Module rewriter 

Query Rewriting Module

Transparent query rewriting at the proxy layer for optimization, compatibility, and security enforcement.

Features

• Pattern Matching: Match queries by fingerprint, regex, AST, or table
• Transformations: Index hints, SELECT * expansion, LIMIT addition
• Rule Engine: Priority-based rule application
• AI Safety: Agent query limits and forbidden table enforcement

Architecture

  Original Query → Parse → Match Rules → Apply Transformations → Rewritten Query
                     │         │                  │
                     │         │                  ├── Replace
                     │         │                  ├── AddIndexHint
                     │         ├── Fingerprint    ├── ExpandSelectStar
                     │         ├── Regex          ├── AddLimit
                     │         ├── AST            ├── AddWhereClause
                     │         └── Table          └── ReplaceTable
                     │
                  SQL AST

Example

use heliosdb::proxy::rewriter::{QueryRewriter, RewriteRule, QueryPattern, Transformation};

let mut rewriter = QueryRewriter::builder()
    .rule(RewriteRule::new("expand_star")
        .pattern(QueryPattern::table("users"))
        .transform(Transformation::ExpandSelectStar {
            columns: vec!["id", "name", "email"]
        }))
    .rule(RewriteRule::new("add_limit")
        .pattern(QueryPattern::all())
        .transform(Transformation::AddLimit(1000)))
    .build();

let result = rewriter.rewrite("SELECT * FROM users")?;
// Result: SELECT id, name, email FROM users LIMIT 1000

Re-exports

pub use config::RewriterConfig;

pub use config::RewriterConfigBuilder;

pub use rules::RewriteRule;

pub use rules::RewriteRuleBuilder;

pub use rules::QueryPattern;

pub use rules::AstPattern;

pub use rules::Transformation;

pub use rules::Condition;

pub use matcher::RuleMatcher;

pub use matcher::MatchResult;

pub use transformer::TransformationEngine;

pub use transformer::TransformError;

pub use parser::SqlParser;

pub use parser::ParsedQuery;

pub use parser::SqlStatement;

pub use metrics::RewriteMetrics;

pub use metrics::RewriteStats;

pub use metrics::RuleStats;

Modules

config

Query Rewriter Configuration

matcher

Rule Matcher

metrics

Rewrite Metrics

parser

SQL Parser

rules

Rewrite Rules

transformer

Transformation Engine

Structs

QueryRewriter

Query rewriter

QueryRewriterBuilder

Query rewriter builder

RewriteResult

Result of a rewrite operation

Enums

RewriteError

Rewrite error