {
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// .UseFirst => {},
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// .Error => {},
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// .UseLast => {},
|
||||
// }
|
||||
if (options.duplicate_field_behavior == .UseFirst) {
|
||||
// unconditonally ignore value. for comptime fields, this skips check against default_value
|
||||
const next_token = (try tokens.next()) orelse return error.UnexpectedEndOfJson;
|
||||
parseFreeInternal(field.field_type, try parseInternal(field.field_type, next_token, tokens, child_options), child_options);
|
||||
found = true;
|
||||
break;
|
||||
} else if (options.duplicate_field_behavior == .Error) {
|
||||
return error.DuplicateJSONField;
|
||||
} else if (options.duplicate_field_behavior == .UseLast) {
|
||||
if (!field.is_comptime) {
|
||||
parseFreeInternal(field.field_type, @field(r, field.name), child_options);
|
||||
}
|
||||
fields_seen[i] = false;
|
||||
}
|
||||
}
|
||||
if (field.is_comptime) {
|
||||
if (!try parsesTo(field.field_type, @ptrCast(*const field.field_type, field.default_value.?).*, tokens, child_options)) {
|
||||
return error.UnexpectedValue;
|
||||
}
|
||||
} else {
|
||||
const next_token = (try tokens.next()) orelse return error.UnexpectedEndOfJson;
|
||||
@field(r, field.name) = try parseInternal(field.field_type, next_token, tokens, child_options);
|
||||
}
|
||||
fields_seen[i] = true;
|
||||
found = true;
|
||||
break;
|
||||
}
|
||||
}
|
||||
if (!found) {
|
||||
if (options.ignore_unknown_fields) {
|
||||
try skipValue(tokens);
|
||||
continue;
|
||||
} else {
|
||||
return error.UnknownField;
|
||||
}
|
||||
}
|
||||
},
|
||||
else => return error.UnexpectedToken,
|
||||
}
|
||||
}
|
||||
inline for (structInfo.fields) |field, i| {
|
||||
if (!fields_seen[i]) {
|
||||
if (field.default_value) |default_ptr| {
|
||||
if (!field.is_comptime) {
|
||||
const default = @ptrCast(*align(1) const field.field_type, default_ptr).*;
|
||||
@field(r, field.name) = default;
|
||||
}
|
||||
} else {
|
||||
return error.MissingField;
|
||||
}
|
||||
}
|
||||
}
|
||||
return r;
|
||||
},
|
||||
.Array => |arrayInfo| {
|
||||
switch (token) {
|
||||
.ArrayBegin => {
|
||||
var r: T = undefined;
|
||||
var i: usize = 0;
|
||||
var child_options = options;
|
||||
child_options.allow_trailing_data = true;
|
||||
errdefer {
|
||||
// Without the r.len check `r[i]` is not allowed
|
||||
if (r.len > 0) while (true) : (i -= 1) {
|
||||
parseFreeInternal(arrayInfo.child, r[i], options);
|
||||
if (i == 0) break;
|
||||
};
|
||||
}
|
||||
while (i < r.len) : (i += 1) {
|
||||
const next_token = (try tokens.next()) orelse return error.UnexpectedEndOfJson;
|
||||
r[i] = try parseInternal(arrayInfo.child, next_token, tokens, child_options);
|
||||
}
|
||||
const tok = (try tokens.next()) orelse return error.UnexpectedEndOfJson;
|
||||
switch (tok) {
|
||||
.ArrayEnd => {},
|
||||
else => return error.UnexpectedToken,
|
||||
}
|
||||
return r;
|
||||
},
|
||||
.String => |stringToken| {
|
||||
if (arrayInfo.child != u8) return error.UnexpectedToken;
|
||||
var r: T = undefined;
|
||||
const source_slice = stringToken.slice(tokens.slice, tokens.i - 1);
|
||||
switch (stringToken.escapes) {
|
||||
.None => mem.copy(u8, &r, source_slice),
|
||||
.Some => try unescapeValidString(&r, source_slice),
|
||||
}
|
||||
return r;
|
||||
},
|
||||
else => return error.UnexpectedToken,
|
||||
}
|
||||
},
|
||||
.Pointer => |ptrInfo| {
|
||||
const allocator = options.allocator orelse return error.AllocatorRequired;
|
||||
switch (ptrInfo.size) {
|
||||
.One => {
|
||||
const r: T = try allocator.create(ptrInfo.child);
|
||||
errdefer allocator.destroy(r);
|
||||
r.* = try parseInternal(ptrInfo.child, token, tokens, options);
|
||||
return r;
|
||||
},
|
||||
.Slice => {
|
||||
switch (token) {
|
||||
.ArrayBegin => {
|
||||
var arraylist = std.ArrayList(ptrInfo.child).init(allocator);
|
||||
errdefer {
|
||||
while (arraylist.popOrNull()) |v| {
|
||||
parseFreeInternal(ptrInfo.child, v, options);
|
||||
}
|
||||
arraylist.deinit();
|
||||
}
|
||||
|
||||
while (true) {
|
||||
const tok = (try tokens.next()) orelse return error.UnexpectedEndOfJson;
|
||||
switch (tok) {
|
||||
.ArrayEnd => break,
|
||||
else => {},
|
||||
}
|
||||
|
||||
try arraylist.ensureUnusedCapacity(1);
|
||||
const v = try parseInternal(ptrInfo.child, tok, tokens, options);
|
||||
arraylist.appendAssumeCapacity(v);
|
||||
}
|
||||
|
||||
if (ptrInfo.sentinel) |some| {
|
||||
const sentinel_value = @ptrCast(*const ptrInfo.child, some).*;
|
||||
try arraylist.append(sentinel_value);
|
||||
const output = arraylist.toOwnedSlice();
|
||||
return output[0 .. output.len - 1 :sentinel_value];
|
||||
}
|
||||
|
||||
return arraylist.toOwnedSlice();
|
||||
},
|
||||
.String => |stringToken| {
|
||||
if (ptrInfo.child != u8) return error.UnexpectedToken;
|
||||
const source_slice = stringToken.slice(tokens.slice, tokens.i - 1);
|
||||
const len = stringToken.decodedLength();
|
||||
const output = try allocator.alloc(u8, len + @boolToInt(ptrInfo.sentinel != null));
|
||||
errdefer allocator.free(output);
|
||||
switch (stringToken.escapes) {
|
||||
.None => mem.copy(u8, output, source_slice),
|
||||
.Some => try unescapeValidString(output, source_slice),
|
||||
}
|
||||
|
||||
if (ptrInfo.sentinel) |some| {
|
||||
const char = @ptrCast(*const u8, some).*;
|
||||
output[len] = char;
|
||||
return output[0..len :char];
|
||||
}
|
||||
|
||||
return output;
|
||||
},
|
||||
else => return error.UnexpectedToken,
|
||||
}
|
||||
},
|
||||
else => @compileError("Unable to parse into type '" ++ @typeName(T) ++ "'"),
|
||||
}
|
||||
},
|
||||
else => @compileError("Unable to parse into type '" ++ @typeName(T) ++ "'"),
|
||||
}
|
||||
unreachable;
|
||||
}
|
||||
|
||||
fn ParseError(comptime T: type) type {
|
||||
return ParseInternalError(T) || error{UnexpectedEndOfJson} || TokenStream.Error;
|
||||
}
|
||||
|
||||
/// Releases resources created by `parse`.
|
||||
/// Should be called with the same type and `ParseOptions` that were passed to `parse`
|
||||
fn parseFreeInternal(comptime T: type, value: T, options: ParseOptions) void {
|
||||
switch (@typeInfo(T)) {
|
||||
.Bool, .Float, .ComptimeFloat, .Int, .ComptimeInt, .Enum => {},
|
||||
.Optional => {
|
||||
if (value) |v| {
|
||||
return parseFreeInternal(@TypeOf(v), v, options);
|
||||
}
|
||||
},
|
||||
.Union => |unionInfo| {
|
||||
if (unionInfo.tag_type) |UnionTagType| {
|
||||
inline for (unionInfo.fields) |u_field| {
|
||||
if (value == @field(UnionTagType, u_field.name)) {
|
||||
parseFreeInternal(u_field.field_type, @field(value, u_field.name), options);
|
||||
break;
|
||||
}
|
||||
}
|
||||
} else {
|
||||
unreachable;
|
||||
}
|
||||
},
|
||||
.Struct => |structInfo| {
|
||||
inline for (structInfo.fields) |field| {
|
||||
if (!field.is_comptime) {
|
||||
parseFreeInternal(field.field_type, @field(value, field.name), options);
|
||||
}
|
||||
}
|
||||
},
|
||||
.Array => |arrayInfo| {
|
||||
for (value) |v| {
|
||||
parseFreeInternal(arrayInfo.child, v, options);
|
||||
}
|
||||
},
|
||||
.Pointer => |ptrInfo| {
|
||||
const allocator = options.allocator orelse unreachable;
|
||||
switch (ptrInfo.size) {
|
||||
.One => {
|
||||
parseFreeInternal(ptrInfo.child, value.*, options);
|
||||
allocator.destroy(value);
|
||||
},
|
||||
.Slice => {
|
||||
for (value) |v| {
|
||||
parseFreeInternal(ptrInfo.child, v, options);
|
||||
}
|
||||
allocator.free(value);
|
||||
},
|
||||
else => unreachable,
|
||||
}
|
||||
},
|
||||
else => unreachable,
|
||||
}
|
||||
}
|
||||
380
src/http/query.zig
Normal file
380
src/http/query.zig
Normal file
|
|
@ -0,0 +1,380 @@
|
|||
const std = @import("std");
|
||||
|
||||
const QueryIter = @import("util").QueryIter;
|
||||
|
||||
/// Parses a set of query parameters described by the struct `T`.
|
||||
///
|
||||
/// To specify query parameters, provide a struct similar to the following:
|
||||
/// ```
|
||||
/// struct {
|
||||
/// foo: bool = false,
|
||||
/// bar: ?[]const u8 = null,
|
||||
/// baz: usize = 10,
|
||||
/// qux: enum { quux, snap } = .quux,
|
||||
/// }
|
||||
/// ```
|
||||
///
|
||||
/// This will allow it to parse a query string like the following:
|
||||
/// `?foo&bar=abc&qux=snap`
|
||||
///
|
||||
/// Every parameter must have a default value that will be used when the
|
||||
/// parameter is not provided, and parameter keys.
|
||||
/// Numbers are parsed from their string representations, and a parameter
|
||||
/// provided in the query string without a value is parsed either as a bool
|
||||
/// `true` flag or as `null` depending on the type of its param.
|
||||
///
|
||||
/// Parameter types supported:
|
||||
/// - []const u8
|
||||
/// - numbers (both integer and float)
|
||||
/// + Numbers are parsed in base 10
|
||||
/// - bool
|
||||
/// + See below for detals
|
||||
/// - exhaustive enums
|
||||
/// + Enums are treated as strings with values equal to the enum fields
|
||||
/// - ?F (where isScalar(F) and F != bool)
|
||||
/// - Any type that implements:
|
||||
/// + pub fn parse([]const u8) !F
|
||||
///
|
||||
/// Boolean Parameters:
|
||||
/// The following query strings will all parse a `true` value for the
|
||||
/// parameter `foo: bool = false`:
|
||||
/// - `?foo`
|
||||
/// - `?foo=true`
|
||||
/// - `?foo=t`
|
||||
/// - `?foo=yes`
|
||||
/// - `?foo=y`
|
||||
/// - `?foo=1`
|
||||
/// And the following query strings all parse a `false` value:
|
||||
/// - `?`
|
||||
/// - `?foo=false`
|
||||
/// - `?foo=f`
|
||||
/// - `?foo=no`
|
||||
/// - `?foo=n`
|
||||
/// - `?foo=0`
|
||||
///
|
||||
/// Compound Types:
|
||||
/// Compound (struct) types are also supported, with the parameter key
|
||||
/// for its parameters consisting of the struct's field + '.' + parameter
|
||||
/// field. For example:
|
||||
/// ```
|
||||
/// struct {
|
||||
/// foo: struct {
|
||||
/// baz: usize = 0,
|
||||
/// } = .{},
|
||||
/// }
|
||||
/// ```
|
||||
/// Would be used to parse a query string like
|
||||
/// `?foo.baz=12345`
|
||||
///
|
||||
/// Compound types cannot currently be nullable, and must be structs.
|
||||
///
|
||||
/// TODO: values are currently case-sensitive, and are not url-decoded properly.
|
||||
/// This should be fixed.
|
||||
pub fn parseQuery(alloc: std.mem.Allocator, comptime T: type, query: []const u8) !T {
|
||||
if (comptime !std.meta.trait.isContainer(T)) @compileError("T must be a struct");
|
||||
var iter = QueryIter.from(query);
|
||||
|
||||
var fields = Intermediary(T){};
|
||||
while (iter.next()) |pair| {
|
||||
// TODO: Hash map
|
||||
inline for (std.meta.fields(Intermediary(T))) |field| {
|
||||
if (std.ascii.eqlIgnoreCase(field.name[2..], pair.key)) {
|
||||
@field(fields, field.name) = if (pair.value) |v| .{ .value = v } else .{ .no_value = {} };
|
||||
break;
|
||||
}
|
||||
} else std.log.debug("unknown param {s}", .{pair.key});
|
||||
}
|
||||
|
||||
return (try parse(alloc, T, "", "", fields)) orelse error.NoQuery;
|
||||
}
|
||||
|
||||
fn decodeString(alloc: std.mem.Allocator, val: []const u8) ![]const u8 {
|
||||
var list = try std.ArrayList(u8).initCapacity(alloc, val.len);
|
||||
errdefer list.deinit();
|
||||
|
||||
var idx: usize = 0;
|
||||
while (idx < val.len) : (idx += 1) {
|
||||
if (val[idx] != '%') {
|
||||
try list.append(val[idx]);
|
||||
} else {
|
||||
if (val.len < idx + 2) return error.InvalidEscape;
|
||||
const buf = [2]u8{ val[idx + 1], val[idx + 2] };
|
||||
idx += 2;
|
||||
|
||||
const ch = try std.fmt.parseInt(u8, &buf, 16);
|
||||
try list.append(ch);
|
||||
}
|
||||
}
|
||||
|
||||
return list.toOwnedSlice();
|
||||
}
|
||||
|
||||
fn parseScalar(alloc: std.mem.Allocator, comptime T: type, comptime name: []const u8, fields: anytype) !?T {
|
||||
const param = @field(fields, name);
|
||||
return switch (param) {
|
||||
.not_specified => null,
|
||||
.no_value => try parseQueryValue(alloc, T, null),
|
||||
.value => |v| try parseQueryValue(alloc, T, v),
|
||||
};
|
||||
}
|
||||
|
||||
fn parse(
|
||||
alloc: std.mem.Allocator,
|
||||
comptime T: type,
|
||||
comptime prefix: []const u8,
|
||||
comptime name: []const u8,
|
||||
fields: anytype,
|
||||
) !?T {
|
||||
if (comptime isScalar(T)) return parseScalar(alloc, T, prefix ++ "." ++ name, fields);
|
||||
switch (@typeInfo(T)) {
|
||||
.Union => |info| {
|
||||
var result: ?T = null;
|
||||
inline for (info.fields) |field| {
|
||||
const F = field.field_type;
|
||||
|
||||
const maybe_value = try parse(alloc, F, prefix, field.name, fields);
|
||||
if (maybe_value) |value| {
|
||||
if (result != null) return error.DuplicateUnionField;
|
||||
|
||||
result = @unionInit(T, field.name, value);
|
||||
}
|
||||
}
|
||||
std.log.debug("{any}", .{result});
|
||||
return result;
|
||||
},
|
||||
|
||||
.Struct => |info| {
|
||||
var result: T = undefined;
|
||||
var fields_specified: usize = 0;
|
||||
|
||||
inline for (info.fields) |field| {
|
||||
const F = field.field_type;
|
||||
|
||||
var maybe_value: ?F = null;
|
||||
if (try parse(alloc, F, prefix ++ "." ++ name, field.name, fields)) |v| {
|
||||
maybe_value = v;
|
||||
} else if (field.default_value) |default| {
|
||||
if (comptime @sizeOf(F) != 0) {
|
||||
maybe_value = @ptrCast(*const F, @alignCast(@alignOf(F), default)).*;
|
||||
} else {
|
||||
maybe_value = std.mem.zeroes(F);
|
||||
}
|
||||
}
|
||||
|
||||
if (maybe_value) |v| {
|
||||
fields_specified += 1;
|
||||
@field(result, field.name) = v;
|
||||
}
|
||||
}
|
||||
|
||||
if (fields_specified == 0) {
|
||||
return null;
|
||||
} else if (fields_specified != info.fields.len) {
|
||||
std.log.debug("{} {s} {s}", .{ T, prefix, name });
|
||||
return error.PartiallySpecifiedStruct;
|
||||
} else {
|
||||
return result;
|
||||
}
|
||||
},
|
||||
|
||||
// Only applies to non-scalar optionals
|
||||
.Optional => |info| return try parse(alloc, info.child, prefix, name, fields),
|
||||
|
||||
else => @compileError("tmp"),
|
||||
}
|
||||
}
|
||||
|
||||
fn recursiveFieldPaths(comptime T: type, comptime prefix: []const u8) []const []const u8 {
|
||||
comptime {
|
||||
if (std.meta.trait.is(.Optional)(T)) return recursiveFieldPaths(std.meta.Child(T), prefix);
|
||||
|
||||
var fields: []const []const u8 = &.{};
|
||||
|
||||
for (std.meta.fields(T)) |f| {
|
||||
const full_name = prefix ++ f.name;
|
||||
|
||||
if (isScalar(f.field_type)) {
|
||||
fields = fields ++ @as([]const []const u8, &.{full_name});
|
||||
} else {
|
||||
const field_prefix = if (@typeInfo(f.field_type) == .Union) prefix else full_name ++ ".";
|
||||
fields = fields ++ recursiveFieldPaths(f.field_type, field_prefix);
|
||||
}
|
||||
}
|
||||
|
||||
return fields;
|
||||
}
|
||||
}
|
||||
|
||||
const QueryParam = union(enum) {
|
||||
not_specified: void,
|
||||
no_value: void,
|
||||
value: []const u8,
|
||||
};
|
||||
|
||||
fn Intermediary(comptime T: type) type {
|
||||
const field_names = recursiveFieldPaths(T, "..");
|
||||
|
||||
var fields: [field_names.len]std.builtin.Type.StructField = undefined;
|
||||
for (field_names) |name, i| fields[i] = .{
|
||||
.name = name,
|
||||
.field_type = QueryParam,
|
||||
.default_value = &QueryParam{ .not_specified = {} },
|
||||
.is_comptime = false,
|
||||
.alignment = @alignOf(QueryParam),
|
||||
};
|
||||
|
||||
return @Type(.{ .Struct = .{
|
||||
.layout = .Auto,
|
||||
.fields = &fields,
|
||||
.decls = &.{},
|
||||
.is_tuple = false,
|
||||
} });
|
||||
}
|
||||
|
||||
fn parseQueryValue(alloc: std.mem.Allocator, comptime T: type, value: ?[]const u8) !T {
|
||||
const is_optional = comptime std.meta.trait.is(.Optional)(T);
|
||||
// If param is present, but without an associated value
|
||||
if (value == null) {
|
||||
return if (is_optional)
|
||||
null
|
||||
else if (T == bool)
|
||||
true
|
||||
else
|
||||
error.InvalidValue;
|
||||
}
|
||||
|
||||
return try parseQueryValueNotNull(alloc, if (is_optional) std.meta.Child(T) else T, value.?);
|
||||
}
|
||||
|
||||
const bool_map = std.ComptimeStringMap(bool, .{
|
||||
.{ "true", true },
|
||||
.{ "t", true },
|
||||
.{ "yes", true },
|
||||
.{ "y", true },
|
||||
.{ "1", true },
|
||||
|
||||
.{ "false", false },
|
||||
.{ "f", false },
|
||||
.{ "no", false },
|
||||
.{ "n", false },
|
||||
.{ "0", false },
|
||||
});
|
||||
|
||||
fn parseQueryValueNotNull(alloc: std.mem.Allocator, comptime T: type, value: []const u8) !T {
|
||||
const decoded = try decodeString(alloc, value);
|
||||
errdefer alloc.free(decoded);
|
||||
|
||||
if (comptime std.meta.trait.isZigString(T)) return decoded;
|
||||
|
||||
const result = if (comptime std.meta.trait.isIntegral(T))
|
||||
try std.fmt.parseInt(T, decoded, 0)
|
||||
else if (comptime std.meta.trait.isFloat(T))
|
||||
try std.fmt.parseFloat(T, decoded)
|
||||
else if (comptime std.meta.trait.is(.Enum)(T))
|
||||
std.meta.stringToEnum(T, decoded) orelse return error.InvalidEnumValue
|
||||
else if (T == bool)
|
||||
bool_map.get(value) orelse return error.InvalidBool
|
||||
else if (comptime std.meta.trait.hasFn("parse")(T))
|
||||
try T.parse(value)
|
||||
else
|
||||
@compileError("Invalid type " ++ @typeName(T));
|
||||
|
||||
alloc.free(decoded);
|
||||
return result;
|
||||
}
|
||||
|
||||
fn isScalar(comptime T: type) bool {
|
||||
if (comptime std.meta.trait.isZigString(T)) return true;
|
||||
if (comptime std.meta.trait.isIntegral(T)) return true;
|
||||
if (comptime std.meta.trait.isFloat(T)) return true;
|
||||
if (comptime std.meta.trait.is(.Enum)(T)) return true;
|
||||
if (T == bool) return true;
|
||||
if (comptime std.meta.trait.hasFn("parse")(T)) return true;
|
||||
|
||||
if (comptime std.meta.trait.is(.Optional)(T) and isScalar(std.meta.Child(T))) return true;
|
||||
|
||||
return false;
|
||||
}
|
||||
|
||||
pub fn formatQuery(params: anytype, writer: anytype) !void {
|
||||
try format("", "", params, writer);
|
||||
}
|
||||
|
||||
fn urlFormatString(writer: anytype, val: []const u8) !void {
|
||||
for (val) |ch| {
|
||||
const printable = switch (ch) {
|
||||
'0'...'9', 'a'...'z', 'A'...'Z' => true,
|
||||
'-', '.', '_', '~', ':', '@', '!', '$', '&', '\'', '(', ')', '*', '+', ',', ';', '=' => true,
|
||||
else => false,
|
||||
};
|
||||
|
||||
try if (printable) writer.writeByte(ch) else std.fmt.format(writer, "%{x:0>2}", .{ch});
|
||||
}
|
||||
}
|
||||
|
||||
fn formatScalar(comptime name: []const u8, val: anytype, writer: anytype) !void {
|
||||
const T = @TypeOf(val);
|
||||
if (comptime std.meta.trait.is(.Optional)(T)) {
|
||||
return if (val) |v| formatScalar(name, v, writer) else {};
|
||||
}
|
||||
|
||||
try urlFormatString(writer, name);
|
||||
try writer.writeByte('=');
|
||||
if (comptime std.meta.trait.isZigString(T)) {
|
||||
try urlFormatString(writer, val);
|
||||
} else try switch (@typeInfo(T)) {
|
||||
.Enum => urlFormatString(writer, @tagName(val)),
|
||||
else => std.fmt.format(writer, "{}", .{val}),
|
||||
};
|
||||
|
||||
try writer.writeByte('&');
|
||||
}
|
||||
|
||||
fn format(comptime prefix: []const u8, comptime name: []const u8, params: anytype, writer: anytype) !void {
|
||||
const T = @TypeOf(params);
|
||||
const eff_prefix = if (prefix.len == 0) "" else prefix ++ ".";
|
||||
if (comptime isScalar(T)) return formatScalar(eff_prefix ++ name, params, writer);
|
||||
|
||||
switch (@typeInfo(T)) {
|
||||
.Struct => {
|
||||
inline for (std.meta.fields(T)) |field| {
|
||||
const val = @field(params, field.name);
|
||||
try format(eff_prefix ++ name, field.name, val, writer);
|
||||
}
|
||||
},
|
||||
.Union => {
|
||||
inline for (std.meta.fields(T)) |field| {
|
||||
const tag = @field(std.meta.Tag(T), field.name);
|
||||
const tag_name = field.name;
|
||||
if (@as(std.meta.Tag(T), params) == tag) {
|
||||
const val = @field(params, tag_name);
|
||||
try format(prefix, tag_name, val, writer);
|
||||
}
|
||||
}
|
||||
},
|
||||
.Optional => {
|
||||
if (params) |p| try format(prefix, name, p, writer);
|
||||
},
|
||||
else => @compileError("Unsupported query type"),
|
||||
}
|
||||
}
|
||||
|
||||
test {
|
||||
const TestQuery = struct {
|
||||
int: usize = 3,
|
||||
boolean: bool = false,
|
||||
str_enum: ?enum { foo, bar } = null,
|
||||
};
|
||||
|
||||
try std.testing.expectEqual(TestQuery{
|
||||
.int = 3,
|
||||
.boolean = false,
|
||||
.str_enum = null,
|
||||
}, try parseQuery(TestQuery, ""));
|
||||
|
||||
try std.testing.expectEqual(TestQuery{
|
||||
.int = 5,
|
||||
.boolean = true,
|
||||
.str_enum = .foo,
|
||||
}, try parseQuery(TestQuery, "?int=5&boolean=yes&str_enum=foo"));
|
||||
}
|
||||
Loading…
Reference in a new issue