openauth-core 0.0.4

Core types and primitives for OpenAuth.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142

use super::*;

/// Builds the dialect-specific statement trio used by SQL-backed rate-limit stores.
pub fn rate_limit_consume_statements(
    dialect: SqlDialect,
    table: &str,
    key: &str,
    count: &str,
    last_request: &str,
) -> Result<SqlRateLimitPlan, OpenAuthError> {
    let table = dialect.quote_identifier(table)?;
    let key = dialect.quote_identifier(key)?;
    let count = dialect.quote_identifier(count)?;
    let last_request = dialect.quote_identifier(last_request)?;
    let insert_keyword = match dialect {
        SqlDialect::Postgres | SqlDialect::MySql => "INSERT",
        SqlDialect::Sqlite => "INSERT OR IGNORE",
    };
    let conflict_suffix = match dialect {
        SqlDialect::Postgres => format!(" ON CONFLICT ({key}) DO NOTHING"),
        SqlDialect::MySql => String::new(),
        SqlDialect::Sqlite => String::new(),
    };
    let insert_prefix = match dialect {
        SqlDialect::MySql => "INSERT IGNORE",
        SqlDialect::Postgres | SqlDialect::Sqlite => insert_keyword,
    };
    let lock_suffix = match dialect {
        SqlDialect::Postgres | SqlDialect::MySql => " FOR UPDATE",
        SqlDialect::Sqlite => "",
    };

    Ok(SqlRateLimitPlan {
        insert_ignore: SqlStatement::new(format!(
            "{insert_prefix} INTO {table} ({key}, {count}, {last_request}) VALUES ({}, 0, {}){conflict_suffix}",
            dialect.placeholder(1),
            dialect.placeholder(2)
        )),
        select: SqlStatement::new(format!(
            "SELECT {count} AS count, {last_request} AS last_request FROM {table} WHERE {key} = {}{lock_suffix}",
            dialect.placeholder(1)
        )),
        update: SqlStatement::new(format!(
            "UPDATE {table} SET {count} = {}, {last_request} = {} WHERE {key} = {}",
            dialect.placeholder(1),
            dialect.placeholder(2),
            dialect.placeholder(3)
        )),
    })
}

/// Applies OpenAuth rate-limit semantics to a locked database record.
///
/// SQL adapters share this decision logic after they insert/select the row
/// inside their own transaction or locking primitive.
pub fn consume_sql_rate_limit_record(
    input: RateLimitConsumeInput,
    existing: Option<RateLimitRecord>,
) -> (RateLimitDecision, RateLimitRecord, bool) {
    let window_ms = input.rule.window.saturating_mul(1000) as i64;
    match existing {
        Some(record)
            if input.now_ms.saturating_sub(record.last_request) <= window_ms
                && record.count >= input.rule.max =>
        {
            let retry_ms = record
                .last_request
                .saturating_add(window_ms)
                .saturating_sub(input.now_ms)
                .max(0);
            (
                RateLimitDecision {
                    permitted: false,
                    retry_after: ceil_millis_to_seconds(retry_ms),
                    limit: input.rule.max,
                    remaining: 0,
                    reset_after: ceil_millis_to_seconds(retry_ms),
                },
                record,
                true,
            )
        }
        Some(mut record) if input.now_ms.saturating_sub(record.last_request) <= window_ms => {
            record.key = input.key;
            record.count = record.count.saturating_add(1);
            record.last_request = input.now_ms;
            let remaining = input.rule.max.saturating_sub(record.count);
            (
                RateLimitDecision {
                    permitted: true,
                    retry_after: 0,
                    limit: input.rule.max,
                    remaining,
                    reset_after: input.rule.window,
                },
                record,
                true,
            )
        }
        Some(mut record) => {
            record.key = input.key;
            record.count = 1;
            record.last_request = input.now_ms;
            (
                RateLimitDecision {
                    permitted: true,
                    retry_after: 0,
                    limit: input.rule.max,
                    remaining: input.rule.max.saturating_sub(1),
                    reset_after: input.rule.window,
                },
                record,
                true,
            )
        }
        None => {
            let record = RateLimitRecord {
                key: input.key,
                count: 1,
                last_request: input.now_ms,
            };
            (
                RateLimitDecision {
                    permitted: true,
                    retry_after: 0,
                    limit: input.rule.max,
                    remaining: input.rule.max.saturating_sub(1),
                    reset_after: input.rule.window,
                },
                record,
                false,
            )
        }
    }
}

fn ceil_millis_to_seconds(milliseconds: i64) -> u64 {
    if milliseconds <= 0 {
        return 0;
    }
    ((milliseconds as u64).saturating_add(999)) / 1000
}