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zig server-sent events parser
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const std = @import("std"); | |
pub const Event = struct { | |
event: ?[]const u8, | |
data: ?std.ArrayListUnmanaged(u8), | |
id: ?[]const u8, | |
retry: ?u64, | |
pub fn deinit(event: Event, ally: std.mem.Allocator) void { | |
inline for (.{ event.event, event.id }) |mx| if (mx) |x| ally.free(x); | |
if (event.data) |d| { | |
var mut_d = d; | |
mut_d.deinit(ally); | |
} | |
} | |
pub const empty = .{ .event = null, .data = null, .id = null, .retry = null }; | |
}; | |
pub const EventStreamParser = struct { | |
event: Event = Event.empty, | |
pub fn feed(state: *EventStreamParser, line: []const u8, ally: std.mem.Allocator) !?Event { | |
if (line.len == 0) { | |
defer state.event = Event.empty; | |
// free up some memory | |
if (state.event.data) |d| d.shrinkAndFree(ally, d.items.len); | |
return state.event; | |
} | |
const index_of_colon = std.mem.indexOfScalar(u8, line, ':') orelse line.len; | |
if (index_of_colon == 0) return null; // comment | |
const kind = line[0..index_of_colon]; | |
const raw_value = line[@min(index_of_colon + 1, line.len)..]; | |
const value = if (std.mem.startsWith(u8, raw_value, " ")) raw_value[1..] else raw_value; | |
if (std.mem.eql(u8, kind, "data")) { | |
if (state.event.data) |d| { | |
try d.append(ally, '\n'); | |
} else { | |
state.event.data = std.ArrayListUnmanaged(u8){}; | |
} | |
try state.event.data.?.appendSlice(ally, value); | |
} else if (std.mem.eql(u8, kind, "event")) { | |
if (state.event.event != null) return error.DuplicateEvent; | |
state.event.event = try ally.dupe(u8, value); | |
} else if (std.mem.eql(u8, kind, "id")) { | |
if (state.event.id != null) return error.DuplicateId; | |
state.event.id = try ally.dupe(u8, value); | |
} else if (std.mem.eql(u8, kind, "retry")) { | |
state.event.retry = std.fmt.parseInt(u64, value, 10) catch null; | |
} | |
return null; | |
} | |
}; |
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